UV-optical colors as probes of early-type galaxy evolution
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 ∼3...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Journal article |
| Jezik: | English |
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2007
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| _version_ | 1826286882396307456 |
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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 |
| 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 |
| author_sort | Kaviraj, S |
| collection | OXFORD |
| description | 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. © 2007. The American Astronomical Society. All rights reserved. |
| first_indexed | 2024-03-07T01:50:19Z |
| format | Journal article |
| id | oxford-uuid:99dd6f18-ba0f-43ed-8203-3ec7edf15749 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T01:50:19Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:99dd6f18-ba0f-43ed-8203-3ec7edf157492022-03-27T00:17:23ZUV-optical colors as probes of early-type galaxy evolutionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:99dd6f18-ba0f-43ed-8203-3ec7edf15749EnglishSymplectic Elements at Oxford2007Kaviraj, SSchawinski, KDevriendt, JFerreras, IKhochfar, SYoon, SYi, SDeharveng, JBoselli, ABarlow, TConrow, TForster, KFriedman, PMartin, DMorrissey, PNeff, SSchiminovich, DSeibert, MSmall, TWyder, TBianchi, LDonas, JHeckman, TLee, YMadore, BWe 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. © 2007. The American Astronomical Society. All rights reserved. |
| 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 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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