VERY STRONG EMISSION-LINE GALAXIES IN THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY AND IMPLICATIONS FOR HIGH-REDSHIFT GALAXIES

被引：188

作者：

Atek, H. ^{[1
]}

Siana, B. ^{[2
]}

Scarlata, C. ^{[3
]}

Malkan, M. ^{[4
]}

McCarthy, P. ^{[5
]}

Teplitz, H. ^{[6
]}

Henry, A. ^{[7
]}

Colbert, J. ^{[1
]}

Bridge, C. ^{[2
]}

Bunker, A. J. ^{[8
]}

Dressler, A. ^{[5
]}

Fosbury, R. A. E. ^{[9
]}

Hathi, N. P. ^{[5
]}

Martin, C. ^{[7
]}

Ross, N. R. ^{[4
]}

Shim, H. ^{[1
]}

机构：

[1] CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA

[2] CALTECH, Dept Astron, Pasadena, CA 91125 USA

[3] Univ Minnesota Twin Cities, Dept Astron, Minneapolis, MN 55455 USA

[4] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA USA

[5] Observ Carnegie Inst Sci, Pasadena, CA 91101 USA

[6] CALTECH, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA

[7] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

[8] Univ Oxford, Dept Phys, Oxford OX1 3RH, England

[9] European So Observ, Space Telescope European Coordinating Facil, D-8046 Garching, Germany

来源：

ASTROPHYSICAL JOURNAL | 2011年 / 743卷 / 02期

关键词：

cosmology: observations; galaxies: evolution; galaxies: high-redshift; galaxies: statistics; infrared: galaxies; surveys; STAR-FORMING GALAXIES; LY-ALPHA EMITTERS; LYMAN-BREAK GALAXIES; DIGITAL SKY SURVEY; MASS-METALLICITY RELATION; ACTIVE GALACTIC NUCLEI; EARLY RELEASE SCIENCE; EXTREMELY METAL-POOR; SIMILAR-TO; HUBBLE-SPACE-TELESCOPE;

D O I：

10.1088/0004-637X/743/2/121

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths (EWs) higher than 200 angstrom. A total of 176 objects are found over the redshift range 0.35 < z < 2.3 in the 180 arcmin(2) area that we have analyzed so far. This population consists of young and low-mass starbursts with high specific star formation rates (sSFR). After spectroscopic follow-up of one of these galaxies with Keck/Low Resolution Imaging Spectrometer, we report the detection at z = 0.7 of an extremely metal-poor galaxy with 12 + log(O/H) = 7.47 +/- 0.11. After estimating the active galactic nucleus fraction in the sample, we show that the high-EW galaxies have higher sSFR than normal star-forming galaxies at any redshift. We find that the nebular emission lines can substantially affect the total broadband flux density with a median brightening of 0.3 mag, with some examples of line contamination producing brightening of up to 1 mag. We show that the presence of strong emission lines in low-z galaxies can mimic the color-selection criteria used in the z similar to 8 dropout surveys. In order to effectively remove low-redshift interlopers, deep optical imaging is needed, at least 1 mag deeper than the bands in which the objects are detected. Without deep optical data, most of the interlopers cannot be ruled out in the wide shallow HST imaging surveys. Finally, we empirically demonstrate that strong nebular lines can lead to an overestimation of the mass and the age of galaxies derived from fitting of their spectral energy distribution (SED). Without removing emission lines, the age and the stellar mass estimates are overestimated by a factor of 2 on average and up to a factor of 10 for the high-EW galaxies. Therefore, the contribution of emission lines should be systematically taken into account in SED fitting of star-forming galaxies at all redshifts.

引用

页数：13

共 98 条

[1] THE WFC3 INFRARED SPECTROSCOPIC PARALLEL (WISP) SURVEY [J].