Publication: Stellar populations of early-type galaxies in different environments - III. Line-strength gradients
Loading...
Official URL
Full text at PDC
Publication Date
2006-10
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
EDP Sciencies
Citations
Exportar
Abstract
Aims. This is the third paper of a series devoted to the study of the stellar content of early-type galaxies. The goal of the series is to set constraints on the evolutionary status of these objects. Methods. We present line-strength gradients for 22 spectral indices measured in a sample of 82 early-type galaxies in different environments, including the high-density cores of the Coma cluster, the Virgo cluster, poor groups, and isolated field galaxies. Using new evolutionary population synthesis models, we derive age and metallicity gradients, and compare the mean values with the predictions of different galaxy formation models. We explore the behaviour of individual chemical species by deriving the metallicity gradient with different indicators. Results. We find that the strength of the metallicity gradient inferred from stellar population models depends on the specific Lick index employed. In particular, metallicity gradients obtained with CN2 and C4668 combined with H beta are steeper than those measured using Ca4227 or Fe4383. The correlation of the metallicity gradients with other parameters also depends on the specific index employed. If the metallicity gradient is obtained using CN2 and Mgb, then it correlates with the central age of the galaxies. On the contrary, if Fe4383 or Ca4227 is used, the metallicity gradient correlates with the velocity dispersion gradient. Conclusions. This may suggest that several mechanisms have helped to set the age and metallicity gradients in early-type galaxies. While we do not find any correlation between the metallicity gradient and the central velocity dispersion for galaxies in low-density environments, we find a marginal correlation between the metallicity gradient and the mass for galaxies in the centre of the Coma cluster. We also find a trend for which galaxies in denser environments show a steeper metallicity gradient than galaxies in less dense environments. We interpret these results in light of the different mechanisms proposed to explain the observed changes between galaxies as a function of environment.
Description
© ESO 2006. We would like to thank the anonymous referee for very helpful comments. The WHT is operated on the island of La Palma by the Royal Greenwich Observatory at the Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. The Calar Alto Observatory is operated jointly by the Max-Planck Institute für Astronomie, Heidelberg, and the Spanish Instituto de Astrofísica de Andalucía (CSIC). This work was partially supported by the Spanish research project AYA 2003-01840 and by the Australian Research Council. We are grateful to the CATs for their generous allocations of telescope time.
UCM subjects
Unesco subjects
Keywords
Citation
Arimoto, N., & Yoshii, Y. 1987, A&A, 173, 23
Barnes, J. E., & Hernquist, L. E. 1991, ApJ, 370, L65
Baugh, C. M., Cole, S., & Frenk, C. S. 1996, MNRAS, 283, 1361
Bender, R., & Surma, P. 1992, A&A, 258, 250
Binney, J. 1978, MNRAS, 183, 501
Boroson, T. A., & Thompson, I. B. 1991, AJ, 101, 111
Bekki, K., & Shioya, Y. 1999, ApJ, 513, 108
Burstein, D. 1979, ApJ, 232, 74
Cardiel, N., Gorgas, J., & Aragón Salamanca, A. 1998a, MNRAS, 298, 977
Cardiel, N., Gorgas, J., Cenarro, J., & González, J. J. 1998b, A&AS, 127, 597
Carlberg, R. G. 1984, ApJ, 286, 403
Carollo, C. M., & Danziger, I. J. 1994, MNRAS, 270, 523
Carollo, C. M., Danziger, I. J., & Buson, L. 1993, MNRAS, 265, 553
Cenarro, A. J., Gorgas, J., Vazdekis, A., Cardiel, N., & Peletier, R. F. 2003, MNRAS, 339, L12
Cohen, J. G. 1979, ApJ, 228, 405
Chiosi, C., & Carraro, G. 2002, MNRAS, 335, 335
Cole, S., Aragón Salamanca, A., Frenk, C. S., Navarro, J. F., & Zepf, S. E. 1994, MNRAS, 271, 781
Couture, J., & Hardy, E. 1988, AJ, 96, 867
Davidge, T. J. 1991, AJ, 102, 896
Davidge, T. J. 1992, AJ, 103, 1512
Davies, R. L., & Sadler, E. M. 1987, Structure and Dynamics of Elliptical
Galaxies, ed. T. de Zeeuw (Dordrecth: Reidel), IAU Symp., 127, 441
Davies, R. L., Sadler, E. M., & Peletier, R. F. 1993, MNRAS, 262, 650
Efstathiou, G., & Gorgas, J. 1985, MNRAS, 215, P37
Eggen, O. J., Lynden-Bell, D., & Sandage, A. R. 1962, ApJ, 136, 748
Faber, S. M., Friel, E. D., Burstein, D., & Gaskell, C. M. 1985, ApJS, 57, 711
Fisher, D., Franx, M., & Illingworth, G. 1995, ApJ, 448, 119
Fisher, D., Franx, M., & Illingworth, G. 1996, ApJ, 459, 110
Franx, M., & Illingworth, G. 1990, ApJ, 359, L41
Franx, M., Illingworth, G., & Heckman, T., 1989, AJ, 98, 538
Gibson, B. K. 1997, MNRAS, 290, 471
González, J. J. 1993, Ph.D. Thesis, University of California
González, J. J., & Gorgas, J. 1996, in Fresh Views of Elliptical Galaxies, ed. A. Buzzoni, A. Renzini, & A. Serrano (San Francisco: ASP) ASP Conf. Ser., 86., 225
Gorgas, J., Efstathiou, G., & Aragón Salamanca, A. 1990, MNRAS, 245, 217 (G90)
Gorgas, J., Faber, S. M., Burstein, D., et al. 1993, ApJS, 86, 153
Gorgas, J., Pedraz, S., Guzmán, R., Cardiel, N., & González, J. J. 1997, ApJ, 481, L19
Joly, M., & Andrillat, Y. 1973, A&A, 26, 95
Jørgensen, I., Franx, M., & Kjærgaard, P. 1992, A&AS, 95, 489
Kauffmann, G. 1996, MNRAS, 281, 487
Kauffmann, G., & Charlot, S. 1998, MNRAS, 294, 705
Kawata, D. 1999, PASJ, 51, 931
Kawata, D., & Gibson, B. 2003, MNRAS, 346, 135
Kobayashi, C. 2004, MNRAS, 347, 740
Kobayashi, C., & Arimoto, N. 1999, ApJ, 527, 573
Kormendy, J., & Djorgovski, S. 1989, ARA&A, 27, 235
Larson, R. B. 1974a, MNRAS, 166, 585
Larson, R. B. 1974b, MNRAS, 169, 229
Larson, R. B. 1975, MNRAS, 173, 671
Mathews, W. G., & Baker, J. C. 1971, ApJ, 170, 241
Martinelli, A., Matteucci, F., & Colafrancesco, S. 1998, MNRAS, 298, 42
McClure, R. D. 1969, AJ, 74, 50
Mehlert, D., Thomas, D., Saglia, R. P., Bender, R., & Wegner, G. 2003, A&A, 407, 423
Mihos, J. C., & Hernquist, L. 1994, ApJ, 427, 112
Mould, J. R. 1978, ApJ, 220, 434
Munn, J. A. 1992, ApJ, 399, 444
Oke, J. B., & Schwarzschild, M. 1975, ApJ, 198, 630
Peletier, R. F. 1989, Ph.D. Thesis, University of Groningen
Peletier, R. F., Davies, R. L., Illingworth, G. D., Davis, L. E., & Cawson, M. 1990, AJ, 100, 1091
Sánchez Blázquez, P. 2004, Ph.D. Thesis, Universidad Complutense de Madrid
Sánchez Blázquez, P., Gorgas, J., Cardiel, N., Cenarro, A. J., & González, J. J. 2003, ApJ, 590, L91
Sánchez Blázquez, P., Gorgas, J., Cardiel, N., & González, J. J. 2006a, A&A, 457, 787 (Paper I)
Sánchez Blázquez, P., Gorgas, J., Cardiel, N., & González, J. J. 2006b, A&A, 457, 809 (Paper II)
Sánchez Blázquez, P., Peletier, R. F., Jiménez, J., et al. 2006c, MNRAS [arXiv:astro-ph/0607009]
Spinrad, H., Smith, H. E., & Taylor, D. J. 1972, ApJ, 175, 649
Spinrad, H., Gunn, J. E., Taylor, B. J., McClure, R. D., & Young, J. W. 1971, ApJ, 164, 11
Schweizer, F., Seitzer, P., Faber, S. M., et al. 1990, ApJ, 364, L33
Tamura, N., & Ohta, K. 2003, AJ, 126, 596
Thomas, D., Maraston, C., & Bender, R. 2003, MNRAS, 339, 897
Thomsen, B., & Baum, W. A. 1989, ApJ, 347, 214
Trager, S. C., Worthey, G., Faber, S. M., Burstein, D., & González, J. J. 1998, ApJS, 116, 1
Trager, S. C., Faber, S. M., Worthey, G., & González, J. J. 2000a, AJ, 119, 1645
Trager, S. C., Faber, S. M., Worthey, G., & González, J. J. 2000b, AJ, 120, 165
van Albada, T. S. 1982, MNRAS, 201, 939
Vazdekis, A. 1999, ApJ, 513, 224
Welch, G. A., & Forrester, W. T. 1972, AJ, 77, 333
White, S. D. M. 1980, MNRAS, 191, 1
Worthey, G. 1994, ApJS, 95, 107
Worthey, G., Faber, S. M., González, J. J., & Burstein, D. 1994, ApJS, 94, 687