Heated Disk Stars in the Stellar Halo (2009)
Purcell, Chris W., Bullock, James S., Kazantzidis, Stelios
Minor accretion events with mass ratio M_sat : M_host ~ 1:10 are common in the context of LCDM cosmology. We use high-resolution simulations of Galaxy-analogue systems to show that these mergers can...
Tracking Evolutionary Processes with Large Samples of Galaxy Pairs (2009)
Barton, Elizabeth J., Trinh, Christopher Q., Bullock, James S., Wright, Shelley A.
Modern redshift surveys enable the identification of large samples of galaxies in pairs, taken from many different environments. Meanwhile, cosmological simulations allow a detailed understanding of...
Accurate masses for dispersion-supported galaxies (2009)
Wolf, Joe, Martinez, Gregory D., Bullock, James S., Kaplinghat, Manoj, Geha, Marla, Munoz, Ricardo R., ...
We derive an accurate mass estimator for dispersion-supported stellar systems and demonstrate its validity by analyzing resolved line-of-sight velocity data for globular clusters, dwarf galaxies, and...
The Dark Disk of the Milky Way (2009)
Purcell, Chris W., Bullock, James S., Kaplinghat, Manoj
Massive satellite accretions onto early galactic disks can lead to the deposition of dark matter in disk-like configurations that co-rotate with the galaxy. This phenomenon has potentially dramatic...
Martinez, Gregory D., Bullock, James S., Kaplinghat, Manoj, Strigari, Louis E., Trotta, Roberto
We present a general methodology for determining the gamma-ray flux from annihilation of dark matter particles in Milky Way satellite galaxies, focusing on two promising satellites as examples: Segue...
Bullock, James S., Kaplinghat, Manoj, Fruchter, Andrew, Geha, Marla, Simon, Joshua D., Strigari, Louis E., ...
Over the past five years, searches in Sloan Digital Sky Survey data have more than doubled the number of known dwarf satellite galaxies of the Milky Way, and have revealed a population of ultra-faint...
Strong gravitational lensing probes of the particle nature of dark matter (2009)
Moustakas, Leonidas A., Abazajian, Kevork, Benson, Andrew, Bolton, Adam S., Bullock, James S., Chen, Jacqueline, ...
There is a vast menagerie of plausible candidates for the constituents of dark matter, both within and beyond extensions of the Standard Model of particle physics. Each of these candidates may have...
Structure and Substructure of Galactic Spheroids (2009)
Romanowsky, Aaron J., Brodie, Jean P., Bullock, James S., Ciardullo, Robin, Guhathakurta, Puraga, Hoffman, Loren, ...
The full spatio-chemo-dynamical structure of galaxies of all types and environments at low redshift provides a critical accompaniment to observations of galaxy formation at high redshift. The next...
The Role of Dwarf Galaxies in Building Large Stellar Halos (2009)
Kirby, Evan N., Guhathakurta, Puragra, Bullock, James S., Frebel, Anna, Geha, Marla, Gilbert, Karoline M., ...
The hierarchical theory of galaxy formation rests on the idea that smaller galactic structures merge to form the galaxies that we see today. The past decade has provided remarkable observational...
Kazantzidis, Stelios, Zentner, Andrew R., Kravtsov, Andrey V., Bullock, James S., Debattista, V. P.
(Abridged) We perform dissipationless N-body simulations to elucidate the dynamical response of thin disks to bombardment by cold dark matter (CDM) substructure. Our method combines (1) cosmological...
Gas-Rich Mergers in LCDM: Disk Survivability and the Baryonic Assembly of Galaxies (2009)
Stewart, Kyle R., Bullock, James S., Wechsler, Risa H., Maller, Ariyeh H.
We use N-body simulations and observationally-normalized relations between dark matter halo mass, stellar mass, and cold gas mass to derive robust, arguably inevitable expectations about the baryonic...
Kaufmann, Tobias, Bullock, James S., Maller, Ariyeh H., Fang, Taotao, Wadsley, James
We present a pair of high-resolution smoothed particle hydrodynamics (SPH) simulations that explore the evolution and cooling behavior of hot gas around Milky-Way size galaxies. The simulations...
Stewart, Kyle R., Bullock, James S., Barton, Elizabeth J., Wechsler, Risa H.
We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies--such as close pair...
Mergers and Disk Survival in LCDM (2008)
Bullock, James S., Stewart, Kyle R., Purcell, Chris W.
Disk galaxies are common in our universe and this is a source of concern for hierarchical formation models like LCDM. Here we investigate this issue as motivated by raw merger statistics derived for...
The Destruction of Thin Stellar Disks Via Cosmologically Common Satellite Accretion Events (2008)
Purcell, Chris W., Kazantzidis, Stelios, Bullock, James S.
Most Galaxy-sized systems (M_host ~ 10^12 M_sun) in the LCDM cosmology are expected to have accreted at least one satellite with a total mass M_sat ~ 10^11 M_sun = 3M_disk in the past 8 Gyr. Analytic...
A common mass scale for satellite galaxies of the Milky Way (2008)
Strigari, Louis E., Bullock, James S., Kaplinghat, Manoj, Simon, Joshua D., Geha, Marla, Willman, Beth, ...
The Milky Way has at least twenty-three known satellite galaxies that shine with luminosities ranging from about a thousand to a billion times that of the Sun. Half of these galaxies were discovered...
High-Redshift Galaxy Kinematics: Constraints on Models of Disk Formation (2008)
Robertson, Brant E., Bullock, James S.
Integral field spectroscopy of galaxies at redshift z~2 has revealed a population of early-forming, rotationally-supported disks. These high-redshift systems provide a potentially important clue to...
Johnston, Kathryn V., Bullock, James S., Sharma, Sanjib, Font, Andreea, Robertson, Brant E., Leitner, Samuel N.
This paper explores the mapping between the observable properties of a stellar halo in phase- and abundance-space and the parent galaxy's accretion history in terms of the characteristic epoch of...
Cold Dark Matter Substructure and Galactic Disks (2008)
Kazantzidis, Stelios, Zentner, Andrew R., Bullock, James S.
We perform a set of high-resolution, dissipationless N-body simulations to investigate the influence of cold dark matter (CDM) substructure on the dynamical evolution of thin galactic disks. Our...
Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function (2008)
Tollerud, Erik J., Bullock, James S., Strigari, Louis E., Willman, Beth
We correct the observed Milky Way satellite luminosity function for luminosity bias using published completeness limits for the Sloan Digital Sky Survey DR5. Assuming that the spatial distribution of...
The Observatory for Multi-Epoch Gravitational Lens Astrophysics (OMEGA) (2008)
Moustakas, Leonidas A, Bolton, Adam J, Booth, Jeffrey T, Bullock, James S, Cheng, Edward, Coe, Dan, ...
(abridged) The Observatory for Multi-Epoch Gravitational Lens Astrophysics (OMEGA) is a mission concept for a 1.5-m near-UV through near-IR space observatory that will be dedicated to frequent...
The Metallicity of Diffuse Intrahalo Light (2008)
Purcell, Chris W., Bullock, James S., Zentner, Andrew R.
We make predictions for the metallicity of diffuse stellar components in systems ranging from small spiral galaxies to rich galaxy clusters. We extend the formalism of Purcell et al. (2007), in which...
Strigari, Louis E., Koushiappas, Savvas M., Bullock, James S., Kaplinghat, Manoj, Simon, Joshua D., Geha, Marla, ...
We use kinematic data from three new nearby, extremely low luminosity Milky Way dwarf galaxies (Ursa Major II, Willman 1, and Coma Berenices) to constrain the properties of their dark matter halos,...
The Assembly of Galaxy Clusters (2008)
Berrier, Joel C., Stewart, Kyle R., Bullock, James S., Purcell, Chris W., Barton, Elizabeth J., Wechsler, Risa H.
We study the formation of fifty-three galaxy cluster-size dark matter halos formed within a pair of cosmological LCDM N-body simulations, and track the accretion histories of cluster subhalos with...
A Candidate Brightest Proto-Cluster Galaxy at z = 3.03 (2008)
Cooke, Jeff, Barton, Elizabeth J., Bullock, James S., Stewart, Kyle R., Wolfe, Arthur M.
We report the discovery of a very bright (m_R = 22.2) Lyman break galaxy at z = 3.03 that appears to be a massive system in a late stage of merging. Deep imaging reveals multiple peaks in the...
Simulating the Gaseous Halos of Galaxies (2008)
Kaufmann, Tobias, Bullock, James S., Maller, Ari, Fang, Taotao
Observations of local X-ray absorbers, high-velocity clouds, and distant quasar absorption line systems suggest that a significant fraction of baryons may reside in multi-phase, low-density,...
The Observatory for Multi-Epoch Gravitational Lens Astrophysics (OMEGA) (2008)
Moustakas, Leonidas A., Bolton, Adam J., Booth, Jeffrey T., Bullock, James S., Cheng, Edward, Coe, Dan, ...
The accretion origin of the Milky Way's stellar halo (2008)
Bell, Eric F., Zucker, Daniel B., Belokurov, Vasily, Sharma, Sanjib, Johnston, Kathryn V., Bullock, James S., ...
We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using ~4 million color-selected...
Merger Histories of Galaxy Halos and Implications for Disk Survival (2007)
Stewart, Kyle R., Bullock, James S., Wechsler, Risa H., Maller, Ariyeh H., Zentner, Andrew R.
We study the merger histories of galaxy dark matter halos using a high resolution LCDM N-body simulation. Our merger trees follow ~17,000 halos with masses M_0 = (10^11--10^13) Msun at z=0 and track...
Font, Andreea S., Johnston, Kathryn V., Ferguson, Annette M. N., Bullock, James S., Robertson, Brant E., Tumlinson, Jason, ...
Recent observations have revealed that high surface-brightness, metal-rich debris is present over large regions of the Andromeda (M31) stellar halo. We use a set of numerical models to determine...
Strigari, Louis E., Koushiappas, Savvas M., Bullock, James S., Kaplinghat, Manoj, Simon, Joshua D., Geha, Marla, ...
We use kinematic data from three new, nearby, extremely low-luminosity Milky Way dwarf galaxies (Ursa Major II, Willman 1, and Coma Berenices) to constrain the properties of their dark matter halos,...
Isolating Triggered Star Formation (2007)
Barton, Elizabeth J., Arnold, Jacob A., Zentner, Andrew R., Bullock, James S., Wechsler, Risa H.
Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic...
Kazantzidis, Stelios, Bullock, James S., Zentner, Andrew R., Kravtsov, Andrey V., Moustakas, Leonidas A.
(Abridged) We conduct a series of high-resolution, dissipationless N-body simulations to investigate the cumulative effect of substructure mergers onto thin disk galaxies in the context of the LCDM...
On the morphologies, gas fractions, and star formation rates of small galaxies (2007)
Kaufmann, Tobias, Wheeler, Coral, Bullock, James S.
We use a series of N-body/smoothed particle hydrodynamics simulations and analytic arguments to show that the presence of an effective temperature floor in the interstellar medium at T_F ~ 10^4 K...
The accretion origin of the Milky Way's stellar halo (2007)
Bell, Eric F., Zucker, Daniel B., Belokurov, Vasily, Sharma, Sanjib, Johnston, Kathryn V., Bullock, James S., ...
We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using about 4 million color-selected...
Redefining the Missing Satellites Problem (2007)
Strigari, Louis E., Bullock, James S., Kaplinghat, Manoj, Diemand, Juerg, Kuhlen, Michael, Madau, Piero
Numerical simulations of Milky-Way size Cold Dark Matter (CDM) halos predict a steeply rising mass function of small dark matter subhalos and a substructure count that greatly outnumbers the observed...
Shredded Galaxies as the Source of Diffuse Intrahalo Light On Varying Scales (2007)
Purcell, Chris W., Bullock, James S., Zentner, Andrew R.
We make predictions for diffuse stellar mass fractions in dark matter halos from the scales of small spiral galaxies to those of large galaxy clusters. We use an extensively-tested analytic model for...
Determining the Nature of Dark Matter with Astrometry (2007)
Strigari, Louis E., Bullock, James S., Kaplinghat, Manoj
We show that measurements of stellar proper motions in dwarf spheroidal galaxies provide a powerful probe of the nature of dark matter. Allowing for general dark matter density profiles and stellar...
Redefining the missing satellites problem (2007)
Strigari, Louis E., Bullock, James S., Kaplinghat, Manoj, Diemand, Juerg, Kuhlen, Michael, Madau, Piero
A Revised LCDM Mass Model For The Andromeda Galaxy (2006)
Seigar, Marc S., Barth, Aaron J., Bullock, James S.
We present an updated mass model for M31 that makes use of a Spitzer 3.6 $\mu$m image, a mass-to-light ratio gradient based on the galaxy's B-R colour profile, and observed rotation curve data from a...
Strigari, Louis E., Koushiappas, Savvas M., Bullock, James S., Kaplinghat, Manoj
We examine the prospects for detecting gamma-rays from dark matter annihilation in the six most promising dwarf spheroidal (dSph) satellite galaxies of the Milky Way. We use recently-measured...
Gastaldello, Fabio, Buote, David A., Humphrey, Philip J., Zappacosta, Luca, Bullock, James S., Brighenti, Fabrizio, ...
We present radial mass profiles within 0.3 r_vir for 16 relaxed galaxy groups-poor clusters (kT range 1-3 keV) selected for optimal mass constraints from the Chandra and XMM data archives. After...
The X-Ray Concentration-Virial Mass Relation (2006)
Buote, David A., Gastaldello, Fabio, Humphrey, Philip J., Zappacosta, Luca, Bullock, James S., Brighenti, Fabrizio, ...
We present the concentration (c)-virial mass (M) relation of 39 galaxy systems ranging in mass from individual early-type galaxies up to the most massive galaxy clusters, (0.06-20) x 10^{14} M_sun....
Dark Matter Halos with Cores from Hierarchical Structure Formation (2006)
Strigari, Louis E., Kaplinghat, Manoj, Bullock, James S.
We show that dark matter emerging from late decays (z < 1000) produces a linear power spectrum identical to that of Cold Dark Matter (CDM) on all observationally relavant scales (> 0.1 Mpc), and...
Close Galaxy Counts as a Probe of Hierarchical Structure Formation (2006)
Berrier, Joel C., Bullock, James S., Barton, Elizabeth J., Guenther, Heather D., Zentner, Andrew R., Wechsler, Risa H.
Standard LCDM predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with redshift. The average number of close companions per galaxy, Nc, is often used to infer the...
The Effect of Substructure on Mass Estimates of Galaxies (2006)
Yencho, Brian M., Johnston, Kathryn V., Bullock, James S., Rhode, Katherine L.
Large galaxies are thought to form hierarchically, from the accretion and disruption of many smaller galaxies. Such a scenario should naturally lead to galactic phase-space distributions containing...
A Large Dark Matter Core in the Fornax Dwarf Spheroidal Galaxy? (2006)
Strigari, Louis E., Bullock, James S., Kaplinghat, Manoj, Kravtsov, Andrey V., Gnedin, Oleg Y., Abazajian, Kevork, ...
We use measurements of the stellar velocity dispersion profile of the Fornax dwarf spheroidal galaxy to derive constraints on its dark matter distribution. Though the data are unable to distinguish...
Seigar, Marc S., Bullock, James S., Barth, Aaron J., Ho, Luis C.
We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well-correlated with the rate of shear...
A Chandra View of Dark Matter in Early-Type Galaxies (2006)
Humphrey, Philip J., Buote, David A., Gastaldello, Fabio, Zappacosta, Luca, Bullock, James S., Brighenti, Fabrizio, ...
We present a Chandra study of mass profiles in 7 elliptical galaxies, of which 3 have galaxy-scale and 4 group-scale halos demarcated at 1E13Msun. These represent the best available data for nearby...
A merger-driven scenario for cosmological disk galaxy formation (2006)
Robertson, Brant, Bullock, James S., Cox, Thomas J., Di Matteo, Tiziana, Hernquist, Lars, Springel, Volker, ...
Phase-Space Distributions of Chemical Abundances in Milky Way-type Galaxy Halos (2005)
Font, Andreea S., Johnston, Kathryn V., Bullock, James S., Robertson, Brant E.
[Abridged] Motivated by upcoming data from astrometric and spectroscopic surveys of the Galaxy, we explore the chemical abundance properties and phase-space distributions in hierarchically-formed...
The Dependence of Halo Clustering on Halo Formation History, Concentration, and Occupation (2005)
Wechsler, Risa H., Zentner, Andrew R., Bullock, James S., Kravtsov, Andrey V., Allgood, Brandon
We investigate the dependence of dark matter halo clustering on halo formation time, density profile concentration, and subhalo occupation number, using high-resolution numerical simulations of a...
Dark-Matter Halos of Early-Type Galaxies (2005)
Humphrey, Philip J., Buote, David A., Gastaldello, Fabio, Zappacosta, Luca, Bullock, James S., Brighenti, Fabrizio, ...
Cosmological simulations of galaxy formation predict a universal form for the mass profile of dark matter (DM) halos from cluster to galaxy scales. Remarkably few interesting constraints exist,...
The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation (2005)
Allgood, Brandon, Flores, Ricardo A., Primack, Joel R., Kravtsov, Andrey V., Wechsler, Risa H., Faltenbacher, Andreas, ...
Using six high resolution dissipationless simulations with a varying box size in a flat LCDM universe, we study the mass and redshift dependence of dark matter halo shapes for M_vir = 9.0e11 -...
Flores, Ricardo A., Allgood, Brandon, Kravtsov, Andrey V., Primack, Joel R., Buote, David A., Bullock, James S.
(Abridged) We study predictions for galaxy cluster observables that can test the statistics of dark matter halo shapes expected in a flat LCDM universe. We present a simple analytical model for the...
Font, Andreea S., Johnston, Kathryn V., Bullock, James S., Robertson, Brant
We present a cosmologically motivated model for the hierachical formation of the stellar halo which includes a semi-analytic treatment of galactic chemical enrichment coupled to numerical simulations...
Tracing Galaxy Formation with Stellar Halos I: Methods (2005)
Bullock, James S., Johnston, Kathryn V.
If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted ~100-200 luminous satellite galaxies in the past \~12 Gyr. We model this process using a...
A Merger-Driven Scenario for Cosmological Disk Galaxy Formation (2005)
Robertson, Brant, Bullock, James S., Cox, Thomas J., Di Matteo, Tiziana, Hernquist, Lars, Springel, Volker, ...
(Abridged) The violent hierarchical nature of the LCDM cosmology poses serious difficulties for the formation of disk galaxies. To help resolve these issues, we describe a new, merger-driven scenario...
Observational Gamma-ray Cosmology (2005)
Primack, Joel R., Bullock, James S., Somerville, Rachel S.
We discuss how measurements of the absorption of gamma-rays from GeV to TeV energies via pair production on the extragalactic background light (EBL) can probe important issues in galaxy formation....
Lambda-Cold Dark Matter, Stellar Feedback, and the Galactic Halo Abundance Pattern (2005)
Robertson, Brant, Bullock, James S., Font, Andreea S., Johnston, Kathryn V., Hernquist, Lars
(Abridged) The hierarchical formation scenario for the stellar halo requires the accretion and disruption of dwarf galaxies, yet low-metallicity halo stars are enriched in alpha-elements compared to...
The Physics of Galaxy Clustering I: A Model for Subhalo Populations (2004)
Zentner, Andrew R., Berlind, Andreas A., Bullock, James S., Kravtsov, Andrey V., Wechsler, Risa H.
(Abridged) We present a semi-analytic model for Cold Dark Matter halo substructure that can be used as a framework for studying galaxy formation and an ingredient in halo models of galaxy clustering....
Multi-Phase Galaxy Formation: High Velocity Clouds and the Missing Baryon Problem (2004)
Maller, Ariyeh H., Bullock, James S.
The standard treatment of cooling in Cold Dark Matter halos assumes that all of the gas within a ``cooling radius'' cools and contracts monolithically to fuel galaxy formation. Here we take into...
Cosmology and the Stellar Halo (2004)
Bullock, James S., Johnston, Kathryn V.
If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted and subsequently tidally destroyed ~100 low-mass galaxies in the past ~12 Gyr. We model this...
Halo Substructure And The Power Spectrum (2003)
Zentner, Andrew R., Bullock, James S.
(ABRIDGED) We present a semi-analytic model to explore merger histories, destruction rates, and survival probabilities of substructure in dark matter halos and use it to study the substructure...
The Epoch of Reionization in Models with Reduced Small Scale Power (2003)
Somerville, Rachel S., Bullock, James S., Livio, Mario
Reducing the power on small scales relative to the `standard' LCDM model alleviates a number of possible discrepancies with observations, and is favored by the recent analysis of WMAP plus galaxy and...
Halo Substructure and the Power Spectrum (2002)
Zentner, Andrew R., Bullock, James S.
In this proceeding, we present the results of a semi-analytic study of CDM substructure as a function of the primordial power spectrum. We apply our method to several tilted models in the LCDM...
Dark halo densities, substructure, and the initial power spectrum (2002)
Bullock, James S., Zentner, Andrew R.
Although the currently favored cold dark matter plus cosmological constant model for structure formation assumes an n=1 scale-invariant initial power spectrum, most inflation models produce at least...
Faint AGN and the Ionizing Background (2002)
Schirber, Michael, Bullock, James S.
We determine the evolution of the faint, high-redshift, optical luminosity function (LF) of AGN implied by several observationally-motivated models of the ionizing background. Our results depend...
Inflation, cold dark matter, and the central density problem (2002)
Zentner, Andrew R., Bullock, James S.
A problem with high central densities in dark halos has arisen in the context of LCDM cosmologies with scale-invariant initial power spectra. Although n=1 is often justified by appealing to the...
Concentrations and Assembly Histories of Dark Matter Halos (2001)
Wechsler, Risa H., Bullock, James S., Primack, J. R., Kravtsov, Andrey V., Dekel, Avishai
We study the relation between the density profiles of dark matter halos and their mass assembly histories, using a statistical sample of halos in a high-resolution N-body simulation of the LCDM...
Tilted CDM versus WDM in the Subgalactic Scuffle (2001)
Although the currently favored cold dark matter plus cosmological constant model (LCDM) has proven to be remarkably successful on large scales, on subgalactic scales it faces some potentially fatal...
Angular Momentum Profiles of Warm Dark Matter Halos (2001)
Bullock, James S., Kravtsov, Andrey V., Colin, Pedro
We compare the specific angular momentum profiles of virialized dark halos in cold dark matter (CDM) and warm dark matter (WDM) models using high-resolution dissipationless simulations. The...
Dark Matter Properties and Halo Central Densities (2001)
Alam, S. M. Khairul, Bullock, James S., Weinberg, David H.
Using an analytic model calibrated against numerical simulations, we calculate the central densities of dark matter halos in a ``conventional'' cold dark matter model with a cosmological constant...
Concentrations of Dark Halos from their Assembly Histories (2001)
Wechsler, Risa H., Bullock, James S., Primack, Joel R., Kravtsov, Andrey V., Dekel, Avishai
(abridged) We study the relation between the density profiles of dark matter halos and their mass assembly histories, using a statistical sample of halos in a high-resolution N-body simulation of the...
Shapes of dark matter halos (2001)
I present an analysis of the density shapes of dark matter halos in LCDM and LWDM cosmologies. The main results are derived from a statistical sample of galaxy-mass halos drawn from a high resolution...
Galaxy Halo Occupation at High Redshift (2001)
Bullock, James S., Wechsler, Risa H., Somerville, Rachel S.
We discuss how current and future data on the clustering and number density of z~3 Lyman-break galaxies (LBGs) can be used to constrain their relationship to dark matter haloes. We explore a...
Interpreting Debris from Satellite Disruption In External Galaxies (2001)
Johnston, Kathryn V., Sackett, Penny D., Bullock, James S.
We examine the detectability and interpretation of debris trails caused by satellite disruption in external galaxies using semi-analytic approximations for the dependence of streamer length, width...
Probing Galaxy Formation with High Energy Gamma-Rays (2000)
Primack, Joel R., Somerville, Rachel S., Bullock, James S., Devriendt, Julien E. G.
We discuss how measurements of the absorption of $\gamma$-rays from GeV to TeV energies via pair production on the extragalactic background light (EBL) can probe important issues in galaxy formation....
Galaxy Formation at z~3: Constraints from Spatial Clustering (2000)
Wechsler, Risa H., Somerville, Rachel S., Bullock, James S., Kolatt, Tsafrir S., Primack, Joel R., Blumenthal, George R., ...
We use N-body simulations combined with semi-analytic models to compute the clustering properties of modeled galaxies at z~3, and confront these predictions with the clustering properties of the...
A universal angular momentum profile for galactic halos (2000)
Bullock, James S., Dekel, Avishai, Kolatt, Tsafrir S., Kravtsov, Andrey V., Klypin, Anatoly A., Porciani, Cristiano, ...
[Abridged] We study the angular-momentum profiles of a statistical sample of halos drawn from a high-resolution N-body simulation of the LCDM cosmology. We find that the cumulative mass distribution...
Interaction rates of dark-matter halos and subhalos (2000)
Kolatt, Tsafrir S., Bullock, James S., Sigad, Yair, Kravtsov, Andrey V., Klypin, Anatoly A., Primack, Joel R., ...
[Abridged] The interaction rates of dark-matter halos and subhalos, are computed using high-resolution cosmological N-body simulations of the Lambda-CDM model. Although the number fraction of...
Origin and Destiny of Dark Matter Halos: Cosmological Matter Exchange and Metal Enrichment (2000)
Kolatt, Tsafrir S., Bullock, James S., Dekel, Avishai, Primack, Joel R., Sigad, Yair, Kravtsov, Andrey V., ...
[Abridged] We analyze the exchange of dark matter between halos, subhalos, and their environments in a high-resolution cosmological N-body simulation of a Lambda CDM cosmology. At each analyzed...
Hierarchical galaxy formation and substructure in the Galaxy's stellar halo (2000)
Bullock, James S., Kravtsov, Andrey V., Weinberg, David H.
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...
Velocity and Mass Functions of Galactic Halos: Evolution and Environmental Dependence (2000)
Sigad, Yair, Kolatt, Tsafrir S., Bullock, James S., Kravtsov, Andrey V., Klypin, Anatoly A., Primack, Joel R., ...
We study the distribution functions of mass and circular velocity for dark matter halos in N-body simulations of the $\Lambda$CDM cosmology, addressing redshift and environmental dependence. The...
Strong Evolution in the Luminosity-Velocity Relation at z>1? (2000)
Bullock, James S., Dekel, Avishai, Primack, Joel R., Somerville, Rachel S.
We present a method for constraining the evolution of the galaxy luminosity-velocity (LV) relation in hierarchical scenarios of structure formation. The comoving number density of dark-matter halos...
Reionization and the abundance of galactic satellites (2000)
Bullock, James S., Kravtsov, Andrey V., Weinberg, David H.
One of the main challenges facing standard hierarchical structure formation models is that the predicted abundance of galactic subhalos with circular velocities of 10-30 km/s is an order of magnitude...
Clustering of high-redshift galaxies: relating LBGs to dark matter halos (1999)
Wechsler, Risa H., Bullock, James S., Somerville, Rachel S., Kolatt, Tsafrir, Primack, Joel R., Blumenthal, George R., ...
We investigate the clustering properties of high-redshift galaxies within three competing scenarios for assigning luminous galaxies to dark matter halos from N-body simulations: a one galaxy per...
Profiles of dark haloes: evolution, scatter, and environment (1999)
Bullock, James S., Kolatt, Tsafrir S., Sigad, Yair, Somerville, Rachel S., Kravtsov, Andrey V., Klypin, Anatoly A., ...
We study dark-matter halo density profiles in a high-resolution N-body simulation of an LCDM cosmology. Our statistical sample contains ~5000 haloes in the range 10^{11}-10^{14} M_sun. The profiles...
The Velocity Function of Galaxies (1999)
Gonzalez, Anthony H., Williams, Kurtis A., Bullock, James S., Kolatt, Tsafrir S., Primack, Joel R.
We present a galaxy circular velocity function, Psi(log v), derived from existing luminosity functions and luminosity-velocity relations. Such a velocity function is desirable for several reasons....
Young galaxies: what turns them on? (1999)
Kolatt, Tsafrir S., Bullock, James S., Somerville, Rachel S., Sigad, Yair, Jonsson, Patrik, Kravtsov, Andrey V., ...
Lyman break galaxies (LBGs) at $z \sim 3$ exhibit number densities and clustering similar to local $L_*$ galaxies; however, their star formation rates (SFRs) are much higher. We explore the scenario...
Probing Galaxy Formation with TeV Gamma Ray Absorption (1998)
Primack, Joel R., Bullock, James S., Somerville, Rachel S., MacMinn, Donn
We present here the extragalactic background light (EBL) predicted by semi-analytic models of galaxy formation, and show how measurements of the absorption of gamma rays of $\sim$ TeV energies via...
Comments on non-Gaussian density perturbations and the production of primordial black holes (1998)
Bullock, James S., Primack, Joel R.
We review the basic arguments for the likelihood of non-Gaussian density perturbations in inflation models with primordial black hole (PBH) production. We discuss our derived distributions of field...
The Cores of Dark Matter Dominated Galaxies: theory vs. observations (1997)
Kravtsov, Andrey V., Klypin, Anatoly A., Bullock, James S., Primack, Joel R.
We use the rotation curves of a sample of dark matter dominated dwarf and low-surface brightness (LSB) late-type galaxies to study their radial mass distributions. We find that the shape of the...
Non-Gaussian Fluctuations and Primordial Black Holes from Inflation (1996)
Bullock, James S., Primack, Joel R.
We explore the role of non-Gaussian fluctuations in primordial black hole (PBH) formation and show that the standard Gaussian assumption, used in all PBH formation papers to date, is not justified....