Hierarchical Galaxy Formation and Substructure in the Galaxy’s Stellar Halo

By James S. Bullock, Andrey V. Kravtsov, D. Weinberg. 2000

262 citations recorded by the source corpus.

We develop an explicit model for the formation of the stellar halo from tidally disrupted, accreted dwarf satellites in the cold dark matter (CDM) framework, focusing on predictions testable with the Sloan Digital Sky Survey (SDSS) and other wide-field surveys. Subhalo accretion and orbital evolution are calculated using a semianalytic approach based on the extended Press-Schechter formalism. Motivated by our previous work, we assume that low-mass subhalos (vc < 30 km s-1) form significant populations of stars only if they accreted a substantial fraction of their mass before the epoch of reionization. With this assumption, the model reproduces the observed velocity function of galactic satellites in the Local Group, solving the "dwarf satellite problem" without modifying the basic tenets of the popular Λ + CDM cosmological scenario. The tidally disrupted satellites in this model yield a stellar distribution whose total mass and radial density profile are consistent with those observed for the Milky Way stellar halo. Most significantly, the model predicts the presence of many large-scale, coherent substructures in the outer halo. These substructures are remnants of individual tidally disrupted dwarf satellite galaxies. Substructure is more pronounced at large galactocentric radii because of the smaller number density of tidal streams and the longer orbital times. This model provides a natural explanation for the coherent structures in the outer stellar halo found in the SDSS commissioning data, and it predicts that many more such structures should be found as the survey covers more of the sky. The detection (or nondetection) and characterization of such structures could eventually test variants of the CDM scenario, especially those that aim to solve the dwarf satellite problem by enhancing satellite disruption.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/696104e5200183834c7329a02aae08ea1f2978c9

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Citations in the corpus

The stellar halo of the Galaxy (2008, background): “In particular, a stellar halo is easily built up via the superposition of disrupted satellites (Johnston et al. 1996; Helmi & White 1999; Bullock et al. 2001; Harding et al. 2001).”
The Luminosity Function of the Milky Way Satellites (2007, background): “Alternatively, star formation in low mass systems could be inhibited by photoionization in the early Universe (Bullock et al. 2001; Somerville 2002; Benson et al. 2002).”
Exploring the Variable Sky with the Sloan Digital Sky Survey (2007, background): “The apparent ‘‘clumpiness’’ of the candidate RR Lyrae distribution increases with increasing radius, similar to CDM predictions by Bullock et al. (2001).”
Direct Detection of Warm Dark Matter in the X-Ray (2001, background): “On the other hand, the lack of dwarf galaxies may be caused by feedback processes from supernovae and heating in small halos because of the initial formation of very massive stars in a zero-metallicity environment (Bullock et al. 2001; Binney et al. 2001; Abel et al. 1998).”
Two Distinct Ancient Components in the Sculptor Dwarf Spheroidal Galaxy: First Results from the Dwarf Abundances and Radial Velocities Team (2004, background): “It might also be that events surrounding the epoch of reionization strongly influenced the evolution of these small galaxies (e.g., Bullock et al. 2001; Skillman et al. 2003) and resulted in the stripping or photoevaporation of the outer layers of gas in the dSph galaxy, meaning that subsequent…”
Λ Cold Dark Matter, Stellar Feedback, and the Galactic Halo Abundance Pattern (2005, background): “…as the dissipationless dark halo of the host is built from the dark matter that was originally associated with accreted and destroyed subhalos, the stellar halo is built from the dissipationlessstellar matter that was associated with the same population of destroyed galaxies (Bullock et al. 2001).”
Tracing Galaxy Formation with Stellar Halos. I. Methods (2005, methodology): “For satellites, we set the value of c using the simulation results of Bullock et al. (2001) and the corresponding relationship between halo mass, redshift, and concentration summarized by their analytic model.”
Farthest Neighbor: The Distant Milky Way Satellite Eridanus II (2016, background): “Alternatively, the quenching of Eri II could have been caused by cosmic reionization at high redshift (e.g., Bul- lock et al. 2001; Brown et al. 2014).”
Unusually Large Fluctuations in the Statistics of Galaxy Formation at High Redshift (2003, background): “For instance, photoionization heating suppresses the formation of dwarf galaxies after reionization, suggesting that the smallest galaxies seen today may have formed prior to reionization (Bullock et al. 2001; Somerville 2002; Benson et al. 2002).”
Compound Gravitational Lensing as a Probe of Dark Matter Substructure within Galaxy Halos (2001, background): “…near this boundary of destruction and survival at RD 30 kpc. High-resolution N-body simulations show, however, a large scatter about this relation (Bullock et al. 2001a), and in low-density models such as currently popular "CDM, the halos are more concentrated and thus more able to is reduced by…”
EIGHT ULTRA-FAINT GALAXY CANDIDATES DISCOVERED IN YEAR TWO OF THE DARK ENERGY SURVEY (2015, background): “…population of near-field galaxies in a unique position to allow the testing of models of galaxy formation and the cold dark matter paradigm (e.g., Bullock et al. 2001), and has motivated studies ranging from the physical conditions at the time of reionization (e.g., Bullock et al. 2000; Benson…”
A White Paper on keV sterile neutrino Dark Matter (2016, result): “[416, 417] and more recent simulations, confirm this conclusion.”
Merger Histories of Galaxy Halos and Implications for Disk Survival (2007, background): “…et al. 2005; Kazantzidis et al. 2007; Hayashi & Chiba 2006), cause anti-truncation (Younger et al. 2007), and produce extended diffuse light components around galaxies (Johnston et al. 1996; Helmi & White 1999; Bullock et al. 2001; Bullock & Johnston 2005; Purcell et al. 2007; Bell et al. 2007).”
Not so lumpy after all: modelling the depletion of dark matter subhaloes by Milky Way-like galaxies (2017, background): “…structure of the stellar halo, particularly close to the MW. Specifically, the majority of the destroyed satellites that make up the stellar halo (Bullock et al. 2001; Bullock & Johnston 2005; Bell et al. 2008) were likely on plunging, highly radial orbits, such that their resultant stellar…”