Stellar populations in compact galaxy groups: A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies

I. S. Konstantopoulos, A. Maybhate, J. C. Charlton, K. Fedotov, P. R. Durrell, J. S. Mulchaey, J. English, T. D. Desjardins, S. C. Gallagher, L. M. Walker, K. E. Johnson, P. Tzanavaris, C. Gronwall

Research output: Contribution to journalArticle

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Abstract

We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

Original languageEnglish (US)
Article number114
JournalAstrophysical Journal
Volume770
Issue number2
DOIs
StatePublished - Jun 20 2013

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compact galaxies
galactic clusters
star clusters
dwarf galaxies
wavelength
observatory
wavelengths
spectroscopy
Hubble Space Telescope
star formation
observatories
gas
dichotomies
paints
isolation
time measurement
inclusions

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Konstantopoulos, I. S. ; Maybhate, A. ; Charlton, J. C. ; Fedotov, K. ; Durrell, P. R. ; Mulchaey, J. S. ; English, J. ; Desjardins, T. D. ; Gallagher, S. C. ; Walker, L. M. ; Johnson, K. E. ; Tzanavaris, P. ; Gronwall, C. / Stellar populations in compact galaxy groups : A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies. In: Astrophysical Journal. 2013 ; Vol. 770, No. 2.
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Konstantopoulos, IS, Maybhate, A, Charlton, JC, Fedotov, K, Durrell, PR, Mulchaey, JS, English, J, Desjardins, TD, Gallagher, SC, Walker, LM, Johnson, KE, Tzanavaris, P & Gronwall, C 2013, 'Stellar populations in compact galaxy groups: A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies', Astrophysical Journal, vol. 770, no. 2, 114. https://doi.org/10.1088/0004-637X/770/2/114

Stellar populations in compact galaxy groups : A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies. / Konstantopoulos, I. S.; Maybhate, A.; Charlton, J. C.; Fedotov, K.; Durrell, P. R.; Mulchaey, J. S.; English, J.; Desjardins, T. D.; Gallagher, S. C.; Walker, L. M.; Johnson, K. E.; Tzanavaris, P.; Gronwall, C.

In: Astrophysical Journal, Vol. 770, No. 2, 114, 20.06.2013.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Stellar populations in compact galaxy groups

T2 - A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies

AU - Konstantopoulos, I. S.

AU - Maybhate, A.

AU - Charlton, J. C.

AU - Fedotov, K.

AU - Durrell, P. R.

AU - Mulchaey, J. S.

AU - English, J.

AU - Desjardins, T. D.

AU - Gallagher, S. C.

AU - Walker, L. M.

AU - Johnson, K. E.

AU - Tzanavaris, P.

AU - Gronwall, C.

PY - 2013/6/20

Y1 - 2013/6/20

N2 - We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

AB - We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

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