Galaxy and Mass Assembly (GAMA): halo formation times and halo assembly bias on the cosmic web

Rita Tojeiro, Elizabeth Eardley, John A. Peacock, Peder Norberg, Mehmet Alpaslan, Simon P. Driver, Bruno Henriques, Andrew M. Hopkins, Prajwal R. Kafle, Aaron S. G. Robotham, Peter Thomas, Chiara Tonini, Vivienne Wild

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.

Original languageEnglish
Pages (from-to)3720-3741
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Volume470
Issue number3
DOIs
Publication statusPublished - Sep 2017

Cite this

Tojeiro, Rita ; Eardley, Elizabeth ; Peacock, John A. ; Norberg, Peder ; Alpaslan, Mehmet ; Driver, Simon P. ; Henriques, Bruno ; Hopkins, Andrew M. ; Kafle, Prajwal R. ; Robotham, Aaron S. G. ; Thomas, Peter ; Tonini, Chiara ; Wild, Vivienne. / Galaxy and Mass Assembly (GAMA) : halo formation times and halo assembly bias on the cosmic web. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 470, No. 3. pp. 3720-3741.
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abstract = "We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.",
keywords = "galaxies: haloes, cosmology: observations, large-scale structure of Universe, LUMINOUS RED GALAXIES, DIGITAL SKY SURVEY, OSCILLATION SPECTROSCOPIC SURVEY, STELLAR POPULATION SYNTHESIS, DARK-MATTER HALOES, STAR-FORMATION, OCCUPATION DISTRIBUTION, COLOR DEPENDENCE, REDSHIFT SURVEY, SDSS-III",
author = "Rita Tojeiro and Elizabeth Eardley and Peacock, {John A.} and Peder Norberg and Mehmet Alpaslan and Driver, {Simon P.} and Bruno Henriques and Hopkins, {Andrew M.} and Kafle, {Prajwal R.} and Robotham, {Aaron S. G.} and Peter Thomas and Chiara Tonini and Vivienne Wild",
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Tojeiro, R, Eardley, E, Peacock, JA, Norberg, P, Alpaslan, M, Driver, SP, Henriques, B, Hopkins, AM, Kafle, PR, Robotham, ASG, Thomas, P, Tonini, C & Wild, V 2017, 'Galaxy and Mass Assembly (GAMA): halo formation times and halo assembly bias on the cosmic web' Monthly Notices of the Royal Astronomical Society, vol. 470, no. 3, pp. 3720-3741. https://doi.org/10.1093/mnras/stx1466

Galaxy and Mass Assembly (GAMA) : halo formation times and halo assembly bias on the cosmic web. / Tojeiro, Rita; Eardley, Elizabeth; Peacock, John A.; Norberg, Peder; Alpaslan, Mehmet; Driver, Simon P.; Henriques, Bruno; Hopkins, Andrew M.; Kafle, Prajwal R.; Robotham, Aaron S. G.; Thomas, Peter; Tonini, Chiara; Wild, Vivienne.

In: Monthly Notices of the Royal Astronomical Society, Vol. 470, No. 3, 09.2017, p. 3720-3741.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Galaxy and Mass Assembly (GAMA)

T2 - halo formation times and halo assembly bias on the cosmic web

AU - Tojeiro, Rita

AU - Eardley, Elizabeth

AU - Peacock, John A.

AU - Norberg, Peder

AU - Alpaslan, Mehmet

AU - Driver, Simon P.

AU - Henriques, Bruno

AU - Hopkins, Andrew M.

AU - Kafle, Prajwal R.

AU - Robotham, Aaron S. G.

AU - Thomas, Peter

AU - Tonini, Chiara

AU - Wild, Vivienne

PY - 2017/9

Y1 - 2017/9

N2 - We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.

AB - We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.

KW - galaxies: haloes

KW - cosmology: observations

KW - large-scale structure of Universe

KW - LUMINOUS RED GALAXIES

KW - DIGITAL SKY SURVEY

KW - OSCILLATION SPECTROSCOPIC SURVEY

KW - STELLAR POPULATION SYNTHESIS

KW - DARK-MATTER HALOES

KW - STAR-FORMATION

KW - OCCUPATION DISTRIBUTION

KW - COLOR DEPENDENCE

KW - REDSHIFT SURVEY

KW - SDSS-III

U2 - 10.1093/mnras/stx1466

DO - 10.1093/mnras/stx1466

M3 - Article

VL - 470

SP - 3720

EP - 3741

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -