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The mid-infrared colour-magnitude relation of early-type galaxies in the Coma cluster as measured by Spitzer-IRS ⋆
| Content Provider | Semantic Scholar |
|---|---|
| Author | Clemens, Michael S. Bressan, Alessandro Panuzzo, Pasquale Rampazzo, Roberto Silva, Laura Buson, Lucio M. Granato, Gian Luigi |
| Copyright Year | 2008 |
| Abstract | We use 16 μm, Spitzer-IRS, blue peakup photometry of 50 early-type galaxies in the Coma cluster to define the mid-infrared colour-magnitude relation. We compare with recent simple stellar population models that include the mid-infrared emission from the extended, dusty envelopes of evolved stars. The Ks-[16] colour in these models is very sensitive to the relative population of dusty AGB stars. We find that the passively evolving early-type galaxies define a sequence of approximately constant age (∼ 10 Gyr) with varying metallicity. Several galaxies that lie on the optical/nearinfrared colour-magnitude relation do not lie on the mid-infrared relation. This illustrates the sensitivity of the Ks-[16] colour to age. The fact that a colour-magnitude relation is seen in the mid-infrared underlines the extremely passive nature of the majority (68 %) of early-type galaxies in the Coma cluster. The corollary of this is that 32% of the early-type galaxies in our sample are not ‘passive’, insofar as they are either significantly younger than 10 Gyr or they have had some rejuvenation episode within the last few Gyr. We also conclude that external effects, such as disruption of the dusty AGB star envelopes by the interstellar medium, does not effect the 16 μm emission. This midinfrared emission is relatively short-lived and occurs well within the radius at which such effects become important. Given the robustness of mid-infrared emitting envelopes to environmental effects, the observation that galaxies with excess 16 μm emission lie preferentially at small radii within the cluster, indicates that the cluster environment influences the star formation history. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0808.2899v1.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/0808.2899v2.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | ABRA gene Comatose Denial-of-service attack GUCY2C protein, human Galaxy Offset binary Photometry Rejuvenation Stars, Celestial Stellar (payment network) |
| Content Type | Text |
| Resource Type | Article |
