UV-optical colors as probes of early-type galaxy evolution
<p>We have studied ~2100 early-type galaxies in the SDSS DR3 which have been detected by the <i>GALEX</i> Medium Imaging Survey (MIS), in the redshift range 0 < <i>z</i> < 0.11. Combining <i>GALEX</i> UV photometry with corollary optical data...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Journal article |
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American Astronomical Society
2007
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| _version_ | 1826283599031173120 |
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| author | Kaviraj, S Schawinski, K Devriendt, J Ferreras, I Khochfar, S Yoon, S Yi, S Deharveng, J Boselli, A Barlow, T Conrow, T Forster, K Friedman, P Martin, D Morrissey, P Neff, S Schiminovich, D Seibert, M Small, T Wyder, T Bianchi, L Donas, J Heckman, T Lee, Y Madore, B Milliard, B Rich, R Szalay, A |
| author_facet | Kaviraj, S Schawinski, K Devriendt, J Ferreras, I Khochfar, S Yoon, S Yi, S Deharveng, J Boselli, A Barlow, T Conrow, T Forster, K Friedman, P Martin, D Morrissey, P Neff, S Schiminovich, D Seibert, M Small, T Wyder, T Bianchi, L Donas, J Heckman, T Lee, Y Madore, B Milliard, B Rich, R Szalay, A |
| author_sort | Kaviraj, S |
| collection | OXFORD |
| description | <p>We have studied ~2100 early-type galaxies in the SDSS DR3 which have been detected by the <i>GALEX</i> Medium Imaging Survey (MIS), in the redshift range 0 < <i>z</i> < 0.11. Combining <i>GALEX</i> UV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, <i>at least</i> ~30% of galaxies in this sample have UV to optical colors consistent with <i>some</i> recent star formation within the last Gyr. In particular, galaxies with an NUV − <i>r</i> color less than 5.5 are <i>very</i> 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 ΛCDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < <i>z</i> < 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 <i>solely</i> by recycled gas from stellar mass loss, <i>cannot</i> exhibit the blue colors (NUV − <i>r</i> < 5.5) seen in a significant fraction (~30%) of our observed sample.</p> |
| first_indexed | 2024-03-07T01:01:17Z |
| format | Journal article |
| id | oxford-uuid:89d3a63e-660b-492a-9e96-bcb9224c277d |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:01:17Z |
| publishDate | 2007 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | oxford-uuid:89d3a63e-660b-492a-9e96-bcb9224c277d2022-03-26T22:27:14ZUV-optical colors as probes of early-type galaxy evolutionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:89d3a63e-660b-492a-9e96-bcb9224c277dSymplectic Elements at OxfordAmerican Astronomical Society2007Kaviraj, SSchawinski, KDevriendt, JFerreras, IKhochfar, SYoon, SYi, SDeharveng, JBoselli, ABarlow, TConrow, TForster, KFriedman, PMartin, DMorrissey, PNeff, SSchiminovich, DSeibert, MSmall, TWyder, TBianchi, LDonas, JHeckman, TLee, YMadore, BMilliard, BRich, RSzalay, A <p>We have studied ~2100 early-type galaxies in the SDSS DR3 which have been detected by the <i>GALEX</i> Medium Imaging Survey (MIS), in the redshift range 0 < <i>z</i> < 0.11. Combining <i>GALEX</i> UV photometry with corollary optical data from the SDSS, we find that, at a 95% confidence level, <i>at least</i> ~30% of galaxies in this sample have UV to optical colors consistent with <i>some</i> recent star formation within the last Gyr. In particular, galaxies with an NUV − <i>r</i> color less than 5.5 are <i>very</i> 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 ΛCDM hierarchical merger model and deduce that early-type galaxies in the redshift range 0 < <i>z</i> < 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 <i>solely</i> by recycled gas from stellar mass loss, <i>cannot</i> exhibit the blue colors (NUV − <i>r</i> < 5.5) seen in a significant fraction (~30%) of our observed sample.</p> |
| spellingShingle | Kaviraj, S Schawinski, K Devriendt, J Ferreras, I Khochfar, S Yoon, S Yi, S Deharveng, J Boselli, A Barlow, T Conrow, T Forster, K Friedman, P Martin, D Morrissey, P Neff, S Schiminovich, D Seibert, M Small, T Wyder, T Bianchi, L Donas, J Heckman, T Lee, Y Madore, B Milliard, B Rich, R Szalay, A UV-optical colors as probes of early-type galaxy evolution |
| title | UV-optical colors as probes of early-type galaxy evolution |
| title_full | UV-optical colors as probes of early-type galaxy evolution |
| title_fullStr | UV-optical colors as probes of early-type galaxy evolution |
| title_full_unstemmed | UV-optical colors as probes of early-type galaxy evolution |
| title_short | UV-optical colors as probes of early-type galaxy evolution |
| title_sort | uv optical colors as probes of early type galaxy evolution |
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