@article{92056a01634b41eebfebfdf9968c356c,
title = "Sumo Puff: Tidal debris or disturbed ultra-diffuse galaxy?",
abstract = "We report the discovery of a diffuse stellar cloud with an angular extent 30, which we term {"}Sumo Puff{"} in data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP).While we do not have a redshift for this object, it is in close angular proximity to a post-merger galaxy at redshift z = 0.0431 and is projected within a few virial radii (assuming similar redshifts) of two other ∼L∗ galaxies, which we use to bracket a potential redshift range of 0.0055 < z < 0.0431. The object's light distribution is flat, as characterized by a low S{\'e}rsic index (n ∼ 0.3). It has a low central g-band surface brightness of ∼26.4mag arcsec-2, large effective radius of ∼13 (∼11 kpc at z = 0.0431 and ∼1.5 kpc at z = 0.0055), and an elongated morphology (b/a ∼ 0.4). Its red color (g - i ∼ 1) is consistent with a passively evolving stellar population and similar to the nearby post-merger galaxy, and we may see tidal material connecting Sumo Puff with this galaxy. We offer two possible interpretations for the nature of this object: (1) it is an extreme, galaxy-sized tidal feature associated with a recent merger event, or (2) it is a foreground dwarf galaxy with properties consistent with a quenched, disturbed, ultra-diffuse galaxy. We present a qualitative comparison with simulations that demonstrates the feasibility of forming a structure similar to this object in a merger event. Follow-up spectroscopy and/or deeper imaging to confirm the presence of the bridge of tidalmaterial will be necessary to reveal the true nature of this object.",
keywords = "Dwarf-galaxies, Galaxies, General-galaxies, Interactions",
author = "Greco, {Johnny P.} and Greene, {Jenny E.} and Price-Whelan, {Adrian M.} and Alexie Leauthaud and Song Huang and Goulding, {Andy D.} and Strauss, {Michael A.} and Yutaka Komiyama and Lupton, {Robert H.} and Satoshi Miyazaki and Masahiro Takada and Masayuki Tanaka and Tomonori Usuda",
note = "Funding Information: The Hyper Suprime-Cam (HSC) collaboration includes the astronomical communities of Japan and Taiwan, and Princeton University. The HSC instrumentation and software were developed by the National Astronomical Observatory of Japan (NAOJ), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), the University of Tokyo, the High Energy Accelerator Research Organization (KEK), the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan (ASIAA), and Princeton University. Funding was contributed by the FIRST program from Japanese Cabinet Office, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), the Toray Science Foundation, NAOJ, Kavli IPMU, KEK, ASIAA, and Princeton University. Funding Information: We thank our referee, Pierre-Alain Duc, for providing useful feedback, which improved this paper. We thank Kathryn Johnston, David Hendel, and David Spergel for useful discussions and Jim Gunn and Sebastien Peirani for providing insight into the possible origin of Sumo Puff. We also thank Kathryn Johnston for sharing simulation data, which informed this work. J.P.G. is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE 1148900. J.E.G. is partially supported by NSF AST-1411642. Funding Information: J.P.G. is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE 1148900. J.E.G. is partially supported by NSF AST-1411642 Funding Information: The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen{\textquoteright}s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE) and the Los Alamos National Laboratory. Publisher Copyright: {\textcopyright} The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved.",
year = "2018",
month = jan,
day = "1",
doi = "10.1093/pasj/psx051",
language = "English (US)",
volume = "70",
journal = "Publication of the Astronomical Society of Japan",
issn = "0004-6264",
publisher = "Astronomical Society of Japan",
number = "Special Issue 1",
}