Galaxy formation and evolution

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The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 504:4 (2021) 5098-5130

Authors:

Francesco D’Eugenio, Matthew Colless, Nicholas Scott, Arjen van der Wel, Roger L Davies, Jesse van de Sande, Sarah M Sweet, Sree Oh, Brent Groves, Rob Sharp, Matt S Owers, Joss Bland-Hawthorn, Scott M Croom, Sarah Brough, Julia J Bryant, Michael Goodwin, Jon S Lawrence, Nuria PF Lorente, Samuel N Richards
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EDGE: two routes to dark matter core formation in ultra-faint dwarfs

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 504:3 (2021) 3509-3522

Authors:

Matthew DA Orkney, Justin I Read, Martin P Rey, Imran Nasim, Andrew Pontzen, Oscar Agertz, Stacy Y Kim, Maxime Delorme, Walter Dehnen

Abstract:

ABSTRACT In the standard Lambda cold dark matter paradigm, pure dark matter simulations predict dwarf galaxies should inhabit dark matter haloes with a centrally diverging density ‘cusp’. This is in conflict with observations that typically favour a constant density ‘core’. We investigate this ‘cusp-core problem’ in ‘ultra-faint’ dwarf galaxies simulated as part of the ‘Engineering Dwarfs at Galaxy formation’s Edge’ project. We find, similarly to previous work, that gravitational potential fluctuations within the central region of the simulated dwarfs kinematically heat the dark matter particles, lowering the dwarfs’ central dark matter density. However, these fluctuations are not exclusively caused by gas inflow/outflow, but also by impulsive heating from minor mergers. We use the genetic modification approach on one of our dwarf’s initial conditions to show how a delayed assembly history leads to more late minor mergers and, correspondingly, more dark matter heating. This provides a mechanism by which even ultra-faint dwarfs ($M_* \lt 10^5\, \text{M}_{\odot }$), in which star formation was fully quenched at high redshift, can have their central dark matter density lowered over time. In contrast, we find that late major mergers can regenerate a central dark matter cusp, if the merging galaxy had sufficiently little star formation. The combination of these effects leads us to predict significant stochasticity in the central dark matter density slopes of the smallest dwarfs, driven by their unique star formation and mass assembly histories.
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A Complete 16 μm Selected Galaxy Sample at z ∼ 1: Mid-infrared Spectral Energy Distributions

The Astrophysical Journal American Astronomical Society 912:2 (2021) 161

Authors:

J-S Huang, Y-S Dai, SP Willner, SM Faber, C Cheng, H Xu, H Yan, S Wu, X Shao, C Hao, X Xia, D Rigopoulou, M Pereira Santaella, G Magdis, I Cortzen, GG Fazio, P Assmann, L Fan, M Musin, Z Wang, KC Xu, C He, G Jin, A Esamdin
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Accurate Identification of Galaxy Mergers with Stellar Kinematics

The Astrophysical Journal American Astronomical Society 912:1 (2021) 45

Authors:

R Nevin, L Blecha, J Comerford, JE Greene, DR Law, DV Stark, KB Westfall, JA Vazquez-Mata, R Smethurst, M Argudo-Fernández, JR Brownstein, N Drory
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Investigating Clumpy Galaxies in the Sloan Digital Sky Survey Stripe 82 Using the Galaxy Zoo

The Astrophysical Journal American Astronomical Society 912:1 (2021) 49

Authors:

Vihang Mehta, Claudia Scarlata, Lucy Fortson, Hugh Dickinson, Dominic Adams, Jacopo Chevallard, Stéphane Charlot, Melanie Beck, Sandor Kruk, Brooke Simmons
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