Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies

By Fabio Governato, A. Zolotov, Andrew Pontzen, C. Christensen, S. Oh, A. Brooks, Thomas Quinn, S. Shen, J. W. U. O. Washington, Hebrew Univ. Univ. of Oxford and 6 more. 2012

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We examine the evolution of the inner dark matter (DM) and baryonic density profile of a new sample of simulated field galaxies using fully cosmological, Lambda CDM, high resolution SPH + N-Body simulations. These simulations include explicit H2 and metal cooling, star formation (SF) and supernovae (SNe) driven gas outflows. Starting at high redshift, rapid, repeated gas outflows following bursty SF transfer energy to the DM component and significantly flatten the originally `cuspy' central DM mass profile of galaxies with present day stellar masses in the 10^4.5 -- 10^9.8 Msolar range. At z=0, the central slope of the DM density profile of our galaxies (measured between 0.3 and 0.7 kpc from their centre) is well fitted by rhoDM propto r^alpha with alpha \simeq -0.5 + 0.35 log_10(Mstar/10^8Msolar) where Mstar is the stellar mass of the galaxy and 4 < log_10 Mstar < 9.4. These values imply DM profiles flatter than those obtained in DM--only simulations and in close agreement with those inferred in galaxies from the THINGS and LITTLE THINGS survey. Only in very small halos, where by z=0 star formation has converted less than ~ 0.03% of the original baryon abundance into stars, outflows do not flatten the original cuspy DM profile out to radii resolved by our simulations. The mass (DM and baryonic) measured within the inner 500 pc of each simulated galaxy remains nearly constant over four orders of magnitudes in stellar mass for Mstar 10^9 Msolar. This finding is consistent with estimates for faint Local Group dwarfs and field galaxies. These results address one of the outstanding problems faced by the CDM model, namely the strong discrepancy between the original predictions of cuspy DM profiles and the shallower central DM distribution observed in galaxies.

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

View Paper: https://www.semanticscholar.org/paper/38198bc3c425c7047188db01774ec5c1f372e4a9

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Citations in the corpus

Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, background): “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 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).”
NIHAO project – I. Reproducing the inefficiency of galaxy formation across cosmic time with a large sample of cosmological hydrodynamical simulations (2015, neutral): “2 shows the mass resolution of our simulations compared to a number of state-of-the-art zoom-in (ERIS - Guedes et al. 2011; Governato et al. 2012; Aumer et al. 2013; Marinacci et al. 2014; FIRE - Hopkins et al. 2014) and large volume (ILLUSTRIS - Vogelsberger et al. 2014; EAGLE - Schaye et al.…”
Core formation in dwarf haloes with self-interacting dark matter: no fine-tuning necessary (2014, background): “For example, baryonic processes may act to reduce and flatten the central densities of small galaxies in CDM (e.g. Pontzen & Governato, 2012; Governato et al., 2012; Di Cintio et al., 2014; Navarro et al., 1996).”
The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology (2012, methodology): “A possible solution has been suggested by the simulations of Governato et al. (2012) but relies among other assumptions on a bursty star-formation rate (SFR) required to repeatedly blow out gas and a steep Kennicutt-Schmidt exponent (n¼ 1.5) in SFRprgas n , where SFR is the star formation rate and…”
How Stellar Feedback Simultaneously Regulates Star Formation and Drives Outflows (2015, methodology): “The other commonly used technique is the ‘blastwave’ model, in which thermal energy is injected into the ISM surrounding supernova particles (e.g.Katz et al. 1996; Thacker & Couchman 2000; Stinson et al. 2006, 2013; Governato et al. 2007, 2010, 2012; Dubois & Teyssier 2008; Bournaud et al. 2010).”
The SAMI Galaxy Survey: Instrument specification and target selection (2014, background): “Recent simulations also suggest that the transformation of cuspy dark matter density profiles into shallower cored profiles varies with mass (Governato et al. 2012; di Cinto et al. 2014).”
Can feedback solve the too-big-to-fail problem? (2013, background): “Some groups (e.g. Governato et al. 2012; Del Popolo 2012) have successfully reproduced the low central densities of LSBs by invoking supernovae feedback in cosmological zoom-in simulations.”
Axion dark matter, solitons and the cusp–core problem (2015, background): “Baryonic physics, for example feedback or dynamical friction, offers possibilities to resolve some or all of these problems within the framework of CDM (e.g. Del Popolo 2009; Governato et al. 2012; Pontzen & Governato 2014, and references therein).”
The dependence of dark matter profiles on the stellar-to-halo mass ratio: a prediction for cusps versus cores (2013, methodology): “The wide mass range of our simulated galaxies,5.0 × 105 < M⋆/M⊙ < 8.3×10 10 , allows us to confirm and extend the results of Governato et al. (2012).”
The current status of galaxy formation (2012, background): “Outflows may reproduce the observed cores (Governato et al., 2012) if the SFE is high at early epochs, but such models fail to result in the strong evolution observed at low redshift (Weinmann et al., 2012).”
The accretion history of dark matter haloes - III. A physical model for the concentration-mass relation (2015, methodology): “M relation and will modify the inner density profile (e.g. Duffy et al. 2010; Governato et al. 2012; Teyssier et al. 2013; Schaller et al. 2014).”
Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter (2014, background): “…is efficient and (ii) for the mass scale we are considering, halo mass ∼1010 M for halo dA, the energy released by SNe is not expected to be sufficient to create sizeable DM cores (Governato et al. 2012; Peñarrubia et al. 2012; Garrison-Kimmel et al. 2013), although see Teyssier et al. (2013).”
Galaxies on FIRE (Feedback In Realistic Environments): stellar feedback explains cosmologically inefficient star formation (2013, methodology): “…wide range of galaxy properties and numerical methods (Pelupessy et al. 2004; Stinson et al. 2007, 2013; Mashchenko et al. 2008; Valcke et al. 2008; Governato et al. 2010, 2012; Oser et al. 2010; Feldmann et al. 2009; Brooks et al. 2011; Guedes et al. 2011; Sawala et al. 2011; Scannapieco et al.…”
Constraining self-interacting dark matter with the Milky Way’s dwarf spheroidals (2012, background): “Current hydrodynamical simulations have shown that such a mechanism is able to create large cores in intermediate-mass galaxies (Governato et al. 2010, 2012), and, once tidal stripping is taken into account, it might solve the too big to fail problem as well (Brooks & Zolotov 2012).”