%0 Generic %1 valentino2014metal %A Valentino, F. %A Daddi, E. %A Strazzullo, V. %A Gobat, R. %A Onodera, M. %A Bournaud, F. %A Juneau, S. %A Renzini, A. %A Arimoto, N. %A Carollo, M. %A Zanella, A. %D 2014 %K cluster gas metallicity sfr %T Metal deficiency in cluster star-forming galaxies at z=2 %U http://arxiv.org/abs/1410.1437 %X We investigate the role of the environment in the history of metal enrichment of star-forming galaxies (SFGs) in the farthest spectroscopically confirmed and X-ray detected cluster, CL J1449+0856 at z=1.99. Combining HST/WFC3 G141 slitless spectroscopic data, our 13-bands photometry, and a recent Subaru/MOIRCS near infrared spectroscopic follow-up, we constrained the physical properties of SFGs in CL J1449+0856 and in a mass-matched field sample. After AGN removal, stacking individual MOIRCS spectra for 6 (31) sources in the cluster (field) with masses 10 < log(M/Msun) < 11, we find a ~4-sigma significant lower N II/Ha ratio in the cluster than in the field. Stacking a subsample of 16 field galaxies with Hb and O III in the observed range, we measure a O III/Hb ratio fully compatible with the cluster value. Converting these ratios into metallicities, we find that the cluster SFGs are up to 0.25 dex poorer in metals than their field counterparts, depending on the adopted calibration. The low metallicity in cluster sources is confirmed when stacking their WFC3 spectra, measuring O II, and using the O32, R23 indicators. Furthermore it is supported by a low N/O ratio, close to the primary nitrogen abundance predicted by current models. The ionization parameter in the cluster stacked sample is comparable to current measurements in high redshift field SFGs. We observe a significantly higher Ha luminosity and equivalent width in the average cluster spectrum than in the field. This might be due to enhanced specific star formation rate or lower dust reddening in cluster sources, but we cannot disentangle the two effects given the uncertainties. Our findings might be caused by the accretion of reservoirs of pristine gas around galaxies at z=2 and on cluster scales, possibly connected with a phase of rapid mass assembly of the dark matter structure at z>2 and of high galaxy merger rate.

@misc{valentino2014metal, abstract = {We investigate the role of the environment in the history of metal enrichment of star-forming galaxies (SFGs) in the farthest spectroscopically confirmed and X-ray detected cluster, CL J1449+0856 at z=1.99. Combining HST/WFC3 G141 slitless spectroscopic data, our 13-bands photometry, and a recent Subaru/MOIRCS near infrared spectroscopic follow-up, we constrained the physical properties of SFGs in CL J1449+0856 and in a mass-matched field sample. After AGN removal, stacking individual MOIRCS spectra for 6 (31) sources in the cluster (field) with masses 10 < log(M/Msun) < 11, we find a ~4-sigma significant lower [N II]/Ha ratio in the cluster than in the field. Stacking a subsample of 16 field galaxies with Hb and [O III] in the observed range, we measure a [O III]/Hb ratio fully compatible with the cluster value. Converting these ratios into metallicities, we find that the cluster SFGs are up to 0.25 dex poorer in metals than their field counterparts, depending on the adopted calibration. The low metallicity in cluster sources is confirmed when stacking their WFC3 spectra, measuring [O II], and using the O32, R23 indicators. Furthermore it is supported by a low N/O ratio, close to the primary nitrogen abundance predicted by current models. The ionization parameter in the cluster stacked sample is comparable to current measurements in high redshift field SFGs. We observe a significantly higher Ha luminosity and equivalent width in the average cluster spectrum than in the field. This might be due to enhanced specific star formation rate or lower dust reddening in cluster sources, but we cannot disentangle the two effects given the uncertainties. Our findings might be caused by the accretion of reservoirs of pristine gas around galaxies at z=2 and on cluster scales, possibly connected with a phase of rapid mass assembly of the dark matter structure at z>2 and of high galaxy merger rate.}, added-at = {2014-10-07T09:41:07.000+0200}, author = {Valentino, F. and Daddi, E. and Strazzullo, V. and Gobat, R. and Onodera, M. and Bournaud, F. and Juneau, S. and Renzini, A. and Arimoto, N. and Carollo, M. and Zanella, A.}, biburl = {https://www.bibsonomy.org/bibtex/2b362cec3b7a6a3bc372d5deaa08e8180/miki}, description = {[1410.1437] Metal deficiency in cluster star-forming galaxies at z=2}, interhash = {efb8fc90966cdc8a0d39ac35e7bf74c8}, intrahash = {b362cec3b7a6a3bc372d5deaa08e8180}, keywords = {cluster gas metallicity sfr}, note = {cite arxiv:1410.1437Comment: 18 pages, 18 figures, Submitted to ApJ}, timestamp = {2014-10-07T09:41:07.000+0200}, title = {Metal deficiency in cluster star-forming galaxies at z=2}, url = {http://arxiv.org/abs/1410.1437}, year = 2014 }