An overdensity of Lyman break galaxies around the hot dust-obscured galaxy WISE J224607.56−052634.9
Abstract
We report the identification of Lyman break galaxy (LBG) candidates around the most luminous hot dust-Obscured galaxy (Hot DOG) known, WISE J224607.56−052634.9 (W2246−0526) at z = 4.601, using deep r-, i-, and z-band imaging from the Gemini Multi-Object Spectrograph South (GMOS-S). We used the surface density of LBGs to probe the megaparsec-scale environment of W2246−0526 to characterize its richness and evolutionary state. We identified LBG candidates in the vicinity of W2246−0526 using the selection criteria developed in the Subaru Deep Field and in the Subaru XMM-Newton Deep Field, slightly modified to account for the difference between the filters used, and we find 37 and 55 LBG candidates, respectively. Matching to the z-band depths of those studies, this corresponds to δ = 5.8−1.9+2.4 times the surface density of LBGs expected in the field. Interestingly, the Hot DOG itself, as well as a confirmed neighbor, do not satisfy either LBG selection criteria, suggesting we may be missing a large number of companion galaxies. Our analysis shows that we have mostly likely only found those with a higher than average intergalactic medium (IGM) optical depth or moderately high dust obscuration. The number density of LBG candidates is not concentrated around W2246−0526, suggesting an early evolutionary stage for the proto-cluster, that the Hot DOG may not be the most massive galaxy, or that the Hot DOG may be affecting the IGM transparency in its vicinity. The overdensity around W2246−0526 is comparable to overdensities found around other Hot DOGs and is somewhat higher than what is typically found for radio galaxies and luminous quasars at a similar redshift.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- September 2023
- DOI:
- 10.1051/0004-6361/202346695
- arXiv:
- arXiv:2306.17163
- Bibcode:
- 2023A&A...677A..54Z
- Keywords:
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- galaxies: formation;
- galaxies: high-redshift;
- galaxies: structure;
- galaxies: evolution;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 20 pages, 15 figures. The main results are in Figures 9 and 12. Accepted for publication in A&