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New submissions for Wed, 11 Mar 20
- [1] arXiv:2003.04316 [pdf, other]
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Title: Charge exchange, from the sky to the laboratory: A method to determine state-selective cross-sections for improved modelingComments: 6 pages, 6 figuresJournal-ref: Astronomische Nachrichten 2020; 1-6Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Atomic Physics (physics.atom-ph)
Charge exchange (CX) is a semi-resonant recombination process that can lead to spectral line emission in the X-ray band. It occurs in nearly any environment where hot plasma and cold gas interact: in the solar system, in comets and planetary atmospheres, and likely astrophysically, in, for example, supernova remnants and galaxy clusters. It also contributes to the soft X-ray background. Accurate spectral modeling of CX is thus critical to properly interpreting our astrophysical observations, but the commonly used CX models in popular spectral fitting packages often rely on scaling equations and may not accurately describe observations or laboratory measurements. This paper introduces a method that can be applied to high-resolution CX spectra to directly extract state-selective CX cross-sections for electron capture, a key parameter for properly simulating the resulting CX spectrum.
- [2] arXiv:2003.04317 [pdf, other]
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Title: The Northern Cross Fast Radio Burst project. I. Overview and pilot observations at 408 MHzAuthors: Nicola T. Locatelli, Gianni Bernardi, Germano Bianchi, Riccardo Chiello, Alessio Magro, Giovanni Naldi, Maura Pilia, Giuseppe Pupillo, Alessandro Ridolfi, Giancarlo Setti, Franco VazzaComments: 8 pages, 9 figures, submitted to MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Fast radio bursts remain one of the most enigmatic astrophysical sources. Observations have significantly progressed over the last few years, thanks to the capabilities of new radio telescopes and the refurbishment of existing ones. Here we describe the upgrade of the Northern Cross radio telescope operating in the 400-416~MHz frequency band, with the ultimate goal of turning the array into a dedicated instrument to survey the sky for fast radio bursts. We present test observations of the pulsar B0329+54 to characterize the system performance and forecast detectability. Observations with the system currently in place are still limited by modest sky coverage ($\sim 9.4$~deg$^2$) and biased by smearing of high dispersion measure events within each frequency channels. In its final, upgraded configuration, however, the telescope will be able to carry out unbiased fast radio burst surveys over a $\sim 350$~deg$^2$ instantaneous field of view up to $z \sim 5$, with a (nearly constant) $\sim 760 \, (\tau/{\rm ms})^{-0.5}$~mJy rms sensitivity.
- [3] arXiv:2003.04318 [pdf, other]
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Title: Measuring the Matter Density of the Galactic Disk Using Stellar StreamsComments: 15 pages, 10 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a novel method for determining the total matter surface density of the Galactic disk by analysing the kinematics of a dynamically cold stellar stream that passes through or close to the Galactic plane. The method relies on the fact that the vertical component of energy for such stream stars is approximately constant, such that their vertical positions and vertical velocities are interrelated via the matter density of the Galactic disk. By testing our method on mock data stellar streams, with realistic phase-space dispersions and Gaia uncertainties, we demonstrate that it is applicable to small streams out to a distance of a few kilo-parsec, and that the surface density of the disk can be determined to a precision of 6 %. This method is complementary to other mass measurements. In particular, it does not rely on any equilibrium assumption for stars in the Galactic disk, and also makes it possible to measure the surface density to good precision at large distances from the Sun. Such measurements would inform us of the matter composition of the Galactic disk and its spatial variation, place stronger constraints on dark disk sub-structure, and even diagnose possible non-equilibrium effects that bias other types of dynamical mass measurements.
- [4] arXiv:2003.04320 [pdf, other]
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Title: The impact of fallback on the compact remnants and chemical yields of core-collapse supernovaeComments: 12 pages, 13 figures, submitted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Fallback in core-collapse supernovae plays a crucial role in determining the properties of the compact remnants and of the ejecta composition. We perform three-dimensional simulations of mixing and fallback for selected non-rotating supernova models to study how explosion energy and asymmetries correlate with the remnant mass, remnant kick, and remnant spin. We find that the strongest kick and spin is imparted by partial fallback in an asymmetric explosion. Black hole (BH) kicks of several hundred $\mathrm{km}\,\mathrm{s}^{-1}$ and spin parameters of $\mathord{\sim}0.25$ can be obtained in this scenario. If the initial explosion energy barely exceeds the envelope binding energy, stronger fallback results, and the remnant kick and spin remain small. If the explosion energy is high with respect to the envelope binding energy, there is little fallback with a small effect on the remnant kick, but the spin-up by fallback can be substantial. For a non-rotating $12\,\mathrm{M}_\odot$ progenitor, we find that the neutron star (NS) is spun up to millisecond periods. The high specific angular momentum of the fallback material can also lead to disk formation around black holes. Fallback may thus be a pathway towards millisecond-magnetar or collapsar-type engines for hypernovae and gamma-ray bursts that does not require rapid progenitor rotation. Within our small set of simulations, none reproduced the peculiar layered fallback necessary to explain the metal-rich iron-poor composition of many carbon-enhanced metal-poor (CEMP) stars. Models with different explosion energy and different realisations of asymmetries may, however, be compatible with CEMP abundance patterns.
- [5] arXiv:2003.04321 [pdf, other]
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Title: Setting the Stage: Structures from Gaussian Random FieldsAuthors: Till Sawala, Adrian Jenkins, Stuart McAlpine, Jens Jasche, Guilhem Lavaux, Peter H. Johansson, Carlos S. FrenkComments: 18 pages, 22 figures, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We study structure formation in a set of cosmological simulations to uncover the scales in the initial density field that gave rise to the formation of present-day structures. Our simulations share a common primordial power spectrum (here Lambda-CDM), but the introduction of hierarchical variations of the phase information allows us to systematically study the scales that determine the formation of structure at later times. We consider the variance in z=0 statistics such as the matter power spectrum and halo mass function. We also define a criterion for the existence of individual haloes across simulations, and determine what scales in the initial density field contain sufficient information for the non-linear formation of unique haloes. We study how the characteristics of individual haloes such as the mass and concentration, as well as the position and velocity, are affected by variations on different scales, and give scaling relations for haloes of different mass. Finally, we use the example of a cluster-mass halo to show how our hierarchical parametrisation of the initial density field can be used to create variants of particular objects. With properties such as mass, concentration, kinematics and substructure of haloes set on distinct and well-determined scales, and its unique ability to introduce variations localised in real space, our method is a powerful tool to study structure formation in cosmological simulations.
- [6] arXiv:2003.04322 [pdf, other]
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Title: Testing The Lamp-Post and Wind Reverberation Models with XMM-Newton Observations of NGC 5506Comments: Accepted for publication in ApJ. Analysis codes and data are available on this https URLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The lamp-post geometry is often used to model X-ray data of accreting black holes. Despite its simple assumptions, it has proven to be powerful in inferring fundamental black hole properties such as the spin. Early results of X-ray reverberations showed support for such a simple picture, though wind-reverberation models have also been shown to explain the observed delays. Here, we analyze new and old XMM-Newton observations of the variable Seyfert-1 galaxy NGC 5506 to test these models. The source shows an emission line feature around 6.7 keV that is delayed relative to harder and softer energy bands. The spectral feature can be modeled with either a weakly relativistic disk line or by scattering in distant material. By modeling both the spectral and timing signatures, we find that the reflection fraction needed to explain the lags is larger than observed in the time-averaged spectrum, ruling out both a static lamp-post and simple wind reverberation models.
- [7] arXiv:2003.04326 [pdf, other]
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Title: Simulating JWST/NIRCam Color Selection of High-Redshift GalaxiesAuthors: Kevin N. Hainline, Raphael E. Hviding, Marcia Rieke, Irene Shivaei, Ryan Endsley, Emma Curtis-Lake, Renske Smit, Christina C. Williams, Stacey Alberts, Kristan N K Boyett, Andrew J. Bunker, Eiichi Egami, Michael V. Maseda, Sandro Tacchella, Christopher N.A. WillmerComments: 24 pages, 20 figures, accepted for publication in the Astrophysical JournalSubjects: Astrophysics of Galaxies (astro-ph.GA)
The NIRCam instrument on the upcoming James Webb Space Telescope (JWST) will offer an unprecedented view of the most distant galaxies. In preparation for future deep NIRCam extragalactic surveys, it is crucial to understand the color selection of high-redshift galaxies using the Lyman dropout technique. To that end, we have used the JAdes extraGalactic Ultradeep Artificial Realizations (JAGUAR) mock catalog to simulate a series of extragalactic surveys with realistic noise estimates. This enables us to explore different color selections and their impact on the number density of recovered high-redshift galaxies and lower-redshift interlopers. We explore how survey depth, detection signal-to-noise ratio, color selection method, detection filter choice, and the presence of the Ly$\alpha$ emission line affects the resulting dropout selected samples. We find that redder selection colors reduce the number of recovered high-redshift galaxies, but the overall accuracy of the final sample is higher. In addition, we find that methods that utilize two or three color cuts have higher accuracy because of their ability to select against low-redshift quiescent and faint dusty interloper galaxies. We also explore the near-IR colors of brown dwarfs and demonstrate that, while they are predicted to have low on-sky densities, they are most likely to be recovered in F090W dropout selection, but there are color cuts which help to mitigate this contamination. Overall, our results provide NIRCam selection methods to aid in the creation of large, pure samples of ultra high-redshift galaxies from photometry alone.
- [8] arXiv:2003.04329 [pdf, other]
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Title: A comparison of $\text{H}_2$ formation models at high redshiftAuthors: Alexander Schäbe, Emilio Romano-Díaz, Cristiano Porciani, Aaron D. Ludlow, Matteo TomassettiComments: 18 pages, 11 figures, 1 table, submitted to MNRAS, comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA)
Modelling the molecular gas that is routinely detected through CO observations of high-redshift galaxies constitutes a major challenge for ab initio simulations of galaxy formation. We carry out a suite of cosmological hydrodynamic simulations in order to compare three approximate methods that have been used in the literature to track the formation and evolution of the simplest and most abundant molecule, H$_2$. Namely, we consider: i) a semi-empirical procedure that associates H$_2$ to dark-matter haloes based on a series of scaling relations inferred from observations; ii) a model that assumes chemical equilibrium between the H$_2$ formation and destruction rates; and iii) a model that fully solves the out-of-equilibrium rate equations and accounts for the unresolved structure of molecular clouds. We study the impact of finite spatial resolution and show that robust H$_2$ masses at redshift $z\approx 4$ can only be obtained for galaxies that are sufficiently metal enriched in which H$_2$ formation is fast. This corresponds to H$_2$ reservoirs with masses $M_{\mathrm{H_2}}\gtrsim 6\times 10^9 \mathrm{M}_\odot$. In this range, equilibrium and non-equilibrium models predict similar molecular masses (but different galaxy morphologies) while the semi-empirical method produces less H$_2$. The star-formation rates as well as the stellar and H$_2$ masses of the simulated galaxies are in line with those observed in actual galaxies at similar redshifts that are not massive starbursts. The H$_2$ mass functions extracted from the simulations at $z\approx 4$ agree well with recent observations that only sample the high-mass end. However, our results indicate that most molecular material at high-$z$ lies yet undetected in reservoirs with $10^9<M_{\mathrm H_2}<10^{10} \mathrm{M}_\odot$.
- [9] arXiv:2003.04330 [pdf, other]
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Title: Magnetic reconnection and hot-spot formation in black-hole accretion disksComments: submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Plasma Physics (physics.plasm-ph)
Hot spots, or plasmoids, forming due to magnetic reconnection in thin current sheets, are conjectured to power frequent bright X-ray and near-infrared flares from Sgr A*, the supermassive black hole in the center of our Galaxy. It is of yet unclear how, where, and when such thin current sheets form in black-hole accretion disks or astrophysical jets. In this work we perform axisymmetric general-relativistic resistive magnetohydrodynamics simulations to model magnetic reconnection and associated plasmoid formation in a wide range of accretion flows. We show that current sheets and plasmoids are ubiquitous features which form regardless of the initial size of the disk and the magnetization in the quasi-steady-state phase of accretion. In all cases we observe plasmoids forming in current sheets close to the event horizon within 5 to 10 Schwarzschild radii. These plasmoids can then merge, grow to macroscopic scales of the order of a Schwarzschild radius, and are ultimately advected along the jet's sheath or into the disk. The largest plasmoids are efficiently energized to relativistic temperatures via magnetic reconnection and contribute to the heating of the jet's sheath. In all cases we find reconnection rates between 0.01c and 0.03c, consistent with studies of reconnection in isolated Harris-type current sheets. We quantify magnetic dissipation and strong non-ideal electric fields which can efficiently inject non-thermal particles. We also show that an explicit resistivity allows for converged numerical solutions, such that the electromagnetic energy density evolution and dissipation become independent of the grid scale for the extreme resolutions considered here.
- [10] arXiv:2003.04331 [pdf, other]
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Title: PORTAL--three-dimensional polarized (sub)millimeter line radiative transferComments: 13 pages, 8 figures, Accepted for publication in A&ASubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Context. Magnetic fields are important to the dynamics of many astrophysical processes and can typically be studied through polarization observations. Polarimetric interferometry capabilities of modern (sub)millimeter telescope facilities have made it possible to obtain detailed velocity resolved maps of molecular line polarization. To properly analyze these for the information they carry regarding the magnetic field, the development of adaptive three-dimensional polarized line radiative transfer models is necessary. Aims. We aim to develop an easy-to-use program to simulate the polarization maps of molecular and atomic (sub)millimeter lines in magnetized astrophysical regions, such as protostellar disks, circumstellar envelopes, or molecular clouds. Methods. By considering the local anisotropy of the radiation field as the only alignment mechanism, we can model the alignment of molecular or atomic species inside a regular line radiative transfer simulation by only making use of the converged output of this simulation. Calculations of the aligned molecular or atomic states can subsequently be used to ray trace the polarized maps of the three-dimensional simulation. Results. We present a three-dimensional radiative transfer code, POlarized Radiative Transfer Adapted to Lines (PORTAL), that can simulate the emergence of polarization in line emission through a magnetic field of arbitrary morphology. Our model can be used in stand-alone mode, assuming LTE excitation, but it is best used when processing the output of regular three-dimensional (nonpolarized) line radiative transfer modeling codes. We present the spectral polarization map of test cases of a collapsing sphere and protoplanetary disk for multiple three-dimensional magnetic field morphologies.
- [11] arXiv:2003.04334 [pdf, other]
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Title: An ALMA view of SO and SO$_2$ around oxygen-rich AGB starsComments: Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present and analyse SO and SO$_2$, recently observed with high angular resolution and sensitivity in a spectral line survey with ALMA, for two oxygen-rich AGB stars: the low mass-loss rate R Dor and high mass-loss rate IK Tau. We analyse 8 lines of SO detected towards both stars, 78 lines of SO$_2$detected towards R Dor and 52 lines of SO$_2$ detected towards IK Tau. We detect several lines of $^{34}$SO, $^{33}$SO and $^{34}$SO$_2$ towards both stars, and tentatively S$^{18}$O towards R Dor, and hence derive isotopic ratios for these species. The spatially resolved observations show us that the two sulphur oxides are co-located towards R Dor and trace out the same wind structures in the circumstellar envelope (CSE). Much of the emission is well reproduced with a Gaussian abundance distribution spatially centred on the star. Emission from the higher energy levels of SO and SO$_2$ towards R Dor provide evidence in support of a rotating inner region of gas identified in earlier work. The new observations allow us to refine the abundance distribution of SO in IK Tau derived from prior observations with single antennas, and confirm the distribution is shell-like with the peak in the fractional abundance not centred on the star. The confirmation of different types of SO abundance distributions will help fine-tune chemical models and allows for an additional method to discriminate between low and high mass-loss rates for oxygen-rich AGB stars.
- [12] arXiv:2003.04336 [pdf, other]
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Title: Comparing focal plane wavefront control techniques:\\Numerical simulations and laboratory experimentsComments: 12 pages, 11 figures. Accepted for publication in section 13. Astronomical instrumentation of A&ASubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Fewer than 1% of all exoplanets detected to date have been characterized on the basis of spectroscopic observations of their atmosphere. Unlike indirect methods, high-contrast imaging offers access to atmospheric signatures by separating the light of a faint off-axis source from that of its parent star. Forthcoming space facilities, such as WFIRST/LUVOIR/HabEX, are expected to use coronagraphic instruments capable of imaging and spectroscopy in order to understand the physical properties of remote worlds. The primary technological challenge that drives the design of these instruments involves the precision control of wavefront phase and amplitude errors. Several FPWS and control techniques have been proposed and demonstrated in laboratory to achieve the required accuracy. However, these techniques have never been tested and compared under the same laboratory conditions. This paper compares two of these techniques in a closed loop in visible light: the pair-wise (PW) associated with electric field conjugation (EFC) and self-coherent camera (SCC). We first ran numerical simulations to optimize PW wavefront sensing and to predict the performance of a coronagraphic instrument with PW associated to EFC wavefront control, assuming modeling errors for both PW and EFC. Then we implemented the techniques on a laboratory testbed. We introduced known aberrations into the system and compared the wavefront sensing using both PW and SCC. The speckle intensity in the coronagraphic image was then minimized using PW+EFC and SCC independently. We demonstrate that both SCC and PW+EFC can generate a dark hole in space-like conditions in a few iterations. Both techniques reach the current limitation of our laboratory bench and provide coronagraphic contrast levels of 5e-9 in a narrow spectral band (<0.25% bandwidth)
- [13] arXiv:2003.04342 [pdf, other]
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Title: The Typical Massive Quiescent Galaxy at z$\sim$3 is a Post-starburstAuthors: C. D'Eugenio, E. Daddi, R. Gobat, V. Strazzullo, P. Lustig, I. Delvecchio, S. Jin, A. Puglisi, A. Calabró, C. Mancini, M. Dickinson, A. Cimatti, M. OnoderaComments: 8 pages, 4 figures. To appear on ApJ LettersSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We have obtained spectroscopic confirmation with Hubble Space Telescope WFC3/G141 of a first sizeable sample of nine quiescent galaxies at 2.4<z<3.3. Their average near-UV/optical rest-frame spectrum is characterized by low attenuation (Av$\sim$0.6 mag) and a strong Balmer break, larger than the 4000 A break, corresponding to a fairly young age of $\sim$300 Myr. This formally classifies a substantial fraction of classically selected quiescent galaxies at z $\sim$ 3 as post-starbursts, marking their convergence to the quenching epoch. The rapid spectral evolution with respect to z $\sim$ 1.5 quiescent galaxies is not matched by an increase of residual star-formation, as judged from the weak detection of [O II]3727A emission, pointing to a flattening of the steep increase in gas fractions previously seen from z $\sim$ 0 to 1.8. However, radio 3GHz stacked emission implies either much stronger dust-obscured star formation or substantial further evolution in radio-mode AGN activity with respect to z $\sim$ 1.5.
- [14] arXiv:2003.04343 [pdf, other]
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Title: Numerical simulations of large-amplitude oscillations in flux-rope solar prominencesComments: 15 pages, 10 figures, accepted for publication in Astronomy and AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Context. Large-amplitude oscillations (LAOs) of the solar prominences are very spectacular but poorly understood phenomena. These motions have amplitudes larger than $10 {\mathrm{\, km \,s^{-1}}}$ and can be triggered by the external perturbations, e.g., Moreton or EIT waves.
Aims. Our aim is to analyze the properties of large-amplitude oscillations using realistic prominence models and the triggering mechanism by external disturbances.
Methods. We perform time-dependent numerical simulations of LAOs using a magnetic flux rope model with two values of the shear angle and the density contrast. We study the internal modes of the prominence using the horizontal and vertical triggering. In addition, we use the perturbation that arrives from outside in order to understand how such external disturbance can produce LAOs.
Results. The period of longitudinal oscillations and its behavior with height show good agreement with the pendulum model. The period of transverse oscillations remains constant with height, suggesting a global normal mode. The transverse oscillations typically have shorter periods than the longitudinal oscillations.
Conclusions. The periods of the longitudinal and transverse oscillations show only weak dependence on the shear angle of the magnetic structure and the prominence density contrast. The external disturbance perturbs the flux rope exciting oscillations of both polarizations. Their properties are a mixture of those excited by purely horizontal and vertical driving. - [15] arXiv:2003.04346 [pdf, other]
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Title: The $\it{XXL}$ survey: XL. Obscuration properties of red AGN in $\it{XXL-N}$Authors: V. A. Masoura, I. Georgantopoulos, G. Mountrichas, C. Vignali, E. Koulouridis, L. Chiappetti, S. Fotopoulou, S. Paltani, M. PierreComments: A&A accepted, 37 pages, 51 figures, 7 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
The combination of optical and mid-infrared (mid-IR) photometry has been extensively used to select red Active Galactic Nuclei (AGN). Our aim is to explore the obscuration properties of these red AGN with both X-ray spectroscopy as well as Spectral Energy Distributions (SEDs). In this study, we re-visit the relation between optical/mid-IR extinction and X-ray absorption. We use IR selection criteria, specifically the $W1$ and $W2$ WISE bands (Assef et al.), to identify 4798 AGN in the $\it{XMM-XXL}$ area ($\sim 25$\,deg$^2$). Application of optical/mid-IR colours ($r- W2 > 6$) reveals 561 red AGN (14$\%$). 47/561 have available X-ray spectra with at least 50 net (background-subtracted) counts per detector. For these sources, we construct SEDs from the optical to the mid-IR using the CIGALE code. The SED fitting shows that 44/47 sources present clear signs of obscuration, based on the AGN emission and the estimated inclination angle. SED fitting also reveals ten systems ($\sim20\%$) which are dominated by the galaxy. In these cases, the red colours are attributed to the host galaxy rather than AGN absorption. Excluding these ten systems from our sample and applying X-ray spectral fitting analysis, shows that up to $76\%$ (28/37) of the IR red AGN present signs of X-ray absorption. Thus, there are nine sources ($\sim20\%$ of the sample) that although optically red, are not substantially X-ray absorbed. $\sim 50\%$ of these sources present broad emission lines in their optical spectra. We suggest that the reason for this apparent discrepancy is that the r-W2 criterion is sensitive to smaller amounts of obscuration relative to the X-ray spectroscopy. In conclusion, it appears that the majority of red AGN present considerable obscuration levels as shown by their SEDs. Their X-ray absorption is moderate with a mean of $\rm N_H \sim 10^{22}\, \rm{cm^{-2}}$.
- [16] arXiv:2003.04348 [pdf, other]
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Title: Architectures of Exoplanetary Systems. II: An Intrinsic Relation between Planetary System Occurrence and Spectral Type for Kepler's FGK DwarfsComments: Submitted to MNRAS; 17 pages, 6 figures, plus supplemental online materials with 3 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
The Kepler mission observed thousands of transiting exoplanet candidates around hundreds of thousands of FGK dwarf stars. He, Ford, & Ragozzine (2019) (arXiv:1907.07773) applied forward modelling to infer the distribution of intrinsic architectures of planetary systems, developed a clustered Poisson point process model for exoplanetary systems (SysSim) to reproduce the marginal distributions of the observed Kepler population, and showed that orbital periods and planet radii are clustered within a given planetary system. Here, we extend the clustered model to explore correlations between planetary systems and their host star properties. We split the sample of Kepler FGK dwarfs into two halves and model the fraction of stars with planets (between $0.5-10 R_\oplus$ and 3--300 d), $f_{\rm swpa}$, as a linear function of the Gaia DR2 $b_p - r_p$ color. We find that the occurrence of these planets rises significantly towards later type (redder or higher $b_p - r_p$) stars, with a slope of $df_{\rm swpa}/d(b_p - r_p) = 0.53_{-0.19}^{+0.19}$. The fraction of stars with planets increases from $f_{\rm swpa} = 0.34_{-0.11}^{+0.08}$ for F2V dwarfs to $f_{\rm swpa} = 0.91_{-0.18}^{+0.09}$ for mid K-dwarfs. About half ($f_{\rm swpa} = 0.54_{-0.13}^{+0.08}$) of all solar-type (G2V) dwarfs harbour a planetary system between 3 and 300 d. While this linear $f_{\rm swpa}(b_p - r_p)$ model is simple, it can closely match the observed multiplicity distributions of both bluer and redder halves in our sample, suggesting that the architectures of planetary systems around stars of different spectral types may be similar aside from a shift in the overall fraction of planet hosting stars.
- [17] arXiv:2003.04370 [pdf, other]
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Title: A spectroscopic analysis of the eclipsing nova-like EC21178-5417 -- discovery of spiral density structuresComments: 13 pages, 9 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present phase-resolved optical spectroscopy of the eclipsing nova-like cataclysmic variable EC21178-5417 obtained between 2002 and 2013. The average spectrum of EC21178-5417 shows broad double-peaked emission lines from HeII 4686 \AA{} (strongest feature) and the Balmer series. The high-excitation feature, CIII/NIII at 4640-4650 \AA{}, is also present and appears broad in emission. A number of other lines, mostly HeI, are clearly present in absorption and/or emission. The average spectrum of EC21178-5417 taken at different months and years shows variability in spectral features, especially in the Balmer lines beyond H$\gamma$, from pure line emission, mixed line absorption and emission to pure absorption lines. Doppler maps of the HeII 4686 \AA{} emission reveal the presence of a highly-inclined asymmetric accretion disc and a two spiral arm-like structure, whereas that of the Balmer lines (H$\alpha$ and H$\beta$) reveal a more circular accretion disc. There is no evidence of a bright spot in the Doppler maps of EC21178-5417 and no emission from the secondary star is seen in the tomograms of the HeII 4686 \AA{} and Balmer lines. Generally, the emission in EC21178-5417 is dominated by emission from the accretion disc. We conclude that EC21178-5417 is a member of the RW Tri or UX UMa sub-type of nova-like variables based on these results and because it shows different spectral characteristics at different dates. This spectral behaviour suggests that EC21178-5417 undergoes distinct variations in mass transfer rate on the observed time scales of months and years.
- [18] arXiv:2003.04379 [pdf, ps, other]
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Title: On the early evolution of massive star clusters: the case of cloud D1 and its embedded cluster in NGC 5253Comments: 12 pages, 10 figures, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We discuss a theoretical model for the early evolution of massive star clusters and confront it with the ALMA, radio and infrared observations of the young stellar cluster highly obscured by the molecular cloud D1 in the nearby dwarf spheroidal galaxy NGC 5253. We show that a large turbulent pressure in the central zones of D1 cluster may cause individual wind-blown bubbles to reach pressure confinement before encountering their neighbors. In this case stellar winds are added to the hot shocked wind pockets of gas around individual massive stars that leads them to meet and produce a cluster wind in time-scales less than $10^5$ yrs. In order to inhibit the possibility of cloud dispersal, or the early negative star formation feedback, one should account for mass loading that may come, for example, from pre-main sequence (PMS) low-mass stars through photo-evaporation of their proto-stellar disks. Mass loading at a rate in excess of 8$\times 10^{-9}$ M$_{\odot}$ yr$^{-1}$ per each PMS star is required to extend the hidden star cluster phase in this particular cluster. In this regime, the parental cloud remains relatively unperturbed, while pockets of molecular, photoionized and hot gas coexist within the star forming region. Nevertheless, the most likely scenario for cloud D1 and its embedded cluster is that the hot shocked winds around individual massive stars should merge at an age of a few millions of years when the PMS star proto-stellar disks vanish and mass loading ceases that allows a cluster to form a global wind.
- [19] arXiv:2003.04393 [pdf, other]
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Title: Revealing the Dark Threads of the Cosmic WebAuthors: Joseph N. Burchett, Oskar Elek, Nicolas Tejos, J. Xavier Prochaska, Todd M. Tripp, Rongmon Bordoloi, Angus G. ForbesComments: Published in ApJL, 891, L35Subjects: Astrophysics of Galaxies (astro-ph.GA); Biological Physics (physics.bio-ph)
Modern cosmology predicts that matter in our Universe has assembled today into a vast network of filamentary structures colloquially termed the Cosmic Web. Because this matter is either electromagnetically invisible (i.e., dark) or too diffuse to image in emission, tests of this cosmic web paradigm are limited. Wide-field surveys do reveal web-like structures in the galaxy distribution, but these luminous galaxies represent less than 10% of baryonic matter. Statistics of absorption by the intergalactic medium (IGM) via spectroscopy of distant quasars support the model yet have not conclusively tied the diffuse IGM to the web. Here, we report on a new method inspired by the Physarum polycephalum slime mold that is able to infer the density field of the Cosmic Web from galaxy surveys. Applying our technique to galaxy and absorption-line surveys of the local Universe, we demonstrate that the bulk of the IGM indeed resides in the Cosmic Web. From the outskirts of Cosmic Web filaments, at approximately the cosmic mean matter density (rho_m) and approx. 5 virial radii from nearby galaxies, we detect an increasing H I absorption signature towards higher densities and the circumgalactic medium, to approx. 200 rho_m. However, the absorption is suppressed within the densest environments, suggesting shock-heating and ionization deep within filaments and/or feedback processes within galaxies.
- [20] arXiv:2003.04397 [pdf, other]
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Title: Searching the Entirety of Kepler Data. I. 17 New Planet Candidates Including 1 Habitable Zone WorldComments: 25 pages, 9 figures, published in The Astronomical JournalJournal-ref: AJ, Volume 159, Number 3, ID 124, 2020Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present the results of an independent search of all ~200,000 stars observed over the four year Kepler mission (Q1-Q17) for multiplanet systems, using a three-transit minimum detection criteria to search orbital periods up to hundreds of days. We incorporate both automated and manual triage, and provide estimates of the completeness and reliability of our vetting pipeline. Our search returned 17 planet candidates (PCs) in addition to thousands of known Kepler Objects of Interest (KOIs), with a 98.8% recovery rate of already confirmed planets. We highlight the discovery of one candidate, KIC-7340288 b, that is both rocky (radius < 1.6 $R_{\bigoplus}$) and in the Habitable Zone (insolation between 0.25 and 2.2 times the Earth's insolation). Another candidate is an addition to the already known KOI-4509 system. We also present adaptive optics imaging follow-up for six of our new PCs, two of which reveal a line-of-sight stellar companion within 4''.
- [21] arXiv:2003.04413 [pdf, other]
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Title: When do cosmic peaks, filaments or walls merge? A theory of critical events in a multi-scale landscapeAuthors: Corentin Cadiou, Christophe Pichon, Sandrine Codis, Marcello Musso, Dmitri Pogosyan, Yohan Dubois, Jean-François Cardoso, Simon PrunetComments: 20 pages, 18 figures. Submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
The merging rate of critical points, used as a proxy for cosmic evolution, is computed as a function of smoothing scale from the initial cosmic landscape to forecast special events driving the assembly of dark matter haloes. Beyond the mergers of peaks with saddle points (a proxy for halo mergers), we consider the coalescence and nucleation of all sets of critical points, including wall-saddle to filament-saddle and wall-saddle to minima (a proxy for filaments mergers and void mergers respectively), as they impact the geometry of galactic infall, and in particular filament disconnection. Analytical predictions are validated against multiscale measurements in maps and cubes (the corresponding code being available upon request). Applications to cosmology, astrophysics and other fields of research are discussed. The rate of filament coalescence is compared to the merger rate of haloes and the two-point clustering of these events is computed, along with their cross-correlations with critical points. These correlations are qualitatively consistent with the preservation of the connectivity of dark matter haloes, and the impact of the large scale structures on assembly bias. The cosmic evolution of the destruction rate of haloes and voids as a function of mass and redshift is quantified for a $\Lambda$CDM cosmology. The one-point statistics in higher dimensions is also presented, together with consistency relations between critical point and critical event counts.
- [22] arXiv:2003.04442 [pdf, other]
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Title: A tale of two sites -- I: Inferring the properties of minihalo-hosted galaxies from current observationsAuthors: Yuxiang Qin (1), Andrei Mesinger (1), Jaehong Park (1), Bradley Greig (2,3), Julian B.~Muñoz (4) ((1) Scuola Normale Superiore, Pisa (2) School of Physics, The University of Melbourne (3) ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) (4) Department of Physics, Harvard University)Comments: 19 pages, 8 figures, 1 table; submitted to MNRAS; comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
The very first galaxies that started the cosmic dawn likely resided in so-called ''minihalos'', with masses of $\sim10^5$--$10^8\mathrm{M}_\odot$, accreting their gas from the intergalactic medium through H$_2$ cooling. Such molecularly-cooled galaxies (MCGs), mostly formed in pristine environments, hosted massive, metal-free stars, and were eventually sterilized by the build-up of a disassociating (Lyman-Werner; LW) background. Therefore, their properties might be very different from the galaxies we see in the later Universe. Although MCGs are probably too faint to be observed directly, we could nevertheless infer their properties from the imprint they leave in the cosmic 21-cm signal. Here we quantify this imprint by extending the public simulation code 21cmFAST to allow for a distinct population of MCGs. We allow MCGs to have different properties from other galaxies, including unique scaling relations for their stellar to halo mass ratios, ionizing escape fractions, and spectral energy distributions. We track inhomogeneous recombinations, disassociative LW feedback, and photo-heating from reionization. After demonstrating how MCGs can shape the 21-cm signal, we explore to what extent current observations can already place constraints on their properties. The CMB optical depth from Planck sets an upper limit on the product of the ionizing escape fraction and the stellar mass in MCGs. When including also the timing of the putative EDGES absorption signal, we find an additional strong degeneracy between the stellar mass and the X-ray luminosity of MCGs. If proven to be of cosmic origin, the timing of the EDGES signal would have been set by MCGs.
- [23] arXiv:2003.04488 [pdf, other]
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Title: RAiSE X: searching for radio galaxies in X-ray surveysComments: 16 pages, 10 figures, 1 table; accepted in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We model the X-ray surface brightness distribution of emission associated with Fanaroff & Riley type-II radio galaxies. Our approach builds on the RAiSE dynamical model which describes broadband radio-frequency synchrotron evolution of jet-inflated lobes in a wide range of environments. The X-ray version of the model presented here includes: (1) inverse-Compton upscattering of cosmic microwave background radiation; (2) the dynamics of the shocked gas shell and associated bremsstrahlung radiation; and (3) emission from the surrounding ambient medium. We construct X-ray surface brightness maps for a mock catalogue of extended FR-IIs based on the technical characteristics of the eRosita telescope. The integrated X-ray luminosity function at low redshifts ($z\leqslant1$) is found to strongly correlate with the density of the ambient medium in all but the most energetic sources, whilst at high-redshift ($z>1$) the majority of objects are dominated by inverse-Compton lobe emission due to the stronger cosmic microwave background radiation. By inspecting our mock spatial brightness distributions, we conclude that any extended X-ray detection can be attributed to AGN activity at redshifts $z\geqslant1$. We compare the expected detection rates of active and remnant high-redshift radio AGNs for eRosita and LOFAR, and future more sensitive surveys. We find that a factor of ten more remnants can be detected using X-ray wavelengths over radio frequencies at $z>2.2$, increasing to a factor of 100 for redshifts $z>3.1$.
- [24] arXiv:2003.04502 [pdf, ps, other]
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Title: Transition from ordered pinched to warped magnetic field on a 100 au scale in the Class 0 protostar B335Authors: Hsi-Wei Yen, Bo Zhao, Patrick Koch, Ruben Krasnopolsky, Zhi-Yun Li, Nagayoshi Ohashi, Hsien Shang, Shigehisa Takakuwa, Ya-Wen TangComments: 11 pages, 6 figures, Accepted by ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present our observational results of the 0.87 mm polarized dust emission in the Class 0 protostar B335 obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) at a 0.2" (20 au) resolution. We compared our data at 0.87 mm with those at 1.3 mm from the ALMA archive. The observed polarization orientations at the two wavelengths are consistent within the uncertainty, and the polarization percentages are systematically higher at 1.3 mm than 0.87 mm by a factor of ~1.7, suggesting that the polarized emission originates from magnetically aligned dust grains. We inferred the magnetic field orientations from the observed polarization orientations. We found that the magnetic field changes from ordered and highly pinched to more complicated and asymmetric structures within the inner 100 au scale of B335, and the magnetic field connects to the center along the equatorial plane as well as along the directions which are ~40-60 degrees from the equatorial plane. We performed non-ideal MHD simulations of collapsing dense cores. We found that similar magnetic field structures appear in our simulations of dense cores with the magnetic field and rotational axis slightly misaligned by 15 degrees but not in those with the aligned magnetic field and rotational axis. Our results suggest that the midplane of the inner envelope within the inner 100 au scale of B335 could be warped because of the misaligned magnetic field and rotational axis, and the magnetic field could be dragged by the warped accretion flows.
- [25] arXiv:2003.04504 [pdf, other]
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Title: Probability of simultaneous parallax detection for free-floating planet microlensing events near Galactic CentreAuthors: M. BanComments: 20 pages, 14 figures, 6 tables. Submitted to MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
The event rate and the efficiency of mass estimation for free-floating planet (FFP) microlensing events were determined from the simulation of the simultaneous parallax observations by Euclid, WFIRST, and LSST. The stellar population from the Besan\c{c}on Galactic model toward $(l, b)=(1^{\circ},-1.^{\circ}75)$ was applied to our 3D microlensing model, and 30,000 parallax observations were simulated for each following FFP lens masses: Jupiter-mass, Neptune-mass, and Earth-mass assuming the population of one FFP per star. The interstellar dust, unresolved stellar background, nearby star blending were modelled. A signal-to-noise limit considering a finite source effect determined the event detectability. The Euclid-WFIRST combination yielded 30.7 Jupiter-mass FFPs during two 30-day-periods per year in parallax observation. The parallax event rate decreases to 3.9 FFPs for Earth-mass planets. The mass estimation from the parallax light curve allowed recovery of FFP masses to within a factor of two for 20-26% of cases. The Euclid-LSST combination yielded 34.5 Jupiter-mass FFPs down to 0.5 Earth-mass FFPs for the same periods and the mass is recovered to within a factor of two in 20-40% of cases. The event rate will be normalised by the unknown FFP abundance to recover the number of expected detections.
- [26] arXiv:2003.04525 [pdf, other]
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Title: LHS 1815b: The First Thick-Disk Planet Detected By TESSAuthors: Tianjun Gan, Avi Shporer, John H. Livingston, Karen A. Collins, Shude Mao, Alessandro A. Trani, Davide Gandolfi, Teruyuki Hirano, Rafael Luque, Keivan G. Stassun, Carl Ziegler, Steve B. Howell, Coel Hellier, Jonathan M. Irwin, Jennifer G. Winters, David R. Anderson, César Briceño, Nicholas Law, Andrew W. Mann, Xavier Bonfils, Nicola Astudillo-Defru, Eric L. N. Jensen, Guillem Anglada-Escudé, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Gabor Furesz, Natalia M. Guerrero, Elisa Quintana, Joseph D. Twicken, Douglas A. Caldwell, Peter Tenenbaum, Chelsea X. Huang, Pamela Rowden, Bárbara Rojas-AyalaComments: accepted for publication in AJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We report the first discovery of a thick-disk planet, LHS 1815b (TOI-704b, TIC 260004324), detected in the TESS survey. LHS 1815b transits a bright (V = 12.19 mag, K = 7.99 mag) and quiet M dwarf located $ 29.87\pm0.02 pc$ away with a mass of $0.502\pm0.015 M_{\odot}$ and a radius of $0.501\pm0.030 R_{\odot}$. We validate the planet by combining space and ground-based photometry, spectroscopy, and imaging. The planet has a radius of $1.088\pm 0.064 R_{\oplus}$ with a $3 \sigma$ mass upper-limit of $8.7 M_{\oplus}$. We analyze the galactic kinematics and orbit of the host star LHS1815 and find that it has a large probability ($P_{thick}/P_{thin} = 6482$) to be in the thick disk with a much higher expected maximal height ($Z_{max} = 1.8 kpc$) above the Galactic plane compared with other TESS planet host stars. Future studies of the interior structure and atmospheric properties of planets in such systems using for example the upcoming James Webb Space Telescope (JWST), can investigate the differences in formation efficiency and evolution for planetary systems between different Galactic components (thick and thin disks, and halo).
- [27] arXiv:2003.04532 [pdf, other]
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Title: Phase-Space Bounds on the Mass of Dark Matter in Fermi Degenerate Non-Isothermal GalaxiesAuthors: Ahmad BorzouComments: 37 pages, 7 figures, comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Theory (hep-th)
The phase-space bounds on the mass of dark matter are mostly derived for isothermal galactic halos. In this paper, we study slight deviations from the isothermal condition. We show that if fermionic dark matter in galaxies has a Maxwellian distribution, small variations in the temperature of dark matter are negligible. However, in highly Fermi degenerate halos, diversions from constant temperature are multiplied by the infinite Fermi-Dirac integrals and can be significant. We develop computer software to study non-isothermal effects in the full range of classical to highly degenerate dark matter halos. Using the data of the Fornax dwarf galaxy, we show that with a temperature gradient of not more than 0.002 Kelvin per kiloparsec, it is possible to compress fermionic dark matter with the mass of 2 eV into a radius less than 1 kiloparsec and build a halo with the total mass of $\sim 10^8$ of the mass of the sun.
- [28] arXiv:2003.04545 [pdf, other]
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Title: Annual Modulation in Direct Dark Matter SearchesComments: 48 pages, 3 figures, submitted to Journal of Physics G: Nuclear and Particle Physics as a review article. Comments welcomedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
The measurement of an annual modulation in the event rate of direct dark matter detection experiments is a powerful tool for dark matter discovery. Indeed, several experiments have already claimed such a discovery in the past decade. While most of them have later revoked their conclusions, and others have found potentially contradictory results, one still stands today. This paper explains the potential as well as the challenges of annual modulation measurements, and gives an overview of past, present and future direct detection experiments.
- [29] arXiv:2003.04563 [pdf, ps, other]
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Title: Global Evolution of Solar Magnetic Fields and Prediction of Activity CyclesAuthors: Irina N. KitiashviliComments: 10 pages, 6 figures, submitted to Proceedings of IAUS #354Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Chaotic Dynamics (nlin.CD); Data Analysis, Statistics and Probability (physics.data-an); Space Physics (physics.space-ph)
Prediction of solar activity cycles is challenging because physical processes inside the Sun involve a broad range of multiscale dynamics that no model can reproduce and because the available observations are highly limited and cover mostly surface layers. Helioseismology makes it possible to probe solar dynamics in the convective zone, but variations in differential rotation and meridional circulation are currently available for only two solar activity cycles. It has been demonstrated that sunspot observations, which cover over 400 years, can be used to calibrate the Parker-Kleeorin-Ruzmaikin dynamo model, and that the Ensemble Kalman Filter (EnKF) method can be used to link the modeled magnetic fields to sunspot observations and make reliable predictions of a following activity cycle. However, for more accurate predictions, it is necessary to use actual observations of the solar magnetic fields, which are available only for the last four solar cycles. In this paper I briefly discuss the influence of the limited number of available observations on the accuracy of EnKF estimates of solar cycle parameters, the criteria to evaluate the predictions, and application of synoptic magnetograms to the prediction of solar activity.
- [30] arXiv:2003.04565 [pdf, other]
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Title: The Locus Algorithm III: A Grid Computing system to generate catalogues of optimised pointings for Differential PhotometryComments: 12 Pages, 9 FiguresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Distributed, Parallel, and Cluster Computing (cs.DC)
This paper discusses the hardware and software components of the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,799 quasars. The scale of the data, together with initial operational assessments demanded a High Performance Computing (HPC) system to complete the data analysis. Grid computing was chosen as the HPC solution as the optimum choice available within this project. The physical and logical structure of the National Grid computing Infrastructure informed the approach that was taken. That approach was one of layered separation of the different project components to enable maximum flexibility and extensibility.
- [31] arXiv:2003.04570 [pdf, other]
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Title: The Locus Algorithm IV: Performance metrics of a grid computing system used to create catalogues of optimised pointingsComments: 6 Pages, 1 FigureSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Performance (cs.PF)
This paper discusses the requirements for and performance metrics of the the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,779 quasars. Initial operational tests indicated a need for a software system to analyse the data and a High Performance Computing system to run that software in a scalable manner. Practical assessments of the performance of the software in a serial computing environment were used to provide a benchmark against which the performance metrics of the HPC solution could be compared, as well as to indicate any bottlenecks in performance. These performance metrics indicated a distinct split in the performance dictated more by differences in the input data than by differences in the design of the systems used. This indicates a need for experimental analysis of system performance, and suggests that algorithmic complexity analyses may lead to incorrect or naive conclusions, especially in systems with high data I/O overhead such as grid computing. Further, it implies that systems which reduce or eliminate this bottleneck such as in-memory processing could lead to a substantial increase in performance.
- [32] arXiv:2003.04574 [pdf, other]
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Title: The Locus Algorithm II: A robust software system to maximise the quality of fields of view for Differential PhotometryComments: 11 Pages, 13 FiguresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Distributed, Parallel, and Cluster Computing (cs.DC)
We present the software system developed to implement the Locus Algorithm, a novel algorithm designed to maximise the performance of differential photometry systems by optimising the number and quality of reference stars in the Field of View with the target. Firstly, we state the design requirements, constraints and ambitions for the software system required to implement this algorithm. Then, a detailed software design is presented for the system in operation. Next, the data design including file structures used and the data environment required for the system are defined. Finally, we conclude by illustrating the scaling requirements which mandate a high-performance computing implementation of this system, which is discussed in the other papers in this series.
- [33] arXiv:2003.04582 [pdf, other]
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Title: The Locus Algorithm I: A technique for identifying optimised pointings for differential photometryComments: 11 Pages, 6 FiguresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Studies of the photometric variability of astronomical sources from ground-based telescopes must overcome atmospheric extinction effects. Differential photometry by reference to an ensemble of reference stars which closely match the target in terms of magnitude and colour can mitigate these effects. This Paper describes the design, implementation and operation of a new algorithm, The Locus Algorithm; which enables optimised differential photometry. The Algorithm is intended to identify, for a given target and observational parameters, the Field of View (FoV) which includes the target and the maximum number of reference stars similar to the target. A collection of objects from a catalogue (e.g. SDSS) is filtered to identify candidate reference stars and determine a rating for each which quantifies its similarity to the target. The algorithm works by defining a locus of points around each candidate reference star, upon which the FoV can be centred and include the reference at the edge of the FoV. The Points of Intersection (PoI) between these loci are identified and a score for each PoI is calculated. The PoI with the highest score is output as the optimum pointing. The steps of the algorithm are precisely defined in this paper. The application of The Locus Algorithm to a sample target, SDSS1237680117417115655, from the Sloan Digital Sky Survey is described in detail. The algorithm has been defined here and implemented in software which is available online. The algorithm has also been used to generate catalogues of pointings to optimise Quasar variability studies and to generate catalogues of optimised pointings in the search for Exoplanets via the transit method.
- [34] arXiv:2003.04590 [pdf, other]
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Title: A Catalogue of Locus Algorithm Pointings for Optimal Differential Photometry for 23,779 QuasarsComments: 7 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Distributed, Parallel, and Cluster Computing (cs.DC); Digital Libraries (cs.DL)
This paper presents a catalogue of optimised pointings for differential photometry of 23,779 quasars extracted from the Sloan Digital Sky Survey (SDSS) Catalogue and a score for each indicating the quality of the Field of View (FoV) associated with that pointing. Observation of millimagnitude variability on a timescale of minutes typically requires differential observations with reference to an ensemble of reference stars. For optimal performance, these reference stars should have similar colour and magnitude to the target quasar. In addition, the greatest quantity and quality of suitable reference stars may be found by using a telescope pointing which offsets the target object from the centre of the field of view. By comparing each quasar with the stars which appear close to it on the sky in the SDSS Catalogue, an optimum pointing can be calculated, and a figure of merit, referred to as the "score" calculated for that pointing. Highly flexible software has been developed to enable this process to be automated and implemented in a distributed computing paradigm, which enables the creation of catalogues of pointings given a set of input targets. Applying this technique to a sample of 40,000 targets from the 4th SDSS quasar catalogue resulted in the production of pointings and scores for 23,779 quasars. This catalogue is a useful resource for observers planning differential photometry studies and surveys of quasars to select those which have many suitable celestial neighbours for differential photometry
- [35] arXiv:2003.04624 [pdf]
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Title: X-ray properties of X-CLASS-redMaPPer galaxy cluster sample: The luminosity-temperature relationAuthors: Mona Molham, Nicolas Clerc, Ali Takey, Tatyana Sadibekova, A. B. Morcos, Shahinaz Yousef, Z. M. Hayman, Maggie Lieu, Somak Raychaudhury, Evelina R. GaynullinaComments: Accepted for publication in MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
This paper presents results of a spectroscopic analysis of the X-CLASS-redMaPPer (XC1-RM) galaxy cluster sample. X-CLASS is a serendipitous search for clusters in the X-ray wavebands based on the XMM-Newton archive, whereas redMaPPer is an optical cluster catalogue derived from the Sloan Digital Sky Survey (SDSS). The present sample comprises 92 X-ray extended sources identified in optical images within 1\arcmin~separation. The area covered by the cluster sample is $\sim$ 27 deg$^{2}$. The clusters span a wide redshift range (0.05 < z < 0.6) and 88 clusters benefit from spectrosopically confirmed redshifts using data from SDSS Data Release 14. We present an automated pipeline to derive the X-ray properties of the clusters in three distinct apertures: R\textsubscript{500} (at fixed mass overdensity), R\textsubscript{fit} (at fixed signal-to-noise ratio), R\textsubscript{300kpc} (fixed physical radius). The sample extends over wide temperature and luminosity ranges: from 1 to 10 keV and from 6$\times$10$^{42}$ to 11$\times$10$^{44}$ erg\,s$^{-1}$, respectively. We investigate the luminosity-temperature (L-T) relation of the XC1-RM sample and find a slope equals to 3.03 $\pm$ 0.26. It is steeper than predicted by self-similar assumptions, in agreement with independent studies. A simplified approach is developed to estimate the amount and impact of selection biases which might be affecting our recovered L-T parameters. The result of this simulation process suggests that the measured L-T relation is biased to a steeper slope and higher normalization.
- [36] arXiv:2003.04643 [pdf, other]
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Title: Comparison of two- and three-dimensional compressible convection in a pre-main sequence starComments: 13 pages, 8 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Fluid Dynamics (physics.flu-dyn)
Extending our recent studies of two-dimensional stellar convection to 3D, we compare three-dimensional hydrodynamic simulations to identically set-up two-dimensional simulations, for a realistic pre-main sequence star. We compare statistical quantities related to convective flows including: average velocity, vorticity, local enstrophy, and penetration depth beneath a convection zone. These statistics are produced during stationary, steady-state compressible convection in the star's convection zone. Our simulations with the MUSIC code confirm the common result that two-dimensional simulations of stellar convection have a higher magnitude of velocity on average than three-dimensional simulations. Boundary conditions and the extent of the spherical shell can affect the magnitude and variability of convective velocities. The difference between 2D and 3D velocities is dependent on these background points; in our simulations this can have an effect as large as the difference resulting from the dimensionality of the simulation. Nevertheless, radial velocities near the convective boundary are comparable in our 2D and 3D simulations. The average local enstrophy of the flow is lower for two-dimensional simulations than for three-dimensional simulations, indicating a different shape and structuring of 3D stellar convection. We perform a statistical analysis of the depth of convective penetration below the convection zone, using the model proposed in our recent study (Pratt et al. 2017). Here we analyze the convective penetration in three dimensional simulations, and compare the results to identically set-up 2D simulations. In 3D the penetration depth is as large as the penetration depth calculated from 2D simulations.
- [37] arXiv:2003.04644 [pdf, ps, other]
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Title: Periodic Fast Radio Bursts as a Probe of Extragalactic Asteroid BeltsComments: 5 pages in emulateapj format, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The periodic activity of repeating fast radio burst (FRB) 180916.J0158+65 was recently reported by the CHIME/FRB Collaboration team. 28 bursts from this source show a $\sim16$-day period with an active phase of $\sim 4.0$ days and their differential energy distribution exhibits a broken power law. In this paper, we suggest that FRB 180916.J0158+65-like periodic FRBs would provide a unique probe of extragalactic asteroid belts (EABs), based on our previously-proposed pulsar-EAB impact model, in which repeating FRBs arise from an old-aged, slowly-spinning, moderately-magnetized pulsar traveling through an EAB around another stellar-mass object. These two objects form a binary and thus the observed period is in fact the orbital period. We constrain the EAB's properties by using the observed data of FRB 180916.J0158+65. We find that the outer radius of the EAB is smaller than that of its analogue in the solar system by a factor of a few to one order of magnitude and the differential size distribution of the EAB's asteroids at small diameters (large diameters) is shallower (steeper) than that of the solar-system main belt, even though the two belts could have a comparable mass.
- [38] arXiv:2003.04647 [pdf, other]
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Title: Broad-band spectral energy distribution of the X-ray transient Swift J1745-26 from outburst to quiescenceComments: A&A in press, 8 pages, 6 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
We study the X-ray transient Swift J1745-26, using observations obtained from its outburst in September 2012, up to its decay towards quiescence in March 2013. We obtained optical and infrared observations, through override programme at ESO/VLT with FORS2 and ISAAC instruments, and archival optical (VLT/VIRCAM), radio and X-ray (Swift) observations, to build the lightcurve and the broad-band Spectral Energy Distribution (SED) of Swift J1745-26. We show that, during its outburst and also during its decay towards quiescence, Swift J1745-26 SED can be adjusted, from infrared up to X-rays, by the sum of both a viscous irradiated multi-colour blackbody emitted by an accretion disk, and a synchrotron powerlaw at high energy. In the radio domain, the SED arises from synchrotron emission from the jet. While our SED fitting confirms that the source remained in the low/hard state during its outburst, we determine an X-ray spectral break at frequency 3.1 < nu_break < 3.4 x 10^14 Hz, and a radio spectral break at 10^12 Hz < nu_break < 10^13 Hz. We also show that the system is compatible with an absorption Av of ~7.69 magnitudes, lies within a distance interval of D~[2.6-4.8] kpc, with an upper limit of orbital period P_orb = 11.3 hours, and that the companion star is a late-type star of spectral type in the range K0 - M0 V, confirming that the system is a low-mass X-ray binary. We finally plot the position of Swift J1745-26 on an optical-infrared - X-ray luminosity diagram: its localization on this diagram is consistent with the source staying in the low-hard state during outburst and decay phases.
- [39] arXiv:2003.04650 [pdf, other]
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Title: Detection of Fe I and Fe II in the atmosphere of MASCARA-2b using a cross-correlation methodComments: 10 pages, 7 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Ultra-hot Jupiters are gas giants planets whose dayside temperature, due to the strong irradiation received from the host star, is greater than 2200 K. These kind of objects are perfect laboratories to study chemistry of exoplanetary upper atmospheres via transmission spectroscopy. Exo-atmospheric absorption features are buried in the noise of the in-transit residual spectra. However we can retrieve the information of hundreds of atmospheric absorption lines by performing a cross-correlation with an atmospheric transmission model, which allows us to greatly increase the exo-atmospheric signal. At the high-spectral resolution of our data, the Rossiter-McLaughlin effect and centre-to-limb variation have a strong contribution. Here, we present the first detection of Fe I and the confirmation of absorption features of Fe II in the atmosphere of the ultra-hot Jupiter MASCARA-2b/KELT-20b, by using three transit observations with HARPS-N. After combining all transit observations we find a high cross-correlation signal of Fe I and Fe II with signal-to-noise ratios of 10.5 +/- 0.4 and 8.6 +/- 0.5, respectively. The peak absorption for both species appear to be blue-shifted with velocities of -6.3 +/- 0.8 km/s for Fe I and -2.8 +/- 0.8 km/s for Fe II, suggesting the presence of winds from the day- to night-side of the planet's atmosphere. These results confirm previous studies of this planet and add a new atomic species (Fe I) to the long list of detected species in the atmosphere of MASCARA-2b, making it, together with KELT-9b, the most feature-rich ultra-hot Jupiter to date.
- [40] arXiv:2003.04656 [pdf, other]
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Title: Fluorine in the solar neighbourhood: the need for several cosmic sourcesAuthors: Nils Ryde, Henrik Jönsson, Gregory Mace, Katia Cunha, Emanuele Spitoni, Melike Afsar, Daniel Jaffe, Rebecca Forsberg, Kyle F. Kaplan, Benjamin T. Kidder, Jae-Joon Lee, Heeyoung Oh, Verne V. Smith, Christopher Sneden, Kimberly R. Sokal, Emily Strickland, Brian ThorsbroComments: Accepted by ApJ, 17 pages, 10 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
The cosmic origin of fluorine is still not well constrained. Several nucleosynthetic channels at different phases of stellar evolution have been suggested, but these must be constrained by observations. For this, the fluorine abundance trend with metallicity spanning a wide range is required. Our aim is to determine stellar abundances of fluorine for -1.1<[Fe/H]<+0.4. We determine the abundances from HF lines in infrared K-band spectra (at 2.3 microns) of cool giants, observed with the IGRINS and Phoenix high-resolution spectrographs. We derive accurate stellar parameters for all our observed K giants, which is important since the HF lines are very temperature sensitive. We find that [F/Fe] is flat as a function of metallicity at [F/Fe]~0, but increases as the metallicity increases. The fluorine slope shows a clear secondary behavior in this metallicity range. We also find that the [F/Ce] ratio is relatively flat for -0.6<[Fe/H]<0, and that for two metal-poor ([Fe/H]<-0.8), s-process element enhanced giants, we do not detect an elevated fluorine abundance. We interpret all these observational constraints to indicate that several major processes are at play for the cosmic budget of fluorine over time; from those in massive stars at low metallicities, through the asymptotic giant branch-star contribution at -0.6<[Fe/H]<0, to processes with increasing yields with metallicity at super-solar metallicities. The origins of the latter, and whether or not Wolf-Rayet stars and/or novae could contribute at super-solar metallicities, is currently not known. To quantify these observational results, theoretical modelling is required. More observations in the metal-poor region are required to clarify the processes there.
- [41] arXiv:2003.04662 [pdf, other]
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Title: The intra-cluster light as a tracer of the total matter density distribution: a view from simulationsAuthors: Isaac Alonso Asensio, Claudio Dalla Vecchia, Yannick M. Bahé, David J. Barnes, Scott T. KayComments: 7 pages, 5 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
By using deep observations of clusters of galaxies, it has been recently found that the projected stellar mass density closely follows the projected total (dark and baryonic) mass density within the innermost ~140 kpc. In this work, we aim to test these observations using the Cluster-EAGLE simulations, comparing the projected densities inferred directly from the simulations. We compare the iso-density contours using the procedure of Montes \& Trujillo (2019), and find that the shape of the stellar mass distribution follows that of the total matter even more closely than observed, although their radial profiles differ substantially. The ratio between stellar and total matter density profiles in circular apertures, shows a slope close to -1, with a small dependence on the cluster's total mass. We propose an indirect method to calculate the halo mass and mass density profile from the radial profile of the intra-cluster stellar mass density.
- [42] arXiv:2003.04700 [pdf, other]
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Title: Impact of transport modelling on the $^{60}$Fe abundance inside Galactic cosmic ray sourcesComments: 11 pages, 5 figures. Accepted for publication in PRDSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The ACE-CRIS collaboration has recently released the measurement of radioactive $^{60}$Fe nuclei abundance in Galactic Cosmic Rays, in the energy range $\sim 195-500$ MeV per nucleon. We model Cosmic Ray propagation and derive from this measurement the $^{60}$Fe/$^{56}$Fe ratio that is expected in the sources of Galactic Cosmic Rays. We describe Cosmic Ray origin and transport within the framework of the disk/halo diffusion model, namely a scenario in which the matter and the Cosmic Ray sources in our Galaxy are confined to a thin disk, while Cosmic Ray propagation occurs in a much larger halo with negligible matter density. We solve the Cosmic Ray transport equation accounting for spallation reactions, decay and ionization losses as well as advection. We find that the $^{60}$Fe/$^{56}$Fe ratio at the source must be very close to the value detected in the local Cosmic Ray spectrum at Earth, due to the fact that spallation reactions are more effective for $^{56}$Fe than for $^{60}$Fe. Such a result could help identify the sources of Galactic Cosmic Rays.
- [43] arXiv:2003.04701 [pdf, other]
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Title: On the origins of up-bending breaks in disk galaxiesComments: 4 pages, 1 figure, for IAU Symposium 355Subjects: Astrophysics of Galaxies (astro-ph.GA)
Using SPITZER 3.6$\mu$m imaging, we investigate the physical and data-driven origins of up-bending (Type III) disk breaks. We apply a robust new break-finding algorithm to 175 low-inclination disk galaxies previously identified as containing Type III breaks, classify each galaxy by its outermost re-classified (via our new algorithm) break type, and compare the local environments of each resulting subgroup. Using three different measures of the local density of galaxies, we find that galaxies with extended outer spheroids (Type IIIs) occupy the highest density environments in our sample, while those with extended down-bending (Type II) disks and symmetric outskirts occupy the lowest density environments. Among outermost breaks, the most common origin of Type III breaks in our sample is methodological; the use of elliptical apertures to measure the radial profiles of asymmetric galaxies usually results in features akin to Type III breaks.
- [44] arXiv:2003.04752 [pdf, ps, other]
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Title: The self-similar structure of advection-dominated discs with outflow and radial viscositySubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Observational evidence and theoretical arguments postulate that outflows may play a significant role in the advection-dominated accretion discs (ADAFs). While the azimuthal viscosity is the main focus of most previous studies in this context, recent studies indicated that disc structure can also be affected by the radial viscosity. In this work, we incorporate these physical ingredients and the toroidal component of the magnetic field to explore their roles in the steady-state structure of ADAFs. We thereby present a set of similarity solutions where outflows contribute to the mass loss, angular momentum removal, and the energy extraction. Our solutions indicate that the radial viscosity causes the disc to rotate with a slower rate, whereas the radial gas velocity increases. For strong winds, the infall velocity may be of order the Keplerian speed if the radial viscosity is considered and the saturated conduction parameter is high enough. We show that the strength of magnetic field and of wind can affect the effectiveness of radial viscosity.
- [45] arXiv:2003.04783 [pdf, other]
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Title: Probing the inflationary background of gravitational waves from large to small scalesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The detection of Primordial Gravitational Waves (PGWs) is one of the most important goals of modern cosmology since PGWs can both provide substantial evidence for primordial inflation and shed light on its physical nature. Small scale experiments on gravitational waves such as Ligo-Virgo and, in future, LISA and Einstein Telescope (ET), are sensitive to the stochastic background, $\Omega_{\rm{GW}}$. So they can be used to constrain the inflationary parameters. In performing this kind of analysis the primordial spectrum of gravitational waves is usually parametrized with a power law that includes only the amplitude and the spectral tilt. In this paper, we investigate the robustness of such constraints showing that the higher-order terms in the power law approximation (i.e. the runnings of the tensor tilt) can lead to non-negligible corrections on small scales. We start investigating these corrections in the simplest scenario of slow-roll inflation that predicts an almost scale-invariant, slightly red tilted primordial spectrum of gravitational waves. Nevertheless we estimate a correction on $\Omega_{\rm GW}$ of about 39\% on the Ligo-Virgo scales. Then we focus on blue models of inflation analyzing the robustness of the constraints that can be obtained using small scale measurements of the stochastic background. We prove that it is effectively possible to constrain the inflationary parameters on the CMB scales with the small scale data, but also that the higher-order corrections are non-negligible on small scales. We constrain a physical model of blue inflation that employs a pseudo scalar axion naturally coupled to gauge fields. We prove that, once the higher-order corrections are considered in the analysis, future experiments can tightly constraints the spectral tilt $n_{\rm t}$ improving at least of an order of magnitude the constraints.
- [46] arXiv:2003.04795 [pdf, ps, other]
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Title: A serendipitous discovery of GeV gamma-ray emission from supernova 2004dj in a survey of nearby star-forming galaxies with Fermi-LATComments: 8 pages, 5 figures, 1 table, comments are welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The interaction between a supernova ejecta and the circum-stellar medium drives a strong shock wave which accelerates particles (i.e., electrons and protons). The radio and X-ray emission observed after the supernova explosion constitutes the evidence of the electron acceleration. The accelerated protons are expected to produce GeV-TeV gamma-ray emission via $pp$ collisions, but the flux is usually low since only a small fraction of the supernova kinetic energy is converted into the shock energy at the very early time. The low gamma-ray flux of the nearest supernova explosion, SN 1987A, agrees with this picture. Here we report a serendipitous discovery of a fading GeV gamma-ray source in spatial coincidence with the second nearest supernova--SN 2004dj from our gamma-ray survey of nearby star-forming galaxies with Fermi-LAT. The total gamma-ray energy released by SN 2004dj is about $6\times10^{47}{\rm erg}$. We interpret this gamma-ray emission arising from the supernova ejecta interacting with a surrounding high-density shell, which decelerates the ejecta and converts ~1% of the ejecta's kinetic energy to relativistic protons. In addition, our gamma-ray survey of nearby star-forming galaxies discovers GeV emissions from two star-forming galaxies, i.e., Arp 299 and M33, for the first time.
- [47] arXiv:2003.04800 [pdf, other]
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Title: Observational detection of correlation between galaxy spins and initial conditionsComments: 6 pages, 6 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Galaxy spins can be predicted from the initial conditions in the early Universe through the tidal tensor twist. In simulations, their directions are well preserved through cosmic time, consistent with expectations of angular momentum conservation. We report a $\sim 3 \sigma$ detection of correlation between observed oriented directions of galaxy angular momenta and their predictions based on the initial density field reconstructed from the positions of SDSS galaxies. The detection is driven by a group of spiral galaxies classified by the Galaxy Zoo as (anti-)clockwise, with a modest improvement from adding galaxies from MaNGA and SAMI surveys. This is the first such detection of the oriented galaxy spin direction, which opens a way to use measurements of galaxy spins to probe fundamental physics in the early Universe.
- [48] arXiv:2003.04809 [pdf, other]
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Title: The width, density and outflow of solar coronal streamersSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Characterising the large-scale structure and plasma properties of the inner corona is crucial to understand the source and subsequent expansion of the solar wind and related space weather effects. Here we apply a new coronal rotational tomography method, along with a method to narrow streamers and refine the density estimate, to COR2A/STEREO observations from a period near solar minimum and maximum, gaining density maps for heights between 4 and 8\Rs. The coronal structure is highly radial at these heights, and the streamers are very narrow, in some regions only a few degrees in width. The mean densities of streamers is almost identical between solar minimum and maximum. However, streamers at solar maximum contain around 50\%\ more total mass due to their larger area. By assuming a constant mass flux, and constraints on proton flux measured by Parker Solar Probe (PSP), we estimate an outflow speed within solar minimum streamers of 50-120\kms\ at 4\Rs, increasing to 90-250\kms\ at 8\Rs. Accelerations of around 6\mss\ are found for streamers at a height of 4\Rs, decreasing with height. The solar maximum slow wind shows a higher acceleration to extended distances compared to solar minimum. To satisfy the solar wind speeds measured by PSP, there must be a mean residual acceleration of around 1-2\mss\ between 8 and 40\Rs. Several aspects of this study strongly suggest that the coronal streamer belt density is highly variable on small scales, and that the tomography can only reveal a local spatial and temporal average.
- [49] arXiv:2003.04810 [pdf, ps, other]
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Title: Revisiting the distributions of the physical characteristics of Jupiter's irregular moonsComments: 35 pages, 27 figures, 17 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Applications (stat.AP)
As the identified number of Jupiter's moons has skyrocketed to 79, some of them have been regrouped. In this work, we continue to identify the potential distributions of the physical characteristics of Jupiter's irregular moons. By using nonparametric Kolmogorov-Smirnov tests, we verified more than 20 commonly used distributions and found that surprisingly, almost all the physical characteristics (i.e., the equatorial radius, equatorial circumference, circumference, volume, mass, surface gravity and escape velocity) of the moons in the Ananke and Carme groups follow log-logistic distributions. Additionally, more than half of the physical characteristics of the moons in the Pasiphae group are theoretically subject to this type of distribution. Combined with strict analytical derivations, it is increasingly clear and possible to anticipate that the physical characteristics of most irregular moons follow log-logistic distributions with the discovery of an increasing number of Jupiter's irregular moons.
- [50] arXiv:2003.04814 [pdf, other]
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Title: Dust Attenuation Curve for Local Subgalactic Star-forming RegionsAuthors: Berzaf Berhane Teklu, Zesen Lin, Xu Kong, Enci Wang, Yulong Gao, Qing Liu, Ning Hu, Haiyang LiuComments: Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We compile a sample of about 157,000 spaxels from the Mapping Nearby Galaxies at the Apache Point Observatory survey to derive the average dust attenuation curve for subgalactic star-forming regions of local star-forming galaxies (SFGs) in the optical wavelength, following the method of \cite{Calzetti1994}. We obtain a $D_n(4000)$-independent average attenuation curve for spaxels with $1.1\leq D_n(4000)<1.3$, which is similar to the one derived from either local starbursts or normal SFGs. We examine whether and how the shape of the average attenuation curve changes with several local and global physical properties. For spaxels with $1.2\leq D_n(4000)<1.3$, we find no dependence on either local or global physical properties for the shape of the average attenuation curve. However, for spaxels with younger stellar population ($1.1\leq D_n(4000)<1.2$), shallower average attenuation curves are found for star-forming regions with smaller stellar mass surface density, smaller star formation rate surface density, or those residing in the outer region of galaxies. These results emphasize the risk of using one single attenuation curve to correct the dust reddening for all types of star-forming regions, especially for those with fairly young stellar population.
- [51] arXiv:2003.04839 [pdf, other]
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Title: Optimal Gravitational-wave Follow-up Tiling Strategies Using a Genetic AlgorithmComments: 8 pages, 5 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
The identification of electromagnetic emission from gravitational-wave sources typically requires multiple follow-up observations due to the limited fields-of-view of follow-up observatories compared to the poorly localized direction of gravitational waves. Gravitational-wave localization regions are typically covered with multiple telescope pointings using a "honeycomb" structure, which is optimal only on an infinite, flat surface. Here we present a machine-learning algorithm which uses genetic algorithms along with Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization to find an optimal configuration of tiles to cover the gravitational-wave sky localization area on a spherical surface.
- [52] arXiv:2003.04848 [pdf, ps, other]
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Title: On the FRB luminosity function -- II. Event rate densityComments: 16 pages, 6 figures, 7 tables, 4 appendixes, accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The luminosity function of Fast Radio Bursts (FRBs), defined as the event rate per unit cosmic co-moving volume per unit luminosity, may help to reveal the possible origins of FRBs and design the optimal searching strategy. With the Bayesian modelling, we measure the FRB luminosity function using 46 known FRBs. Our Bayesian framework self-consistently models the selection effects, including the survey sensitivity, the telescope beam response, and the electron distributions from Milky Way / the host galaxy / local environment of FRBs. Different from the previous companion paper, we pay attention to the FRB event rate density and model the event counts of FRB surveys based on the Poisson statistics. Assuming a Schechter luminosity function form, we infer (at the 95% confidence level) that the characteristic FRB event rate density at the upper cut-off luminosity $L^*=2.9_{-1.7}^{+11.9}\times10^{44}\,\rm erg\, s^{-1}$ is $\phi^*=339_{-313}^{+1074}\,\rm Gpc^{-3}\, yr^{-1}$, the power-law index is $\alpha=-1.79_{-0.35}^{+0.31}$, and the lower cut-off luminosity is $L_0\le9.1\times10^{41}\,\rm erg\, s^{-1}$. The event rate density of FRBs is found to be $3.5_{-2.4}^{+5.7}\times10^4\,\rm Gpc^{-3}\, yr^{-1}$ above $10^{42}\,\rm erg\, s^{-1}$, $5.0_{-2.3}^{+3.2}\times10^3\,\rm Gpc^{-3}\, yr^{-1}$ above $10^{43}\,\rm erg\, s^{-1}$, and $3.7_{-2.0}^{+3.5}\times10^2\,\rm Gpc^{-3}\, yr^{-1}$ above $10^{44}\,\rm erg\, s^{-1}$. As a result, we find that, for searches conducted at 1.4 GHz, the optimal diameter of single-dish radio telescopes to detect FRBs is 30-40 m. The possible astrophysical implications of the measured event rate density are also discussed in the current paper.
- [53] arXiv:2003.04851 [pdf, ps, other]
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Title: Revisiting distribution laws for orbital characteristics of Jupiter's moonsComments: 30 pages, 8 figures, 19 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Applications (stat.AP)
From the statistical point of view, this paper mainly emphasizes the orbital distribution laws of Jupiter's moons, most of which are located in Ananke group, Carme group and Pasiphae group. By comparing 19 known continuous distributions, it is verified that there are suitable distribution functions to describe the distribution of these natural satellites. For each distribution type, interval estimation is used to estimate the corresponding parameter values. At a given significant level, one-sample Kolmogorov-Smirnov nonparametric test is applied to verify the specified distribution, and we often select the one with the largest $p$-value. The results show that all the semi-major axis, mean inclination and the orbital period of the moons in Ananke group and Carme group obey the Stable distribution. In addition, according to Kepler's third planetary motion law, and by comparing the theoretically calculated best-fit cumulative distribution function (CDF) with the observed CDF, we demonstrate that the theoretical distribution is in good agreement with the empirical distribution. Therefore, these characteristics of Jupiter's moons are indeed very likely to follow some specific distribution laws, and it will be possible to use these laws to help study certain features of poorly investigated moons or even predict undiscovered ones.
- [54] arXiv:2003.04856 [pdf, other]
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Title: Searching for Thermal Inversion Agents in the Transmission Spectrum of MASCARA-2b/KELT-20b: Detection of Neutral Iron and Ionised Calcium H$\&$K LinesAuthors: Stevanus K. Nugroho, Neale P. Gibson, Ernst J. W. de Mooij, Chris A. Watson, Hajime Kawahara, Stephanie MerrittComments: 20 pages, 16 figures, 3 tables, submitted to MNRAS after addressing reviewer commentsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We analyse the transmission spectra of KELT-20b/MASCARA-2b to search for possible thermal inversion agents. The data consist of three transits obtained using HARPS-N and one using CARMENES. We removed stellar and telluric lines before cross-correlating the residuals with spectroscopic templates produced using a 1D plane-parallel model assuming an isothermal atmosphere and chemical equilibrium at solar metallicity. Using a likelihood-mapping method, we detect Fe\,{\sc i} at $>$ 13-$\sigma$, Ca\,{\sc ii} H$\&$K at $>$ 6-$\sigma$ and confirm the previous detections of Fe\,{\sc ii}, Ca\,{\sc ii} IRT and Na\,{\sc i} D. The detected signal of Fe\,{\sc i} is shifted by -3.35$\pm$0.40 km s$^{-1}$ from the planetary rest frame, which indicates a strong day-night wind. Our likelihood-mapping technique also reveals that the detected species originate at different altitudes in the planet's atmosphere. Assuming that the line lists are accurate, we do not detect other potential thermal inversion agents (NaH, MgH, AlO, SH, CaO, VO, FeH and TiO) suggesting that non-chemical equilibrium mechanisms (e.g. a cold-trap) might have removed Ti- and V-bearing species from the upper atmosphere. Our results, therefore, shows that KELT-20b/MASCARA-2b cannot possess an inversion layer caused by a TiO/VO-related mechanism. The presence of an inversion layer would therefore likely be caused by metal atoms such as Fe\,{\sc i} and Fe\,{\sc ii}. Finally, we report a `double-peak' structure in the Fe\,{\sc i} signal in all of our data-sets that could be a signature of atmospheric dynamics. However, further investigation is needed to robustly determine the origin of the signal.
- [55] arXiv:2003.04864 [pdf, other]
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Title: Combining neutrino experimental light-curves for pointing to the next Galactic Core-Collapse SupernovaAuthors: Alexis Coleiro, Marta Colomer Molla, Damien Dornic, Massimiliano Lincetto, Vladimir KulikovskiyComments: 9 pages, 10 figures, 5 tables, corresponding authors: Marta Colomer Molla and Vladimir KulikovskiySubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
The multi-messenger observation of the next galactic core-collapse supernova will shed light on the different physical processes involved in these energetic explosions. Good timing and pointing capabilities of neutrino detectors would help in the search for an electromagnetic or gravitational-wave counterparts.
An approach for the determination of the arrival time delay of the neutrino signal at different experiments using a direct detected neutrino light-curve matching is discussed. A simplified supernova model and detector simulation are used for its application. The arrival time delay and its uncertainty between two neutrino detectors are estimated with chi-square and cross-correlation methods. The direct comparison of the detected light-curves offers the advantage to be model-independent.
Millisecond time resolution on the arrival time delay at two different detectors is needed. Using the computed time delay between different combinations of currently operational and future detectors, a triangulation method is used to infer the supernova localisation in the sky. The combination of IceCube, Hyper-Kamiokande, JUNO and KM3NeT/ARCA provides a 90% confidence area of about 340 deg$^2$. These low-latency analysis methods can be implemented in the SNEWS alert system. - [56] arXiv:2003.04872 [pdf, ps, other]
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Title: Modelling the He I triplet absorption at 10830 Angstroms in the atmosphere of HD 209458 bAuthors: M. Lampón, M. López-Puertas, L. M. Lara, A. Sánchez-López, M. Salz, S. Czesla, J. Sanz-Forcada, K. Molaverdikhani, F. J. Alonso-Floriano, L. Nortmann, J. A. Caballero, F. F. Bauer, E. Pallé, D. Montes, A. Quirrenbach, E. Nagel, I. Ribas, A. Reiners, P. J. AmadoComments: Accepted to A&A. 15 Pages, 15 figures and 3 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
HD 209458b is an exoplanet with an upper atmosphere undergoing blow-off escape that has mainly been studied using measurements of the Ly-alpha absorption. Recently, high-resolution measurements of absorption in the He I triplet line at 10830 angstroms of several exoplanets (including HD 209458b) have been reported, creating a new opportunity to probe escaping atmospheres. We aim to better understand the atmospheric regions of HD 209458b from where the escape originates. We developed a 1D hydrodynamic model with spherical symmetry for the HD 209458 b thermosphere coupled with a non-local thermodynamic model for the population of the He triplet state. In addition, we performed high-resolution radiative transfer calculations of synthetic spectra for the He triplet lines and compared them with the measured absorption spectrum in order to retrieve information about the atmospheric parameters. We find that the measured spectrum constrains the [H]/[H$^{+}$] transition altitude occurring in the range of 1.2 to 1.9Rp. H is almost fully ionised at altitudes above 2.9Rp. We also find that the X-ray and EUV absorption takes place at effective radii from 1.16 to 1.30Rp, and that the He triplet peak density occurs at altitudes from 1.04 to 1.60Rp. Additionally, the averaged mmw is confined to the 0.61-0.73 g/mole interval, and the thermospheric H/He ratio should be larger than 90/10, and most likely approximately 98/2. We also provide a one-to-one relationship between mass-loss rate and temperature. Based on the energy-limited escape approach and assuming heating efficiencies of 0.1-0.2, we find a mass-loss rate in the range of (0.42-1.00)$\times 10^{11}$ g/s and a corresponding temperature range of 7125 to 8125K. The analysis of the measured He triplet absorption spectrum significantly constrains the thermospheric structure of HD 209458b and advances our knowledge of its escaping atmosphere.
- [57] arXiv:2003.04877 [pdf, other]
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Title: Re-inflation of warm and hot JupitersComments: 15 pages, 13 figures, accepted at ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Understanding the anomalous radii of many transiting hot gas giant planets is a fundamental problem of planetary science. Recent detections of re-inflated warm Jupiters orbiting post-main-sequence stars and the re-inflation of hot Jupiters while their host stars evolve on the main-sequence may help constrain models for the anomalous radii of hot Jupiters. In this work, we present evolution models studying the re-inflation of gas giants to determine how varying the depth and intensity of deposited heating affects both main-sequence re-inflation of hot Jupiters and post-main-sequence re-inflation of warm Jupiters. We find that deeper heating is required to re-inflate hot Jupiters than is needed to suppress their cooling, and that the timescale of re-inflation decreases with increasing heating rate and depth. We find a strong degeneracy between heating rate and depth, with either strong shallow heating or weak deep heating providing an explanation for main-sequence re-inflation of hot Jupiters. This degeneracy between heating rate and depth can be broken in the case of post-main-sequence re-inflation of warm Jupiters, as the inflation must be rapid to occur within post-main-sequence evolution timescales. We also show that the dependence of heating rate on incident stellar flux inferred from the sample of hot Jupiters can explain re-inflation of both warm and hot Jupiters. TESS will obtain a large sample of warm Jupiters orbiting post-main-sequence stars, which will help to constrain the mechanism(s) causing the anomalous radii of gas giant planets.
- [58] arXiv:2003.04880 [pdf, other]
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Title: Nonparametric constraints on neutron star matter with existing and upcoming gravitational wave and pulsar observationsComments: 20 pages, 10 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
Observations of neutron stars, whether in binaries or in isolation, provide information about the internal structure of the most extreme material objects in the Universe. In this work, we combine information from recent observations to place joint constraints on the properties of neutron star matter. We use (i) lower limits on the maximum mass of neutron stars obtained through radio observations of heavy pulsars, (ii) constraints on tidal properties inferred through the gravitational waves neutron star binaries emit as they coalesce, and (iii) information about neutron stars' masses and radii obtained through X-ray emission from surface hotspots. In order to combine information from such distinct messengers while avoiding the kind of modeling systematics intrinsic to parametric inference schemes, we employ a nonparametric representation of the neutron-star equation of state based on Gaussian processes conditioned on nuclear theory models. We find that existing astronomical observations imply $R_{1.4}=12.32^{+1.09}_{-1.47}\,$km for the radius of a $1.4\,M_{\odot}$ neutron star and $p(2\rho_\mathrm{nuc})=3.8^{+2.7}_{-2.9}\times10^{34}\,\mathrm{dyn}/\mathrm{cm}^2$ for the pressure at twice nuclear saturation density at the $90\%$ credible level. The upper bounds are driven by the gravitational wave observations, while X-ray and heavy pulsar observations drive the lower bounds. Additionally, we compute expected constraints from potential future astronomical observations and find that they can jointly determine $R_{1.4}$ to ${\cal{O}}(1)\,$km and $p(2\rho_\mathrm{nuc})$ to $80\%$ relative uncertainty in the next five years.
Cross-lists for Wed, 11 Mar 20
- [59] arXiv:2003.04416 (cross-list from gr-qc) [pdf, other]
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Title: Poynting-Robertson effect as a dissipative system in general relativityComments: 13 pages, 3 figures; Accepted on Physical Review D. Much of this work appeared previously as arXiv:1911.03197, which remains un-publishedSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
We determine for the first time in the literature the analytic form of the Rayleigh potential of the general relativistic Poynting-Robertson effect. The employed procedure is based on the use of an integrating factor and a new integration strategy where the test particle's dissipated energy represents the fundamental variable. The obtained results and their implications are discussed. Finally, concluding remarks and future projects are drawn.
- [60] arXiv:2003.04471 (cross-list from nucl-th) [pdf, ps, other]
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Title: Short-range correlations effects on the deformability of neutron starsComments: 7 pages. 4 figuresSubjects: Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
In the present work, we investigate the effects of short-range correlations (SRC) on the dimensionless deformability of the binary neutron system related to the GW170817 event. We implemented phenomenological SRC in a relativistic mean-field model in which the bulk parameters, namely, incompressibility ($K_0$), effective nucleon mass ratio ($m^*$), symmetry energy ($J$) and its slope ($L_0$), are independently controlled. Our results point out that the SRC favor the model to pass through the constraints, established by the LIGO/Virgo Collaboration, on the values of $\Lambda_{1.4}$ and on the $\Lambda_1\times\Lambda_2$ region. We also found a clear linear correlation between $\Lambda_{1.4}$ with $K_0$ and $L_0$ (increasing dependence), and with $m^*$ and $J$ (decreasing dependence). Finally, we also obtained compatible numbers for $R_{1.4}$ (model with and without SRC) in comparison with recent data from the Neutron Star Interior Composition Explorer (NICER) mission.
- [61] arXiv:2003.04506 (cross-list from hep-ph) [pdf, ps, other]
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Title: Light-quark flavours in a triangleAuthors: Renxin Xu (PKU)Comments: 3 pages, 2 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
All of the light flavors seem to work well for bulk strong matter at pressure free, which could be manifested diversely in the form of compact star and strange nugget. Observational tests are discussed.
- [62] arXiv:2003.04513 (cross-list from gr-qc) [pdf, other]
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Title: Source properties of the lowest signal-to-noise-ratio binary black hole detectionsAuthors: Yiwen Huang, Carl-Johan Haster, Salvatore Vitale, Aaron Zimmerman, Javier Roulet, Tejaswi Venumadhav, Barak Zackay, Liang Dai, Matias ZaldarriagaSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
We perform a detailed parameter estimation study of binary black hole merger events reported in Zackay et al. and Venumadhav et al.. These are some of the faintest signals reported so far, and hence, relative to the loud events in the GWTC-1 catalog, the data should have lesser constraining power on their intrinsic parameters. Hence we examine the robustness of parameter inference to choices made in the analysis, as well as any potential systematics. We check the impact of different methods of estimating the noise power spectral density, different waveform models, and different priors for the compact object spins. For most of the events, the resulting differences in the inferred values of the parameters are much smaller than their statistical uncertainties. The estimation of the effective spin parameter $\chi_{\mathrm{eff}}$, i.e. the projection of the mass-weighted total spin along the angular momentum, can be sensitive to analysis choices for two of the sources with the largest effective spin magnitudes, GW151216 and GW170403. The primary differences arise from using a 3D isotropic spin prior: the tails of the posterior distributions should be interpreted with care and due consideration of the other data analysis choices.
- [63] arXiv:2003.04568 (cross-list from gr-qc) [pdf, ps, other]
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Title: Lower surface gravitational redshift induced by higher curvature effectsComments: 30 pages, 16 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Theory (hep-th)
We analyze the influence of higher curvature effects on stellar structure and conclude from empirical results that such effects may significantly change our interpretation of observational data gathered from experiments. A model of a superdense star with strange star equation of state is constructed within the framework of the Einstein--Gauss--Bonnet theory. Under these assumptions large classes of solutions are admitted by the field equations. We isolate a particular class with the ansatz of the Vaidya--Tikekar superdense star spatial gravitational potential. The model is found to satisfy elementary requirements for physical applicability and displays surface redshift ranges comporting to neutron stars in the general relativity limit. In particular, we obtain a pressure profile that is positive definite within a finite radius occurring at a hypersurface of vanishing pressure. Within the radius, the density profile, sound--speed and energy conditions are all well behaved. The surface gravitational redshift function is consistent with the expectation for strange stars. Moreover, the adiabatic stability criterion of Chandrasekhar is satisfied as is the positivity of the difference between the sound speeds squared in the radial and transverse directions. A pleasing equation of state curve is evident for a particular choice of parameters. The mass profile and consequently the compactification index are all found to be reasonable. The parameter values chosen are consistent with observed star models. A significant effect of the higher curvature terms is to reduce the speed of sound and to drastically reduce the values of the surface gravitational redshift compared to the Einstein counterpart. These latter results have implications for observations in relativistic astrophysics which are often made against the background of the standard general theory of relativity.
- [64] arXiv:2003.04609 (cross-list from gr-qc) [pdf, other]
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Title: Bulk viscosity in relativistic fluids: from thermodynamics to hydrodynamicsComments: 30 pages, 5 figures, submitted to PRDSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
Bulk viscosity plays a key role in several astrophysical phenomena linked to neutron stars, from the damping of modes of oscillation in mature stars to the dynamics of the hot remnant of a binary merger. To quantitatively model these systems and constrain the imprint of the equation of state of dense matter it is, however, necessary to resort to a general relativistic description of bulk viscosity. Several prescriptions exist to modify the standard Navier-Stokes equations, which are parabolic and lead to non-causal solutions, to obtain hyperbolic equations that can be used in a relativistic setting. The connection between microphysics and the parameters introduced is not, however, always transparent. In this paper we present a relativistic formalism where any thermodynamic process which contributes to the bulk viscosity is modelled as a set of chemical reactions, whose reaction coordinates are abstract parameters describing the displacement from local thermodynamic equilibrium. The result is a non-equilibrium thermodynamic theory for bulk-viscous fluids which does not rely on any near-equilibrium assumption, and naturally gives rise to telegraph-type equations for the reaction processes. We present also two concrete applications of our theory, to the bulk viscosity in neutron stars and to a non interacting neutron gas and compare our formulation with that of Israel and Stewart (1979), which for a mature neutron star emerges as a perturbative expansion of our theory near equilibrium.
- [65] arXiv:2003.04802 (cross-list from physics.pop-ph) [pdf, other]
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Title: A probabilistic analysis of the Fermi paradox in terms of the Drake formula: the role of the L factorAuthors: Nikos PrantzosComments: 9 pages, 5 figures, to appear in MNRASSubjects: Popular Physics (physics.pop-ph); Astrophysics of Galaxies (astro-ph.GA)
In evaluating the number of technological civilizations N in the Galaxy through the Drake formula, emphasis is mostly put on the astrophysical and biotechnological factors describing the emergence of a civilization and much less on its the lifetime, which is intimately related to its demise. It is argued here that this factor is in fact the most important regarding the practical implications of the Drake formula, because it determines the maximal extent of the "sphere of influence" of any technological civilization. The Fermi paradox is studied in the terms of a simplified version of the Drake formula, through Monte Carlo simulations of N civilizations expanding in the Galaxy during their space faring lifetime L. In the framework of that scheme, the probability of "direct contact" is determined as the fraction of the Galactic volume occupied collectively by the "spheres of influence" of N civilizations. The results of the analysis are used to determine regions in the parameter space where the Fermi paradox holds. It is argued that in a large region of the diagram the corresponding parameters suggest rather a "weak" Fermi paradox. Future research may reveal whether a "strong" paradox holds in some part of the parameter space. Finally, it is argued that the value of N is not bound by N=1 from below, contrary to what is usually assumed, but it may have a statistical interpretation.
Replacements for Wed, 11 Mar 20
- [66] arXiv:1505.05872 (replaced) [pdf, other]
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Title: First Order Electroweak Phase Transition from (Non)Conformal Extensions of the Standard ModelComments: v3: Typos corrected from Eq. 70, results unchanged. v2: Few typos corrected and few comments added, match with the published version. 44 pages, 11 figuresJournal-ref: Phys. Rev. D 92, 045015 (2015)Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Lattice (hep-lat); High Energy Physics - Theory (hep-th)
- [67] arXiv:1807.00846 (replaced) [pdf, other]
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Title: Dark Matter Clusters and Time Correlations in Direct Detection ExperimentsComments: 27 pages, 3 figure, more details on dark matter cluster stability and formation, version to appear in JHEPSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
- [68] arXiv:1808.09974 (replaced) [pdf, other]
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Title: Detecting the Orbital Motion of Nearby Supermassive Black Hole Binaries with GaiaComments: Published in Phys. Rev. DJournal-ref: Phys. Rev. D 100, 103016 (2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [69] arXiv:1901.00499 (replaced) [pdf, other]
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Title: Accelerated core collapse in tidally stripped self-interacting dark matter halosComments: 11 pages, 8 figures, 1 table; v2: published versionJournal-ref: PRD 101, 063009 (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
- [70] arXiv:1906.09980 (replaced) [pdf, ps, other]
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Title: New Type Ia supernova Yields and the Manganese and Nickel Problems in the Milky Way and Dwarf Spheroidal GalaxiesComments: 23 pages, 26 figures, Submitted to the Astrophysical Journal on 29 May 2019Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [71] arXiv:1906.11149 (replaced) [pdf, other]
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Title: Detecting Gravitational Self Lensing from Stellar-Mass Binaries Composed of Black Holes or Neutron StarsComments: Published in MNRASJournal-ref: Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 1, p.1506-1517, January 2020Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [72] arXiv:1907.05909 (replaced) [pdf, other]
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Title: Can Assembly Bias Explain the Lensing Amplitude of the BOSS CMASS Sample in a Planck Cosmology?Comments: 14 pages, 8 figures, published on MNRAS, comments welcomedJournal-ref: Monthly Notices of the Royal Astronomical Society, staa634. Published: 09 March 2020Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [73] arXiv:1907.10575 (replaced) [pdf, ps, other]
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Title: Dynamical evolution of close-in binary systems formed by a super-earth and its host starComments: 29 pages, 11 figures, 5 tables. Submitted to the A&A journalSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [74] arXiv:1907.11087 (replaced) [pdf]
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Title: Enhanced Kinetic Impactor for Deflecting Large Potentially Hazardous Asteroids via Maneuvering Space RocksComments: We added more details about the design results and design methods, which will make it more accessible for reader to reproduce our resultsSubjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP)
- [75] arXiv:1908.03227 (replaced) [pdf, other]
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Title: Testing Seesaw and Leptogenesis with Gravitational WavesComments: 6 pages, 1 figures, published versionJournal-ref: Phys. Rev. Lett. 124, 041804 (2020)Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [76] arXiv:1908.08055 (replaced) [pdf, other]
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Title: Structural and Stellar Population Properties vs. Bulge Types in Sloan Digital Sky Survey Central GalaxiesAuthors: Yifei Luo, S. M. Faber, Aldo Rodriguez-Puebla, Joanna Woo, Yicheng Guo, David C. Koo, Joel R. Primack, Zhu Chen, Hassen M. Yesuf, Lin Lin, Guillermo Barro, Jerome J. Fang, Viraj Pandya, M. Huertas-Company, Shude MaoComments: 23 pages, 17 figures, published in MNRASJournal-ref: Monthly Notices of the Royal Astronomical Society, Volume 493, Issue 2, 2020, p.1686-1707Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [77] arXiv:1908.10637 (replaced) [pdf, other]
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Title: Is the lack of power anomaly in the CMB correlated with the orientation of the Galactic plane?Comments: 23 pages, 21 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [78] arXiv:1910.05344 (replaced) [pdf, ps, other]
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Title: Instability of Supersonic Cold Streams Feeding Galaxies IV: Survival of Radiatively Cooling StreamsComments: 25 pages, 15 figures, 1 table, brief appendix. Revised version submitted to MNRAS. Some new simulations added to analysis, and mild changes to discussion of turbulence. Main conclusions unchanged. Comments still welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [79] arXiv:1911.06330 (replaced) [pdf, other]
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Title: Photometric properties of reionization-epoch galaxies in the Simba simulationsComments: 15 pages, first revisionSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [80] arXiv:1911.06839 (replaced) [pdf, other]
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Title: Estimation of Key Sunquake Parameters through Hydrodynamic Modeling and Cross-Correlation AnalysisSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [81] arXiv:1911.07645 (replaced) [pdf, other]
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Title: Influence of weak electromagnetic fields on charged particle ISCOsComments: 19 pages, 9 figues; v2: typos correctedJournal-ref: Gen. Relativ. Gravit. 52:22 (2020)Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [82] arXiv:1912.03466 (replaced) [pdf, ps, other]
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Title: The Possible Electromagnetic Counterparts of the First High-Probability NSBH Merger LIGO/Virgo S190814bvComments: 12 pages, 1 figure, 3 tables, revtex4; v2: discussions added, Commun. Theor. Phys. in pressSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
- [83] arXiv:1912.07610 (replaced) [pdf, other]
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Title: Conformal $α$-attractor Inflation with Weyl Gauge FieldComments: 16 pages, 1 figure; Accepted version on JCAPSubjects: 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)
- [84] arXiv:1912.12360 (replaced) [pdf, other]
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Title: Interpreting LSTM Prediction on Solar Flare Eruption with Time-series ClusteringAuthors: Hu Sun (1), Ward Manchester (2), Zhenbang Jiao (1), Xiantong Wang (2), Yang Chen (1 and 3) ((1) Department of Statistics, University of Michigan, Ann Arbor, (2) Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, (3) Michigan Institute for Data Science, University of Michigan, Ann Arbor)Comments: 26 pages, 18 figures, 2 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Machine Learning (stat.ML)
- [85] arXiv:2001.06051 (replaced) [pdf, other]
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Title: The Low Effective Spin of Binary Black Holes and Implications for Individual Gravitational-Wave EventsComments: 11 pages, 5 figures; Minor revisions following referee commentsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [86] arXiv:2001.07730 (replaced) [pdf, other]
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Title: The Clustering of X-ray Luminous QuasarsAuthors: M. C. Powell, C. M. Urry, N. Cappelluti, J. T. Johnson, S. M. LaMassa, T. T. Ananna, K. E. KollmannComments: Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [87] arXiv:2001.10004 (replaced) [pdf, other]
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Title: Angular momentum profiles of Class 0 protostellar envelopesAuthors: M. Gaudel, A. J. Maury, A. Belloche, S. Maret, Ph. André, P. Hennebelle, M. Galametz, L. Testi, S. Cabrit, P. Palmeirim, B. Ladjelate, C. Codella, L. PodioComments: Accepted for publication in Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [88] arXiv:2001.10454 (replaced) [pdf, other]
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Title: Stimulated-emission based model of fast radio burstsComments: MNRAS acceptedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [89] arXiv:2002.00296 (replaced) [pdf, other]
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Title: Extracting the Gravitational Recoil from Black Hole Merger SignalsComments: Matches published version. 10 pages, including supplementSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [90] arXiv:2002.04652 (replaced) [pdf, ps, other]
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Title: Two fundamental constraints on the inner radii of accretion disksComments: revised version after referee's comments; submitted to ApJ, comments are welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [91] arXiv:2002.09257 (replaced) [pdf, other]
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Title: Gas fractions and depletion times in galaxies with different degrees of interactionComments: Accepted for publication in A&A (February 21, 2020). 6 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [92] arXiv:2002.12736 (replaced) [pdf, other]
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Title: Near optimal angular quadratures for polarised radiative transferComments: 7 pages, 3 figures, 2 tables; accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
- [93] arXiv:2003.02430 (replaced) [pdf, other]
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Title: Accurate Machine Learning Atmospheric Retrieval via a Neural Network Surrogate Model for Radiative TransferAuthors: Michael D. Himes, Joseph Harrington, Adam D. Cobb, Atilim Gunes Baydin, Frank Soboczenski, Molly D. O'Beirne, Simone Zorzan, David C. Wright, Zacchaeus Scheffer, Shawn D. Domagal-Goldman, Giada N. ArneyComments: 8 pages, 3 figures, submitted to PSJ 3/4/2020. Only added comment, no changes to textSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
- [94] arXiv:2003.02983 (replaced) [pdf, ps, other]
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Title: Ogle-2018-blg-0677lb: A super earth near the galactic bulgeAuthors: Antonio Herrera-Martín, M. D. Albrow, A. Udalski, A. Gould, Y.-H. Ryu, J. C. Yee, S.-J. Chung, C. Han, K.-H. Hwang, Y. K. Jung, C.-U. Lee, I.-G. Shin, Y. Shvartzvald, W. Zang, S.-M. Cha, D.-J. Kim, H.-W. Kim, S.-L. Kim, D.-J. Lee, Y. Lee, B.-G. Park, R. W. Pogge, M. K. Szymański, P. Mróz, J. Skowron, R. Poleski, I. Soszyński, S. Kozłowski, P. Pietrukowicz, K. Ulaczyk, K. Rybicki, P. Iwanek, M. WronaComments: 14 page, 12 figures, submitted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
- [95] arXiv:2003.03217 (replaced) [pdf, other]
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Title: CosmoHub: Interactive exploration and distribution of astronomical data on HadoopAuthors: Pau Tallada, Jorge Carretero, Jordi Casals, Carles Acosta-Silva, Santiago Serrano, Marc Caubet, Francisco J. Castander, Eduardo César, Martín Crocce, Manuel Delfino, Martin Eriksen, Pablo Fosalba, Enrique Gaztañaga, Gonzalo Merino, Christian Neissner, Nadia TonelloSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Distributed, Parallel, and Cluster Computing (cs.DC); Data Analysis, Statistics and Probability (physics.data-an)
- [96] arXiv:2003.03380 (replaced) [pdf, other]
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Title: Silicate grain growth due to ion trapping in oxygen-rich supernova remnants like Cassiopeia AComments: Accepted by ApJ. Author accepted manuscript. Accepted on 06/03/2020. Deposited on 06/03/2020. 11 pagesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
- [97] arXiv:2003.04022 (replaced) [pdf, other]
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Title: Search for neutrino counterparts of catalogued gravitational-wave events detected by Advanced-LIGO and Virgo during run O2 with ANTARESAuthors: ANTARES Collaboration: A. Albert, M. André, M. Anghinolfi, G. Anton, M. Ardid, J. J. Aubert, J. Aublin, B. Baret, S. Basa, B. Belhorma, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, M. Bouta, M. C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, A. Capone, L. Caramete, J. Carr, S. Celli, M. Chabab, T. N. Chau, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, A. Coleiro, M. Colomer-Molla, R. Coniglione, P. Coyle, A. Creusot, A. F. Díaz, G. de Wasseige, A. Deschamps, C. Distefano, I. Di Palma, A. Domi, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, N. El Khayati, A. Enzenhöfer, A. Ettahiri, P. Fermani, G. Ferrara, F. Filippini, L. Fusco, P. Gay, H. Glotin, R. Gozzini, R. Gracia Ruiz, K. Graf, C. Guidi, S. Hallmann, H. van Haren, A. J. Heijboer, Y. Hello, J. J. Hernández-Rey, et al. (75 additional authors not shown)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
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