The connection between the UV colour of early-type galaxies and the stellar initial mass function revisited

Thumbnail Image
Full text at PDC
Publication Date
Advisors (or tutors)
Journal Title
Journal ISSN
Volume Title
Google Scholar
Research Projects
Organizational Units
Journal Issue
We extend our initial study of the connection between the UV colour of galaxies and both the inferred stellar mass-to-light ratio, Upsilon(*), and a mass-to-light ratio referenced to Salpeter initial mass function (IMF) models of the same age and metallicity, Upsilon(*)/Upsilon(Sal), using new UV magnitude measurements for a much larger sample of early-type galaxies, ETGs, with dynamically determined mass-to-light ratios. We confirm the principal empirical finding of our first study, a strong correlation between the GALEX FUV-NUV colour and Upsilon(*). We show that this finding is not the result of spectral distortions limited to a single passband (e.g. metallicity-dependent line-blanketing in the NUV band), or of the analysis methodology used to measure Upsilon(*), or of the inclusion or exclusion of the correction for stellar population effects as accounted for using Upsilon(*)/Upsilon(Sal). The sense of the correlation is that galaxies with larger Upsilon(*), or larger Upsilon(*)/Upsilon(Sal), are bluer in the UV. We conjecture that differences in the low-mass end of the stellar IMF are related to the nature of the extreme horizontal branch stars generally responsible for the UV flux in ETGs. If so, then UV colour can be used to identify ETGs with particular IMF properties and to estimate Upsilon(*). We also demonstrate that UV colour can be used to decrease the scatter about the Fundamental Plane and Manifold, and to select peculiar galaxies for follow-up with which to further explore the cause of variations in Upsilon(*) and UV colour.
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society © 2014 RAS. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. DZ acknowledges financial support from NASA ADAP NNX12AE27G and NYU CCPP for its hospitality during long-term visits. The authors acknowledge the support from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement PITN-GA-2011-289313. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.
Bernardi M. et al., 2003, AJ, 125, 1866 Bouquin A., Gil de Paz A., Boissier S., Muñoz Mateos J.-C., 2014, ApJ Bressan A., Chiosi C., Fagotto F., 1994, ApJS, 94, 63 Burstein D., Bertola F., Buson L. M., Faber S. M., Lauer T. R., 1988, ApJ, 328, 440 Cappellari M. et al., 2012, Nature, 484, 485 Cappellari M. et al., 2013a, MNRAS, 432, 1862 Cappellari M. et al., 2013b, MNRAS, 432, 1709 Code A. D., Welch G. A., 1979, ApJ, 228, 95 Conroy C., van Dokkum P. G., 2012, ApJ, 760, 71 Donas J. et al., 2007, ApJS, 173, 597 Dorman B., O’Connell R. W., Rood R. T., 1995, ApJ, 442, 105 Dutton A. A. et al., 2011, MNRAS, 417, 1621 Ferreras I., La Barbera F., de la Rosa I. G., Vazdekis A., de Carvalho R. R., Falcón Barroso J., Ricciardelli E., 2013, MNRAS, 429, L15 Gil de Paz A. et al., 2007, ApJS, 173, 185 Golev V., Prugniel P., Simien F., Longhetti M., 1999, A&AS, 136, 519 Graves G. J., Faber S. M., Schiavon R. P., 2009, ApJ, 698, 1590 Han Z., Podsiadlowski P., Lynas-Gray A. E., 2007, MNRAS, 380, 1098 Isobe T., Feigelson E. D., Akritas M. G., Babu G. J., 1990, ApJ, 364, 104 Kaviraj S. et al., 2007, ApJS, 173, 619 Kendall M. G., Stuart A., 1973, Advanced Theory of Statistics, vol. 2. Longon: Griffin Läsker R., van den Bosch R. C. E., van de Ven G., Ferreras I., La Barbera F., Vazdekis A., Falcón Barroso J., 2013, MNRAS, 434, L31 Lee J. C. et al., 2011, ApJS, 192, 6 Lee Y.-W., 1994, ApJ, 430, L113 Martin D. C. et al., 2005, ApJ, 619, L1 Martín Navarro I., La Barbera F., Vazdekis A., Falcón Barroso J., Ferreras I., 2014, ArXiv e-prints 1404.6533 McGaugh S. S., Schombert J. M., de Blok W. J. G., Zagursky M. J., 2010, ApJ, 708, L14 O’Connell R. W., 1999, ARA&A, 37, 603 Park J.-H., Lee Y.-W., 1997, ApJ, 476, 28 Spiniello C., Trager S. C., Koopmans L. V. E., Chen Y. P., 2012, ApJ, 753, L32 Springob C. M. et al., 2012, MNRAS, 420, 2773 Strader J., Caldwell N., Seth A. C., 2011, AJ, 142, 8 Treu T., Auger M. W., Koopmans L. V. E., Gavazzi R., Marshall P. J., Bolton A. S., 2010, ApJ, 709, 1195 Tully R. B., Fisher J. R., 1977, A&A, 54, 661 van Dokkum P. G., Conroy C., 2010, Nature, 468, 940 Yi S. K. et al., 2005, ApJ, 619, L111 Young L. M. et al., 2013, ArXiv e-prints Zaritsky D., Colucci J. E., Pessev P. M., Bernstein R. A., Chandar R., 2012, ApJ, 761, 93 Zaritsky D., Colucci J. E., Pessev P. M., Bernstein R. A., Chandar R., 2013, ApJ, 770, 121 Zaritsky D., Colucci J. E., Pessev P. M., Bernstein R. A., Chandar R., 2014, ApJ Zaritsky D., Gil de Paz A., Bouquin A. Y. K., 2014, ApJ, 780, L1 Zaritsky D., Gonzalez A. H., Zabludoff A. I., 2006, ApJ, 638, 725 Zaritsky D., Zabludoff A. I., Gonzalez A. H., 2008, ApJ, 682, 68