| Title | CONSTRAINING VERY HIGH MASS POPULATION III STARS THROUGH He II EMISSION IN GALAXY BDF-521 AT z=7.01 |
| Authors | Cai, Zheng Fan, Xiaohui Jiang, Linhua Dave, Romeel Oh, S. Peng Yang, Yujin Zabludoff, Ann |
| Affiliation | Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China. Univ Western Cape, ZA-7535 Bellville, Cape Town, South Africa. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Argelander Inst fuer Astron, D-53121 Bonn, Germany. |
| Keywords | dark ages, reionization first stars galaxies: high-redshift stars: Population III ULTRA-DEEP FIELD SIMILAR-TO 7 HIGH-REDSHIFT GALAXIES LYMAN BREAK GALAXIES LY-ALPHA EMITTERS SPECTROSCOPIC CONFIRMATION STELLAR POPULATIONS CANDIDATE GALAXIES STARBURST GALAXIES 1ST GALAXIES |
| Issue Date | 2015 |
| Publisher | astrophysical journal letters |
| Citation | ASTROPHYSICAL JOURNAL LETTERS.2015,799,(2). |
| Abstract | Numerous theoretical models have long proposed that a strong He II lambda 1640 emission line is the most prominent and unique feature of massive Population III (Pop III) stars in high-redshift galaxies. The He II lambda 1640 line strength can constrain the mass and initial mass function (IMF) of Pop III stars. We use F132N narrowband filter on the Hubble Space Telescope's (HST) Wide Field Camera 3 to look for strong He II lambda 1640 emission in the galaxy BDF-521 at z = 7.01, one of the most distant spectroscopically confirmed galaxies to date. Using deep F132N narrowband imaging, together with our broadband imaging with F125W and F160W filters, we do not detect He II emission from this galaxy, but place a 2 sigma upper limit on the flux of 5.3x10(-19) erg s(-1) cm(-2). This measurement corresponds to a 2 sigma upper limit on the Pop III star formation rate (SFRPopIII) of similar to 0.2 M-circle dot yr(-1), assuming a Salpeter IMF with 50 less than or similar to M/M-circle dot less than or similar to 1000. From the high signal-to-noise broadband measurements in F125W and F160W, we fit the UV continuum for BDF-521. The spectral flux density is similar to 3.6 x 10(-11) x lambda(-2.32) erg s(-1) cm(-2) angstrom(-1), which corresponds to an overall unobscured SFR of similar to 5 M-circle dot yr(-1). Our upper limit on SFRPopIII suggests that massive Pop III stars represent less than or similar to 4% of the total star formation. Further, the HST high-resolution imaging suggests that BDF-521 is an extremely compact galaxy, with a half-light radius of 0.6 kpc. |
| URI | http://hdl.handle.net/20.500.11897/206411 |
| ISSN | 2041-8205 |
| DOI | 10.1088/2041-8205/799/2/L19 |
| Indexed | SCI(E) |
| Appears in Collections: | 科维理天文与天体物理研究所 |
