The ALPINE-ALMA [C II] Survey: On the nature of an extremely obscured serendipitous galaxy

M. Romano*, P. Cassata, L. Morselli, B. C. Lemaux, M. M. Béthermin, P. Capak, A. Faisst, O. Le Fèvre, D. Schaerer, J. Silverman, L. Yan, S. Bardelli, M. Boquien, A. Cimatti, M. Dessauges-Zavadsky, A. Enia, Y. Fudamoto, S. Fujimoto, M. Ginolfi, C. GruppioniN. P. Hathi, E. Ibar, G. C. Jones, A. M. Koekemoer, F. Loiacono, C. Mancini, D. A. Riechers, G. Rodighiero, L. Rodríguez-Muñoz, M. Talia, L. Vallini, D. Vergani, G. Zamorani, E. Zucca

*この研究の対応する著者

研究成果: Article査読

12 被引用数 (Scopus)

抄録

We report the serendipitous discovery of a dust-obscured galaxy observed as part of the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [C ii] at Early times (ALPINE). While this galaxy is detected both in line and continuum emissions in ALMA Band 7, it is completely dark in the observed optical/near-infrared bands and only shows a significant detection in the UltraVISTA Ks band. We discuss the nature of the observed ALMA line, that is [C ii] at z ∼4.6 or high-J CO transitions at z ∼2.2. In the first case, we find a [C ii]/FIR luminosity ratio of log(L-[C\rm small II]/L FIR) ∼-2.5, consistent with the average value for local star-forming galaxies (SFGs). In the second case instead, the source would lie at larger CO luminosities than those expected for local SFGs and high-z submillimetre galaxies. At both redshifts, we derive the star formation rate (SFR) from the ALMA continuum and the physical parameters of the galaxy, such as the stellar mass (M), by fitting its spectral energy distribution. Exploiting the results of this work, we believe that our source is a 'main-sequence', dusty SFG at z = 4.6 (i.e. [C ii] emitter) with log(SFR/M⊙ yr-1)∼ 1.4 and log(M/M·) ∼9.9. As a support to this scenario our galaxy, if at this redshift, lies in a massive protocluster recently discovered at z ∼4.57, at only ∼1 proper Mpc from its centre. This work underlines the crucial role of the ALPINE survey in making a census of this class of objects, in order to unveil their contribution to the global SFR density at the end of the Reionization epoch.

本文言語English
ページ(範囲)875-887
ページ数13
ジャーナルMonthly Notices of the Royal Astronomical Society
496
1
DOI
出版ステータスPublished - 2020 6月 11
外部発表はい

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

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