Abstract
We report the detection of CO(2-1) emission coincident with the brightest cluster galaxy (BCG) of the high-redshift galaxy cluster SpARCS1049+56, with the Redshift Search Receiver (RSR) on the Large Millimeter Telescope (LMT). We confirm a spectroscopic redshift for the gas of z = 1.7091 ± 0.0004, which is consistent with the systemic redshift of the cluster galaxies of z = 1.709. The line is well fit by a single-component Gaussian with an RSR-resolution-corrected FWHM of 569 ± 63 km s-1. We see no evidence for multiple velocity components in the gas, as might be expected from the multiple image components seen in near-infrared imaging with the Hubble Space Telescope. We measure the integrated flux of the line to be 3.6 ± 0.3 Jy km s-1, and using = 0.8 Mo(K km s-1 pc2)-1, we estimate a total molecular gas mass of 1.1 ± 0.1 × 1011 M o and a M H2/M ∗ ∼ 0.4. This is the largest gas reservoir detected in a BCG above z > 1 to date. Given the infrared-estimated star formation rate of 860 ± 130 M o yr-1, this corresponds to a gas depletion timescale of ∼0.1 Gyr. We discuss several possible mechanisms for depositing such a large gas reservoir to the cluster center - e.g., a cooling flow, a major galaxy-galaxy merger, or the stripping of gas from several galaxies - but conclude that these LMT data are not sufficient to differentiate between them.
Original language | English (US) |
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Article number | L17 |
Journal | Astrophysical Journal Letters |
Volume | 844 |
Issue number | 2 |
DOIs | |
State | Published - Aug 1 2017 |
Externally published | Yes |
Keywords
- ISM: molecules
- galaxies: clusters: individual (SpARCS1049+56)
- galaxies: evolution
- galaxies: starburst
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science