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Title: METAL DEFICIENCY IN CLUSTER STAR-FORMING GALAXIES AT Z = 2

Abstract

We investigate the environmental effect on the metal enrichment of star-forming galaxies (SFGs) in the farthest spectroscopically confirmed and X-ray-detected cluster, CL J1449+0856 at z = 1.99. We combined Hubble Space Telescope/WFC3 G141 slitless spectroscopic data, our thirteen-band photometry, and a recent Subaru/Multi-object InfraRed Camera and Spectrograph (MOIRCS) near-infrared spectroscopic follow-up to constrain the physical properties of SFGs in CL J1449+0856 and in a mass-matched field sample. After a conservative removal of active galactic nuclei, stacking individual MOIRCS spectra of 6 (31) sources in the cluster (field) in the mass range 10 ≤ log(M/M{sub ⊙}) ≤ 11, we find a ∼4σ lower [N ii]/Hα ratio in the cluster than in the field. Stacking a subsample of 16 field galaxies with Hβ and [O iii] in the observed range, we measure an [O iii]/Hβ 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 using alternative indicators. Furthermore, we observe a significantly higher Hα luminosity and equivalent width in the average cluster spectrum than in the field. This ismore » likely due to the enhanced specific star formation rate; even if lower dust reddening and/or an uncertain environmental dependence on the continuum-to-nebular emission differential reddening may play a role. Our findings might be explained by the accretion of pristine gas around galaxies at z = 2 and from cluster-scale reservoirs, possibly connected with a phase of rapid halo mass assembly at z > 2 and of a high galaxy merging rate.« less

Authors:
; ; ; ; ; ;  [1]; ;  [2];  [3];  [4]
  1. Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif sur Yvette (France)
  2. Institute for Astronomy, ETH Zürich Wolfgang-Pauli-strasse 27, 8093 Zürich (Switzerland)
  3. INAF-Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5, I-35122 Padova (Italy)
  4. Subaru Telescope, National Astronomical Observatory of Japan 650 North A’ohoku Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22522079
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 801; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CALIBRATION; CAMERAS; GALAXIES; GALAXY CLUSTERS; GALAXY NUCLEI; LUMINOSITY; MASS; METALLICITY; NEAR INFRARED RADIATION; PHOTOMETRY; SPACE; STAR CLUSTERS; STAR EVOLUTION; STARS; TELESCOPES; X RADIATION

Citation Formats

Valentino, F., Daddi, E., Strazzullo, V., Gobat, R., Bournaud, F., Juneau, S., Zanella, A., Onodera, M., Carollo, M., Renzini, A., and Arimoto, N., E-mail: francesco.valentino@cea.fr. METAL DEFICIENCY IN CLUSTER STAR-FORMING GALAXIES AT Z = 2. United States: N. p., 2015. Web. doi:10.1088/0004-637X/801/2/132.
Valentino, F., Daddi, E., Strazzullo, V., Gobat, R., Bournaud, F., Juneau, S., Zanella, A., Onodera, M., Carollo, M., Renzini, A., & Arimoto, N., E-mail: francesco.valentino@cea.fr. METAL DEFICIENCY IN CLUSTER STAR-FORMING GALAXIES AT Z = 2. United States. doi:10.1088/0004-637X/801/2/132.
Valentino, F., Daddi, E., Strazzullo, V., Gobat, R., Bournaud, F., Juneau, S., Zanella, A., Onodera, M., Carollo, M., Renzini, A., and Arimoto, N., E-mail: francesco.valentino@cea.fr. Tue . "METAL DEFICIENCY IN CLUSTER STAR-FORMING GALAXIES AT Z = 2". United States. doi:10.1088/0004-637X/801/2/132.
@article{osti_22522079,
title = {METAL DEFICIENCY IN CLUSTER STAR-FORMING GALAXIES AT Z = 2},
author = {Valentino, F. and Daddi, E. and Strazzullo, V. and Gobat, R. and Bournaud, F. and Juneau, S. and Zanella, A. and Onodera, M. and Carollo, M. and Renzini, A. and Arimoto, N., E-mail: francesco.valentino@cea.fr},
abstractNote = {We investigate the environmental effect on the metal enrichment of star-forming galaxies (SFGs) in the farthest spectroscopically confirmed and X-ray-detected cluster, CL J1449+0856 at z = 1.99. We combined Hubble Space Telescope/WFC3 G141 slitless spectroscopic data, our thirteen-band photometry, and a recent Subaru/Multi-object InfraRed Camera and Spectrograph (MOIRCS) near-infrared spectroscopic follow-up to constrain the physical properties of SFGs in CL J1449+0856 and in a mass-matched field sample. After a conservative removal of active galactic nuclei, stacking individual MOIRCS spectra of 6 (31) sources in the cluster (field) in the mass range 10 ≤ log(M/M{sub ⊙}) ≤ 11, we find a ∼4σ lower [N ii]/Hα ratio in the cluster than in the field. Stacking a subsample of 16 field galaxies with Hβ and [O iii] in the observed range, we measure an [O iii]/Hβ 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 using alternative indicators. Furthermore, we observe a significantly higher Hα luminosity and equivalent width in the average cluster spectrum than in the field. This is likely due to the enhanced specific star formation rate; even if lower dust reddening and/or an uncertain environmental dependence on the continuum-to-nebular emission differential reddening may play a role. Our findings might be explained by the accretion of pristine gas around galaxies at z = 2 and from cluster-scale reservoirs, possibly connected with a phase of rapid halo mass assembly at z > 2 and of a high galaxy merging rate.},
doi = {10.1088/0004-637X/801/2/132},
journal = {Astrophysical Journal},
number = 2,
volume = 801,
place = {United States},
year = {Tue Mar 10 00:00:00 EDT 2015},
month = {Tue Mar 10 00:00:00 EDT 2015}
}