| Full text | |
| Author(s): |
Lagana, T. F.
;
Ulmer, M. P.
;
Martins, L. P.
;
da Cunha, E.
Total Authors: 4
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 825, n. 2 JUL 10 2016. |
| Web of Science Citations: | 1 |
| Abstract | |
The galaxy cluster RX J1257+4738 at z = 0.866 is one of the highest redshift clusters with a richness of multi-wavelength data, and is thus a good target to study the star formation-density relation at early epochs. Using a sample of spectroscopically confirmed cluster members, we derive the star-formation rates (SFRs) of our galaxies using two methods: (1) the relation between SFR and total infrared luminosity extrapolated from the observed Spitzer Multiband Imaging Photometer for Spitzer. 24 mu m imaging data; and (2) spectral energy distribution fitting using the MAGPHYS code, including eight different bands. We show that, for this cluster, the SFR-density relation is very weak and seems to be dominated by the two central galaxies and the SFR presents a mild dependence on stellar mass, with more massive galaxies having higher SFR. However, the specific SFR (SSFR) decreases with stellar mass, meaning that more massive galaxies are forming fewer stars per unit of mass, and thus suggesting that the increase in star-forming members is driven by cluster assembly and infall. If the environment is somehow driving the star formation, one would expect a relation between the SSFR and the cluster centric distance, but that is not the case. A possible scenario to explain this lack of correlation is the contamination by infalling galaxies in the inner part of the cluster, which may be on their initial pass through the cluster center. As these galaxies have higher SFRs for their stellar mass, they enhance the mean SSFR in the center of the cluster. (AU) | |
| FAPESP's process: | 12/00578-0 - Matter distribution in galaxy clusters: a comprehensive picture of baryons in the largest virialized structures in the universe |
| Grantee: | Tatiana Ferraz Laganá |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 15/14575-0 - Improoving stellar libraries for stellar population synthesis |
| Grantee: | Lucimara Pires Martins |
| Support Opportunities: | Regular Research Grants |