Dwarf galaxies in the Coma cluster – I. Velocity dispersion measurements

  1. E. Kourkchi1,2,*,
  2. H. G. Khosroshahi1,
  3. D. Carter3,
  4. A. M. Karick3,
  5. E. Mármol-Queraltó4,
  6. K. Chiboucas5,6,
  7. R. B. Tully5,
  8. B. Mobasher7,
  9. R. Guzmán8,
  10. A. Matković9,
  11. N. Gruel10

Article first published online: 10 FEB 2012

DOI: 10.1111/j.1365-2966.2011.19899.x

Issue

Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society

Volume 420, Issue 4, pages 2819–2834, March 2012

Additional Information

How to Cite

Kourkchi, E., Khosroshahi, H. G., Carter, D., Karick, A. M., Mármol-Queraltó, E., Chiboucas, K., Tully, R. B., Mobasher, B., Guzmán, R., Matković, A. and Gruel, N. (2012), Dwarf galaxies in the Coma cluster – I. Velocity dispersion measurements. Monthly Notices of the Royal Astronomical Society, 420: 2819–2834. doi: 10.1111/j.1365-2966.2011.19899.x

Author Information

  1. 1

    School of Astronomy, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5531, Tehran, Iran

  2. 2

    Department of Physics, Sharif University of Technology, PO Box 11155-9161, Tehran, Iran

  3. 3

    Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD

  4. 4

    Departamento de Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

  5. 5

    Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96821, USA

  6. 6

    Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720, USA

  7. 7

    Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA

  8. 8

    Department of Astronomy, University of Florida, PO Box 112055, Gainsville, FL 32611-2055, USA

  9. 9

    Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802, USA

  10. 10

    Centro de Estudios de Física del Cosmos de Aragón, C. General Pizarro, 1-3 44001 Teruel, Spain

* Based in part on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programme GO10861.
Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.
E-mail: ehsan@ipm.ir

Publication History

  1. Issue published online: 1 MAR 2012
  2. Article first published online: 10 FEB 2012
  3. Accepted 2011 September 27. Received 2011 September 13; in original form 2010 December 18

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Keywords:

  • galaxies: clusters: individual: Coma;
  • galaxies: dwarf;
  • galaxies: elliptical and lenticular, cD;
  • galaxies: evolution;
  • galaxies: fundamental parameters;
  • galaxies: kinematics and dynamics

ABSTRACT

We present the study of a large sample of early-type dwarf galaxies in the Coma cluster observed with DEIMOS on the Keck II to determine their internal velocity dispersion. We focus on a subsample of 41 member dwarf elliptical galaxies for which the velocity dispersion can be reliably measured, 26 of which were studied for the first time. The magnitude range of our sample is −21 < MR < −15 mag.

This paper (Paper I) focuses on the measurement of the velocity dispersion and their error estimates. The measurements were performed using penalized pixel fitting (ppxf) and using the calcium triplet absorption lines. We use Monte Carlo bootstrapping to study various sources of uncertainty in our measurements, namely statistical uncertainty, template mismatch and other systematics. We find that the main source of uncertainty is the template mismatch effect which is reduced by using templates with a range of spectral types.

Combining our measurements with those from the literature, we study the Faber–Jackson relation (L∝σα) and find that the slope of the relation is α= 1.99 ± 0.14 for galaxies brighter than MR≃−16 mag. A comprehensive analysis of the results combined with the photometric properties of these galaxies is reported in Paper II.

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