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New submissions for Thu, 14 Nov 19

[1]  arXiv:1911.05077 [pdf, other]

Title: The survival of star clusters with black hole subsystems

Authors: Long Wang

Comments: 12 pages, 13 figures, accepted for MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Recent observations have detected top-heavy IMFs in dense star forming regions like the Arches cluster. Whether such IMFs also exist in old dense stellar systems like globular clusters is difficult to constrain, because massive stars already became black holes (BHs) and neutron stars (NSs). However, studies of stellar dynamics find that BHs/NSs influence the long-term evolution of star clusters. Following Breen & Heggie (2013) and by carrying out two-component $N$-body simulations, we demonstrate how this dynamical impact connects with the shape of IMFs. By investigating the energy balance between the BH subsystem and the global, we find that to properly describe the evolution of clusters, a corrected two-body relaxation time, $T_{rh,p} = T_{rh}/\psi$, is necessary. Because $\psi$ depends on the total mass fraction of BHs, $M_2 / M$, and the mass ratio, $m_2 / m_1$, the cluster dissolution time is sensitive to the property of BHs or IMFs. Especially, the escape rate of BHs via ejections from few-body encounters is linked to mass segregation. In strong tidal fields, top-heavy IMFs easily lead to the fast dissolution of star clusters and the formation of BH-dominant dark clusters, which suggests that the observed massive GCs with dense cores are unlikely to have extreme top-heavy IMFs. With the future observations of gravitational waves providing unique information of BHs/NSs, it is possible to combine the multi-message observations to have better constrains on the IMFs of old star clusters.

[2]  arXiv:1911.05078 [pdf, other]

Title: Cloud Properties and Correlations with Star Formation in Numerical Simulations of the Three-Phase ISM

Authors: S. Alwin Mao, Eve C. Ostriker, Chang-Goo Kim

Comments: 31 pages, 17 figures, submitted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We apply gravity-based and density-based methods to identify clouds in numerical simulations of the star-forming, three-phase interstellar medium (ISM), and compare their properties and their global correlation with the star formation rate over time. The gravity-based method identifies bound objects, which have masses M ~ 10^3 - 10^4 M_solar at densities n_H ~ 100 cm^-3, and traditional virial parameters alpha_v ~ 0.5 - 5. For clouds defined by a density threshold n_H,min , the average virial parameter decreases, and the fraction of material that is genuinely bound increases, at higher n_H,min. Surprisingly, these clouds can be unbound even when alpha_v < 2, and high mass clouds (10^4 - 10^6 M_solar) are generally unbound. This suggests that the traditional alpha_v is at best an approximate measure of boundedness in the ISM. All clouds have internal turbulent motions increasing with size as sigma ~ 1 km/s(R/ pc)^1/2, similar to observed relations. Bound structures comprise a small fraction of the total simulation mass, with star formation efficiency per free-fall time epsilon_ff ~ 0.4. For n_H,min = 10 - 100 cm^-3, epsilon_ff ~ 0.03 - 0.3, increasing with density. Temporal correlation analysis between SFR(t) and aggregate mass M(n_H,min;t) at varying n_H,min shows that time delays to star formation are t_delay ~ t_ff(n_H,min). Correlation between SFR(t) and M(nH,min;t) systematically tightens at higher n_H,min. Considering moderate-density gas, selecting against high virial parameter clouds improves correlation with SFR, consistent with previous work. Even at high n_H,min, the temporal dispersion in (SFR-epsilon_ff M/t_ff )/<SFR> is ~ 50%, due to the large-amplitude variations and inherent stochasticity of the system.

[3]  arXiv:1911.05079 [pdf, other]

Title: Supernovae within Pre-existing Wind-Blown Bubbles: Dust Injection vs. Ambient Dust Destruction

Authors: Sergio Martínez-González, Richard Wünsch, Sergiy Silich, Guillermo Tenorio-Tagle, Jan Palouš, Andrea Ferrara

Comments: 9 pages, 5 figures. Accepted for publication in The Astrophysical Journal

Subjects: Astrophysics of Galaxies (astro-ph.GA)

By means of 3-D hydrodynamical simulations, here we evaluate the impact that supernova explosions occurring within wind-driven bubbles have on the survival or destruction of dust grains. We consider both, the dust generated within the ejecta and the dust initially present in the ambient gas and later locked-up in the surrounding wind-driven shell. The collision of the supernova blast wave with the wind-driven shell leads to a transmitted shock that moves into the shell and a reflected shock into the ejecta. The transmitted shock is capable of destroying large amounts of the dust locked in the shell, but only if the mass of the wind-driven shell is small, less than a few tens the ejected mass. Conversely, massive wind-driven shells, with several times the ejected mass, lead upon the interaction to strong radiative cooling, which inhibits the Sedov-Taylor phase and weakens the transmitted shock, making it unable to traverse the wind-driven shell. In such a case, the destruction/disruption of the ambient dust is largely inhibited. On the other hand, the SNRs grow rapidly in the very tenuous region excavated by the stellar winds, and thus a large fraction of the dust generated within the ejecta is not efficiently destroyed by the supernova reverse shock, nor by the reflected shock. Our calculations favor a scenario in which core-collapse supernovae within sufficiently massive wind-driven shells supply more dust to the ISM than what they are able to destroy.

[4]  arXiv:1911.05081 [pdf, other]

Title: The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2

Authors: Marcel S. Pawlowski, Pavel Kroupa

Comments: 20 pages, 10 figures, 4 tables. 11 classical satellites, 8 correlated, of which 7 co-orbit. Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structure, the plane (or disk) of satellite galaxies defined by their positions. The orbital planes of eight satellites align to $<20^\circ$ with a common direction, seven even orbit in the same sense. Most also share similar specific angular momenta, though their wide distribution on the sky does not support a recent group infall or satellites-of-satellites origin. The orbital pole concentration has continuously increased as more precise proper motions were measured, as expected if the underlying distribution shows true correlation that is washed out by observational uncertainties. The orbital poles of the up to seven most correlated satellites are in fact almost as concentrated as expected for the best-possible orbital alignment achievable given the satellite positions. Combining the best-available proper motions substantially increases the tension with $\Lambda$CDM cosmological expectations: <0.1 per cent of simulated satellite systems in IllustrisTNG contain seven orbital poles as closely aligned as observed. Simulated systems that simultaneously reproduce the concentration of orbital poles and the flattening of the satellite distribution have a frequency of <0.1 per cent for any number of k > 3 combined orbital poles, indicating that these results are not affected by a look-elsewhere effect. This compounds the Planes of Satellite Galaxies Problem.

[5]  arXiv:1911.05083 [pdf, ps, other]

Title: Over-constrained Gravitational Lens Models and the Hubble Constant

Authors: C. S. Kochanek (1) ((1) Department of Astronomy, the Ohio State University)

Comments: submitted to MNRAS

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

It is well known that measurements of H0 from gravitational lens time delays scale as H0~1-k_E where k_E is the mean convergence at the Einstein radius R_E but that all available lens data other than the delays provide no direct constraints on k_E. The properties of the radial mass distribution constrained by lens data are R_E and the dimensionless quantity x=R_E a''(R_E)/(1-k_E)$ where a''(R_E) is the second derivative of the deflection profile at R_E. Lens models with too few degrees of freedom, like power law models with densities ~r^(-n), have a one-to-one correspondence between x and k_E (for a power law model, x=2(n-2) and k_E=(3-n)/2=(2-x)/4). This means that highly constrained lens models with few parameters quickly lead to very precise but inaccurate estimates of k_E and hence H0. Based on experiments with a broad range of plausible dark matter halo models, it is unlikely that any current estimates of H0 from gravitational lens time delays are more accurate than ~10%, regardless of the reported precision.

[6]  arXiv:1911.05091 [pdf, other]

Title: Decoupling the rotation of stars and gas -- II: the link between black hole activity and MaNGA kinematics in TNG

Authors: Christopher Duckworth, Tjitske K. Starkenburg, Shy Genel, Timothy Davis, Melanie Habouzit, Katarina Kraljic, Rita Tojeiro

Comments: 5 pages, 3 Figures, Submitted to MNRAS letters. For first paper in series, see arXiv:1910.10744

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We study the relationship between supermassive black hole (BH) feedback, BH luminosity and the kinematics of stars and gas for galaxies in IllustrisTNG. We use a sample of galaxies with mock MaNGA observations to identify kinematic misalignment at $z=0$ (difference in rotation of stars and gas), for which we follow the evolutionary history of BH activity and gas properties over the last 8 Gyrs. Misaligned low mass galaxies typically have boosted BH luminosity, BH growth and have had more energy injected into the gas over the last 8 Gyr in comparison to aligned galaxies. These properties likely lead to outflows and gas loss, in agreement with active low mass galaxies in observations. We show that splitting on BH luminosity at $z=0$ produces statistically consistent distributions of kinematic misalignment at $z=0$, however, splitting on the maximum BH luminosity over the last 8 Gyrs does not. While instantaneous correlation at $z=0$ is difficult due to misalignment persisting on longer timescales, the relationship between BH activity and misalignment is clear. High mass quenched galaxies with misalignment typically have similar BH luminosities, show no overall gas loss, and have typically lower gas phase metallicity over the last 8 Gyrs in comparison to those aligned; suggesting external origin.

[7]  arXiv:1911.05093 [pdf, other]

Title: The GRIFFIN project -- Formation of star clusters with individual massive stars in a simulated dwarf galaxy starburst

Authors: Natalia Lahén, Thorsten Naab, Peter H. Johansson, Bruce Elmegreen, Chia-Yu Hu, Stefanie Walch, Ulrich P. Steinwandel, Benjamin P. Moster

Comments: 19 pages, 10 figures, submitted to ApJ, comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We describe a population of young star clusters (SCs) formed in a hydrodynamical simulation of a gas-rich dwarf galaxy merger resolved with individual massive stars at sub-parsec spatial resolution. The simulation is part of the \textsc{griffin} (Galaxy Realizations Including Feedback From INdividual massive stars) project. The star formation environment during the simulation spans seven orders of magnitude in gas surface density and thermal pressure, and the global star formation rate surface density ($\Sigma_\mathrm{SFR}$) varies by more than three orders of magnitude during the simulation. Young SCs more massive than $M_{\mathrm{*,cl}}\sim 10^{2.5}\,M_{\odot}$ form along a mass function with a power-law index $\alpha\sim-1.7$ ($\alpha\sim-2$ for $M_{\mathrm{*,cl}}\gtrsim10^{3}\,M_{\odot}$) at all merger phases, while the normalization and the highest SC masses (up to $\sim 10^6 M_{\odot}$) correlate with $\Sigma_\mathrm{SFR}$. The cluster formation efficiency varies from $\Gamma\sim20\%$ in early merger phases to $\Gamma\sim80\%$ at the peak of the starburst and is compared to observations and model predictions. The massive SCs ($\gtrsim10^4\,M_{\odot}$) have sizes and mean surface densities similar to observed young massive SCs. Simulated lower mass clusters appear slightly more concentrated than observed. All SCs form on timescales of a few Myr and lose their gas rapidly resulting in typical stellar age spreads between $\sigma\sim0.1-2$ Myr ($1\sigma$), consistent with observations. The age spreads increase with cluster mass, with the most massive cluster ($\sim10^6\, M_{\odot}$) reaching a spread of $5\, \mathrm{Myr}$ once its hierarchical formation finishes. Our study shows that it is now feasible to investigate the SC population of entire galaxies with novel high-resolution numerical simulations.

[8]  arXiv:1911.05094 [pdf, other]

Title: Origin of Non-axisymmetric Features of Virgo Cluster Early-type Dwarf Galaxies. II. Tidal Effects on Disk Features and Stability

Authors: SungWon Kwak, Woong-Tae Kim, Soo-Chang Rey, Thomas R. Quinn

Comments: Accepted for publication in the ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

A fraction of dwarf galaxies in the Virgo cluster contain disk features like bars and spiral arms. Using $N$-body simulations, we investigate the effects of tidal forces on the formation of such disk features in disk dwarf galaxies resembling VCC856. We consider 8 Cluster-Galaxy models in which disk dwarf galaxies with differing pericenter distance and spin orientation experience the tidal gravitational force of a Virgo-like NFW halo, and additional 8 Galaxy-Galaxy models in which two dwarf galaxies undergo tidal interactions with different strength. We find that the cluster tidal effect is moderate due to the small galaxy size, making the bars form earlier by $\sim1$--$1.5\Gyr$ compared to the cases in isolation. While the galactic halos significantly lose their mass within the virial radius due to the cluster tidal force, the mass of the stellar disks is nearly unchanged, suggesting that the inner regions of a disk-halo system is secured from the tidal force. The tidal forcing from either the cluster potential or a companion galaxy triggers the formation of two-armed spirals at early time before a bar develops. The tidally-driven arms decay and wind with time, suggesting that they are kinematic density waves. In terms of the strength and pitch angle, the faint arms in VCC856 are best matched with the arms in a marginally unstable galaxy produced by a distant tidal encounter with its neighbor $\sim0.85\Gyr$ ago.

[9]  arXiv:1911.05105 [pdf, ps, other]

Title: Large-scale dynamo action of magnetized Taylor-Couette flows

Authors: G. Rüdiger, M. Schultz

Comments: 12 pages, 12 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Fluid Dynamics (physics.flu-dyn)

A conducting Taylor-Couette flow with quasi-Keplerian rotation law containing a toroidal magnetic field -- due to an axial electric current between the cylinders -- serves as a mean-field dynamo model of the Tayler-Spruit-type. The flows are unstable against nonaxisymmetric perturbations which form electromotive forces defining $\alpha$ effect and eddy diffusivity. If both degenerated modes with $|m|=1$ are excited with the same power then the global $\alpha$ effect vanishes and a dynamo does not work. It is shown, however, that the Tayler instability produces finite $\alpha$ effects if only one mode is considered but this intrinsic helicity of the single-mode is too low for an $\alpha^2$ dynamo. Moreover, an $\alpha\Om$ dynamo model with quasi-Keplerian rotation requires a minimum magnetic Reynolds number of rotation of $\Rm\simeq 2.000$ to work. Whether it really works depends on assumptions about the turbulence energy. For a steeper-than-quadratic dependence of the turbulence intensity on the magnetic field, however, dynamos are only excited if the resulting magnetic eddy diffusivity approximates its microscopic value, $\etaT\simeq \eta$. By basically lower or larger eddy diffusivities the dynamo instability is suppressed.

[10]  arXiv:1911.05107 [pdf, other]

Title: Unsupervised star, galaxy, qso classification: Application of HDBSCAN

Authors: Crispin Logan, Sotiria Fotopoulou

Comments: Accepted to A&A 12 November 2019

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Classification will be an important first step for upcoming surveys that will detect billions of new sources such as LSST and Euclid, as well as DESI, 4MOST and MOONS. The application of traditional methods of model fitting and colour-colour selections will face significant computational constraints, while machine-learning (ML) methods offer a viable approach to tackle datasets of that volume. While supervised learning methods can perform very well for classification tasks, the creation of representative and accurate training sets is a resource and time consuming task. We present a viable alternative using an unsupervised ML method to separate stars, galaxies and QSOs using photometric data. The heart of our work uses HDBSCAN to find the star, galaxy and QSO clusters in a multidimensional colour space. We optimized the hyperparameters and input attributes of three separate HDBSCAN runs, each to select a particular object class, and thus treat the output of each separate run as a binary classifier. We subsequently consolidate the output to give our final classifications, optimized on their F1 scores. We explore the use of Random Forest and PCA as part of the pre-processing stage for feature selection and dimensionality reduction. Using our dataset of 50,000 spectroscopically labelled objects we obtain an F1 score of 98.9, 98.9 and 93.13 respectively for star, galaxy and QSO selection using our unsupervised learning method. We find that careful attribute selection is a vital part of accurate classification with HDBSCAN. We applied our classification to a subset of the SDSS spectroscopic catalogue and demonstrate the potential of our approach in correcting misclassified spectra useful for DESI and 4MOST. Finally, we create a multiwavelength catalogue of 2.7 million sources using the KiDS, VIKING and ALLWISE surveys and publish corresponding classifications and photometric redshifts.

[11]  arXiv:1911.05108 [pdf, other]

Title: Exploring the Grain Properties in the Disk of HL Tau with an Evolutionary Model

Authors: Carlos Tapia, Susana Lizano, Anibal Sierra, Carlos Carrasco-González, Elly Bayona-Bobadilla

Comments: 17 pages, 11 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)

We model the ALMA and VLA millimeter radial profiles of the disk around HL Tau to constrain the properties of the dust grains. We adopt the disk evolutionary models of Lynden-Bell \& Pringle and calculate their temperature and density structure and emission. These disks are heated by the internal viscosity and irradiated by the central star and a warm envelope. We consider a dust size distribution $n(a) da \propto a^{-3.5} da $, and vary the maximum grain size in the atmosphere and the midplane, $a_{\rm max}=100\ \mu$m, 1 mm, and 1cm. We also include dust settling and vary the dust-to-gas mass ratio from 1 to 9 times the ISM value. We find that the models that can fit the observed level of emission along the profiles at all wavelengths have an atmosphere with a maximum grain size $a_{\rm max} = 100 \ \mu$m, and a midplane with $a_{\rm max}=1$ cm. The disk substructure, with a deficit of emission in the gaps, can be due to dust properties in these regions that are different from those in the rings. We test an opacity effect (different $a_{\rm max}$) and a dust mass deficit (smaller dust-to-gas mass ratio) in the gaps. We find that the emission profiles are better reproduced by models with a dust deficit in the gaps, although a combined effect is also possible. These models have a global dust-to-gas mass ratio twice the ISM value, needed to reach the level of emission of the 7.8 mm VLA profile.

[12]  arXiv:1911.05131 [pdf, ps, other]

Title: Modelling the distributions of white dwarf atmospheric pollution: a low Mg abundance for accreted planetesimals?

Authors: Samuel G. D. Turner, Mark C. Wyatt

Comments: 20 pages, 19 figures, accepted for publication in MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

The accretion of planetesimals onto white dwarf atmospheres allows determination of the composition of this polluting material. This composition is usually inferred from observed pollution levels by assuming it originated from a single body. This paper instead uses a stochastic model wherein polluting planetesimals are chosen randomly from a mass distribution, finding that the single body assumption is invalid in >20% of cases. Planetesimal compositions are modelled assuming parent bodies that differentiated into core, mantle and crust components. Atmospheric levels of Ca, Mg and Fe in the model are compared to a sample of 230 DZ white dwarfs for which such pollution is measured. A good fit is obtained when each planetesimal has its core, mantle and crust fractions chosen independently from logit-normal distributions which lead to average mass fractions of $f_\text{Cru}=0.15$, $f_\text{Man}=0.49$ and $f_\text{Cor}=0.36$. However, achieving this fit requires a factor 4 depletion of Mg relative to stellar material. This depletion is unlikely to originate in planetesimal formation processes, but might occur from heating while the star is on the giant branch. Alternatively the accreted material has stellar abundance, and either the inferred low Mg abundance was caused by an incorrect assumption that Mg sinks slower than Ca and Fe, or there are unmodelled biases in the observed sample. Finally, the model makes predictions for the timescale on which the observed pollutant composition varies, which should be the longer of the sinking and disc timescales, implying variability on decadal timescales for DA white dwarfs.

[13]  arXiv:1911.05143 [pdf, other]

Title: LRP2020: The Opportunity of Young Nearby Associations with the Advent of the Gaia Mission

Authors: Jonathan Gagné, Joel Kastner, Semyeong Oh, Jacqueline K. Faherty, John Gizis, Adam Burgasser, Evgenya L. Shkolnik, Trevor J. David, Jinhee Lee, Inseok Song, David Lafrenière, Stanimir Metchev, René Doyon, Adam Schneider, Étienne Artigau

Comments: Submitted to CASCA Long-Range Plan 2020

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)

This white paper proposes leveraging high-quality Gaia data available to the worldwide scientific community and complement it with support from Canadian-related facilities to place Canada as a leader in the fields of stellar associations and exoplanet science, and to train Canadian highly qualified personnel through graduate and post-graduate research grants.
Gaia has sparked a new era in the study of stellar kinematics by measuring precise distances and proper motions for 1.3 billion stars. These data have already generated more than 1700 scientific papers and are guaranteed to remain the source of many more papers for the upcoming decades. More than 900 new age-calibrated young low-mass stars have already been discovered as a direct consequence of the second Gaia data release. Some of these may already be host stars to known exoplanet systems or may become so with the progress of the TESS mission that is expected to discover 10,000 nearby transiting exoplanets in the upcoming decade. This places Canada in a strategic position to leverage Gaia data because it has access to several high-resolution spectrometers on 1-4 m class telescopes (e.g. The ESPaDOnS, SPIRou and NIRPS), that would allow to quickly characterize this large number of low-mass stars and their exoplanet systems. This white paper describes the opportunity in such scientific projects that could place Canada as a leader in the fields of stellar associations and exoplanets.

[14]  arXiv:1911.05150 [pdf, other]

Title: TESS Reveals HD 118203 b to be a Transiting Planet

Authors: Joshua Pepper, Stephen R. Kane, Joseph E. Rodriguez, Natalie R. Hinkel, Jason D. Eastman, Tansu Daylan, Teo Mocnik, Paul A. Dalba, Tara Fetherolf, Keivan G. Stassun, Tiago L. Campante, Andrew Vanderburg, Daniel Huber, B. Scott Gaudi, Diego Bossini, Ian Crossfield, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Joseph D. Twicken, Mark Rose, Jeffrey C. Smith, Ana Glidden, Alan M. Levine, Stephen Rinehart, Karen A. Collins, Andrew W. Mann, Jennifer A. Burt, David J. James, Robert J. Siverd

Comments: 15 pages, 6 figures, submitted to AAS Journals

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

The exoplanet HD 118203 b, orbiting a bright (V = 8.05) host star, was discovered using the radial velocity method by da Silva et al. (2006), but was not previously known to transit. TESS photometry has revealed that this planet transits its host star. Five planetary transits were observed by TESS, allowing us to measure the radius of the planet to be $1.133 \pm 0.031 R_J$, and to calculate the planet mass to be $2.173 \pm 0.078 M_J$. The host star is slightly evolved with an effective temperature of $T_{\rm eff} = 5692 \pm 83$ K and a surface gravity of ${\rm log}(g) = 3.891 \pm 0.019$. With an orbital period of $6.134980 \pm 0.000038$ days and an eccentricity of $0.316 \pm 0.021$, the planet occupies a transitional regime between circularized hot Jupiters and more dynamically active planets at longer orbital periods. The host star is among the ten brightest known to have transiting giant planets, providing opportunities for both planetary atmospheric and asteroseismic studies.

[15]  arXiv:1911.05158 [pdf, other]

Title: Cloudlet capture by Transitional Disk and FU Orionis stars

Authors: Cornelis Petrus Dullemond, Michael Küffmeier, Felipe Goicovic, Misato Fukagawa, Veronika Oehl, Manuel Kramer

Journal-ref: Astronomy and Astrophysics, 628, 20 (2019)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

After its formation, a young star spends some time traversing the molecular cloud complex in which it was born. It is therefore not unlikely that, well after the initial cloud collapse event which produced the star, it will encounter one or more low mass cloud fragments, which we call "cloudlets" to distinguish them from full-fledged molecular clouds. Some of this cloudlet material may accrete onto the star+disk system, while other material may fly by in a hyperbolic orbit. In contrast to the original cloud collapse event, this process will be a "cloudlet flyby" and/or "cloudlet capture" event: A Bondi-Hoyle-Lyttleton type accretion event, driven by the relative velocity between the star and the cloudlet. As we will show in this paper, if the cloudlet is small enough and has an impact parameter similar or less than $GM_{*}/v^2_\infty$ (with $v_\infty$ being the approach velocity), such a flyby and/or capture event would lead to arc-shaped or tail-shaped reflection nebulosity near the star. Those shapes of reflection nebulosity can be seen around several transitional disks and FU Orionis stars. Although the masses in the those arcs appears to be much less than the disk masses in these sources, we speculate that higher-mass cloudlet capture events may also happen occasionally. If so, they may lead to the tilting of the outer disk, because the newly infalling matter will have an angular momentum orientation entirely unrelated to that of the disk. This may be one possible explanation for the highly warped/tilted inner/outer disk geometries found in several transitional disks. We also speculate that such events, if massive enough, may lead to FU Orionis outbursts.

[16]  arXiv:1911.05174 [pdf]

Title: Star Formation Rate in late-type galaxies: I- The H(alpha) and FUV integrated values

Authors: Marco A. Magaña-Serrano, Ana M. Hidalgo-Gámez, Ignacio Vega-Acevedo, Héctor O. Castañeda

Comments: 25 pages, 8 figures, 5 tables. Submitted to RevMex A&A, referee's comments included

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The Star Formation Rate (SFR) was determined from a sample of 36 late-type galaxies (14 dS and 22 Sm), from the H(alpha) and Far Ultraviolet (FUV) flux. We found that the SFR(FUV) was in most cases higher than the SFR(H(alpha)).We also obtained that the SFR is larger for Sm galaxies and smaller for barred galaxies, for any morphological type, in both diagnostic methods. In addition, a study of the spatial distribution of star formation within these galaxies was made, concluding that there is not a preferential place for the star formation. Finally, we studied the role of the Diffuse Ionized Gas in the SFR value, finding that the H(alpha) flux contribution coming from this gas should not be included in the SFR determination unless it is verified that leaking photons are the only source of the neutral gas ionization.

[17]  arXiv:1911.05175 [pdf, other]

Title: Influence of structural discontinuities present in the core of red-giant stars on the observed mixed-mode pattern and characterization of their properties

Authors: Mathieu Vrard, Margarida S. Cunha

Comments: Conference proceeding, Banyuls-sur-Mer, September 2018, 7 pages, 10 figures, 1 table

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

The space-borne missions CoRoT and Kepler have provided seismic data of unprecedented quality. Among the observed stars, red giants show a complex oscillation pattern exhibiting pressure modes as well as mixed modes. The latter carry information on the radiative region properties of these stars. The very high precision of Kepler data provide enough accuracy to decipher the complex structure of the mixed-mode pattern and, therefore, deduce precise information on the structure of the stellar core. In this work, we studied the precise influence of the core structural discontinuities on the mixed-mode pattern. These phenomena have indeed an influence on the gravity waves that propagate inside the core of the star and, therefore, on the mixed-mode pattern. In this study, we aim to investigate the impact of core structural discontinuities on the observed mixed-mode pattern and measure their properties for several red giants. We identified several objects showing evidence of deviations in their mixed-mode frequency pattern that are characteristic of core structural discontinuities. We fitted these deviations and showed that they likely correspond to the influence of the inner convective core of these stars.

[18]  arXiv:1911.05178 [pdf, other]

Title: Spectra of Ni V and Fe V in the Vacuum Ultraviolet

Authors: J. W. Ward, A. J. J. Raassen, A. Kramida, G. Nave

Comments: Uses AASTex, 12 Pages, 8 Figures, 4 Tables

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atomic Physics (physics.atom-ph)

This work presents 97 remeasured Fe V wavelengths (1200 \r{A} to 1600 \r{A}) and 123 remeasured Ni V wavelengths (1200 \r{A} to 1400 \r{A}) with uncertainties of approximately 2m\r{A}. An additional 67 remeasured Fe V wavelengths and 72 remeasured Ni V wavelengths with uncertainties greater than 2m\r{A} are also reported. A systematic calibration error is also identified in the previous Ni V wavelengths and is corrected in this work. Furthermore, a new energy level optimization of Ni V is presented that includes level values as well as Ritz wavelengths. This work improves upon the available data used for observations of quadruply ionized nickel (Ni V) in white dwarf stars. This compilation is specifically targeted towards observations of the G191-B2B white dwarf spectrum that has been used to test for variations in the fine structure constant, $\alpha$, in the presence of strong gravitational fields. The laboratory wavelengths for these ions were thought to be the cause of inconsistent conclusions regarding the variation limit of $\alpha$ as observed through the white dwarf spectrum. These inconsistencies can now be addressed with the improved laboratory data presented here.

[19]  arXiv:1911.05179 [pdf, other]

Title: WASP-52b. The effect of starspot correction on atmospheric retrievals

Authors: Giovanni Bruno, Nikole K. Lewis, Munazza K. Alam, Mercedes López-Morales, Joanna K. Barstow, Hannah R. Wakeford, David Sing, Gregory W. Henry, Gilda E. Ballester, Vincent Bourrier, Lars A. Buchhave, Ofer Cohen, Thomas Mikal-Evans, Antonio García Muñoz, Panayotis Lavvas, Jorge Sanz-Forcada

Comments: 16 pages, 11 figures, 1 table

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

We perform atmospheric retrievals on the full optical to infrared ($0.3-5 \, \mu \mathrm{m}$) transmission spectrum of the inflated hot Jupiter WASP-52b by combining HST/STIS, WFC3 IR, and Spitzer/IRAC observations. As WASP-52 is an active star which shows both out-of-transit photometric variability and starspot crossings during transits, we account for the contribution of non-occulted active regions in the retrieval. We recover a $0.1-10\times$ solar atmospheric composition, in agreement with core accretion predictions for giant planets, and a weak contribution of aerosols. We also obtain a $<3000$ K temperature for the starspots, a measure which is likely affected by the models used to fit instrumental effects in the transits, and a 5% starspot fractional coverage, compatible with expectations for the host star's spectral type. Such constraints on the planetary atmosphere and on the activity of its host star will inform future JWST GTO observations of this target.

[20]  arXiv:1911.05207 [pdf, other]

Title: Globular clusters in the inner Galaxy classified from dynamical orbital criteria

Authors: Angeles Pérez-Villegas, Beatriz Barbuy, Leandro Kerber, Sergio Ortolani, Stefano O. Souza, Eduardo Bica

Comments: 17 pages, 9 figures, 7 tables. Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Globular clusters (GCs) are the most ancient stellar systems in the Milky Way. Therefore, they play a key role in the understanding of the early chemical and dynamical evolution of our Galaxy. Around $40\%$ of them are placed within $\sim4$ kpc from the Galactic center. In that region, all Galactic components overlap, making their disentanglement a challenging task. With Gaia DR2, we have accurate absolute proper motions for the entire sample of known GCs that have been associated with the bulge/bar region. Combining them with distances, from RR Lyrae when available, as well as radial velocities from spectroscopy, we can perform an orbital analysis of the sample, employing a steady Galactic potential with a bar. We applied a clustering algorithm to the orbital parameters apogalactic distance and the maximum vertical excursion from the plane, in order to identify the clusters that have high probability to belong to the bulge/bar, thick disk, inner halo, or outer halo component. We found that $\sim 30\%$ of the clusters classified as bulge GCs based on their location are just passing by the inner Galaxy, they appear to belong to the inner halo or thick disk component, instead. Most of GCs that are confirmed to be bulge GCs are not following the bar structure and are older than the epoch of the bar formation.

[21]  arXiv:1911.05209 [pdf, other]

Title: Artificial Intelligence Assisted Inversion (AIAI) of Synthetic Type Ia Supernova Spectra

Authors: Xingzhuo Chen, Lei Hu, Lifan Wang

Comments: 49 pages, 31 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We generate $\sim$ 100,000 model spectra of Type Ia Supernovae (SNIa) to form a spectral library for the purpose to build an Artificial Intelligence Assisted Inversion (AIAI) algorithm for theoretical models. As a first attempt, we restrict our studies to time around $B$-band maximum and compute theoretical spectra with a broad spectral wavelength coverage from 2000 $-$ 10000 \AA using TARDIS. Based on the library of theoretically calculated spectra, we construct the AIAI algorithm with a Multi-Residual Convolutional Neural Network (MRNN) which backs out the contribution of different ionic species to the heavily blended spectral profiles of the theoretical spectra. The AIAI is found to be very powerful in distinguishing spectral patterns due to coupled atomic transitions and has the capacity of measuring the contributions from different ionic species. By applying the AIAI algorithm to a set of well observed SNIa spectra, we demonstrate that the model can yield powerful constraints on the chemical structures of these SNIa. Using the chemical structures deduced from AIAI, we successfully reconstructed the observed data, thus confirming the validity of the method. We show that the light curve decline rate of SNIa is correlated with the amount of $^{56}$Ni above the photosphere in the ejecta. We detect a clear decrease of $^{56}$Ni mass with time that can be attributed to its radioactive decay.

[22]  arXiv:1911.05217 [pdf, ps, other]

Title: A Compact Source for Quasi-Periodic Pulsation in an M-class Solar Flare

Authors: Ding Yuan, Song Feng, Dong Li, Zhongjun Ning, Baolin Tan

Comments: 4 figures, accepted for ApJ Letter

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Quasi-periodic pulsations (QPP) are usually found in the light curves of solar and stellar flares, they carry the features of time characteristics and plasma emission of the flaring core, and could be used to diagnose the coronas of the Sun and remote stars. In this study, we combined the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory and the Nobeyama Radioheliograph (NoRH) to observe an M7.7 class flare occurred at active region 11520 on 19 July 2012. A QPP was detected both in the AIA $131\unit{\AA{}}$ bandpass and the NoRH $17\unit{GHz}$ channel, it had a period of about four minutes. In the spatial distribution of Fourier power, we found that this QPP originated from a compact source and that it overlapped with the X-ray source above the loop top. The plasma emission intensities in the AIA $131\unit{\AA{}}$ bandpass were highly correlated within this region. The source region is further segmented into stripes that oscillated with distinctive phases. Evidence in this event suggests that this QPP was likely to be generated by intermittent energy injection into the reconnection region.

[23]  arXiv:1911.05221 [pdf, other]

Title: The GALAH Survey: Temporal Chemical Enrichment of the Galactic Disk

Authors: Jane Lin, Martin Asplund, Yuan-Sen Ting, Luca Casagrande, Sven Buder, Joss Bland-Hawthorn, Andrew R. Casey, Gayandhi M. De Silva, Valentina D'Orazi, Ken C. Freeman, Janez Kos, K Lind, Sarah L. Martell, Sanjib Sharma, Jeffrey D. Simpson, Tomaž Zwitter, Daniel B. Zucker, Ivan Minchev, Klemen Čotar, Michael Hayden, Jonti Horner, Geraint F. Lewis, Thomas Nordlander, Rosemary F. G. Wyse, Maruša Žerjal

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

We present isochrone ages and initial bulk metallicities ($\rm [Fe/H]_{bulk}$, by accounting for diffusion) of 163,722 stars from the GALAH Data Release 2, mainly composed of main sequence turn-off stars and subgiants ($\rm 7000 K>T_{eff}>4000 K$ and $\rm log g>3$ dex). The local age-metallicity relationship (AMR) is nearly flat but with significant scatter at all ages; the scatter is even higher when considering the observed surface abundances. After correcting for selection effects, the AMR appear to have intrinsic structures indicative of two star formation events, which we speculate are connected to the thin and thick disks in the solar neighborhood. We also present abundance ratio trends for 16 elements as a function of age, across different $\rm [Fe/H]_{bulk}$ bins. In general, we find the trends in terms of [X/Fe] vs age from our far larger sample to be compatible with studies based on small ($\sim$ 100 stars) samples of solar twins but we now extend it to both sub- and super-solar metallicities. The $\alpha$-elements show differing behaviour: the hydrostatic $\alpha$-elements O and Mg show a steady decline with time for all metallicities while the explosive $\alpha$-elements Si, Ca and Ti are nearly constant during the thin disk epoch (ages $\lessapprox $ 12 Gyr). The s-process elements Y and Ba show increasing [X/Fe] with time while the r-process element Eu have the opposite trend, thus favouring a primary production from sources with a short time-delay such as core-collapse supernovae over long-delay events such as neutron star mergers.

[24]  arXiv:1911.05243 [pdf, other]

Title: Concerning Li-rich status of KIC~9821622: A Kepler field RGB star reported as Li-rich Giant

Authors: Raghubar Singh, Bharat Kumar Yerra, Bacham E. Reddy, Wako Aoki

Comments: 6 Pages, 4 Figures, Accepted, MNRAS

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Given the implications for the origin of Li enhancement in red giants we have reviewed Li-rich classification of KIC~9821622, the only bonafide RGB giant with He inert-core till date, reported as a Li-rich giant by reanalyzing the high-resolution spectra. We have obtained $A(Li)_{LTE} = 1.42 \pm 0.05$ dex. After correcting for non-LTE it is $A(Li)_{NLTE} = 1.57 \pm 0.05 $ dex which is significantly less than the reported A(Li) = $1.80 \pm 0.2$~dex. We found the sub-ordinate line at 6103 \AA\ is too weak or absent to measure Li abundance. The derived abundance is normal for red giants undergoing dilution during the 1st dredge-up. Since all the known Kepler field Li-rich giants belong to the red clump region, this clarification removes the anomaly and strengthens the evidence that the Li enhancement in low mass giants may be associated only with the He-core burning phase. The Li excess origin, probably, lies during He-flash at the RGB tip, an immediate preceding phase to red clump.

[25]  arXiv:1911.05251 [pdf, other]

Title: Live Fast, Die Young: GMC lifetimes in the FIRE cosmological simulations of Milky Way-mass galaxies

Authors: Samantha M. Benincasa, Sarah R. Loebman, Andrew Wetzel, Philip F. Hopkins, Norman Murray, Matthew A. Bellardini, Claude-André Faucher-Giguère, Dávid Guszejnov, Matthew Orr

Comments: submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present the first measurement of the lifetimes of Giant Molecular Clouds (GMCs) in cosmological simulations at $z = 0$, using the Latte suite of FIRE-2 simulations of Milky Way-mass galaxies. We track GMCs with total gas mass $\gtrsim 10^5$ M$_\odot$ at high spatial ($\sim1$ pc), mass ($7100$ M$_{\odot}$), and temporal (1 Myr) resolution. Our simulated GMCs are consistent with the distribution of masses for massive GMCs in the Milky Way and nearby galaxies. We find GMC lifetimes of $5-7$ Myr, or 1-2 freefall times, on average, with less than 1\% of clouds living longer than 20 Myr. We find increasing GMC lifetimes with galactocentric radius, implying that environment affects the evolutionary cycle of GMCs. However, our GMC lifetimes show no systematic dependence on GMC mass or amount of star formation. These results are broadly consistent with inferences from the literature and provide an initial investigation into ultimately understanding the physical processes that govern GMC lifetimes in a cosmological setting.

[26]  arXiv:1911.05252 [pdf, other]

Title: The Anatomy of a Star-Forming Galaxy II: the role of FUV heating in the structure of galaxies

Authors: Samantha M. Benincasa, James W. Wadsley, Hugh M. P. Couchman, Alex R. Pettitt, Ben W. Keller, Rory M. Woods, Jasper J. Grond

Comments: submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Far-Ultraviolet (FUV) radiation greatly exceeds ultraviolet, supernovae and winds in the energy budget of young star clusters but is poorly modelled in galaxy simulations. We present results of the first full isolated galaxy disk simulations to include FUV radiation self-consistently. This is the first science application of the TREVR radiative transfer algorithm. We find that FUV radiation alone cannot regulate star formation. However, FUV radiation is crucial for producing warm neutral gas. FUV is also a long-range feedback and is more important in the outer disks of galaxies. We also use the super-bubble feedback model, which depends only on the supernova energy per stellar mass, is more physically realistic than common, parameter-driven alternatives and thus better constrains supernova feedback impacts. FUV and supernovae together can regulate star formation, reproducing the tight Kennicutt-Schmidt relation observed for an individual galaxy, without producing too much hot ionized medium and with less disruption to the ISM compared to supernovae alone.

[27]  arXiv:1911.05257 [pdf, ps, other]

Title: Warm dark matter model with a few keV mass is bad for the too-big-to-fail problem

Authors: Xi Kang

Comments: 17 pages, 12 figures, MNRAS in press

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Theoretical studying of the very inner structure of faint satellite galaxy requires very high-resolution hydro-dynamical simulations with realistic models for star formation, which are beginning to emerge recently. In this work we present an analytical description to model the inner kinematic of satellites in the Milky Way (MW). We use a Monte-Carlo method to produce merger trees for MW mass halo and analytical models to produce stellar mass in the satellite galaxies. We consider two important processes which can significantly modify the inner mass distribution in satellite galaxy. The first is baryonic feedback which can induce a flat inner profile depending on the star formation efficiency in the galaxy. The second is the tidal stripping to reduce and re-distribute the mass inside satellite. We apply this model to MW satellite galaxies in both CDM and thermal relic WDM models. It is found that tidal heating must be effective to produce a relatively flat distribution of the satellite circular velocities, to agree with the data. The constraint on WDM mass depends on the host halo mass. For a MW halo with dark matter mass lower than $2\times 10^{12}M_{\odot}$, a 2 keV WDM model can be safely excluded as the predicted satellite circular velocities are systematically lower than the data. For WDM with mass of 3.5 keV, it requires the MW halo mass to be larger than $1.5\times 10^{12}M_{\odot}$, otherwise the 3.5 Kev model can also be excluded. Our current model can not exclude the WDM model with mass larger than 10 Kev.

[28]  arXiv:1911.05285 [pdf, other]

Title: The First Full-Scale Prototypes of the Fluorescence detector Array of Single-pixel Telescopes

Authors: M. Malacari, J. Farmer, T. Fujii, J. Albury, J.A. Bellido, L. Chytka, P. Hamal, P. Horvath, M. Hrabovsky, D. Mandat, J.N. Matthews, L. Nozka, M. Palatka, M. Pech, P. Privitera, P. Schovanek, R. Smida, S.B. Thomas, P. Travnicek

Comments: 26 pages, 23 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for a next-generation UHECR observatory, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of ultra-high energy cosmic rays (UHECRs), having energies exceeding $10^{19.5}$\,eV, with an unprecedented aperture. We have developed a full-scale prototype consisting of four 200\,mm diameter photo-multiplier tubes at the focus of a segmented mirror of 1.6\,m in diameter. In October 2016, September 2017, and September 2018 we installed three such prototypes at the Black Rock Mesa site of the Telescope Array experiment in central Utah, USA. All three telescopes have been steadily taking data since installation. We report on the design and installation of these prototypes, and present some preliminary results, including measurements of artificial light sources, distant ultraviolet lasers, and UHECRs. Furthermore, we discuss some additional uses for these simplified low-cost fluorescence telescopes, including the facilitation of a systematic comparison of the transparency of the atmosphere above the Telescope Array experiment and the Pierre Auger Observatory, a study of the systematic uncertainty associated with the existing fluorescence detectors of these two experiments, and a cross-calibration of their energy and $X_{\text{max}}$ scales.

[29]  arXiv:1911.05288 [pdf, ps, other]

Title: Big Data Challenges of FAST

Authors: Youling Yue, Di Li

Comments: 4 pages, 1 figure

Journal-ref: Big Scientific Data Management. BigSDM 2018. Lecture Notes in Computer Science, vol 11473. Springer, Cham

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

We present the big-data challenges posed by the science operation of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Unlike the common usage of the word `big-data', which tend to emphasize both quantity and diversity, the main characteristics of FAST data stream is its single-source data rate at more than 6 GB/s and the resulting data volume at about 20 PB per year. We describe here the main culprit of such a high data rate and large volume, namely pulsar search, and our solution.

[30]  arXiv:1911.05293 [pdf, ps, other]

Title: Determining electron temperature and density in a H II region by using the relative strengths of hydrogen radio recombination lines

Authors: F.-Y. Zhu, Q.-F. Zhu, J.-Z. Wang, J.-S Zhang

Comments: 17 pages, 12 figures

Journal-ref: The Astrophysical Journal, Volume 881, Issue 1, article id. 14, 14 pp. (2019)

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We have introduced a new method of estimating the electron temperature and density of H II regions by using single dish observations. In this method, multiple hydrogen radio recombination lines of different bands are computed under the assumption of low optical depth. We use evolutionary hydrodynamical models of H II regions to model hydrogen recombination line emission from a variety of H II regions and assess the reliability of the method. According to the simulated results, the error of the estimated temperature is commonly < 13%, and that of the estimated density is < 25% for a < 1% uncertainty of the observed line fluxes. A reasonable estimated value of electron density can be achieved if the uncertainty of the line fluxes are lower than 3%. In addition, the estimated values are more representative of the properties in the relatively high-density region if the gas density gradient is present in the H II region. Our method can be independent of the radio continuum observations. But the accuracy will be improved if a line-to-continuum ratio at millimeter wavelengths is added to the estimation. Our method provides a way to measure the temperature and density in ionized regions without interferometers.

[31]  arXiv:1911.05300 [pdf]

Title: Interactions of Atomic and Molecular Hydrogen with a Diamond-like Carbon Surface: H2 Formation and Desorption

Authors: Masashi Tsuge, Tetsuya Hama, Yuki Kimura, Akira Kouchi, Naoki Watanabe

Comments: 33 pages, 8 figures, Accepted for publication in ApJ

Journal-ref: ApJ 878 23 (2019)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The interactions of atomic and molecular hydrogen with bare interstellar dust grain surfaces are important for understanding H2 formation at relatively high temperatures (>20 K). We investigate the diffusion of physisorbed H atoms and the desorption energetics of H2 molecules on an amorphous diamond-like carbon (DLC) surface. From temperature-programmed desorption experiments with a resonance-enhanced multiphoton ionization (REMPI) method for H2 detection, the H2 coverage-dependent activation energies for H2 desorption are determined. The activation energies decrease with increasing H2 coverage and are centered at 30 meV with a narrow distribution. Using a combination of photostimulated desorption and REMPI methods, the time variations of the surface number density of H2 following atomic and molecular hydrogen depositions are studied. From these measurements, we show that H2 formation on a DLC surface is quite efficient, even at 20 K. A significant kinetic isotope effect for H2 and D2 recombination reactions suggests that H-atom diffusion on a DLC surface is mediated by quantum mechanical tunneling. In astrophysically relevant conditions, H2 recombination due to physisorbed H-atoms is unlikely to occur at 20 K, suggesting that chemisorbed H atoms might play a role in H2 formation at relatively high temperatures.

[32]  arXiv:1911.05319 [pdf, ps, other]

Title: Activity time series of old stars from late F to early K. IV. Limits of the correction of radial velocities using chromospheric emission

Authors: Nadège Meunier, Anne-Marie Lagrange, Sylvain Cuzacq

Comments: Paper accepted in Astronomy and astrophysics, 15 pages

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

Inhibition of the convective blueshift in active regions is a major contribution to the radial velocity variations, at least for solar-like stars. A common technique to correct for this component is to model the RV as a linear function of chromospheric emission, because both are strongly correlated with the coverage by plages. This correction is not perfect: the aim of the present study is to understand the limits of this correction and to improve it. We investigate these questions by analysing a large set of synthetic time series corresponding to old main sequence F6-K4 stars modelled using a consistent set of parameters. We focus here on the analysis of the correlation between time series, in particular between RV and chromospheric emission on different timescales. We also study the temporal variation for each time series. Inclination strongly impacts these correlations, as well as additional signals (granulation and supergranulation). Although RV and LogR'HK are often well correlated, a combination of geometrical effects (butterfly diagrams related to dynamo processes and inclination) and activity level variations over time create an hysteresis pattern during the cycle, which produces a departure from an excellent correlation: for a given activity level, the RV is higher or lower during the ascending phase compared to the descending phase of the cycle depending on inclination, with a reversal for inclinations about 60 deg from pole-on. This hysteresis is also observed for the Sun and other stars. This property is due to the spatio-temporal distribution of the activity pattern and to the difference in projection effects of the RV and chromospheric emission. These results allow us to propose a new method which significantly improves the correction for long timescales, and could be crucial to improving detection rates of planets in the habitable zone around F6-K4 stars.

[33]  arXiv:1911.05323 [pdf, other]

Title: XMM-Newton RGS spectroscopy of the M31 bulge. I: Evidences for a past AGN half a million years ago

Authors: Shuinai Zhang, Q. Daniel Wang, Adam R. Foster, Wei Sun, Zhiyuan Li, Li Ji

Comments: 22 pages, 11 figures

Journal-ref: ApJ, 2019, 885, 157

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Existing analysis based on XMM-Newton/RGS spectra already shows that the G-ratio of the OVII He$\alpha$ triplet in the inner bulge of M31 is too high to be consistent with a pure optically thin thermal plasma in collisional ionization equilibrium (CIE). Different processes that may affect properties of diffuse hot plasma were proposed, such as resonance scattering (RS) and charge exchange (CX) with cold gas. To determine which physical process(es) may be responsible for this inconsistency, we present a systematic spectroscopic analysis based on 0.8 Ms XMM-Newton/RGS data, together with complementary Chandra/ACIS-S images. The combination of these data enables us to reveal multiple non-CIE spectroscopic diagnostics, including but not limited to the large G-ratios of He$\alpha$ triplets (OVII, NVI, and NeIX) and the high Lyman series line ratios (OVIII Ly$\beta$/Ly$\alpha$ and Ly$\gamma$/Ly$\alpha$, and NVII Ly$\beta$/Ly$\alpha$), which are not expected for a CIE plasma, and the high iron line ratios (FeXVIII 14.2 \AA/FeXVII~17 \AA and FeXVII~15 \AA/17 \AA), which suggest much higher temperatures than other line ratios, as well as their spatial variations. Neither CX nor RS explains all these spectroscopic diagnostics satisfactorily. Alternatively, we find that an active galactic nucleus (AGN) relic scenario provides a plausible explanation for virtually all the signatures. We estimate that an AGN was present at the center of M31 about half a million years ago and that the initial ionization parameter $\xi$ of the relic plasma is in the range of 3-4.

[34]  arXiv:1911.05337 [pdf, other]

Title: Onset Mechanism of M6.5 Solar Flare Observed in Active Region 12371

Authors: Jihye Kang, Satoshi Inoue, Kanya Kusano, Sung-Hong Park, Yong-Jae Moon

Comments: 11 pages, 6 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

We studied a flare onset process in terms of stability of a three-dimensional (3D) magnetic field in active region 12371 producing an eruptive M6.5 flare in 2015 June 22. In order to reveal the 3D magnetic structure, we first extrapolated the 3D coronal magnetic fields based on time series of the photospheric vector magnetic fields under a nonlinear force-free field (NLFFF) approximation. The NLFFFs nicely reproduced the observed sigmoidal structure which is widely considered as pre-eruptive magnetic configuration. We, in particular, found that the sigmoid is composed of two branches of sheared arcade loops. On the basis of the NLFFFs, we investigated the sheared arcade loops to explore the onset process of the eruptive flare using three representative MHD instabilities: the kink, torus and double arc instabilities. The double arc instability, recently proposed by Ishiguro & Kusano, is a double arc loop can be more easily destabilized than a torus loop. Consequently, the NLFFFs are found to be quite stable against the kink and torus instabilities. However, the sheared arcade loops formed prior to the flare possibly becomes unstable against the double arc instability. As a possible scenario on the onset process of the M6.5 flare, we suggest three-step process: (1) double arc loop are formed by the sheared arcade loops through the tether-cutting reconnection during an early phase of the flare, (2) the double arc instability contributes to the expansion of destabilized double arc loops and (3) finally, the torus instability makes the full eruption.

[35]  arXiv:1911.05348 [pdf, ps, other]

Title: Particle Acceleration in Shearing Flows: Efficiencies and Limits

Authors: Frank M. Rieger, Peter Duffy

Comments: ApJL accepted, 5 pages, 2 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We examine limits to the efficiency for particles acceleration in shearing flows, showing that relativistic flow speeds are required for efficient gradual shear acceleration. We estimate maximum achievable particle energies for parameters applicable to relativistic AGN jets. The implications of our estimates is that if large-scale jets are relativistic, then efficient electron acceleration up to several PeV, and proton acceleration up to several EeV energies appears feasible. This suggests that shear particle acceleration could lead to a continued energization of synchrotron X-ray emitting electrons, and be of relevance for the production of ultra-high-energy cosmic-ray particles.

[36]  arXiv:1911.05357 [pdf, other]

Title: GLADIS: GLobal Accretion Disk Instability Simulation

Authors: Agnieszka Janiuk (CTP PAS)

Comments: 8 pages; submitted to the proceedings of Science; based on invited talk presented on the "Multifrequency Behaviour of High Energy Cosmic Sources - XIII", Palermo, June 3-8 2019

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

I present the publicly available code GLADIS (GLobal Accretion Disk Instability Simulation) developed in my reserach group over the years 2002-2017.
It can be freely downloaded and modified by the users via the link from the Astrophysics Source Code Library. The software computes time-dependent evolution of a black hole accretion disk, in one-dimensional, axisymmetric, vertically integrated scheme. The main applications are to explain the variability of accretion disks that can be subject to radiation-pressure instability. The phenomenon is relevant for fast variable microquasars, as well as for a class of changing-look AGN.

[37]  arXiv:1911.05364 [pdf, other]

Title: Multi-messenger signals from short gamma ray bursts

Authors: Agnieszka Janiuk (CTP PAS), Kostas Sapountzis, Martin Kolos

Comments: 12 pages; submitted to the Proceedings of Science; based on contributed talk at "Multifrequency Behaviour of High Energy Cosmic Sources - XIII", Palermo, 3-8 June 2019

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We present the results of simulations done with the code HARM-COOL developed in the CTP PAS Warsaw research group over the years 2017-2019. It is based in the original GR MHD scheme proposed by Gammie et al. (2003) for the simulation of Active Galactic Nucleus, but now it has been suited for the engine of a short Gamma Ray Burst event.
We compute time-dependent evolution of a black hole accretion disk, in two-dimensional, axisymmetric scheme. The code includes neutrino cooling and accounts for nuclear structure of dense, degenerate matter. Free protons, neutrons, and electron-positron pairs form a neutron-rich, magnetically driven outflow that provides site for subsequent r-process nucleosynthesis.
Here the heavy elements up to the Uranium and Gold are synthesized and may contribute to the chemical enrichment of the circum-burst medium. Their radio-active decay will give signal in lower energies in a timescale of weeks-months after the GRB prompt phase.
In addition, the magnetic fields are responsible for the launching of ultra-relativistic jets along the rotation axis of the central black hole, according to the well-known Blandford-Znajek mechanism. These jets are sites of variable high energy emission in gamma rays. We find that the magnetic field and the black hole spin account for the observed variability timescales and jet energetics.

[38]  arXiv:1911.05372 [pdf, ps, other]

Title: Simulated Predictions for HI at $z = 3.35$ with the Ooty Wide Field Array (OWFA) -- II: Foreground Avoidance

Authors: Suman Chatterjee, Somnath Bharadwaj, Visweshwar Ram Marthi

Comments: 18 pages, 10+1 figures; submitted to MNRAS

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Considering the upcoming OWFA, we use simulations of the foregrounds and the $z = 3.35$ HI 21-cm intensity mapping signal to identify the $(k_{\perp},k_{\parallel})$ modes where the expected 21-cm power spectrum $P(k_{\perp},k_{\parallel})$ is substantially larger than the predicted foreground contribution. Only these uncontaminated $k$-modes are used for measuring $P(k_{\perp},k_{\parallel})$ in the "Foreground Avoidance" technique. Though the foregrounds are largely localised within a wedge. we find that the small leakage beyond the wedge surpasses the 21-cm signal across a significant part of the $(k_{\perp},k_{\parallel})$ plane. The extent of foreground leakage is extremely sensitive to the frequency window function used to estimate $P(k_{\perp},k_{\parallel})$. It is possible to reduce the leakage by making the window function narrower, however this comes at the expense of losing a larger fraction of the 21-cm signal. It is necessary to balance these competing effects to identify an optimal window function. Considering a broad class of cosine window functions, we identify a six term window function as optimal for 21-cm power spectrum estimation with OWFA. Considering only the $k$-modes where the expected 21-cm power spectrum exceeds the predicted foregrounds by a factor of $100$ or larger, a $5\,\sigma$ detection of the binned power spectrum is possible in the $k$ ranges $0.18 \leq k \leq 0.3 \, {\rm Mpc}^{-1}$ and $0.18 \le k \le 0.8 \, {\rm Mpc}^{-1}$ with $1,000-2,000$ hours and $10^4$ hours of observation respectively.

[39]  arXiv:1911.05394 [pdf, other]

Title: Phase-space structure of cold dark matter halos inside splashback: multi-stream flows and self-similar solution

Authors: Hiromu Sugiura, Takahiro Nishimichi, Yann Rasera, Atsushi Taruya

Comments: 18 pages, 14 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Using the motion of accreting particles onto halos in cosmological $N$-body simulations, we study the radial phase-space structures of cold dark matter (CDM) halos. In CDM cosmology, formation of virialized halos generically produces radial caustics, followed by multi-stream flows of accreted dark matter inside the halos, which are clues to discriminate from non-standard dark matter models. In particular, the radius of the outermost caustic called the splashback radius exhibits a sharp drop in the slope of the density profile, and is recognized with great interest as a physical boundary of CDM halos in both theory and observation. Here, we focus on the multi-stream structure of CDM halos inside the splashback radius. To analyze this, we use and extend the SPARTA algorithm developed by Diemer (2017), and by tracking the particle trajectories accreting onto the halos, we count their number of apocenter passages, which is then used to reveal the multi-stream flows of the dark matter particles. The resultant multi-stream structure in radial phase space is then compared with the prediction of the self-similar solution by Fillmore & Goldreich (1984) for each halo. We find that $\sim30\%$ of the simulated halos satisfy our criteria to be regarded as being well fitted to the self-similar solution. The fitting parameters in the self-similar solution characterizes physical properties of the halos, including the mass accretion rate and the size of the outermost caustic (i.e., the splashback radius). We discuss in detail the correlation of these fitting parameters and other measures directly extracted from the $N$-body simulation.

[40]  arXiv:1911.05412 [pdf, other]

Title: Magnetic fields in a hot dense neutrino plasma and the Gravitational Waves

Authors: Arun Kumar Pandey, Pravin Kumar Natwariya, Jitesh R Bhatt

Comments: 9 pages, 6 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

In the present work, we have studied the spectrum of the primordial gravitational waves due to magnetic instability in the presence of neutrino asymmetry. The magnetic instability generates a helical magnetic field on a large scale. The anisotropic stress generated by the magnetic field shown to be a source of primordial gravitational waves (GWs) at the time of matter-neutrino decoupling. We expect that the theoretically predicted GWs by this mechanism may be detected by Square Kilometer Array (SKA) or pulsar time array (PTA) observations. We also compare our findings with the results obtained by the earlier work where the effect of magnetic instability was not considered.

[41]  arXiv:1911.05418 [pdf, other]

Title: Asteroid mass estimation with the robust adaptive Metropolis algorithm

Authors: L. Siltala, M. Granvik

Comments: 13 pages, 12 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

The bulk density of an asteroid informs us about its interior structure and composition. To constrain the bulk density one needs an estimate for the mass of the asteroid. The mass is estimated by analyzing an asteroid's gravitational interaction with another object, such as another asteroid during a close encounter. An estimate for the mass has typically been obtained with linearized least-squares methods despite the fact that this family of methods is not able to properly describe non-Gaussian parameter distributions. In addition, the uncertainties reported for asteroid masses in the literature are sometimes inconsistent with each other and suspected to be unrealistically low. We present a Markov-chain Monte Carlo (MCMC) algorithm for the asteroid mass estimation problem based on asteroid-asteroid close encounters. We verify that our algorithm works correctly by applying it to synthetic data sets. We then use astrometry available through the Minor Planet Center to estimate masses for a few example cases and compare our results to results reported in the literature.
Our mass estimates for the synthetic data sets are fully consistent with the ground truth. The nominal masses for real example cases typically agree with the literature but tend to have greater uncertainties than what is reported in recent literature. Possible reasons for this include different astrometric datasets and/or weights, different test asteroids, different force models and different algorithms. For (16) Psyche, the target of NASA's Psyche mission, our maximum likelihood mass is approximately 55% of what is reported in the literature. Such a low mass would imply that the bulk density is significantly lower than previously expected and hence disagrees with the theory of (16) Psyche being the metallic core of a protoplanet. We however note that masses reported in recent literature remain within our 3-sigma limits.

[42]  arXiv:1911.05429 [pdf]

Title: ARISE: A granular matter experiment on the International Space Station

Authors: Tobias Steinpilz, Grzegorz Musiolik, Maximilian Kruss, Felix Jungmann, Tunahan Demirci, Manfred Aderholz, Jonathan E. Kollmer, Jens Teiser, Tetyana Bila, Evelyn Guay, Gerhard Wurm

Comments: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in (Review of Scientific Instruments 90:10 2019) and may be found at (this https URL)

Journal-ref: Review of Scientific Instruments, 90:10 (2019)

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Soft Condensed Matter (cond-mat.soft)

We developed an experiment to study different aspects of granular matter under microgravity. The 1.5U small experiment was carried out on the International Space Station. About 3500 almost identical spherical glass particles with 856 um diameter were placed in a container of 50*50 mm cross section. Adjusting the height between 5 and 50 mm, the filling factor can be varied. The sample was vibrated under different frequencies and amplitudes. The majority of the data are video images of the particles motion. Here, we first give an overview of the general setup and a first qualitative account of different phenomena observed in about 700 experimental runs. These phenomena include collisional cooling, collective motion via gas-cluster coupling, and the influence of electrostatic forces on particle-particle interactions.

[43]  arXiv:1911.05432 [pdf, other]

Title: Optimising gravitational waves follow-up using galaxies stellar mass

Authors: J.-G. Ducoin, D. Corre, N. Leroy, E. Le Floch

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

We present a new strategy to optimise the electromagnetic follow-up of gravitational wave triggers. This method is based on the widely used galaxy targeting approach where we add the stellar mass of galaxies in order to prioritise the more massive galaxies. We crossmatched the GLADE galaxy catalog with the AllWISE catalog up to 400Mpc with an efficiency of $\sim$93%, and derived stellar masses using a stellar-to-mass ratio using the WISE1 band luminosity. We developed a new grade to rank galaxies combining their 3D localisation probability associated to the gravitational wave event with the new stellar mass information. The efficiency of this new approach is illustrated with the GW170817 event, which shows that its host galaxy, NGC4993, is ranked at the first place using this new method. The catalog, named Mangrove, is publicly available and the ranking of galaxies is automatically provided through a dedicated web site for each gravitational wave event.

[44]  arXiv:1911.05453 [pdf, ps, other]

Title: Comment on "The Flyby Anomaly and the Gravitational-Magnetic Field Induced Frame-Dragging Effect around the Earth"

Authors: V. Guruprasad

Comments: To be submitted

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Independent radar data with larger discrepancies left out in JPL's 2008 summary on the anomaly has already led to a signal processing cause, and obviates frame-dragging.

[45]  arXiv:1911.05471 [pdf, other]

Title: Tracing The Physical Conditions of Planet Formation with Molecular Excitation

Authors: Richard Teague

Comments: Proceedings for Laboratory Astrophysics IAU symposium

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Understanding the physical structure of the planet formation environment, the protoplanetary disk, is essential for the interpretation of high resolution observations of the dust and future observations of the magnetic field structure. Observations of multiple transitions of molecular species offers a unique view of the underlying physical structure through excitation analyses. Here we describe a new method to extract high-resolution spectra from low-resolution observations, then provide two case studies of how molecular excitation analyses were used to constrain the physical structure in TW Hya, the closest protoplanetary disk to Earth.

[46]  arXiv:1911.05506 [pdf, ps, other]

Title: Circumbinary Disks: Accretion and Torque as a Function of Mass Ratio and Disk Viscosity

Authors: Paul C. Duffell, Daniel D'Orazio, Andrea Derdzinski, Zoltan Haiman, Andrew MacFadyen, Anna L. Rosen, Jonathan Zrake

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

Using numerical hydrodynamics calculations and a novel method for densely sampling parameter space, we measure the accretion and torque on a binary system from a circumbinary disk. In agreement with previous studies, we find that the net torque on the binary is positive for mass ratios close to unity, and that accretion always drives the binary towards equal mass. Accretion variability depends sensitively on the numerical sink prescription, but the torque and relative accretion onto each component do not depend on the sink timescale. Positive torque and highly variable accretion occurs only for mass ratios greater than around $0.05$. This means that for mass ratios below $0.05$, the binary would migrate inward until the secondary accreted sufficient mass, after which it would execute a U-turn and migrate outward. We explore a range of viscosities, from $\alpha = 0.03$ to $\alpha = 0.15$, and find that this outward torque is proportional to the viscous torque, simply proportional to viscosity in this range. Dependence of accretion and torque on mass ratio is explored in detail, densely sampling mass ratios between $0.01$ and unity. For mass ratio $q > 0.6$, accretion variability is found to exhibit a distinct sawtooth pattern, typically with a five-orbit cycle that provides a "smoking gun" prediction for variable quasars observed over long periods, as a potential means to confirm the presence of a binary.

[47]  arXiv:1911.05568 [pdf, other]

Title: Dark Energy Survey Year 3 results: cosmology with moments of weak lensing mass maps -- validation on simulations

Authors: M. Gatti, C. Chang, O. Friedrich, B. Jain, D. Bacon, M. Crocce, J. DeRose, I. Ferrero, P. Fosalba, E. Gaztanaga, D. Gruen, I.Harrison, N. Jeffrey, N.MacCrann, T. McClintock, L. Secco, L. Whiteway, T. M. C. Abbott, S. Allam, J. Annis, S. Avila, D. Brooks, E. Buckley-Geer, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, R. Cawthon, M. Crocce, L. N. da Costa, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, T. F. Eifler, J. Estrada, S. Everett, A. E. Evrard, P. Fosalba, J. Frieman, J. Garcia-Bellido, D. W. Gerdes, R. A. Gruendl, J. Gschwend, G. Gutierrez, D. J. James, M. D. Johnson, E. Krause, K.Kuehn, K. Kuehn, M. Lima, M. A. G. Maia, M. March, J. L. Marshall, P. Melchior, F. Menanteau, R. Miquel, A. Palmese, F. Paz-Chinchon, A. A. Plazas, C. Sanchez, E. Sanchez, V.Scarpine, M. Schubnell, et al. (11 additional authors not shown)

Comments: submitted to MNRAS

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We present a simulated cosmology analysis using the second and third moments of the weak lensing mass (convergence) maps. The analysis is geared towards the third year (Y3) data from the Dark Energy Survey (DES), but the methodology can be applied to other weak lensing data sets. The second moment, or variances, of the convergence as a function of smoothing scale contains information similar to standard shear 2-point statistics. The third moment, or the skewness, contains additional non-Gaussian information. We present the formalism for obtaining the convergence maps from the measured shear and for obtaining the second and third moments of these maps given partial sky coverage. We estimate the covariance matrix from a large suite of numerical simulations. We test our pipeline through a simulated likelihood analyses varying 5 cosmological parameters and 10 nuisance parameters. Our forecast shows that the combination of second and third moments provides a 1.5 percent constraint on $S_8 \equiv \sigma_8 (\Omega_{\rm m}/0.3)^{0.5}$ for DES Y3 data. This is 20 percent better than an analysis using a simulated DES Y3 shear 2-point statistics, owing to the non-Gaussian information captured by the inclusion of higher-order statistics. The methodology developed here can be applied to current and future weak lensing datasets to make use of information from non-Gaussianity in the cosmic density field and to improve constraints on cosmological parameters.

[48]  arXiv:1911.05574 [pdf, other]

Title: TOI-677 b: A Warm Jupiter (P=11.2d) on an eccentric orbit transiting a late F-type star

Authors: Andrés Jordán, Rafael Brahm, Néstor Espinoza, Thomas Henning, Matías I. Jones, Diana Kossakowski, Paula Sarkis, Trifon Trifonov, Felipe Rojas, Pascal Torres, Holger Drass, Sangeetha Nandakumar, Mauro Barbieri, Allen Davis, Songhu Wang, Daniel Bayliss, Luke Bouma, Diana Dragomir, Jason D. Eastman, Tansu Daylan, Natalia Guerrero, Thomas Barclay, Eric B. Ting, Christopher E. Henze, George Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua Winn, Jon M. Jenkins, Robert A. Wittenmyer, Brendan P. Bowler, Ian Crossfield, Jonathan Horner, Stephen R. Kane, John F. Kielkopf, Timothy D. Morton, Peter Plavchan, C.G. Tinney, Brett Addison, Matthew W. Mengel, Jack Okumura, Sahar Shahaf, Tsevi Mazeh, Markus Rabus, Avi Shporer, Carl Ziegler, Andrew W. Mann, Rhodes Hart

Comments: Submitted to AAS journals, 15 pages, 8 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of M_p = 1.236$^{+0.069}_{-0.067}$ M_J, a radius of R_p = 1.170 +- 0.03 R_J,and orbits its bright host star (V=9.8 mag) with an orbital period of 11.23660 +- 0.00011 d, on an eccentric orbit with e = 0.435 +- 0.024. The host star has a mass of M_* = 1.181 +- 0.058 M_sun, a radius of R_* = 1.28 +- 0.03 R_sun, an age of 2.92$^{+0.80}_{-0.73}$ Gyr and solar metallicity, properties consistent with a main sequence late F star with T_eff = 6295 +- 77 K. We find evidence in the radial velocity measurements of a secondary long term signal which could be due to an outer companion. The TOI-677 b system is a well suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

[49]  arXiv:1911.05575 [pdf, ps, other]

Title: The dust effects on galaxy scaling relations

Authors: Bogdan A. Pastrav

Comments: 12 pages, 7 figures, MNRAS submitted, with changes from the first revision included

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Accurate galaxy scaling relations are essential for a successful model of galaxy formation and evolution as they provide direct information about the physical mechanisms of galaxy assembly over cosmic time. We present here a detailed analysis of a sample of nearby spiral galaxies taken from the KINGFISH survey. The photometric parameters of the morphological components are obtained from bulge-disk decompositions using GALFIT data analysis algorithm, with surface photometry of the sample done beforehand. Dust opacities are determined using a previously discovered correlation between the central face-on dust opacity of the disk and the stellar mass surface density. The method and the library of numerical results previously obtained are used to correct the measured photometric and structural parameteres for projection (inclination), dust and decomposition effects in order to derive their intrinsic values. Galaxy disk scaling relations are then presented, both the measured (observed) and the intrinsic (corrected) ones, in the optical regime, to show the scale of the biases introduced by the aforementioned effects. The slopes of the size-luminosity relations and the dust vs stellar mass are in agreement with values found in other works. We derive mean dust optical depth and dust/stellar mass ratios of the sample, which we find to be consistent with previous studies of nearby spiral galaxies. While our sample is rather small, it is sufficient to quantify the influence of galaxy environment (dust, in this case) when deriving scaling relations.

[50]  arXiv:1911.05577 [pdf, other]

Title: Constraining the magnitude of climate extremes from time-varying instellation on a circumbinary terrestrial planet

Authors: Jacob Haqq-Misra, Eric T. Wolf, William F. Welsh, Ravi Kumar Kopparapu, Veselin Kostov, Stephen R. Kane

Comments: Accepted for publication in JGR-Planets

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)

Planets that revolve around a binary pair of stars are known as circumbinary planets. The orbital motion of the stars around their center of mass causes a periodic variation in the total instellation incident upon a circumbinary planet. This study uses both an analytic and numerical energy balance model to calculate the extent to which this effect can drive changes in surface temperature on circumbinary terrestrial planets. We show that the amplitude of the temperature variation is largely constrained by the effective heat capacity, which corresponds to the ocean-to-land ratio on the planet. Planets with large ocean fractions should experience only modest warming and cooling of only a few degrees, which suggests that habitability cannot be precluded for such circumbinary planets. Planets with large land fractions that experience extreme periodic forcing could be prone to changes in temperature of tens of degrees or more, which could drive more extreme climate changes that inhibit continuously habitable conditions.

[51]  arXiv:1911.05597 [pdf]

Title: How to Characterize Habitable Worlds and Signs of Life

Authors: L. Kaltenegger

Comments: 50 Pages, 14 figures, Annual Reviews of Astronomy and Astrophysics. arXiv admin note: text overlap with arXiv:1708.05829 by other authors

Journal-ref: Annual Review of Astronomy and Astrophysics, 2017, 55, 433

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

The detection of exoplanets orbiting other stars has revolutionized our view of the cosmos. First results suggest that it is teeming with a fascinating diversity of rocky planets, including those in the habitable zone. Even our closest star, Proxima Centauri, harbors a small planet in its habitable zone, Proxima b. With the next generation of telescopes, we will be able to peer into the atmospheres of rocky planets and get a glimpse into other worlds. Using our own planet and its wide range of biota as a Rosetta stone, we explore how we could detect habitability and signs of life on exoplanets over interstellar distances. Current telescopes are not yet powerful enough to characterize habitable exoplanets, but the next generation of telescopes that is already being built will have the capabilities to characterize close-by habitable worlds. The discussion on what makes a planet a habitat and how to detect signs of life is lively. This review will show the latest results, the challenges of how to identify and characterize such habitable worlds, and how near-future telescopes will revolutionize the field. For the first time in human history, we have developed the technology to detect potential habitable worlds. Finding thousands of exoplanets has taken the field of comparative planetology beyond the Solar System.

[52]  arXiv:1911.05598 [pdf]

Title: Chemically-distinct regions within Venus' atmosphere revealed by MESSENGER-measured N2 concentrations

Authors: Patrick N. Peplowski, David J. Wilson, Jack T. Wilson

Comments: 12 pages (incl. references), 3 figures, plus supplemental online materials with 3 figures and 1 table)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

A defining characteristic of the planet Venus is its thick, CO2-dominated atmosphere. Despite over fifty years of robotic exploration, including thirteen successful atmosphere probes and landers, our knowledge of N2, the second-most-abundant compound in the atmosphere, is highly uncertain (von Zahn et al., 1983). We report the first measurement of the nitrogen content of Venus' atmosphere at altitudes between 60 and 100 km. Our result, 5.0 +/- 0.4 v% N2, is significantly higher than the value of 3.5 v% N2 reported for the lower atmosphere (<50 km altitude). We conclude that Venus' atmosphere contains two chemically-distinct regions, contrasting sharply with the expectation that it should be uniform across these altitude due to turbulent mixing (e.g. Oyama et al., 1980). That the lower-mass component is more concentrated at high altitudes suggests that the chemical profile of the atmosphere above 50-km altitude reflects mass segregation of CO2 and N2. A similar boundary between well-mixed and mass-segregated materials exists for Earth, however it is located at a substantially higher altitude of ~100 km. That Venus' upper and lower atmosphere are not in chemical equilibrium complicates efforts to use remote sensing measurements to infer the properties of the lower atmosphere and surface, a lesson that also applied to the growing field of exoplanet astronomy. The observation of periodic increases in SO2 concentrations in Venus' upper atmosphere, which has been cited as evidence for active volcanic eruptions at the surface (Esposito et al., 1984), may instead be attributable to atmosphere processes that periodically inject SO2 from the lower atmosphere into the upper atmosphere.

[53]  arXiv:1911.05608 [pdf, other]

Title: Molecular outflows in local galaxies: Method comparison and a role of intermittent AGN driving

Authors: D. Lutz, E. Sturm, A. Janssen, S. Veilleux, S. Aalto, C. Cicone, A. Contursi, R.I. Davies, C. Feruglio, J. Fischer, S. Garcia-Burillo, R. Genzel, E. González-Alfonso, J. Gracía-Carpio R. Herrera-Camus, R. Maiolino, A. Schruba, T. Shimizu, A. Sternberg, L.J. Tacconi, A. Weiß

Comments: 37 pages. Accepted for publication in Astronomy & Astrophysics

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We report new detections and limits from a NOEMA and ALMA CO(1-0) search for molecular outflows in 13 local galaxies with high FIR surface brightness, and combine with results from the literature. CO line ratios and outflow structure provide some constraints on the conversion from observables to quantities such as molecular mass outflow rates. Ratios between outflow emission in higher J CO transitions and in CO(1-0) typically are consistent with excitation Ri1<~1. For IRAS 13120-5453, however, R31=2.10 indicates optically thin CO in the outflow. Like much of the outflow literature, we use alpha(CO) = 0.8, and we present arguments for using C=1 in deriving molecular mass outflow rates Mdot = C*M*v/R. We compare the two main methods for molecular outflow detection: CO mm interferometry and Herschel OH spectroscopy. For 26 sources studied with both methods, we find 80% agreement in detecting vout>~150km/s outflows, and non-matches can be plausibly ascribed to outflow geometry and SNR. For 12 bright ULIRGs with detailed OH-based outflow modeling, CO outflows are detected in all but one. Outflow masses, velocities, and sizes for these 11 sources agree well between the two methods, and modest remaining differences may relate to the different but overlapping regions sampled by CO emission and OH absorption. Outflow properties correlate better with AGN luminosity and with bolometric luminosity than with FIR surface brightness. The most massive outflows are found for systems with current AGN activity, but significant outflows in non-AGN systems must relate to star formation or to AGN activity in the recent past. We report scaling relations for the increase of outflow mass, rate, momentum rate, and kinetic power with bolometric luminosity. Short ~10^6yr flow times and some sources with resolved multiple outflow episodes support a role of intermittent driving, likely by AGN. (abridged)

[54]  arXiv:1911.05690 [pdf, other]

Title: Modeling of the Variable Circumstellar Absorption Features of WD 1145+017

Authors: M. Fortin-Archambault, P. Dufour, S. Xu

Comments: 22 pages, 27 figures, submitted to The Astrophysical Journal

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

We present an eccentric precessing gas disk model designed to study the variable circumstellar absorption features detected for WD 1145+017, a metal polluted white dwarf with an actively disintegrating asteroid around it. This model, inspired by one recently proposed by Cauley et al., calculates explicitly the gas opacity for any predetermined physical conditions in the disk, predicting the strength and shape of all absorption features, from the UV to the optical, at any given phase of the precession cycle. The successes and failures of this simple model provide valuable insight on the physical characteristics of the gas surrounding the star, notably its composition, temperature and density. This eccentric disk model also highlights the need for supplementary components, most likely circular rings, in order to explain the presence of zero velocity absorption as well as highly ionized Si IV lines. We find that a precession period of $4.6\pm0.3$ yrs can successfully reproduce the shape of the velocity profile observed at most epochs from April 2015 to January 2018, although minor discrepancies at certain times indicate that the assumed geometric configuration may not be optimal yet. Finally, we show that our model can quantitatively explain the change in morphology of the circumstellar features during transiting events.

[55]  arXiv:1911.05709 [pdf, other]

Title: Uncovering a 260 pc wide, 35 Myr old filamentary relic of star formation

Authors: Giacomo Beccari, Henri M.J. Boffin, Tereza Jerabkova

Comments: Accepted for publication in MNRAS

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

Several recent studies have shown that the Vela OB2 region hosts a complex constellation of sub-populations with ages in the range 10 to 50 Myr. Such populations might represent the best example of the outcome of clustered star formation in Giant Molecular clouds (GMC). We use Gaia DR2 data over an area of 40 deg radius around the open cluster Collinder 135 to extend the study of the stellar populations of the Vela OB2 region over an area of several hundreds of parsecs on sky. Detailed clustering algorithms combined with the exquisite astrometric quality of the GAIA catalogue allow us to detect a new cluster named BBJ 1 that shows the same age as NGC 2547 (30 to 35 Myr), but located at a distance of 260 pc from it. Deeper investigation of the region via clustering in 5D parameter space and in the colour-magnitude diagram allows us to detect a filamentary structure of stars that bridges the two clusters. Given the extent in space of such structure (260 pc) and the young age (~35 Myr), we exclude that such population originates by the same mechanism responsible to create tidal streams around older clusters. Even if we miss a complete picture of the 3D motion of the studied stellar structure because of the lack of accurate radial velocity measurements, we propose that such structure represent the detection of a 35 Myr old outcome of a mechanism of filamentary star formation in a GMC.

[56]  arXiv:1911.05714 [pdf, other]

Title: Imaging Systematics and Clustering of DESI Main Targets

Authors: Ellie Kitanidis, Martin White, Yu Feng, David Schlegel, Julien Guy, Arjun Dey, Martin Landriau, David Brooks, Michael Levi, John Moustakas, Francisco Prada, Gregory Tarle, Benjamin Alan Weaver

Comments: 30 pages, 28 figures, 11 tables

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We evaluate the impact of imaging systematics on the clustering of luminous red galaxies (LRG), emission-line galaxies (ELG) and quasars (QSO) targeted for the upcoming Dark Energy Spectroscopic Instrument (DESI) survey. Using Data Release 7 of the DECam Legacy Survey, we study the effects of astrophysical foregrounds, stellar contamination, differences between north galactic cap and south galactic cap measurements, and variations in imaging depth, stellar density, galactic extinction, seeing, airmass, sky brightness, and exposure time before presenting survey masks and weights to mitigate these effects. With our sanitized samples in hand, we conduct a preliminary analysis of the clustering amplitude and evolution of the DESI main targets. From measurements of the angular correlation functions, we determine power law fits $r_0 = 7.78 \pm 0.26$ $h^{-1}$Mpc, $\gamma = 1.98 \pm 0.02$ for LRGs and $r_0 = 5.45 \pm 0.1$ $h^{-1}$Mpc, $\gamma = 1.54 \pm 0.01$ for ELGs. Additionally, from the angular power spectra, we measure the linear biases and model the scale dependent biases in the weakly nonlinear regime. Both sets of clustering measurements show good agreement with survey requirements for LRGs and ELGs, attesting that these samples will enable DESI to achieve precise cosmological constraints. We also present clustering as a function of magnitude, use cross-correlations with external spectroscopy to infer $dN/dz$ and measure clustering as a function of luminosity, and probe higher order clustering statistics through counts-in-cells moments.

[57]  arXiv:1911.05717 [pdf, other]

Title: The Atacama Cosmology Telescope: Component-separated maps of CMB temperature and the thermal Sunyaev-Zel'dovich effect

Authors: Mathew S. Madhavacheril, J. Colin Hill, Sigurd Naess, Graeme E. Addison, Simone Aiola, Taylor Baildon, Nicholas Battaglia, Rachel Bean, J. Richard Bond, Erminia Calabrese, Victoria Calafut, Steve K. Choi, Omar Darwish, Mark J. Devlin, Joanna Dunkley, Rolando Dünner, Simone Ferraro, Patricio A. Gallardo, Mark Halpern, Dongwon Han, Matthew Hasselfield, Matt Hilton, Adam D. Hincks, Renée Hložek, Shuay-Pwu Patty Ho, Kevin M. Huffenberger, John P. Hughes, Brian J. Koopman, Arthur Kosowsky, Martine Lokken, Thibaut Louis, Marius Lungu, Amanda MacInnis, Loïc Maurin, Jeffrey J. McMahon, Kavilan Moodley, Federico Nati, Michael D. Niemack, Lyman A. Page, Bruce Partridge, Naomi Robertson, Neelima Sehgal, Emmanuel Schaan, Alessandro Schillaci, Blake D. Sherwin, Cristóbal Sifón, et al. (8 additional authors not shown)

Comments: 23 pages, 11 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Optimal analyses of many signals in the cosmic microwave background (CMB) require map-level extraction of individual components in the microwave sky, rather than measurements at the power spectrum level alone. To date, nearly all map-level component separation in CMB analyses has been performed exclusively using satellite data. In this paper, we implement a component separation method based on the internal linear combination (ILC) approach which we have designed to optimally account for the anisotropic noise (in the 2D Fourier domain) often found in ground-based CMB experiments. Using this method, we combine multi-frequency data from the Planck satellite and the Atacama Cosmology Telescope Polarimeter (ACTPol) to construct the first wide-area, arcminute-resolution component-separated maps (covering approximately 2100 sq. deg.) of the CMB temperature anisotropy and the thermal Sunyaev-Zel'dovich (tSZ) effect sourced by the inverse-Compton scattering of CMB photons off hot, ionized gas. Our ILC pipeline allows for explicit deprojection of various contaminating signals, including a modified blackbody approximation of the cosmic infrared background (CIB) spectral energy distribution. The cleaned CMB maps will be a useful resource for CMB lensing reconstruction, kinematic SZ cross-correlations, and primordial non-Gaussianity studies. The tSZ maps will be used to study the pressure profiles of galaxies, groups, and clusters through cross-correlations with halo catalogs, with dust contamination controlled via CIB deprojection. The data products described in this paper will be made available on LAMBDA.

Cross-lists for Thu, 14 Nov 19

[58]  arXiv:1911.04504 (cross-list from hep-ph) [pdf, other]

Title: Towards a precision calculation of the effective number of neutrinos $N_{\rm eff}$ in the Standard Model I: The QED equation of state

Authors: Jack J. Bennett, Gilles Buldgen, Marco Drewes, Yvonne Y. Y. Wong

Comments: 25 pages, plus appendices and 8 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We revisit several aspects of Standard Model physics at finite temperature that drive the theoretical value of the cosmological parameter $N_{\rm eff}$, the effective number of neutrinos in the early universe, away from 3. Our chief focus is finite-temperature corrections to the equation of state of the QED plasma in the vicinity of neutrino decoupling at $T \sim 1$ MeV, where $T$ is the photon temperature. Working in the instantaneous decoupling approximation, we recover at ${\cal O}(e^2)$, where $e$ is the elementary electric charge, the well-established correction of $\delta N_{\rm eff}^{(2)} \simeq 0.010$ across a range of plausible neutrino decoupling temperatures, in contrast to an erroneous claim in the recent literature which found twice as large an effect. At ${\cal O}(e^3)$ we find a new and significant correction of $\delta N_{\rm eff}^{(3)} \simeq -0.001$ that has so far not been accounted for in any precision calculation of $N_{\rm eff}$, significant because this correction is potentially larger than the change in $N_{\rm eff}$ induced between including and excluding neutrino oscillations in the transport modelling. In addition to the QED equation of state, we make a first pass at quantifying finite-temperature QED corrections to the weak interaction rates that directly affect the neutrino decoupling process, and find that the ${\cal O}(e^2)$ thermal electron mass correction induces a change of $\delta N_{\rm eff}^{m_{\rm th}} \lesssim 10^{-4}$. A complete assessment of the various effects considered in this work on the final value of $N_{\rm eff}$ will necessitate an account of neutrino energy transport beyond the instantaneous decoupling approximation. However, relative to $N_{\rm eff} = 3.044$ obtained in the most recent such calculation, we expect the new effects found in this work to lower the number to $N_{\rm eff} = 3.043$.

[59]  arXiv:1911.05086 (cross-list from hep-ph) [pdf, other]

Title: The Cosmological Evolution of Light Dark Photon Dark Matter

Authors: Samuel D. McDermott, Samuel J. Witte

Comments: 11 pages, 5 figures. Ancillary file containing strongest constraint at each dark photon mass included to ease reproduction of bounds

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Light dark photons are subject to various plasma effects, such as Debye screening and resonant oscillations, which can lead to a more complex cosmological evolution than is experienced by conventional cold dark matter candidates. Maintaining a consistent history of dark photon dark matter requires ensuring that the super-thermal abundance present in the early Universe $\textit{(i)}$ does not deviate significantly after the formation of the CMB, and $\textit{(ii)}$ does not excessively leak into the Standard Model plasma after BBN. We point out that the role of non-resonant absorption, which has previously been neglected in cosmological studies of this dark matter candidate, produces strong constraints on dark photon dark matter with mass as low as $10^{-22}$ eV. Furthermore, we show that resonant conversion of dark photons after recombination can produce excessive heating of the IGM which is capable of prematurely reionizing hydrogen and helium, leaving a distinct imprint on both the Ly$-\alpha$ forest and the integrated optical depth of the CMB. Our constraints surpass existing cosmological bounds by more than five orders of magnitude across a wide range of dark photon masses.

[60]  arXiv:1911.05092 (cross-list from hep-ph) [pdf, ps, other]

Title: Kinetic equations for sterile neutrinos from thermal fluctuations

Authors: Dietrich Bodeker, Dennis Schroder

Comments: 30 pages

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

We obtain non-linear kinetic equations for sterile neutrino occupancies and lepton minus baryon numbers by matching real time correlation functions of thermal fluctuations computed in an effective description to those computed in thermal quantum field theory. After expanding in the sterile-neutrino Yukawa couplings, the coefficients in the equations are written as real time correlation functions of Standard Model operators. Our kinetic equations are valid for an arbitrary number of sterile neutrinos of any mass spectrum. They can be used to describe, e.g., low-scale leptogenesis via neutrino oscillations, or sterile neutrino dark matter production in the Higgs phase.

[61]  arXiv:1911.05128 (cross-list from physics.hist-ph) [pdf, other]

Title: Effective field theories as a novel probe of fine-tuning of cosmic inflation

Authors: Feraz Azhar

Comments: 23 pages, 1 figure

Subjects: History and Philosophy of Physics (physics.hist-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The leading account of several salient observable features of our universe today is provided by the theory of cosmic inflation. But an important and thus far intractable question is whether inflation is generic, or whether it is finely tuned---requiring very precisely specified initial conditions. In this paper I argue that a recent, model-independent characterization of inflation, known as the 'effective field theory (EFT) of inflation', promises to address this question in a thoroughly modern and significantly more comprehensive way than in the existing literature.
To motivate and provide context for this claim, I distill three core problems with the theory of inflation, which I dub the permissiveness problem, the initial conditions problem, and the multiverse problem. I argue that the initial conditions problem lies within the scope of EFTs of inflation as they are currently conceived, whereas the other two problems remain largely intractable: their solution must await a more complete description of the very early universe. I highlight recent work that addresses the initial conditions problem within the context of a dynamical systems analysis of a specific (state-of-the-art) EFT of inflation, and conclude with a roadmap for how such work might be extended to realize the promise claimed above.

[62]  arXiv:1911.05130 (cross-list from gr-qc) [pdf, ps, other]

Title: Turnaround physics beyond spherical symmetry

Authors: Andrea Giusti, Valerio Faraoni

Comments: 11 pages, no figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The concept of turnaround surface in an accelerating universe is generalized to arbitrarily large deviations from spherical symmetry, to close the gap between the idealized theoretical literature and the real world observed by astronomers. As an analytical application, the characterization of turnaround surface is applied to small deviations from spherical symmetry, recovering a previous result while extending it to scalar-tensor gravity.

[63]  arXiv:1911.05196 (cross-list from physics.ins-det) [pdf, other]

Title: DANCE: Dark matter Axion search with riNg Cavity Experiment

Authors: Yuta Michimura, Taihei Watanabe, Takuya Kawasaki, Hiroki Takeda, Masaki Ando, Koji Nagano, Ippei Obata, Tomohiro Fujita

Comments: 4 pages, 2 figures, Proceedings for the 16th International Conference on Topics in Astroparticle and Underground Physics, Toyama, September 9-13, 2019

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph)

We have proposed a new approach to search for axion dark matter with an optical ring cavity [Phys. Rev. Lett. 121, 161301 (2018)]. The coupling of photons to axions or axion-like particles makes a modulated difference in the phase velocity between left- and right-handed photons. Our method is to measure this phase velocity difference with a ring cavity, by measuring the resonant frequency difference between two circular polarizations. Our estimation shows that the sensitivity to axion-photon coupling constant $g_{a \gamma}$ for axion mass $m \lesssim 10^{-10}$ eV can be improved by several orders of magnitude compared with the current best limits. In this paper, we present the principles of the Dark matter Axion search with riNg Cavity Experiment (DANCE) and the status of the prototype experiment, DANCE Act-1.

[64]  arXiv:1911.05230 (cross-list from cond-mat.soft) [pdf, other]

Title: Structure of Multicomponent Coulomb Crystals

Authors: M. E. Caplan

Comments: 10 pages, 8 figures, submitted to PRE

Subjects: Soft Condensed Matter (cond-mat.soft); High Energy Astrophysical Phenomena (astro-ph.HE); Materials Science (cond-mat.mtrl-sci); Nuclear Theory (nucl-th)

Coulomb plasmas crystallize in a number of physical systems, such as dusty plasmas, neutron star crusts, and white dwarf cores. The crystal structure of the one component and binary plasma has received significant attention in the literature, though the less studied multicomponent plasma may be most relevant for many physical systems which contain a large range of particle charges. We report on molecular dynamics simulations of multicomponent plasmas near the melting temperature with mixtures taken to be realistic X-ray burst ash compositions. We quantify the structure of the crystal with the bond order parameters and radial distribution function. Consistent with past work, low charge particles form interstitial defects and we argue that they are in a quasi-liquid state within the lattice. The lattice shows screening effects which preserves long range order despite the large variance in particle charges which may impact transport properties relevant to astrophysics.

[65]  arXiv:1911.05311 (cross-list from gr-qc) [pdf, ps, other]

Title: Gravitational lensing signature of matter distribution around Schwarschild black hole

Authors: Harsha Miriam Reji, Mandar Patil

Comments: 33 pages, 7 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Theory (hep-th)

We live in the era where observational probes like Event Horizon Telescope and GRAVITY have achieved unprecedented resolutions with technique of interferometry combining data taken with multiple telescopes. This enables us to observe and image the supermassive black holes located at the center of our and neighboring galaxies and understand its astrophysical environment and various physical processes occurring in their vicinity. In this work we focus on the situation where significant amount of matter could be located close to the event horizon of the central black hole and how it affects the gravitational lensing signal. We consider a simple toy model where matter is concentrated in the rather small region between the inner photon sphere associated with the mass of central black hole and outer photon sphere associated with the total mass outside. If no photon sphere is present inside the matter distribution, then effective potential displays an interesting trend with maxima at inner and outer photon sphere, with peak at inner photon sphere higher than that at outer photon sphere. In such a case we get three distinct set of infinitely many relativistic images and Einstein rings. This kind of pattern of images is quite unprecedented and would serve as a smoking gun gravitational lensing signature signaling the presence of matter lump in the surrounding of black hole. We further argue that if the mass of the black hole inferred from the observation of size of its shadow is less that the mass inferred from the motion of objects around it, it signals the presence of matter in the vicinity of black hole.

[66]  arXiv:1911.05344 (cross-list from hep-ph) [pdf, ps, other]

Title: Braneworld Cosmological Effect on Freeze-in Dark Matter Density and Lifetime Frontier

Authors: Victor Baules, Nobuchika Okada, Satomi Okada

Comments: 16 pages, 2 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)

In the 5-dimensional braneworld cosmology, the Friedmann equation of our 4-dimensional universe on a brane is modified at high temperatures while the standard Big Bang cosmology is reproduced at low temperatures. Based on two well-known scenarios, the Randall-Sundrum and Gauss-Bonnet braneworld cosmologies, we investigate the braneworld cosmological effect on the relic density of a non-thermal dark matter particle whose interactions with the Standard Model particles are so weak that its relic density is determined by the freeze-in mechanism. For dark matter production processes in the early universe, we assume a simple scenario with a light vector-boson mediator for the dark matter particle to communicate with the Standard Model particles. We find that the braneworld cosmological effect can dramatically alters the resultant dark matter relic density from the one in the standard Big Bang cosmology. As an application, we consider a right-handed neutrino dark matter in the minimal $B-L$ extended Standard Model with a light $B-L$ gauge boson ($Z^\prime$) as a mediator. We find an impact of the braneworld cosmological effect on the search for the long-lived $Z^\prime$ boson at the planned/proposed Lifetime Frontier experiments.

[67]  arXiv:1911.05385 (cross-list from gr-qc) [pdf, other]

Title: Implications of axionic hair on shadow of M87*

Authors: Indrani Banerjee, Subhadip Sau, Soumitra SenGupta

Comments: 18 pages, 4 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)

Detection of axion field can unfold intriguing facets of our universe in several astrophysical and cosmological scenarios. In four dimensions, such a field owes its origin to the completely anti-symmetric Kalb-Ramond field strength tensor. Its invisibility in the solar system based tests compels one to look for its signatures in the strong field regime. The recent observation of the shadow of the supermassive black hole in the galaxy M87 ushers in a new opportunity to test for the footprints of axion in the near horizon region of black holes, where the gravity is expected to be strong. In this paper, we explore the impact of axion on the black hole shadow and compare the result with the available image of M87*. Our analysis indicates that axion which violates the energy condition seems to be favored by observations. The implications are discussed.

[68]  arXiv:1911.05554 (cross-list from hep-th) [pdf, other]

Title: Classification of magnetohydrodynamic transport at strong magnetic field

Authors: Bartosz Benenowski, Napat Poovuttikul

Comments: 5 pages of introduction and summary + 29 pages of technical details + 19 pages of appendices

Subjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

Magnetohydrodynamics is a theory of long-lived, gapless excitations in plasmas. It was argued from the point of view of fluid with higher-form symmetry that magnetohydrodynamics remains a consistent, non-dissipative theory even in the limit where temperature is negligible compared to the magnetic field. In this limit, leading-order corrections to the ideal magnetohydrodynamics arise at the second order in the gradient expansion of relevant fields, not at the first order as in the standard hydrodynamic theory of dissipative fluids and plasmas. In this paper, we classify the non-dissipative second-order transport by constructing the appropriate non-linear effective action. We find that the theory has eleven independent charge and parity invariant transport coefficients for which we derive a set of Kubo formulae. The relation between hydrodynamics with higher-form symmetry and the theory of force-free electrodynamics, which has recently been shown to correspond to the zero-temperature limit of the ideal magnetohydrodynamics, as well as simple astrophysical applications are also discussed.

Replacements for Thu, 14 Nov 19

[69]  arXiv:1710.08892 (replaced) [pdf, other]

Title: K2 Looks Towards WASP-28 and WASP-151

Authors: T. Močnik, C. Hellier, D. R. Anderson

Comments: 7 pages, 5 figures, 4 tables. Accepted for publication in PASP

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[70]  arXiv:1807.02859 (replaced) [pdf, other]

Title: Orbital Migration of Interacting Stellar Mass Black Holes in Disks around Supermassive Black Holes

Authors: Amy Secunda, Jillian Bellovary, Mordecai-Mark Mac Low, K.E. Saavik Ford, Barry McKernan, Nathan Leigh, Wladimir Lyra, Zsolt Sandor

Comments: 18 pages, 13 figures, Accepted to ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

[71]  arXiv:1810.03623 (replaced) [pdf, other]

Title: Probing gas disc physics with LISA: simulations of an intermediate mass ratio inspiral in an accretion disc

Authors: A. Derdzinski, D. D'Orazio, P. Duffell, Z. Haiman, A. MacFadyen

Comments: Incorporates published erratum - revised figures in Section 5, results unchanged

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[72]  arXiv:1811.00812 (replaced) [pdf, ps, other]

Title: An ALMA view of molecular filaments in the Large Magellanic Cloud I: The formation of high-mass stars and pillars in the N159E-Papillon Nebula triggered by a cloud-cloud collision

Authors: Yasuo Fukui, Kazuki Tokuda, Kazuya Saigo, Ryohei Harada, Kengo Tachihara, Kisetsu Tsuge, Tsuyoshi Inoue, Kazufumi Torii, Atsushi Nishimura, Sarolta Zahorecz, Omnarayani Nayak, Margaret Meixner, Tetsuhiro Minamidani, Akiko Kawamura, Norikazu Mizuno, Remy Indebetouw, Marta Sewiło, Suzanne Madden, Maud Galametz, Vianney Lebouteiller, C.-H. Rosie Chen, Toshikazu Onishi

Comments: 18 pages, 9 figures, Accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[73]  arXiv:1811.04400 (replaced) [pdf, ps, other]

Title: An ALMA view of molecular filaments in the Large Magellanic Cloud II: An early stage of high-mass star formation embedded at colliding clouds in N159W-South

Authors: Kazuki Tokuda, Yasuo Fukui, Ryohei Harada, Kazuya Saigo, Kengo Tachihara, Kisetsu Tsuge, Tsuyoshi Inoue, Kazufumi Torii, Atsushi Nishimura, Sarolta Zahorecz, Omnarayani Nayak, Margaret Meixner, Tetsuhiro Minamidani, Akiko Kawamura, Norikazu Mizuno, Remy Indebetouw, Marta Sewiło, Suzanne Madden, Maud Galametz, Vianney Lebouteiller, C.-H. Rosie Chen, Toshikazu Onishi

Comments: Comments: 15 pages, 6 figures; Accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[74]  arXiv:1812.09671 (replaced) [pdf, ps, other]

Title: A meta-analysis of neutron lifetime measurements

Authors: Ashwani Rajan, Shantanu Desai

Comments: 6 pages

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)

[75]  arXiv:1906.04317 (replaced) [pdf, other]

Title: Cosmic Ray Spectrum and Composition from PeV to EeV Using 3 Years of Data From IceTop and IceCube

Authors: IceCube Collaboration

Comments: This was the final submitted version. Changes for this update: four minor typos, addition of figure 15, addition of footnote 7. Differences between this version and the final published version include a few more small typos, updated reference links and journal formatting

Journal-ref: Phys. Rev. D 100, 082002 (2019)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[76]  arXiv:1907.02330 (replaced) [pdf, other]

Title: Reconstructing large-scale structure with neutral hydrogen surveys

Authors: Chirag Modi, Martin White, Anze Slosar, Emanuele Castorina

Comments: 30 pages, 12 figures. Updated text to make discussion more robust

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[77]  arXiv:1907.07625 (replaced) [pdf, other]

Title: Dynamically generated inflationary two-field potential via non-Riemannian volume forms

Authors: David Benisty, Eduardo I. Guendelman, Emil Nissimov, Svetlana Pacheva

Comments: 13 pages. 2 Fig. arXiv admin note: text overlap with arXiv:1906.06691 , v.2 14 pages, typos corrected, additional explanations

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

[78]  arXiv:1907.10523 (replaced) [pdf, ps, other]

Title: Fast Extragalactic X-ray Transients From Binary Neutron Star Mergers

Authors: Shlomo Dado, Arnon Dar

Comments: 3 figures, added references

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[79]  arXiv:1908.02247 (replaced) [pdf, other]

Title: Constraints on the binary black hole nature of GW151226 and GW170608 from the measurement of spin-induced quadrupole moments

Authors: N. V. Krishnendu, M. Saleem, A. Samajdar, K. G. Arun, W. Del Pozzo, Chandra Kant Mishra

Comments: 12 pages, 5 figures Accepted for publication in PRD. Journal reference:Phys. Rev. D 100, 104019, 2019

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[80]  arXiv:1908.05461 (replaced) [pdf, other]

Title: Discarding the disc in a changing state AGN: the UV/X-ray relation in NGC 4151

Authors: Ra'ad D. Mahmoud, Chris Done

Comments: 16 pages, 13 figures, Accepted in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[81]  arXiv:1908.06838 (replaced) [pdf, ps, other]

Title: Revealing Hidden Substructures in the $M_{BH}$-$σ$ Diagram, and Refining the Bend in the $L$-$σ$ Relation

Authors: Nandini Sahu, Alister W. Graham, Benjamin L. Davis

Comments: 33 pages, 15 figures, 5 tables; Accepted for publication in Astrophysical Journal on 22 October 2019

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[82]  arXiv:1909.02677 (replaced) [pdf, other]

Title: Neutrino vertex reconstruction with in-ice radio detectors using surface reflections and implications for the neutrino energy resolution

Authors: A. Anker, S. W. Barwick, H. Bernhoff, D. Z. Besson, N. Bingefors, D. García-Fernández, G. Gaswint, C. Glaser, A. Hallgren, J. C. Hanson, S. R. Klein, S. A. Kleinfelder, R. Lahmann, U. Latif, J. Nam, A. Novikov, A. Nelles, M. P. Paul, C. Persichilli, I. Plaisier, T. Prakash, S. R. Shively, J. Tatar, E. Unger, S. H. Wang, C. Welling, S. Zierke

Comments: replaced with accepted version (Journal of Cosmology and Astroparticle Physics in press)

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

[83]  arXiv:1909.03183 (replaced) [pdf, other]

Title: Determination of Starspot Covering Fraction as a function of Stellar Age from Observational Data

Authors: Fiona Nichols-Fleming, Eric G. Blackman

Comments: 10 Pages, 7 figures, accepted by MNRAS

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

[84]  arXiv:1909.04664 (replaced) [pdf, other]

Title: EDGE: The origin of scatter in ultra-faint dwarf stellar masses and surface brightnesses

Authors: Martin P. Rey, Andrew Pontzen, Oscar Agertz, Matthew D. A. Orkney, Justin I. Read, Amélie Saintonge, Christian Pedersen

Comments: Minor edits to match the published ApJL version. Results unchanged

Journal-ref: ApJL, 2019, Volume 886, Number 1

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[85]  arXiv:1909.06021 (replaced) [pdf, ps, other]

Title: Status on $\mathbf{{}^{12}{\rm C}+{}^{12}{\rm C}}$ fusion at deep subbarrier energies: impact of resonances on astrophysical $S^{*}$ factors

Authors: C. Beck, A. M. Mukhamedzhanov, X. Tang

Comments: 5 pages, 3 figures

Subjects: Nuclear Experiment (nucl-ex); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)

[86]  arXiv:1909.10322 (replaced) [pdf, ps, other]

Title: Can we distinguish black holes from naked singularities by the images of their accretion disks?

Authors: Rajibul Shaikh, Pankaj S. Joshi

Comments: 21 pages, 3 figures, published in JCAP

Journal-ref: JCAP 10 (2019) 064

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[87]  arXiv:1909.10528 (replaced) [pdf, other]

Title: Higgs field in cosmology

Authors: Christian F. Steinwachs

Comments: 36 pages, 9 figures; references added, typos corrected. Invited contribution to the Heraeus-Seminar "Hundred Years of Gauge Theory", 30 July - 3 August 2018, Physikzentrum Bad Honnef, organized by Silvia De Bianchi and Claus Kiefer. To appear in the proceedings "100 Years of Gauge Theory. Past, present and future perspectives" in the series `Fundamental Theories of Physics' (Springer)

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

[88]  arXiv:1910.03457 (replaced) [pdf, ps, other]

Title: Hills and holes in the microlensing light curve due to plasma environment around gravitational lens

Authors: Oleg Yu. Tsupko, Gennady S. Bisnovatyi-Kogan

Comments: 14 pages, 6 figures; observational prospects are rewritten (Section 8); figure with caustics is added (Fig.4)

Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)

[89]  arXiv:1910.06722 (replaced) [pdf, other]

Title: Lensing corrections on galaxy-lensing cross correlations and galaxy-galaxy auto correlations

Authors: Vanessa Böhm, Chirag Modi, Emanuele Castorina

Comments: 26 pages, 6 figures. Code available at this https URL Minor updates in text

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[90]  arXiv:1910.08337 (replaced) [pdf, other]

Title: An ionised accretion disc wind in Hercules X-1

Authors: P. Kosec, A. C. Fabian, C. Pinto, D. J. Walton, S. Dyda, C. S. Reynolds

Comments: Accepted to MNRAS. 23 pages, 16 figures and 7 tables

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[91]  arXiv:1911.01315 (replaced) [pdf]

Title: Forecasting Megaelectron-Volt Electrons inside Earth's Outer Radiation Belt: PreMevE 2.0 Based on Supervised Machine Learning Algorithms

Authors: Rafael Pires de Lima, Yue Chen, Youzuo Lin

Subjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP)

[92]  arXiv:1911.03192 (replaced) [pdf, other]

Title: NIKA2 mapping and cross-instrument SED extraction of extended sources with Scanamorphos

Authors: H. Roussel, N. Ponthieu, R. Adam, P. Ade, P. André, A. Andrianasolo, H. Aussel, A. Beelen, A. Benoît, A. Bideaud, O. Bourrion, M. Calvo, A. Catalano, B. Comis, M. De Petris, F.-X. Désert, S. Doyle, E. F. C. Driessen, A. Gomez, J. Goupy, F. Kéruzoré, C. Kramer, B. Ladjelate, G. Lagache, S. Leclercq, J.-F. Lestrade, J.F. Macías-Pérez, P. Mauskopf, F. Mayet, A. Monfardini, L. Perotto, G. Pisano, V. Revéret, A. Ritacco, C. Romero, F. Ruppin, K. Schuster, S. Shu, A. Sievers, C. Tucker, R. Zylka

Comments: to appear in the proceedings of the international conference entitled mm Universe @ NIKA2, Grenoble (France), June 2019, EPJ Web of conferences

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

[93]  arXiv:1911.03856 (replaced) [pdf, other]

Title: The hydroxyl satellite-line `flip' as a tracer of expanding HII regions

Authors: Anita Petzler, Joanne R Dawson, Mark Wardle

Comments: 8 pages, 7 figures. Submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[94]  arXiv:1911.04579 (replaced) [pdf, other]

Title: The Normalization and Slope of the Dark Matter (Sub-)Halo Mass Function on Sub-Galactic Scales

Authors: Andrew J. Benson (1) ((1) Carnegie Institution for Science)

Comments: 9 pages, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[95]  arXiv:1911.04814 (replaced) [pdf, other]

Title: New constraints on the HR 8799 planetary system from mid-infrared direct imaging

Authors: D. J. M. Petit dit de la Roche, M. E. van den Ancker, M. Kissler-Patig, V. D. Ivanov, D. Fedele

Comments: Published in MNRAS, 5 pages, 5 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

• New submissions
• Cross-lists
• Replacements