On Detecting Halo Assembly Bias With Galaxy Populations

Lin, Yen-Ting; Mandelbaum, Rachel; Huang, Yun; Huang, Hsin‐Hsiang; Dalal, Neal; Diemer, Benedikt; Jian, Hung-Yu; Kravtsov, Andrey V.

doi:10.3847/0004-637x/819/2/119

Cited by 118 publications

(119 citation statements)

References 72 publications

(116 reference statements)

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“…Observational studies of assembly bias have generally produced mixed results. There have been several suggestive detections in observations (Berlind et al 2006;Yang et al 2006;Tinker et al 2008bTinker et al , 2017bWang et al 2008Wang et al , 2013bCooper et al 2010;Lacerna et al 2014a;Hearin et al 2015;Watson et al 2015;Miyatake et al 2016;Saito et al 2016;Zentner et al 2016;Montero-Dorta et al 2017;Tojeiro et al 2017), while numerous other studies indicate the impact of assembly bias to be small (Abbas & Sheth 2006;Blanton & Berlind 2007;Croton & Farrar 2008;Tinker et al 2008aTinker et al , 2011Deason et al 2013;Lacerna et al 2014b;Lin et al 2016;Vakili & Hahn 2016;Dvornik et al 2017). The situation is further complicated as various systematic effects can mimic the effects of assembly bias (e.g., Campbell et al 2015;Busch & White 2017;Lacerna et al 2017;Sin et al 2017;Tinker et al 2017a;Zu & Mandelbaum 2017) and the evidence for assembly bias to date remains inconclusive and controversial.…”

Section: Introductionmentioning

confidence: 95%

The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

Zehavi

Contreras

Padilla

et al. 2018

ApJ

143

150

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We study the dependence of the galaxy content of dark matter halos on large-scale environment and halo formation time using semi-analytic galaxy models applied to the Millennium simulation. We analyze subsamples of halos at the extremes of these distributions and measure the occupation functions for the galaxies they host. We find distinct differences in these occupation functions. The main effect with environment is that central galaxies (and in one model also the satellites) in denser regions start populating lower-mass halos. A similar, but significantly stronger, trend exists with halo age, where early-forming halos are more likely to host central galaxies at lower halo mass. We discuss the origin of these trends and the connection to the stellar mass -halo mass relation. We find that, at fixed halo mass, older halos and to some extent also halos in dense environments tend to host more massive galaxies. Additionally, we see a reverse trend for the satellite galaxies occupation where early-forming halos have fewer satellites, likely due to having more time for them to merge with the central galaxy. We describe these occupancy variations also in terms of the changes in the occupation function parameters, which can aid in constructing realistic mock galaxy catalogs. Finally, we study the corresponding galaxy auto-and cross-correlation functions of the different samples and elucidate the impact of assembly bias on galaxy clustering. Our results can inform theoretical models of assembly bias and attempts to detect it in the real universe.

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Section: Introductionmentioning

confidence: 95%

The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

Zehavi

Contreras

Padilla

et al. 2018

ApJ

143

150

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“…We quantify density by the distance to the fifth nearest neighbor, but using a smoothed galaxy overdensity gives similar results. The trend that galaxies born in overdense environments form earlier holds for all stellar masses, and is a manifestation of the earlier collapse times of halos in overdense regions, known as "assembly bias" (Gao et al 2005;Wechsler et al 2006;Croton et al 2007;Dalal et al 2008;Zentner et al 2014;Lin et al 2016;Miyatake et al 2016;Tinker et al 2016, see also the arguments in Dressler 1980, and Kelson et al 2016. The environment at earlier and later redshifts shows similar relations with t peak , but the correlation weakens at late ( < z 1) and very early (z > 4) redshifts.…”

Section: The Galaxy-halo Connectionmentioning

confidence: 99%

Log-normal Star Formation Histories in Simulated and Observed Galaxies

Diemer

Sparre

Abramson³

et al. 2017

ApJ

Self Cite

108

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Gladders et al. have recently suggested that the star formation histories (SFHs) of individual galaxies are characterized by a log-normal function in time, implying a slow decline rather than rapid quenching. We test their conjecture on theoretical SFHs from the cosmological simulation Illustris and on observationally inferred SFHs. While the log-normal form necessarily ignores short-lived features such as starbursts, it fits the overall shape of the majority of SFHs very well. In particular, 85% of the cumulative SFHs are fitted to within a maximum error of 5% of the total stellar mass formed, and 99% to within 10%. The log-normal performs systematically better than the commonly used delayed-τ model, and is superseded only by functions with more than three free parameters. Poor fits are mostly found in galaxies that were rapidly quenched after becoming satellites. We explore the log-normal parameter space of normalization, peak time, and full width at half maximum, and find that the simulated and observed samples occupy similar regions, though Illustris predicts wider, later-forming SFHs on average. The ensemble of log-normal fits correctly reproduces complex metrics such as the evolution of Illustris galaxies across the star formation main sequence, but overpredicts their quenching timescales. SFHs in Illustris are a diverse population not determined by any one physical property of galaxies, but follow a tight relation, where µ ( ) width peak time 3 2 . We show that such a relation can be explained qualitatively (though not quantitatively) by a close connection between the growth of dark matter halos and their galaxies.

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“…There is scatter in the assignment of halo mass to groups, leading to uncertainties in the halo masses. Also, there are errors in the identification of central galaxies (e.g., Skibba et al 2011;Lin et al 2016;Lange et al 2018). To explore how these two errors impact our results, we employ a mock catalog built by Campbell et al (2015).…”

Section: Impact Of Imperfect Group Catalogsmentioning

confidence: 99%

SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

Greene

Leauthaud

Emsellem

et al. 2018

ApJ

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We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et al. group catalog, we identify central and satellite galaxies in groups with halo masses in the range . As in previous work, we see a sharp dependence on stellar mass, in the sense that ∼70% of galaxies with stellar mass * > - M h M 10 11 2 tend to have very little rotation, while nearly all galaxies at lower mass show some net rotation. The ∼30% of high-mass galaxies that have significant rotation do not stand out in other galaxy properties, except for a higher incidence of ionized gas emission. Our data are consistent with recent simulation results suggesting that major merging and gas accretion have more impact on the rotational support of lower-mass galaxies. When carefully matching the stellar mass distributions, we find no residual differences in angular momentum content between satellite and central galaxies at the 20% level. Similarly, at fixed mass, galaxies have consistent rotation properties across a wide range of halo mass. However, we find that errors in classification of central and satellite galaxies with group finders systematically lower differences between satellite and central galaxies at a level that is comparable to current measurement uncertainties. To improve constraints, the impact of group-finding methods will have to be forward-modeled via mock catalogs.

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On Detecting Halo Assembly Bias With Galaxy Populations

Cited by 118 publications

References 72 publications

The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

Log-normal Star Formation Histories in Simulated and Observed Galaxies

SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

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