TY - JOUR
T1 - SDSS-IV MaNGA
T2 - The Nature of an Off-galaxy Hα Blob - A Multiwavelength View of Offset Cooling in a Merging Galaxy Group
AU - Pan, Hsi An
AU - Lin, Lihwai
AU - Hsieh, Bau Ching
AU - Michałowski, Michał J.
AU - Bothwell, Matthew S.
AU - Huang, Song
AU - Moiseev, Alexei V.
AU - Oparin, Dmitry
AU - O'Sullivan, Ewan
AU - Worrall, Diana M.
AU - Sánchez, Sebastián F.
AU - Gwyn, Stephen
AU - Law, David R.
AU - Stark, David V.
AU - Bizyaev, Dmitry
AU - Li, Cheng
AU - Lee, Chien Hsiu
AU - Fu, Hai
AU - Belfiore, Francesco
AU - Bundy, Kevin
AU - Fernández-Trincado, José G.
AU - Gelfand, Joseph
AU - Peirani, Sébastien
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
PY - 2020/11/1
Y1 - 2020/11/1
N2 - Galaxies in dense environments, such as groups and clusters, experience various processes by which galaxies gain and lose gas. Using data from the SDSS-IV MaNGA survey, we previously reported the discovery of a giant (6 - 8 kpc in diameter) Hα blob, Totoro, about 8 kpc away from a pair of galaxies (Satsuki and Mei) residing in a galaxy group that is experiencing a group-group merger. Here, we combine interferometric 12CO(1-0) molecular gas data, new wide-field Hα, u-band data, and published X-ray data to determine the origin of the blob. Several scenarios are discussed to account for its multiwavelength properties, including (1) Hα gas being stripped from the galaxy Satsuki by ram pressure, (2) a separated low-surface-brightness galaxy, (3) gas being ejected or ionized by an active galactic nucleus (AGN), and (4) a cooling intragroup medium (IGM). Scenarios (1) and (2) are less favored by the present data. Scenario (3) is also less likely as there is no evidence for an active ongoing AGN in the host galaxy. We find that the CO (cold) and Hα (warm) gas coexist with X-ray (hot) structures; moreover, the derived cooling time is within the regime where molecular and Hα gas are expected. The coexistence of gas with different temperatures also agrees with that of cooling gas in other systems. Our multiwavelength results strongly suggest that the CO and Hα gas are the product of cooling from the IGM at its current location, i.e., cooling has occurred, and may be ongoing, well outside the host-galaxy core.
AB - Galaxies in dense environments, such as groups and clusters, experience various processes by which galaxies gain and lose gas. Using data from the SDSS-IV MaNGA survey, we previously reported the discovery of a giant (6 - 8 kpc in diameter) Hα blob, Totoro, about 8 kpc away from a pair of galaxies (Satsuki and Mei) residing in a galaxy group that is experiencing a group-group merger. Here, we combine interferometric 12CO(1-0) molecular gas data, new wide-field Hα, u-band data, and published X-ray data to determine the origin of the blob. Several scenarios are discussed to account for its multiwavelength properties, including (1) Hα gas being stripped from the galaxy Satsuki by ram pressure, (2) a separated low-surface-brightness galaxy, (3) gas being ejected or ionized by an active galactic nucleus (AGN), and (4) a cooling intragroup medium (IGM). Scenarios (1) and (2) are less favored by the present data. Scenario (3) is also less likely as there is no evidence for an active ongoing AGN in the host galaxy. We find that the CO (cold) and Hα (warm) gas coexist with X-ray (hot) structures; moreover, the derived cooling time is within the regime where molecular and Hα gas are expected. The coexistence of gas with different temperatures also agrees with that of cooling gas in other systems. Our multiwavelength results strongly suggest that the CO and Hα gas are the product of cooling from the IGM at its current location, i.e., cooling has occurred, and may be ongoing, well outside the host-galaxy core.
UR - http://www.scopus.com/inward/record.url?scp=85095784898&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095784898&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/abb80c
DO - 10.3847/1538-4357/abb80c
M3 - Article
AN - SCOPUS:85095784898
SN - 0004-637X
VL - 903
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 16
ER -