Gaia17biu/SN 2017egm in NGC 3191: The Closest Hydrogen-poor Superluminous Supernova to Date Is in a “Normal,” Massive, Metal-rich Spiral Galaxy

Journal
Date Issued
2018
Author(s)
Bose, Subhash
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Dong, Subo
•
•
Filippenko, Alexei V.
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Kochanek, C. S.
•
Mauerhan, Jon
•
Romero-Cañizales, C.
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Brink, Thomas G.
•
Chen, Ping
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Prieto, J. L.
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Post, R.
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Ashall, Christopher
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Grupe, Dirk
•
•
•
Shappee, B. J.
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Stanek, K. Z.
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Cai, Zheng
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Falco, E.
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Lundqvist, Peter
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Mattila, Seppo
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Mutel, Robert
•
•
Pooley, David
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Stritzinger, M. D.
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Villanueva, S., Jr.
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Zheng, WeiKang
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Beswick, R. J.
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Brown, Peter J.
•
•
Davis, Scott
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Fraser, Morgan
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de Jaeger, Thomas
•
•
Gall, C.
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Gaudi, B. Scott
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Herczeg, Gregory J.
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Hestenes, Julia
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Holoien, T. W. -S.
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Hosseinzadeh, Griffin
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Hsiao, E. Y.
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Hu, Shaoming
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Jaejin, Shin
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Jeffers, Ben
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Koff, R. A.
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Kumar, Sahana
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Kurtenkov, Alexander
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Lau, Marie Wingyee
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Prentice, Simon
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Reynolds, T.
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Rudy, Richard J.
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Shahbandeh, Melissa
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Somero, Auni
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Stassun, Keivan G.
•
Thompson, Todd A.
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Valenti, Stefano
•
Woo, Jong-Hak
•
Yunus, Sameen
DOI
Abstract
Hydrogen-poor superluminous supernovae (SLSNe-I) have been predominantly found in low-metallicity, star-forming dwarf galaxies. Here we identify Gaia17biu/SN 2017egm as an SLSN-I occurring in a “normal” spiral galaxy (NGC 3191) in terms of stellar mass (several times 1010 M☉) and metallicity (roughly solar). At redshift z = 0.031, Gaia17biu is also the lowest-redshift SLSN-I to date, and the absence of a larger population of SLSNe-I in dwarf galaxies of similar redshift suggests that metallicity is likely less important to the production of SLSNe-I than previously believed. With the smallest distance and highest apparent brightness for an SLSN-I, we are able to study Gaia17biu in unprecedented detail. Its pre-peak near-ultraviolet to optical color is similar to that of Gaia16apd and among the bluest observed for an SLSN-I, while its peak luminosity (Mg = -21 mag) is substantially lower than that of Gaia16apd. Thanks to the high signal-to-noise ratios of our spectra, we identify several new spectroscopic features that may help to probe the properties of these enigmatic explosions. We detect polarization at the ∼0.5% level that is not strongly dependent on wavelength, suggesting a modest, global departure from spherical symmetry. In addition, we put the tightest upper limit yet on the radio luminosity of an SLSN-I with <5.4 × 1026 erg s-1 Hz-1 at 10 GHz, which is almost a factor of 40 better than previous upper limits and one of the few measured at an early stage in the evolution of an SLSN-I. This limit largely rules out an association of this SLSN-I with known populations of gamma-ray-burst-like central engines.
Volume
853
Issue
1
Start page
57
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2018ApJ...853...57B
Rights
open.access
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