{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/the-undiscovered-ultra-diffuse-galaxies-of","title":"The undiscovered ultra-diffuse galaxies of the Local Group","arxiv_id":"2212.05066","date":"2022-12-09","proceeding":null,"authors":["Oliver Newton","Arianna Di Cintio","Salvador Cardona-Barrero","Noam I. Libeskind","Yehuda Hoffman","Alexander Knebe","Jenny Sorce","Matthias Steinmetz","Elmo Tempel"],"abstract":"Ultra-diffuse galaxies (UDGs) are attractive candidates to probe cosmological models and test theories of galaxy formation at low masses; however, they are difficult to detect because of their low surface brightness. In the Local Group a handful of UDGs have been found to date, most of which are satellites of the Milky Way and M31, and only two are isolated galaxies. It is unclear whether so few UDGs are expected. We address this by studying the population of UDGs formed in hydrodynamic constrained simulations of the Local Group from the HESTIA suite. For a Local Group with a total enclosed mass $M_{\\rm LG}\\!\\left(< 2.5\\, {\\rm Mpc}\\right)=8\\times10^{12}\\, {\\rm M_\\odot}$, we predict that there are $12\\pm3$ isolated UDGs (68% confidence) with stellar masses $10^6 \\leq M_\\ast\\, /\\, {\\rm M_\\odot} < 10^9,$ and effective radii $R_{\\rm e} \\geq 1.5\\, {\\rm kpc}$, within 2.5 Mpc of the Local Group, of which $2^{+2}_{-1}$ (68% confidence) are detectable in the footprint of the Sloan Digital Sky Survey (SDSS). Accounting for survey incompleteness, we find that almost the entire population of UDGs in the Local Group field would be observable in a future all-sky survey with a depth similar to the SDSS, the Dark Energy Survey, or the Legacy Survey of Space and Time. Our results suggest that there is a population of UDGs in the Local Group awaiting discovery.","url_abs":"https://arxiv.org/abs/2212.05066v2","url_pdf":"https://arxiv.org/pdf/2212.05066v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"the-undiscovered-ultra-diffuse-galaxies-of","repo_url":"https://github.com/Musical-Neutron/lg_field_udgs","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}