Normal, dust-obscured galaxies in the epoch of reionization
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Two serendipitously detected dust-obscured galaxies are reported at z = 6.7 and 7.4, with estimates that such galaxies provide an additional 10-25% contribution to the total star formation rate density at z > 6.
Over the past decades, rest-frame ultraviolet (UV) observations have provided large samples of UV luminous galaxies at redshift (z) greater than 6 (refs. (1-3)), during the so-called epoch of reionization. While a few of these UV-identified galaxies revealed substantial dust reservoirs(4-7), very heavily dust-obscured sources at these early times have remained elusive. They are limited to a rare population of extreme starburst galaxies(8-12) and companions of rare quasars(13,14). These studies conclude that the contribution of dust-obscured galaxies to the cosmic star formation rate density at z > 6 is sub-dominant. Recent ALMA and Spitzer observations have identified a more abundant, less extreme population of obscured galaxies at z = 3-6 (refs. (15,16)). However, this population has not been confirmed in the reionization epoch so far. Here, we report the discovery of two dust-obscured star-forming galaxies at z = 6.6813 +/- 0.0005 and z = 7.3521 +/- 0.0005. These objects are not detected in existing rest-frame UV data and were discovered only through their far-infrared [C ii] lines and dust continuum emission as companions to typical UV-luminous galaxies at the same redshift. The two galaxies exhibit lower infrared luminosities and star-formation rates than extreme starbursts, in line with typical star-forming galaxies at z approximate to 7. This population of heavily dust-obscured galaxies appears to contribute 10-25% to the z > 6 cosmic star formation rate density.
Originalsprog | Engelsk |
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Tidsskrift | Nature |
Vol/bind | 597 |
Udgave nummer | 7877 |
Sider (fra-til) | 489-492 |
Antal sider | 15 |
ISSN | 0028-0836 |
DOI | |
Status | Udgivet - 23 sep. 2021 |
Links
- https://arxiv.org/pdf/2109.10378.pdf
Indsendt manuskript
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