Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment

Simon Deeley, Michael J. Drinkwater, Daniel Cunnama, Joss Bland-Hawthorn, Sarah Brough, Michelle E. Cluver, Matthew Colless, Luke J. M. Davies, Simon P. Driver, Caroline Foster, Meiert W. Grootes, Andrew M. Hopkins, Prajwal R. Kafle, Maritza A. Lara-Lopez, Jochen Liske, Smriti Mahajan, Steven Phillipps, Chris Power, Aaron Robotham

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Abstract

There are many proposed mechanisms driving the morphological transformation of disc galaxies to elliptical galaxies. In this paper, we determine if the observed transformation in low-mass groups can be explained by the merger histories of galaxies. We measured the group mass-morphology relation for groups from the Galaxy and Mass Assembly group catalogue with masses from 1011 to 1015 M⊙. Contrary to previous studies, the fraction of elliptical galaxies in our more complete group sample increases significantly with group mass across the full range of group mass. The elliptical fraction increases at a rate of 0.163 ± 0.012 per dex of group mass for groups more massive than 1012.5 M⊙. If we allow for uncertainties in the observed group masses, our results are consistent with a continuous increase in elliptical fraction from group masses as low as 1011 M⊙. We tested if this observed relation is consistent with the merger activity using a gadget-2 dark matter simulation of the galaxy groups. We specified that a simulated galaxy would be transformed to an elliptical morphology either if it experienced a major merger or if its cumulative mass gained from minor mergers exceeded 30 per cent of its final mass. We then calculated a group mass-morphology relation for the simulations. The position and slope of the simulated relation were consistent with the observational relation, with a gradient of 0.184 ± 0.010 per dex of group mass. These results demonstrate a strong correlation between the frequency of merger events and disc-to-elliptical galaxy transformation in galaxy group environments.
Original languageEnglish
Pages (from-to)3934-3943
JournalMonthly Notices of the Royal Astronomical Society
Volume467
Issue number4
DOIs
Publication statusPublished - 1 Jun 2017

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elliptical galaxies
assembly
galaxies
merger
galactic clusters
disk galaxies
catalogs
simulation
dark matter
histories
slopes
gradients

Cite this

Deeley, Simon ; Drinkwater, Michael J. ; Cunnama, Daniel ; Bland-Hawthorn, Joss ; Brough, Sarah ; Cluver, Michelle E. ; Colless, Matthew ; Davies, Luke J. M. ; Driver, Simon P. ; Foster, Caroline ; Grootes, Meiert W. ; Hopkins, Andrew M. ; Kafle, Prajwal R. ; Lara-Lopez, Maritza A. ; Liske, Jochen ; Mahajan, Smriti ; Phillipps, Steven ; Power, Chris ; Robotham, Aaron. / Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 467, No. 4. pp. 3934-3943.
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title = "Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment",
abstract = "There are many proposed mechanisms driving the morphological transformation of disc galaxies to elliptical galaxies. In this paper, we determine if the observed transformation in low-mass groups can be explained by the merger histories of galaxies. We measured the group mass-morphology relation for groups from the Galaxy and Mass Assembly group catalogue with masses from 1011 to 1015 M⊙. Contrary to previous studies, the fraction of elliptical galaxies in our more complete group sample increases significantly with group mass across the full range of group mass. The elliptical fraction increases at a rate of 0.163 ± 0.012 per dex of group mass for groups more massive than 1012.5 M⊙. If we allow for uncertainties in the observed group masses, our results are consistent with a continuous increase in elliptical fraction from group masses as low as 1011 M⊙. We tested if this observed relation is consistent with the merger activity using a gadget-2 dark matter simulation of the galaxy groups. We specified that a simulated galaxy would be transformed to an elliptical morphology either if it experienced a major merger or if its cumulative mass gained from minor mergers exceeded 30 per cent of its final mass. We then calculated a group mass-morphology relation for the simulations. The position and slope of the simulated relation were consistent with the observational relation, with a gradient of 0.184 ± 0.010 per dex of group mass. These results demonstrate a strong correlation between the frequency of merger events and disc-to-elliptical galaxy transformation in galaxy group environments.",
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author = "Simon Deeley and Drinkwater, {Michael J.} and Daniel Cunnama and Joss Bland-Hawthorn and Sarah Brough and Cluver, {Michelle E.} and Matthew Colless and Davies, {Luke J. M.} and Driver, {Simon P.} and Caroline Foster and Grootes, {Meiert W.} and Hopkins, {Andrew M.} and Kafle, {Prajwal R.} and Lara-Lopez, {Maritza A.} and Jochen Liske and Smriti Mahajan and Steven Phillipps and Chris Power and Aaron Robotham",
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Deeley, S, Drinkwater, MJ, Cunnama, D, Bland-Hawthorn, J, Brough, S, Cluver, ME, Colless, M, Davies, LJM, Driver, SP, Foster, C, Grootes, MW, Hopkins, AM, Kafle, PR, Lara-Lopez, MA, Liske, J, Mahajan, S, Phillipps, S, Power, C & Robotham, A 2017, 'Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment' Monthly Notices of the Royal Astronomical Society, vol. 467, no. 4, pp. 3934-3943. https://doi.org/10.1093/mnras/stx441

Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment. / Deeley, Simon; Drinkwater, Michael J.; Cunnama, Daniel; Bland-Hawthorn, Joss; Brough, Sarah; Cluver, Michelle E.; Colless, Matthew; Davies, Luke J. M.; Driver, Simon P.; Foster, Caroline; Grootes, Meiert W.; Hopkins, Andrew M.; Kafle, Prajwal R.; Lara-Lopez, Maritza A.; Liske, Jochen; Mahajan, Smriti; Phillipps, Steven; Power, Chris; Robotham, Aaron.

In: Monthly Notices of the Royal Astronomical Society, Vol. 467, No. 4, 01.06.2017, p. 3934-3943.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Galaxy and Mass Assembly (GAMA): formation and growth of elliptical galaxies in the group environment

AU - Deeley, Simon

AU - Drinkwater, Michael J.

AU - Cunnama, Daniel

AU - Bland-Hawthorn, Joss

AU - Brough, Sarah

AU - Cluver, Michelle E.

AU - Colless, Matthew

AU - Davies, Luke J. M.

AU - Driver, Simon P.

AU - Foster, Caroline

AU - Grootes, Meiert W.

AU - Hopkins, Andrew M.

AU - Kafle, Prajwal R.

AU - Lara-Lopez, Maritza A.

AU - Liske, Jochen

AU - Mahajan, Smriti

AU - Phillipps, Steven

AU - Power, Chris

AU - Robotham, Aaron

PY - 2017/6/1

Y1 - 2017/6/1

N2 - There are many proposed mechanisms driving the morphological transformation of disc galaxies to elliptical galaxies. In this paper, we determine if the observed transformation in low-mass groups can be explained by the merger histories of galaxies. We measured the group mass-morphology relation for groups from the Galaxy and Mass Assembly group catalogue with masses from 1011 to 1015 M⊙. Contrary to previous studies, the fraction of elliptical galaxies in our more complete group sample increases significantly with group mass across the full range of group mass. The elliptical fraction increases at a rate of 0.163 ± 0.012 per dex of group mass for groups more massive than 1012.5 M⊙. If we allow for uncertainties in the observed group masses, our results are consistent with a continuous increase in elliptical fraction from group masses as low as 1011 M⊙. We tested if this observed relation is consistent with the merger activity using a gadget-2 dark matter simulation of the galaxy groups. We specified that a simulated galaxy would be transformed to an elliptical morphology either if it experienced a major merger or if its cumulative mass gained from minor mergers exceeded 30 per cent of its final mass. We then calculated a group mass-morphology relation for the simulations. The position and slope of the simulated relation were consistent with the observational relation, with a gradient of 0.184 ± 0.010 per dex of group mass. These results demonstrate a strong correlation between the frequency of merger events and disc-to-elliptical galaxy transformation in galaxy group environments.

AB - There are many proposed mechanisms driving the morphological transformation of disc galaxies to elliptical galaxies. In this paper, we determine if the observed transformation in low-mass groups can be explained by the merger histories of galaxies. We measured the group mass-morphology relation for groups from the Galaxy and Mass Assembly group catalogue with masses from 1011 to 1015 M⊙. Contrary to previous studies, the fraction of elliptical galaxies in our more complete group sample increases significantly with group mass across the full range of group mass. The elliptical fraction increases at a rate of 0.163 ± 0.012 per dex of group mass for groups more massive than 1012.5 M⊙. If we allow for uncertainties in the observed group masses, our results are consistent with a continuous increase in elliptical fraction from group masses as low as 1011 M⊙. We tested if this observed relation is consistent with the merger activity using a gadget-2 dark matter simulation of the galaxy groups. We specified that a simulated galaxy would be transformed to an elliptical morphology either if it experienced a major merger or if its cumulative mass gained from minor mergers exceeded 30 per cent of its final mass. We then calculated a group mass-morphology relation for the simulations. The position and slope of the simulated relation were consistent with the observational relation, with a gradient of 0.184 ± 0.010 per dex of group mass. These results demonstrate a strong correlation between the frequency of merger events and disc-to-elliptical galaxy transformation in galaxy group environments.

KW - galaxies: elliptical and lenticular

KW - cD

KW - galaxies: formation

KW - galaxies: groups: general

KW - galaxies: interactions

U2 - 10.1093/mnras/stx441

DO - 10.1093/mnras/stx441

M3 - Article

VL - 467

SP - 3934

EP - 3943

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -