Mass loss from dwarf spheroidal galaxies: the origins of shallow dark matter cores and exponential surface brightness profiles

By Justin I. Read, G. Gilmore. 2004

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Dwarf spheroidal galaxies have shallow central dark matter density profiles, low angular momentum and approximately exponential surface brightness distributions. Through N-body simulations and analytic calculations we investigate the extent to which these properties can be generated from ‘typical’ΛCDM galaxies, which differ in all of these properties, by the dynamical consequences of feedback. We find that, for a wide range of initial conditions, one impulsive mass-loss event will naturally produce a surface brightness profile in the remaining stellar component of a dwarf spheroidal galaxy (dSph) which is well-fitted over many scalelengths by an exponential, in good qualitative agreement with observations of Local Group dSphs. Furthermore, two impulsive mass-loss phases, punctuated by significant gas re-accretion, are found to be sufficient to transform a central density cusp in the dark matter profile into a near-constant density core. This may then provide the missing link between current cosmological simulations, which predict a central cusp in the dark matter density profile, and current observations, which find much shallower central density profiles. We also look at the angular momentum history of dSphs and demonstrate that if these galaxies have spent most of their lifetime in tidal isolation from massive galaxies then they cannot have formed from high angular momentum gas discs.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/1d8e4549a5d24a96ee2c46a3f6b450c65401e49f

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Citations in the corpus

On the onset of galactic winds in quiescent star forming galaxies (2007, background): “…2003) or “angular momentum” (Navarro & Benz 1991; Sommer-Larsen et al. 1999; Steinmetz & Navarro 1999; Send offprint requests to: Y. Dubois Bullock et al. 2001; Maller & Dekel 2002; Abadi et al. 2003; Sommer-Larsen et al. 2003; Read & Gilmore 2005) problem, may all have the same physical origin.”
Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, result): “500 pc that are consistent with the observations (e.g. Navarro et al. 1996; Read & Gilmore 2005; Mashchenko et al. 2008; Pontzen & Governato 2012; Governato et al. 2012; Amorisco et al. 2014; Gritschneder & Lin 2013; Oñorbe et al. 2015; Chan et al. 2015).”
The haloes of bright satellite galaxies in a warm dark matter universe (2011, result): “Recent simulations (Read & Gilmore 2005; Mashchenko et al. 2008; Governato et al. 2010) suggest that these processes could be important although it remains to be seen if they are enough to reconcile the CDM model with the dynamics of the Milky Way satellites.”
Formation of isolated dwarf galaxies with feedback (2009, methodology): “Within the framework of ΛCDM, numerical simulations by Navarro et al. (1996), Read & Gilmore (2005), Mashchenko et al. (2008) and others have suggested that cores of kpc scale may form either as a result of dynamical coupling to supernova-induced bulk gas motions, or the rapid ejection of large…”
A BARYONIC SOLUTION TO THE MISSING SATELLITES PROBLEM (2012, background): “…matter within halos, potentially steepening (Blumenthal et al. 1986; Gnedin & Zhao 2002; Gnedin et al. 2011) or flattening (Navarro et al. 1996; Read & Gilmore 2005; Mashchenko et al. 2006, 2008; Governato et al. 2010; Pasetto et al. 2010; de Souza et al. 2011; Cloet-Osselaer et al. 2012;…”
BREATHING FIRE: HOW STELLAR FEEDBACK DRIVES RADIAL MIGRATION, RAPID SIZE FLUCTUATIONS, AND POPULATION GRADIENTS IN LOW-MASS GALAXIES (2015, background): “Recently, a number of studies (for example, Read & Gilmore 2005; Pontzen & Governato 2012; Governato et al. 2012; Di Cintio et al. 2014; Oñorbe et al. 2015; Chan et al. 2015) have shown that including stellar feedback in simulations can significantly alter dwarf galaxies’ density profiles,…”
Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies (2012, background): “…halos into halos with ’cored’ density profiles through SN feedback or dynamical friction (Navarro et al. 1996a; Dekel et al. 2003b,a; Mo & Mao 2004; Read & Gilmore 2005; Mashchenko et al. 2006; Goerdt et al. 2006; Tonini et al. 2006; El-Zant et al. 2004; Romano-Dı́az et al. 2009; Del Popolo…”
The DiskMass Survey VII. The distribution of luminous and dark matter in spiral galaxies (2013, background): “…several processes may occur that could also expand the halo, such as dynamical friction between the halo and infalling galaxies (e.g., El-Zant et al. 2001), or mass outflows from central starbursts and active galactic nuclei (Read & Gilmore 2005; Governato et al. 2012; Pontzen & Governato 2012).”
The Milky Way’s bright satellites as an apparent failure of ΛCDM (2011, result): “This may be viewed as an instantaneous blow-out scenario, similar to that envisioned by Navarro et al. (1996) and Read & Gilmore (2005).”
The dependence of dark matter profiles on the stellar-to-halo mass ratio: a prediction for cusps versus cores (2013, background): “As outlined in§1, core formation from stellar feedback depends on repeated starbursts that are able to move gas enoughto have a dynamical effect on the dark matter (Read & Gilmore 2005; Governato et al. 2010; Macciò et al. 2012; Pontzen & Governato 2012; Teyssier et al. 2013).”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “…2000), but even within cold DM cosmology the inner density profiles of galaxy-hosting haloes can be substantially flattened via strong stellar feedback (e.g. El-Zant, Shlosman & Hoffman 2001; Gnedin et al. 2004; Read & Gilmore 2005; Mashchenko, Wadsley & Couchman 2008; Pontzen & Governato 2012).”
THE CENTRAL SLOPE OF DARK MATTER CORES IN DWARF GALAXIES: SIMULATIONS VERSUS THINGS (2010, background): “A rapid change in potential (faster than the dynamical time) due to star burst triggered outflows, is one mechanism which has been shown to be capable of transforming cusp–like profiles into (flatter) cores (Navarro et al. 1996; Read & Gilmore 2005 although see Gnedin & Zhao 2002).”
NIHAO – IV: core creation and destruction in dark matter density profiles across cosmic time (2015, background): “These strong gas outflows are triggered by stellar (and AGN) feedback (Navarro, Eke & Frenk 1996; Read & Gilmore 2005; Mashehenko, Couchman & Wadsley 2006; Pontzen & Governato 2014; Martizzi et al. 2013).”
THE COUPLING BETWEEN THE CORE/CUSP AND MISSING SATELLITE PROBLEMS (2012, background): “…mechanisms have been proposed and demonstrated to be capable of fixing both problemsseparately: e.g. supernova explosions (Navarro et al. 1996, Read & Gilmore 2005; Mashchenko et al. 2008; Governato et al. 2010; Pontzen & Governato 2012), jorpega@iaa.es 1 Ramón y Cajal Fellow, Instituto de…”
The impact of baryonic physics on the structure of dark matter haloes: the view from the FIRE cosmological simulations (2015, methodology): “…also play a role in shaping the dark matter profiles (Blumenthal et al. 1986; Navarro et al. 1996; El-Zant et al. 2001; Gnedin et al. 2004; Read & Gilmore 2005; Governato et al. 2010; Peñarrubia et al. 2012; Governato et al. 2012; Pontzen & Governato 2012; Macciò et al. 2012b; Teyssier et…”