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Title: NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT

Abstract

We present an analysis of high-quality photometry for globular clusters (GCs) in the Virgo cluster core region, based on data from the Next Generation Virgo Cluster Survey (NGVS) pilot field, and in the Milky Way (MW), based on Very Large Telescope/X-Shooter spectrophotometry. We find significant discrepancies in color–color diagrams between sub-samples from different environments, confirming that the environment has a strong influence on the integrated colors of GCs. GC color distributions along a single color are not sufficient to capture the differences we observe in color–color space. While the average photometric colors become bluer with increasing radial distance to the cD galaxy M87, we also find a relation between the environment and the slope and intercept of the color–color relations. A denser environment seems to produce a larger dynamic range in certain color indices. We argue that these results are not due solely to differential extinction, Initial Mass Function variations, calibration uncertainties, or overall age/metallicity variations. We therefore suggest that the relation between the environment and GC colors is, at least in part, due to chemical abundance variations, which affect stellar spectra and stellar evolution tracks. Our results demonstrate that stellar population diagnostics derived from model predictions which are calibratedmore » on one particular sample of GCs may not be appropriate for all extragalactic GCs. These results advocate a more complex model of the assembly history of GC systems in massive galaxies that goes beyond the simple bimodality found in previous decades.« less

Authors:
;  [1]; ; ;  [2]; ;  [3]; ;  [4]; ; ; ;  [5]; ;  [6];  [7];  [8];  [9];
  1. Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, F-67000 Strasbourg (France)
  2. Institute of Astrophysics, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)
  3. Department of Astronomy, Peking University, Beijing 100871 (China)
  4. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany)
  5. Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7 (Canada)
  6. AIM Paris Saclay, CNRS/INSU, CEA/Irfu, Université Paris Diderot, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France)
  7. Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, OH 44555 (United States)
  8. UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
  9. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22654220
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 829; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CALIBRATION; COLOR; DISTRIBUTION; FORECASTING; GALAXY CLUSTERS; LIMITING VALUES; MASS; METALLICITY; MILKY WAY; PARTICLE TRACKS; PHOTOMETRY; SPACE; SPECTRA; SPECTROPHOTOMETRY; STAR CLUSTERS; STAR EVOLUTION; STARS; TELESCOPES

Citation Formats

Powalka, Mathieu, Lançon, Ariane, Puzia, Thomas H., Alamo-Martínez, Karla, Ángel, Simón, Peng, Eric W., Lim, Sungsoon, Schönebeck, Frederik, Grebel, Eva K., Blakeslee, John P., Côté, Patrick, Ferrarese, Laura, Gwyn, S. D. J., Cuillandre, Jean-Charles, Duc, Pierre-Alain, Durrell, Patrick, Guhathakurta, Puragra, Kuntschner, Harald, E-mail: mathieu.powalka@astro.unistra.fr, and and others. NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT. United States: N. p., 2016. Web. doi:10.3847/2041-8205/829/1/L5.
Powalka, Mathieu, Lançon, Ariane, Puzia, Thomas H., Alamo-Martínez, Karla, Ángel, Simón, Peng, Eric W., Lim, Sungsoon, Schönebeck, Frederik, Grebel, Eva K., Blakeslee, John P., Côté, Patrick, Ferrarese, Laura, Gwyn, S. D. J., Cuillandre, Jean-Charles, Duc, Pierre-Alain, Durrell, Patrick, Guhathakurta, Puragra, Kuntschner, Harald, E-mail: mathieu.powalka@astro.unistra.fr, & and others. NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT. United States. doi:10.3847/2041-8205/829/1/L5.
Powalka, Mathieu, Lançon, Ariane, Puzia, Thomas H., Alamo-Martínez, Karla, Ángel, Simón, Peng, Eric W., Lim, Sungsoon, Schönebeck, Frederik, Grebel, Eva K., Blakeslee, John P., Côté, Patrick, Ferrarese, Laura, Gwyn, S. D. J., Cuillandre, Jean-Charles, Duc, Pierre-Alain, Durrell, Patrick, Guhathakurta, Puragra, Kuntschner, Harald, E-mail: mathieu.powalka@astro.unistra.fr, and and others. Tue . "NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT". United States. doi:10.3847/2041-8205/829/1/L5.
@article{osti_22654220,
title = {NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT},
author = {Powalka, Mathieu and Lançon, Ariane and Puzia, Thomas H. and Alamo-Martínez, Karla and Ángel, Simón and Peng, Eric W. and Lim, Sungsoon and Schönebeck, Frederik and Grebel, Eva K. and Blakeslee, John P. and Côté, Patrick and Ferrarese, Laura and Gwyn, S. D. J. and Cuillandre, Jean-Charles and Duc, Pierre-Alain and Durrell, Patrick and Guhathakurta, Puragra and Kuntschner, Harald, E-mail: mathieu.powalka@astro.unistra.fr and and others},
abstractNote = {We present an analysis of high-quality photometry for globular clusters (GCs) in the Virgo cluster core region, based on data from the Next Generation Virgo Cluster Survey (NGVS) pilot field, and in the Milky Way (MW), based on Very Large Telescope/X-Shooter spectrophotometry. We find significant discrepancies in color–color diagrams between sub-samples from different environments, confirming that the environment has a strong influence on the integrated colors of GCs. GC color distributions along a single color are not sufficient to capture the differences we observe in color–color space. While the average photometric colors become bluer with increasing radial distance to the cD galaxy M87, we also find a relation between the environment and the slope and intercept of the color–color relations. A denser environment seems to produce a larger dynamic range in certain color indices. We argue that these results are not due solely to differential extinction, Initial Mass Function variations, calibration uncertainties, or overall age/metallicity variations. We therefore suggest that the relation between the environment and GC colors is, at least in part, due to chemical abundance variations, which affect stellar spectra and stellar evolution tracks. Our results demonstrate that stellar population diagnostics derived from model predictions which are calibrated on one particular sample of GCs may not be appropriate for all extragalactic GCs. These results advocate a more complex model of the assembly history of GC systems in massive galaxies that goes beyond the simple bimodality found in previous decades.},
doi = {10.3847/2041-8205/829/1/L5},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 829,
place = {United States},
year = {Tue Sep 20 00:00:00 EDT 2016},
month = {Tue Sep 20 00:00:00 EDT 2016}
}