We extend the Ultra-Diffuse Galaxy (UDG) abundance relation, NUDG − M200, to lower halo mass hosts $(M_{200}\sim 10^{11.6-12.2}\, \mathrm{M}_{\odot })$. We select UDG satellites from published catalogues of dwarf satellite galaxies around Milky Way analogues, namely the Exploration of Local Volume Satellites (ELVES) survey, the Satellite Around Galactic Analogs (SAGA) survey, and a survey of Milky Way-like systems conducted using the Hyper-Suprime Cam. Of the 516 satellites around a total of 75 Milky Way-like hosts, we find that 41 satellites around 33 hosts satisfy the UDG criteria. The distributions of host halo masses peak around $M_{200}\sim 10^{12}\, \mathrm{M}_{\odot }$, independent of whether the host has a UDG satellite or not. We use literature UDG abundances and those derived here to trace the NUDG − M200 relation over three orders of magnitude down to $M_{200}=10^{11.6}\, \mathrm{M}_{\odot }$ and find the best-fitting linear relation of $N_{\mathrm{ UDG}} = (38\pm 5) (\frac{M_{200}}{10^{14}})^{0.89\,\,\pm ~ 0.04}$. This sub-linear slope is consistent with earlier studies of UDG abundances as well as abundance relations for brighter dwarf galaxies, excluding UDG-formation mechanisms that require high-density environments. However, we highlight the need for further homogeneous characterization of UDGs across a wide range of environments to properly understand the NUDG − M200 relation.
Large diffuse galaxies are hard to find, but understanding the environments where they live, their numbers, and ultimately their origins, is of intense interest and importance for galaxy formation and evolution. Using Subaru’s Hyper Suprime-Cam Strategic Survey Program, we perform a systematic search for low surface brightness galaxies and present novel and effective methods for detecting and modeling them. As a case study, we surveyed 922 Milky Way analogs in the nearby Universe (0.01 <
- NSF-PAR ID:
- 10461984
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 955
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- Article No. 1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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