About Me
Hello, welcome to my personal page! I’m Ines, an Astronomy MSc student at the Leiden Observatory. As an early career researcher, my research interests are quite broad! I am interested in Galaxy Formation and Evolution, Cosmology and Large Scale Structure, as well as Galactic Archaeology. At the moment, I am working on measuring flexion in galaxy clusters observed with Euclid.
Research
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The dark side of star formation: The nature of optically dark galaxies and their contribution to the cosmic star formation rate density – Master research project, supervised by Dr. Jacqueline Hodge, 2024/2025
Abstract: An elusive population of dusty star-forming galaxies lacking an optical counterpart has recently been detected in the ultradeep radio COSMOS-XS survey (van der Vlugt et al., 2021). These so-called optically dark galaxies are suggested to be high-redshift, heavily dust-obscured galaxies with star formation rates of hundreds of solar masses per year (Algera et al., 2020), making them interesting candidates for the study of cosmic star formation rate density (SFRD) in the early Universe (z ≳ 3), which is yet to be fully constrained. In this work, we present ALMA follow-up spectral scans at 84–108 GHz of ten radio-selected optically dark galaxies from the COSMOS-XS survey with SED-estimated 1.1 mm flux of S1.1mm > 3.5 mJy and no detected counterpart in the COSMOS2020 catalogue (Weaver et al., 2022). With the ALMA observations, we find unambiguous redshifts for six sources and identify multiple possible redshifts for the remaining four. For the ambiguous sources, we determine the most likely redshift solutions through SED fitting of photometric redshifts and further verify the results using the L′CO(5−4) − LIR correlation (Daddi et al., 2015). We find that this population is located between zspec = 2.36 − 4.82 with a median redshift of zspec = 3.50. Using the new Super-deblended catalogue (Jin et al., 2018; Jin et al., in prep), new ALMA continuum flux densities and publicly available JWST data, we estimate the galaxy physical properties through SED fitting with MAGPHYS+high-z to uncover their nature. The radio-selected optically dark galaxies are heavily dust-obscured (AV ∼ 3.5), very massive (M∗ ≳ 10¹¹ M⊙), and have high infrared luminosities (LIR > 10¹² L⊙). With SFRs ∼ 450 M⊙ yr−1, they are star-forming main-sequence galaxies. Finally, we determine the contribution of this optically dark population to the cosmic SFRD to be (3.22 ± 0.45) × 10⁻⁴ M⊙ yr⁻¹ Mpc⁻³ at z ∼ 2.4–4.8, confirming previous photometric estimates and highlighting the importance of including optically dark galaxies to obtain a complete picture of cosmic star formation.
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The small galaxies that built up the Galactic halo – BSc Thesis, supervised by Dr. Else Starkenburg, 2024
Abstract: The Milky Way halo is thought to have been created through numerous galactic mergers in the past. However, a complete analysis of its progenitors and their masses remains elusive. To investigate the merger history of the Galactic halo, we use a recent statistical method (Deason et al., 2023) based on the mass–metallicity relation, which links galaxy mass to stellar metallicity. Using a catalogue of halo-like stars (Viswanathan et al., 2023) with high-quality [Fe/H] measurements extending into the extremely metal-poor regime (Martin et al., 2023), we probe even the smallest accreted galaxies. We find that the progenitor mass spectrum is dominated by thousands of small galaxies with masses ≲ 10⁵ M⊙, while only a few tens of more massive progenitors are identified and a single most massive accreted system with mass ∼ 10⁸ M⊙. From this mass distribution, we infer a stellar mass for the Galactic halo of (6.1 ± 2.1) × 10⁸ M⊙. These findings provide new insight into the hierarchical assembly and merger history of the Milky Way halo.
Contact
STRW: bercuk@mail.strw.leidenuniv.nl
Outlook: i.bercuk@mail.umail.leidenuniv.nl