BARYONS MATTER: WHY LUMINOUS SATELLITE GALAXIES HAVE REDUCED CENTRAL MASSES

By A. Zolotov, A. Brooks, B. Willman, Fabio Governato, Andrew Pontzen, C. Christensen, A. Dekel, Thomas R. Quinn, S. Shen, James Wadsley. 2012

269 citations recorded by the source corpus.

Using high-resolution cosmological hydrodynamical simulations of Milky Way-massed disk galaxies, we demonstrate that supernovae feedback and tidal stripping lower the central masses of bright (−15 < MV < −8) satellite galaxies. These simulations resolve high-density regions, comparable to giant molecular clouds, where stars form. This resolution allows us to adopt a prescription for H2 formation and destruction that ties star formation to the presence of shielded, molecular gas. Before infall, supernova feedback from the clumpy, bursty star formation captured by this physically motivated model leads to reduced dark matter (DM) densities and shallower inner density profiles in the massive satellite progenitors (Mvir ⩾ 109 M☉, M* ⩾ 107 M☉) compared with DM-only simulations. The progenitors of the lower mass satellites are unable to maintain bursty star formation histories, due to both heating at reionization and gas loss from initial star-forming events, preserving the steep inner density profile predicted by DM-only simulations. After infall, gas stripping from satellites reduces the total central masses of satellites simulated with DM+baryons relative to DM-only satellites. Additionally, enhanced tidal stripping after infall due to the baryonic disk acts to further reduce the central DM densities of the luminous satellites. Satellites that enter with cored DM halos are particularly vulnerable to the tidal effects of the disk, exacerbating the discrepancy in the central masses predicted by baryon+DM and DM-only simulations. We show that DM-only simulations, which neglect the highly non-adiabatic evolution of baryons described in this work, produce denser satellites with larger central velocities. We provide a simple correction to the central DM mass predicted for satellites by DM-only simulations. We conclude that DM-only simulations should be used with great caution when interpreting kinematic observations of the Milky Way's dwarf satellites.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/fbb39a7d3735f51b1d4df4833fd3d346ab39309f

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “Recent hydrodynamical simulations demonstrate that such feedback from galaxy formation can turn primordial NFW ‘cusps’ into ‘cores’ of near-uniform dark matter density (e.g. Zolotov et al. 2012; Madau, Shen & Governato 2014; Read, Agertz & Collins 2016).”
Toy models for galaxy formation versus simulations (2013, background): “We note that this may not be true for less massive galaxies and at higher redshifts, where feedback is likely to be more effective in suppressing star formation and accumulating a gas reservoir (e.g. Zolotov et al. 2012; Krumholz & Dekel 2012).”
The local dark matter density (2014, background): “Such cored dwarfs are then much more easily tidally disrupted by the Milky Way (MW), plausibly solving the missing satellites problem too (Read et al., 2006b; Zolotov et al., 2012).”
Too big to fail in the Local Group (2014, background): “…supernova feedback, ram pressure stripping, and tidal interactions, may account for the discrepancy (e.g. Del Popolo 2012; Pontzen & Governato 2012; Zolotov et al. 2012; Brooks et al. 2013; Gritschneder & Lin 2013; Amorisco, Zavala & de Boer 2014; Arraki et al. 2014; Brooks & Zolotov 2014; Del…”
Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter (2014, background): “Even though environmental effects such as tidal stripping might alleviate this stringent energetic condition in the case of satellite galaxies (Zolotov et al. 2012; Brooks et al. 2013; Arraki et al. 2014), the issue of low central DM densities seems relevant even for isolated galaxies (Ferrero et…”
(Star)bursts of FIRE: observational signatures of bursty star formation in galaxies (2015, result): “In contrast, several recent simulations have attempted to physically model the effects of feedback on star-forming clouds instead of imposing a sub-resolution description of them (Stinson et al. 2006; Mashchenko et al. 2008; Governato et al. 2010; Zolotov et al. 2012; Teyssier et al. 2013).”
Can feedback solve the too-big-to-fail problem? (2013, methodology): “Others (e.g. Read & Gilmore 2005; Zolotov et al. 2012; Teyssier et al. 2012) have managed to flatten the central density profiles of larger dwarf galaxies (M?”
THE COUPLING BETWEEN THE CORE/CUSP AND MISSING SATELLITE PROBLEMS (2012, background): “Recent hydrodynamical simulations show that baryonic feedback lowers the number of surviving satellites with respect to the DM-only case (Zolotov et al. 2012).”
The impact of baryonic physics on the structure of dark matter haloes: the view from the FIRE cosmological simulations (2015, background): “The effect of host galaxies on satellites, e.g. tidal stripping, could also modify the structure of DM halos (Zolotov et al. 2012; Brooks & Zolotov 2014).”
WHY BARYONS MATTER: THE KINEMATICS OF DWARF SPHEROIDAL SATELLITES (2012, methodology): “After infall, the presence of a baryonic disk in the host galaxy increases the mass loss rate for all satellites via tidal stripping (Zolotov et al. 2012; Arraki et al. 2012).”
A BARYONIC SOLUTION TO THE MISSING SATELLITES PROBLEM (2012, background): “Recently, the effects of baryons on the dark matter halo profiles of luminous satellite galaxies was studied by Zolotov et al. (2012).”
Dark matter cores all the way down (2015, background): “Such cored dwarfs are also much more efficiently tidally stripped, which can significantly alleviate the missing satellites problem (Read et al. 2006c; Peñarrubia et al. 2010; Zolotov et al. 2012; Brooks et al. 2013).”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “…are generally absent in dark-matter-only simulations7), and these environmental influences are often invoked in explaining too-big-to-fail (e.g., Zolotov et al. 2012; Arraki et al. 2014; Brooks & Zolotov 2014; Brook & Di Cintio 2015; Wetzel et al. 2016; Tomozeiu, Mayer & Quinn 2016; Sawala et…”
Quenching and ram pressure stripping of simulated Milky Way satellite galaxies (2017, background): “…MW analog satellite systems have typically focused either on one to a few high resolution cosmological models with gas physics (Okamoto et al. 2010; Zolotov et al. 2012; Wetzel et al. 2016) or have focused on a large suite of dark matter only models that better probe cosmic variance, but do not…”
The stellar mass-halo mass relation of isolated field dwarfs : a critical test of ΛCDM at the edge of galaxy formation (2016, background): “…of dwarfs from discs to spheroids (Mayer et al. 2001a; Lokas et al. 2012; Kazantzidis et al. 2013); and physically reshapes the dark matter halo mass function within groups (Peñarrubia et al. 2010; Zolotov et al. 2012; Brooks et al. 2013; Wetzel et al. 2016, and see the discussion in R16a).”
Forged in FIRE: cusps, cores and baryons in low-mass dwarf galaxies (2015, background): “We have not considered the effects stripping from ram pressure and tides, that may be important for some Milky Way subhalos (Read et al. 2006; Zolotov et al. 2012; Brooks & Zolotov 2014).”