Rejuvenation of spiral bulges
We seek to understand whether the stellar populations of galactic bulges show evidence of secular evolution triggered by the presence of the disc. To this end we re-analyse the sample of Proctor and Sansom (2002), deriving stellar population ages and element abundances from absorption line indices a...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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2007
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| _version_ | 1826289347381428224 |
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| author | Thomas, D Davies, R |
| author_facet | Thomas, D Davies, R |
| author_sort | Thomas, D |
| collection | OXFORD |
| description | We seek to understand whether the stellar populations of galactic bulges show evidence of secular evolution triggered by the presence of the disc. To this end we re-analyse the sample of Proctor and Sansom (2002), deriving stellar population ages and element abundances from absorption line indices as functions of central velocity dispersion and Hubble type. In agreement with other studies in the literature, we find that bulges have relatively low luminosity weighted ages, the lowest age derived being 1.3 Gyr. Hence bulges are not generally old, but actually rejuvenated systems. We discuss evidence that this might be true also for the bulge of the Milky Way. The smallest bulges are the youngest with the lowest /Fe ratios indicating the presence of significant star formation events involving 10 30 per cent of their total mass in the past 1 2 Gyr. No significant correlations of the stellar population parameters with Hubble Type are found. We show that the above relationships with coincide perfectly with those of early-type galaxies. At a given velocity dispersion, bulges and elliptical galaxies are indistinguishable as far as their stellar populations are concerned. These results favour an inside-out formation scenario and indicate that the discs in spiral galaxies of Hubble types Sbc and earlier cannot have a significant influence on the evolution of the stellar populations in the bulge component. The phenomenon of pseudobulge formation must be restricted to spirals of types later than Sbc. © 2008 Copyright International Astronomical Union 2008. |
| first_indexed | 2024-03-07T02:27:29Z |
| format | Journal article |
| id | oxford-uuid:a61c8314-659a-4509-aa5c-3c6711354188 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:27:29Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:a61c8314-659a-4509-aa5c-3c67113541882022-03-27T02:44:58ZRejuvenation of spiral bulgesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a61c8314-659a-4509-aa5c-3c6711354188EnglishSymplectic Elements at Oxford2007Thomas, DDavies, RWe seek to understand whether the stellar populations of galactic bulges show evidence of secular evolution triggered by the presence of the disc. To this end we re-analyse the sample of Proctor and Sansom (2002), deriving stellar population ages and element abundances from absorption line indices as functions of central velocity dispersion and Hubble type. In agreement with other studies in the literature, we find that bulges have relatively low luminosity weighted ages, the lowest age derived being 1.3 Gyr. Hence bulges are not generally old, but actually rejuvenated systems. We discuss evidence that this might be true also for the bulge of the Milky Way. The smallest bulges are the youngest with the lowest /Fe ratios indicating the presence of significant star formation events involving 10 30 per cent of their total mass in the past 1 2 Gyr. No significant correlations of the stellar population parameters with Hubble Type are found. We show that the above relationships with coincide perfectly with those of early-type galaxies. At a given velocity dispersion, bulges and elliptical galaxies are indistinguishable as far as their stellar populations are concerned. These results favour an inside-out formation scenario and indicate that the discs in spiral galaxies of Hubble types Sbc and earlier cannot have a significant influence on the evolution of the stellar populations in the bulge component. The phenomenon of pseudobulge formation must be restricted to spirals of types later than Sbc. © 2008 Copyright International Astronomical Union 2008. |
| spellingShingle | Thomas, D Davies, R Rejuvenation of spiral bulges |
| title | Rejuvenation of spiral bulges |
| title_full | Rejuvenation of spiral bulges |
| title_fullStr | Rejuvenation of spiral bulges |
| title_full_unstemmed | Rejuvenation of spiral bulges |
| title_short | Rejuvenation of spiral bulges |
| title_sort | rejuvenation of spiral bulges |
| work_keys_str_mv | AT thomasd rejuvenationofspiralbulges AT daviesr rejuvenationofspiralbulges |