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LEGUS Discovery of a Light Echo Around Supernova 2012aw

Van Dyk, Schuyler D. and Lee, Janice C. and Anderson, Jay and Andrews, Jennifer E. and Calzetti, Daniela and Bright, Stacey N. and Ubeda, Leonardo and Smith, Linda J. and Sabbi, Elena and Grebel, Eva K. and Herrero, Artemio and de Mink, Selma E. (2015) LEGUS Discovery of a Light Echo Around Supernova 2012aw. Astrophysical Journal, 806 (2). Art. No. 195. ISSN 0004-637X.

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We have discovered a luminous light echo around the normal Type II-Plateau Supernova (SN) 2012aw in Messier 95 (M95; NGC 3351), detected in images obtained approximately two years after explosion with the Wide Field Channel 3 on board the Hubble Space Telescope by the Legacy ExtraGalactic Ultraviolet Survey. The multi-band observations span from the near-ultraviolet through the optical (F275W, F336W, F438W, F555W, and F814W). The apparent brightness of the echo at the time was ~21–22 mag in all of these bands. The echo appears circular, although less obviously as a ring, with an inhomogeneous surface brightness, in particular, a prominent enhanced brightness to the southeast. The SN itself was still detectable, particularly in the redder bands. We are able to model the light echo as the time-integrated SN light scattered off of diffuse interstellar dust in the SN environment. We have assumed that this dust is analogous to that in the Milky Way with R_V=3.1$. The SN light curves that we consider also include models of the unobserved early burst of light from the SN shock breakout. Our analysis of the echo suggests that the distance from the SN to the scattering dust elements along the echo is ≈45 pc. The implied visual extinction for the echo-producing dust is consistent with estimates made previously from the SN itself. Finally, our estimate of the SN brightness in F814W is fainter than that measured for the red supergiant star at the precise SN location in pre-SN images, possibly indicating that the star has vanished and confirming it as the likely SN progenitor.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Van Dyk, Schuyler D.0000-0001-9038-9950
Lee, Janice C.0000-0002-2278-9407
Andrews, Jennifer E.0000-0003-0123-0062
Calzetti, Daniela0000-0002-5189-8004
Smith, Linda J.0000-0002-0806-168X
Sabbi, Elena0000-0003-2954-7643
Grebel, Eva K.0000-0002-1891-3794
de Mink, Selma E.0000-0001-9336-2825
Additional Information:© 2015 American Astronomical Society. Received 2015 March 18; accepted 2015 April 30; published 2015 June 18. We are grateful for the comments provided by the expert referee, which significantly improved this paper. We appreciate helpful discussions we had with Luc Dessart and the generosities of both Ehud Nakar and Nozomu Tominaga. We also appreciate David Pooley sharing his analysis of the Chandra data on SN 2012aw in advance of publication. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13364. Support for this program was provided by NASA through a grant from the Space Telescope Science Institute. This research made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. A.H. acknowledges funding by Spanish MINECO under grants AYA2012-39364-C02-01 and SEV 2011-0187-01. S.E.d.M. acknowledges support by a Marie Sklodowska-Curie Reintegration Fellowship (H2020-MSCA-IF-2014, project ID 661502) awarded by the European Commission.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-26555
Space Telescope Science InstituteUNSPECIFIED
Ministerio de Economía y Competitividad (MINECO)AYA2012-39364-C02-01
Ministerio de Economía y Competitividad (MINECO)SEV 2011-0187-01
Marie Curie FellowshipH2020-MSCA-IF-2014-661502
Subject Keywords:dust, extinction; galaxies: individual (M95); scattering; supernovae: general; supernovae: individual (SN 2012aw)
Issue or Number:2
Record Number:CaltechAUTHORS:20150803-152826333
Persistent URL:
Official Citation:LEGUS Discovery of a Light Echo Around Supernova 2012aw Schuyler D. Van Dyk et al. 2015 ApJ 806 195
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59157
Deposited By: Ruth Sustaita
Deposited On:05 Aug 2015 23:14
Last Modified:09 Mar 2020 13:19

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