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A Diverse Population of z ~ 2 ULIRGs Revealed by JWST Imaging
- Publication Year :
- 2023
-
Abstract
- Four ultra-luminous infrared galaxies (ULIRGs) observed with JWST/NIRcam in the Cosmos Evolution Early Release Science program offer an unbiased preview of the $z\approx2$ ULIRG population. The objects were originally selected at 24 $\mu$m and have strong polycyclic aromatic hydrocarbon emission features observed with Spitzer/IRS. The four objects have similar stellar masses of ${\sim}10^{11}$ M$_\odot$ but otherwise are quite diverse. One is an isolated disk galaxy, but it has an active nucleus as shown by X-ray observations and by a bright point-source nucleus. Two others are merging pairs with mass ratios of 6-7:1. One has active nuclei in both components, while the other has only one active nucleus: the one in the less-massive neighbor, not the ULIRG. The fourth object is clumpy and irregular and is probably a merger, but there is no sign of an active nucleus. The intrinsic spectral energy distributions for the four AGNs in these systems are typical of type-2 QSOs. This study is consistent with the idea that even if internal processes can produce large luminosities at $z\sim2$, galaxy merging may still be necessary for the most luminous objects. The diversity of these four initial examples suggests that large samples will be needed to understand the $z\approx2$ ULIRG population.<br />Comment: 9 pages, 3 figures, 1 table, accepted for publication in ApJ. V2 updates author affiliations and acknowledgments, not scientific content
- Subjects :
- Astrophysics - Astrophysics of Galaxies
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.2304.01378
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.3847/1538-4357/acc9c3