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On the Classification of UGC 1382 as a Giant Low Surface Brightness Galaxy

Hagen, Lea M. Z. and Seibert, Mark and Hagen, Alex and Nyland, Kristina and Neill, James D. and Treyer, Marie and Young, Lisa M. and Rich, Jeffrey A. and Madore, Barry F. (2016) On the Classification of UGC 1382 as a Giant Low Surface Brightness Galaxy. Astrophysical Journal, 826 (2). Art. No. 210. ISSN 0004-637X.

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We provide evidence that UGC 1382, long believed to be a passive elliptical galaxy, is actually a giant low surface brightness (GLSB) galaxy that rivals the archetypical GLSB Malin 1 in size. Like other GLSB galaxies, it has two components: a high surface brightness disk galaxy surrounded by an extended low surface brightness (LSB) disk. For UGC 1382, the central component is a lenticular system with an effective radius of 6 kpc. Beyond this, the LSB disk has an effective radius of ~38 kpc and an extrapolated central surface brightness of ~26 mag arcsec^(−2). Both components have a combined stellar mass of ~8 × 10^(10) M_⊙, and are embedded in a massive (10^(10) M_⊙) low-density (<3 M_⊙ pc^(−2)) HI disk with a radius of 110 kpc, making this one of the largest isolated disk galaxies known. The system resides in a massive dark matter halo of at least 2 × 10^(12) M_⊙. Although possibly part of a small group, its low-density environment likely plays a role in the formation and retention of the giant LSB and HI disks. We model the spectral energy distributions and find that the LSB disk is likely older than the lenticular component. UGC 1382 has UV–optical colors typical of galaxies transitioning through the green valley. Within the LSB disk are spiral arms forming stars at extremely low efficiencies. The gas depletion timescale of ~10^(11) years suggests that UGC 1382 may be a very-long-term resident of the green valley. We find that the formation and evolution of the LSB disk in UGC 1382 is best explained by the accretion of gas-rich LSB dwarf galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hagen, Lea M. Z.0000-0001-8918-1597
Seibert, Mark0000-0002-1143-5515
Nyland, Kristina0000-0003-1991-370X
Neill, James D.0000-0002-0466-1119
Rich, Jeffrey A.0000-0002-5807-5078
Madore, Barry F.0000-0002-1576-1676
Additional Information:© 2016 American Astronomical Society. Received 2015 October 15; revised 2016 May 11; accepted 2016 May 23; published 2016 August 1. We thank the referee for helpful comments that improved this paper. M.H.S. acknowledges support from NASA grant NNX12AE19G. L.M.Y. acknowledges support from NSF AST-1109803 and thanks ASIAA for their hospitality during a sabbatical visit. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of NASA's Astrophysics Data System. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We thank the Research Computer and Cyberinfrastructure Unit of Information Technology Services at The Pennsylvania State University for providing computational support and resources. In particular, we appreciate the very helpful William Brouwer. The Institute for Gravitation and the Cosmos is supported by the Eberly College of Science and the Office of the Senior Vice President for Research at the Pennsylvania State University. Observations are based in part on data obtained at the duPont 2.5 m telescope at the Las Campanas Observatories of the Carnegie Institution for Science.
Group:Infrared Processing and Analysis Center (IPAC), Space Astrophysics Laboratory
Funding AgencyGrant Number
Subject Keywords:galaxies: individual (UGC 1382)
Issue or Number:2
Record Number:CaltechAUTHORS:20161003-095121320
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Official Citation:Lea M. Z. Hagen et al 2016 ApJ 826 210
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70754
Deposited By: Ruth Sustaita
Deposited On:03 Oct 2016 17:45
Last Modified:09 Mar 2020 13:19

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