EVIDENCE FOR UBIQUITOUS HIGH-EQUIVALENT-WIDTH NEBULAR EMISSION IN z ∼ 7 GALAXIES: TOWARD A CLEAN MEASUREMENT OF THE SPECIFIC STAR-FORMATION RATE USING A SAMPLE OF BRIGHT, MAGNIFIED GALAXIES

被引：227

作者：

Smit, R. ^{[1
]}

Bouwens, R. J. ^{[1
]}

Labbe, I. ^{[1
]}

Zheng, W. ^{[2
]}

Bradley, L. ^{[3
]}

Donahue, M. ^{[4
]}

Lemze, D. ^{[2
]}

Moustakas, J. ^{[5
]}

Umetsu, K. ^{[6
]}

Zitrin, A. ^{[7
,8
]}

Coe, D. ^{[3
]}

Postman, M. ^{[3
]}

Gonzalez, V. ^{[9
]}

Bartelmann, M. ^{[7
]}

Benitez, N. ^{[10
]}

Broadhurst, T. ^{[11
]}

Ford, H. ^{[2
]}

Grillo, C. ^{[12
]}

Infante, L. ^{[13
]}

Jimenez-Teja, Y. ^{[10
]}

Jouvel, S. ^{[14
]}

Kelson, D. D. ^{[15
]}

Lahav, O. ^{[16
]}

Maoz, D. ^{[17
]}

Medezinski, E. ^{[2
]}

Melchior, P. ^{[18
,19
]}

Meneghetti, M. ^{[20
,21
]}

Merten, J. ^{[22
]}

Molino, A. ^{[10
]}

Moustakas, L. A. ^{[22
]}

Nonino, M. ^{[23
]}

Rosati, P. ^{[24
]}

Seitz, S. ^{[25
]}

机构：

[1] Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands

[2] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[3] Space Telescope Sci Inst, Baltimore, MD 21208 USA

[4] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA

[5] Siena Coll, Loudonville, NY 12211 USA

[6] Acad Sinica, Inst Astron & Astrophys, Taipei 10617, Taiwan

[7] ZAH, Inst Theoret Astrophys, D-69120 Heidelberg, Germany

[8] CALTECH, Cahill Ctr Astron & Astrophys, Pasadena, CA 91125 USA

[9] Univ Calif Riverside, Dept Phys & Astron, Riverside, CA 92521 USA

[10] CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain

[11] Univ Basque Country, Dept Theoret Phys, Bilbao 48080, Spain

[12] Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark

[13] Pontificia Univ Catolica Chile, Dept Astronoia & Astrofis, Santiago 22, Chile

[14] Inst Cincies Espai IEEC CSIC, Bellaterra, Barcelona, Spain

[15] Observ Carnegie Inst Washington, Pasadena, CA 91101 USA

[16] UCL, Dept Phys & Astron, London WC1E 6BT, England

[17] Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel

[18] Ohio State Univ, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA

[19] Ohio State Univ, Dept Phys, Columbus, OH 43210 USA

[20] INAF, Osservatorio Astron Bologna, I-40127 Bologna, Italy

[21] Ist Nazl Fis Nucl, Sez Bologna, I-40127 Bologna, Italy

[22] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[23] INAF, Osservatorio Astron Trieste, I-40131 Trieste, Italy

[24] ESO European Southern Observ, D-85748 Garching, Germany

[25] Univ Sternwarte, D-81679 Munich, Germany

来源：

ASTROPHYSICAL JOURNAL | 2014年 / 784卷 / 01期

关键词：

galaxies: evolution; galaxies: formation; galaxies: high-redshift; LYMAN-BREAK GALAXIES; HIGH-REDSHIFT GALAXIES; STELLAR MASS DENSITY; ULTRA DEEP FIELD; ULTRAVIOLET LUMINOSITY DENSITY; SPECTRAL ENERGY-DISTRIBUTIONS; EARLY RELEASE SCIENCE; FORMING GALAXIES; FORMATION HISTORY; LENSING ANALYSIS;

D O I：

10.1088/0004-637X/784/1/58

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Growing observational evidence indicates that nebular line emission has a significant impact on the rest-frame optical fluxes of z similar to 5-7 galaxies. This line emission makes z similar to 5-7 galaxies appear more massive, with lower specific star-formation rates (sSFRs). However, corrections for this line emission have been difficult to perform reliably because of huge uncertainties on the strength of such emission at z greater than or similar to 5.5. In this paper, we present the most direct observational evidence thus far for ubiquitous high-equivalent-width (EW) [O (III)]+ H beta line emission in Lyman-break galaxies at z similar to 7, and we present a strategy for an improved measurement of the sSFR at z similar to 7. We accomplish this through the selection of bright galaxies in the narrow redshift window z similar to 6.6-7.0 where the Spitzer/Infrared Array Camera (IRAC) 4.5 mu m flux provides a clean measurement of the stellar continuum light, in contrast with the 3.6 mu m flux, which is contaminated by the prominent [O III]+ H beta lines. To ensure a high signal-to-noise ratio for our IRAC flux measurements, we consider only the brightest (H-160 < 26 mag) magnified galaxies we have identified behind galaxy clusters. It is remarkable that the mean rest-frame optical color for our bright seven-source sample is very blue, [3.6]-[4.5] = - 0.9 +/- 0.3. Such blue colors cannot be explained by the stellar continuum light and require that the rest-frame EW of [O III]+ H beta is greater than 637 angstrom for the average source. The four bluest sources from our seven-source sample require an even more extreme EW of 1582 angstrom. We can also set a robust lower limit of greater than or similar to 4Gyr(-1) on the sSFR of our sample based on the mean spectral energy distribution.

引用

页数：8

共 2 条

[1] The evolution of the equivalent width of the Ha emission line and specific star formation rate in star-forming galaxies at 1 < z < 5
Marmol-Queralto, E.
McLure, R. J.
Cullen, F.
Dunlop, J. S.
Fontana, A.
McLeod, D. J.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2016, 460 (04) : 3587 - 3597
[2] KECK SPECTROSCOPY OF 3 < z < 7 FAINT LYMAN BREAK GALAXIES: THE IMPORTANCE OF NEBULAR EMISSION IN UNDERSTANDING THE SPECIFIC STAR FORMATION RATE AND STELLAR MASS DENSITY
Stark, Daniel P.
Schenker, Matthew A.
Ellis, Richard
Robertson, Brant
McLure, Ross
Dunlop, James
ASTROPHYSICAL JOURNAL, 2013, 763 (02)

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