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Title: Looking at the Distant Universe with the MeerKAT Array: Discovery of a Luminous OH Megamaser at z > 0.5
Abstract In the local universe, OH megamasers (OHMs) are detected almost exclusively in infrared-luminous galaxies, with a prevalence that increases with IR luminosity, suggesting that they trace gas-rich galaxy mergers. Given the proximity of the rest frequencies of OH and the hyperfine transition of neutral atomic hydrogen (Hi), radio surveys to probe the cosmic evolution of Hiin galaxies also offer exciting prospects for exploiting OHMs to probe the cosmic history of gas-rich mergers. Using observations for the Looking At the Distant Universe with the MeerKAT Array (LADUMA) deep Hisurvey, we report the first untargeted detection of an OHM atz> 0.5, LADUMA J033046.20−275518.1 (nicknamed “Nkalakatha”). The host system, WISEA J033046.26−275518.3, is an infrared-luminous radio galaxy whose optical redshiftz≈ 0.52 confirms the MeerKAT emission-line detection as OH at a redshiftzOH= 0.5225 ± 0.0001 rather than Hiat lower redshift. The detected spectral line has 18.4σpeak significance, a width of 459 ± 59 km s−1, and an integrated luminosity of (6.31 ± 0.18 [statistical] ± 0.31 [systematic]) × 103L⊙, placing it among the most luminous OHMs known. The galaxy’s far-infrared luminosityLFIR= (1.576 ±0.013) × 1012L⊙marks it as an ultraluminous infrared galaxy; its ratio of OH and infrared luminosities is similar to those for lower-redshift OHMs. A comparison between optical and OH redshifts offers a slight indication of an OH outflow. This detection represents the first step toward a systematic exploitation of OHMs as a tracer of galaxy growth at high redshifts.  more » « less
Award ID(s):
1814648 1814486 1814682 1814421
PAR ID:
10367384
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal Letters
Volume:
931
Issue:
1
ISSN:
2041-8205
Format(s):
Medium: X Size: Article No. L7
Size(s):
Article No. L7
Sponsoring Org:
National Science Foundation
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