UV-optical colors as probes of early-type galaxy evolution

S. Kaviraj; K. Schawinski; J. E.G. Devriendt; I. Ferreras; S. Khochfar; S. J. Yoon; S. K. Yi; J. M. Deharveng; A. Boselli; T. Barlow; T. Conrow; K. Forster; P. G. Friedman; D. C. Martin; P. Morrissey; S. Neff; D. Schiminovich; M. Seibert; T. Small; T. Wyder; L. Bianchi; J. Donas; T. Heckman; Y. W. Lee; B. Madore; B. Milliard; R. M. Rich; A. Szalay

doi:10.1086/516633

UV-optical colors as probes of early-type galaxy evolution

S. Kaviraj, K. Schawinski, J. E.G. Devriendt, I. Ferreras, S. Khochfar, S. J. Yoon, S. K. Yi, J. M. Deharveng, A. Boselli, T. Barlow, T. Conrow, K. Forster, P. G. Friedman, D. C. Martin, P. Morrissey, S. Neff, D. Schiminovich, M. Seibert, T. Small, T. WyderL. Bianchi, J. Donas, T. Heckman, Y. W. Lee, B. Madore, B. Milliard, R. M. Rich, A. Szalay

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Abstract

We have studied ∼2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range O < z < 0.1.1. Combining GALEXUV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, at least ∼30% of galaxies in this sample have UV to optical colors consistent with some recent star formation within the last Gyr. In particular, galaxies with an NUV - r color less than 5.5 are very likely to have experienced such recent star formation, taking into account the possibility of a contribution to NUV flux from the UV upturn phenomenon. We find quantitative agreement between the observations and the predictions of a semianalytical ACDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < z < 0.11 have ∼ 1 % -3 % of their stellar mass in stars less than 1 Gyr old. The average age of this recently formed population is ∼300-500 Myr. We also find that "monolithically" evolving galaxies, where recent star formation can be driven solely by recycled gas from stellar mass loss, cannot exhibit the blue colors (NUV - r < 5.5) seen in a significant fraction (∼30%) of our observed sample.

Original language	English
Pages (from-to)	619-642
Number of pages	24
Journal	Astrophysical Journal, Supplement Series
Volume	173
Issue number	2
DOIs	https://doi.org/10.1086/516633
Publication status	Published - 2007 Dec

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/516633

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Kaviraj, S., Schawinski, K., Devriendt, J. E. G., Ferreras, I., Khochfar, S., Yoon, S. J., Yi, S. K., Deharveng, J. M., Boselli, A., Barlow, T., Conrow, T., Forster, K., Friedman, P. G., Martin, D. C., Morrissey, P., Neff, S., Schiminovich, D., Seibert, M., Small, T., ... Szalay, A. (2007). UV-optical colors as probes of early-type galaxy evolution. Astrophysical Journal, Supplement Series, 173(2), 619-642. https://doi.org/10.1086/516633

@article{89ae0e09dba247b2b900854c71d584e4,

title = "UV-optical colors as probes of early-type galaxy evolution",

abstract = "We have studied ∼2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range O < z < 0.1.1. Combining GALEXUV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, at least ∼30% of galaxies in this sample have UV to optical colors consistent with some recent star formation within the last Gyr. In particular, galaxies with an NUV - r color less than 5.5 are very likely to have experienced such recent star formation, taking into account the possibility of a contribution to NUV flux from the UV upturn phenomenon. We find quantitative agreement between the observations and the predictions of a semianalytical ACDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < z < 0.11 have ∼ 1 % -3 % of their stellar mass in stars less than 1 Gyr old. The average age of this recently formed population is ∼300-500 Myr. We also find that {"}monolithically{"} evolving galaxies, where recent star formation can be driven solely by recycled gas from stellar mass loss, cannot exhibit the blue colors (NUV - r < 5.5) seen in a significant fraction (∼30%) of our observed sample.",

author = "S. Kaviraj and K. Schawinski and Devriendt, {J. E.G.} and I. Ferreras and S. Khochfar and Yoon, {S. J.} and Yi, {S. K.} and Deharveng, {J. M.} and A. Boselli and T. Barlow and T. Conrow and K. Forster and Friedman, {P. G.} and Martin, {D. C.} and P. Morrissey and S. Neff and D. Schiminovich and M. Seibert and T. Small and T. Wyder and L. Bianchi and J. Donas and T. Heckman and Lee, {Y. W.} and B. Madore and B. Milliard and Rich, {R. M.} and A. Szalay",

year = "2007",

month = dec,

doi = "10.1086/516633",

language = "English",

volume = "173",

pages = "619--642",

journal = "Astrophysical Journal, Supplement Series",

issn = "0067-0049",

publisher = "IOP Publishing Ltd.",

number = "2",

}

Kaviraj, S, Schawinski, K, Devriendt, JEG, Ferreras, I, Khochfar, S, Yoon, SJ , Yi, SK, Deharveng, JM, Boselli, A, Barlow, T, Conrow, T, Forster, K, Friedman, PG, Martin, DC, Morrissey, P, Neff, S, Schiminovich, D, Seibert, M, Small, T, Wyder, T, Bianchi, L, Donas, J, Heckman, T, Lee, YW, Madore, B, Milliard, B, Rich, RM & Szalay, A 2007, 'UV-optical colors as probes of early-type galaxy evolution', Astrophysical Journal, Supplement Series, vol. 173, no. 2, pp. 619-642. https://doi.org/10.1086/516633

TY - JOUR

T1 - UV-optical colors as probes of early-type galaxy evolution

AU - Kaviraj, S.

AU - Schawinski, K.

AU - Devriendt, J. E.G.

AU - Ferreras, I.

AU - Khochfar, S.

AU - Yoon, S. J.

AU - Yi, S. K.

AU - Deharveng, J. M.

AU - Boselli, A.

AU - Barlow, T.

AU - Conrow, T.

AU - Forster, K.

AU - Friedman, P. G.

AU - Martin, D. C.

AU - Morrissey, P.

AU - Neff, S.

AU - Schiminovich, D.

AU - Seibert, M.

AU - Small, T.

AU - Wyder, T.

AU - Bianchi, L.

AU - Donas, J.

AU - Heckman, T.

AU - Lee, Y. W.

AU - Madore, B.

AU - Milliard, B.

AU - Rich, R. M.

AU - Szalay, A.

PY - 2007/12

Y1 - 2007/12

N2 - We have studied ∼2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range O < z < 0.1.1. Combining GALEXUV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, at least ∼30% of galaxies in this sample have UV to optical colors consistent with some recent star formation within the last Gyr. In particular, galaxies with an NUV - r color less than 5.5 are very likely to have experienced such recent star formation, taking into account the possibility of a contribution to NUV flux from the UV upturn phenomenon. We find quantitative agreement between the observations and the predictions of a semianalytical ACDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < z < 0.11 have ∼ 1 % -3 % of their stellar mass in stars less than 1 Gyr old. The average age of this recently formed population is ∼300-500 Myr. We also find that "monolithically" evolving galaxies, where recent star formation can be driven solely by recycled gas from stellar mass loss, cannot exhibit the blue colors (NUV - r < 5.5) seen in a significant fraction (∼30%) of our observed sample.

AB - We have studied ∼2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range O < z < 0.1.1. Combining GALEXUV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, at least ∼30% of galaxies in this sample have UV to optical colors consistent with some recent star formation within the last Gyr. In particular, galaxies with an NUV - r color less than 5.5 are very likely to have experienced such recent star formation, taking into account the possibility of a contribution to NUV flux from the UV upturn phenomenon. We find quantitative agreement between the observations and the predictions of a semianalytical ACDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < z < 0.11 have ∼ 1 % -3 % of their stellar mass in stars less than 1 Gyr old. The average age of this recently formed population is ∼300-500 Myr. We also find that "monolithically" evolving galaxies, where recent star formation can be driven solely by recycled gas from stellar mass loss, cannot exhibit the blue colors (NUV - r < 5.5) seen in a significant fraction (∼30%) of our observed sample.

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UR - http://www.scopus.com/inward/citedby.url?scp=39449090424&partnerID=8YFLogxK

U2 - 10.1086/516633

DO - 10.1086/516633

M3 - Article

AN - SCOPUS:39449090424

SN - 0067-0049

VL - 173

SP - 619

EP - 642

JO - Astrophysical Journal, Supplement Series

JF - Astrophysical Journal, Supplement Series

IS - 2

ER -

UV-optical colors as probes of early-type galaxy evolution

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