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A Non-equipartition Shock Wave Traveling in a Dense Circumstellar Environment around SN 2020oi

Horesh, Assaf and Sfaradi, Itai and Ergon, Mattias and Barbarino, Cristina and Sollerman, Jesper and Moldon, Javier and Dobie, Dougal and Schulze, Steve and Pérez-Torres, Miguel and Williams, David R. A. and Fremling, Christoffer and Gal-Yam, Avishay and Kulkarni, Shrinivas R. and O'Brien, Andrew and Lundqvist, Peter and Murphy, Tara and Fender, Rob and Anand, Shreya and Belicki, Justin and Bellm, Eric C. and Coughlin, Michael W. and De, Kishalay and Ofek, Eran O. and Golkhou, V. Zach and Graham, Matthew J. and Green, Dave A. and Hankins, Matthew and Kasliwal, Mansi M. and Kupfer, Thomas and Laher, Russ R. and Masci, Frank J. and Miller, Adam A. and Neill, James D. and Perrott, Yvette and Porter, Michael and Reiley, Daniel J. and Rigault, Mickael and Rodriguez, Hector and Rusholme, Ben and Shupe, David L. and Titterington, David (2020) A Non-equipartition Shock Wave Traveling in a Dense Circumstellar Environment around SN 2020oi. Astrophysical Journal, 903 (2). Art. No. 132. ISSN 1538-4357. doi:10.3847/1538-4357/abbd38.

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We report the discovery and panchromatic follow-up observations of the young Type Ic supernova (SN Ic) SN 2020oi in M100, a grand-design spiral galaxy at a mere distance of 14 Mpc. We followed up with observations at radio, X-ray, and optical wavelengths from only a few days to several months after explosion. The optical behavior of the supernova is similar to those of other normal SNe Ic. The event was not detected in the X-ray band but our radio observations revealed a bright mJy source (L_ν ≈ 1.2 × 10²⁷ ergs⁻¹ Hz⁻¹). Given the relatively small number of stripped envelope SNe for which radio emission is detectable, we used this opportunity to perform a detailed analysis of the comprehensive radio data set we obtained. The radio-emitting electrons initially experience a phase of inverse Compton cooling, which leads to steepening of the spectral index of the radio emission. Our analysis of the cooling frequency points to a large deviation from equipartition at the level of ϵ_e/ϵ_B ≳ 200, similar to a few other cases of stripped envelope SNe. Our modeling of the radio data suggests that the shock wave driven by the SN ejecta into the circumstellar matter (CSM) is moving at ∼3 × 10⁴ km s⁻¹. Assuming a constant mass loss from the stellar progenitor, we find that the mass-loss rate is Ṁ ≈ 1.4 × 10⁻⁴ M_⊙ yr⁻¹ for an assumed wind velocity of 1000 km s⁻¹. The temporal evolution of the radio emission suggests a radial CSM density structure steeper than the standard r⁻².

Item Type:Article
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URLURL TypeDescription Paper
Horesh, Assaf0000-0002-5936-1156
Sfaradi, Itai0000-0003-0466-3779
Barbarino, Cristina0000-0002-3821-6144
Sollerman, Jesper0000-0003-1546-6615
Moldon, Javier0000-0002-8079-7608
Dobie, Dougal0000-0003-0699-7019
Schulze, Steve0000-0001-6797-1889
Pérez-Torres, Miguel0000-0001-5654-0266
Williams, David R. A.0000-0001-7361-0246
Fremling, Christoffer0000-0002-4223-103X
Gal-Yam, Avishay0000-0002-3653-5598
Kulkarni, Shrinivas R.0000-0001-5390-8563
O'Brien, Andrew0000-0003-4609-2791
Lundqvist, Peter0000-0002-3664-8082
Murphy, Tara0000-0002-2686-438X
Fender, Rob0000-0002-5654-2744
Anand, Shreya0000-0003-3768-7515
Bellm, Eric C.0000-0001-8018-5348
Coughlin, Michael W.0000-0002-8262-2924
De, Kishalay0000-0002-8989-0542
Ofek, Eran O.0000-0002-6786-8774
Golkhou, V. Zach0000-0001-8205-2506
Graham, Matthew J.0000-0002-3168-0139
Hankins, Matthew0000-0001-9315-8437
Kasliwal, Mansi M.0000-0002-5619-4938
Kupfer, Thomas0000-0002-6540-1484
Laher, Russ R.0000-0003-2451-5482
Masci, Frank J.0000-0002-8532-9395
Miller, Adam A.0000-0001-9515-478X
Neill, James D.0000-0002-0466-1119
Perrott, Yvette0000-0002-6255-8240
Porter, Michael0000-0003-3168-5586
Rigault, Mickael0000-0002-8121-2560
Rusholme, Ben0000-0001-7648-4142
Shupe, David L.0000-0003-4401-0430
Alternate Title:A non-equipartition shockwave traveling in a dense circumstellar environment around SN2020oi
Additional Information:© 2020 The American Astronomical Society. Received 2020 June 24; revised 2020 September 6; accepted 2020 September 15; published 2020 November 11. We thank the anonymous referee. A.H. is grateful for the support by grants from the Israel Science Foundation, the US–Israel Binational Science Foundation (BSF), and the I-CORE Program of the Planning and Budgeting Committee and the Israel Science Foundation. T.M. acknowledges the support of the Australian Research Council through grant FT150100099. D.D. is supported by an Australian Government Research Training Program Scholarship. D.R.A.W. was supported by the Oxford Centre for Astrophysical Surveys, which is funded through generous support from the Hintze Family Charitable Foundation. A.A.M. is funded by the Large Synoptic Survey Telescope Corporation, the Brinson Foundation, and the Moore Foundation in support of the LSSTC Data Science Fellowship Program; he also receives support as a CIERA Fellow by the CIERA Postdoctoral Fellowship Program (Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University). M.P.T. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and through grant PGC2018-098915-B-C21 (MCI/AEI/FEDER, UE). J.M. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and from the grant RTI2018-096228-B-C31 (MICIU/FEDER, EU). A.G.Y.'s research is supported by the EU via ERC grant No. 725161, the ISF GW excellence center, an IMOS space infrastructure grant and BSF/Transformative and GIF grants, as well as The Benoziyo Endowment Fund for the Advancement of Science, the Deloro Institute for Advanced Research in Space and Optics, The Veronika A. Rabl Physics Discretionary Fund, Paul and Tina Gardner, Yeda-Sela and the WIS-CIT joint research grant; A.G.Y. is the recipient of the Helen and Martin Kimmel Award for Innovative Investigation. M.R. has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement n759194—USNAC). M.W.C. acknowledges support from the National Science Foundation with grant number PHY-2010970. C.F. gratefully acknowledges support of his research by the Heising–Simons Foundation (#2018-0907). Based on observations obtained with the Samuel Oschin Telescope 48 inch and the 60 inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. Z.T.F. is supported by the National Science Foundation under grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. Partly based on observations made with the Nordic Optical Telescope. SED Machine is based upon work supported by the National Science Foundation under grant No. 1106171. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. e-MERLIN is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC. We thank the staff of the Mullard Radio Astronomy Observatory for their assistance in the commissioning, maintenance, and operation of AMI, which is supported by the Universities of Cambridge and Oxford. We also acknowledge support from the European Research Council under grant ERC-2012-StG-307215 LODESTONE. This work was supported by the GROWTH project funded by the National Science Foundation under grant No. 1545949. Software: ZTF pipeline (Masci et al. 2019), LCO pipeline (Fremling et al. 2020), pySEDM (Rigault et al. 2019), NOT and P200 pipelines (Bellm & Sesar 2016), CASA (McMullin et al. 2007), AMI-LA data reduction package (Perrott et al. 2013), MIRIAD standard routines (Sault et al. 1995), wsclean (Offringa et al. 2014), HEAsoft (Blackburn 1995).
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
Israel Science FoundationUNSPECIFIED
Binational Science Foundation (USA-Israel)UNSPECIFIED
I-CORE Program of the Planning and Budgeting CommitteeUNSPECIFIED
Australian Research CouncilFT150100099
Australian Government Research Training ProgramUNSPECIFIED
Hintze Family Charitable FoundationUNSPECIFIED
Large Synoptic Survey Telescope CorporationUNSPECIFIED
Brinson FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)UNSPECIFIED
Ministerio de Ciencia, Innovación y Universidades (MCIU)UNSPECIFIED
Severo OchoaSEV-2017-0709
Severo OchoaPGC2018-098915-B-C21
Ministerio de Ciencia, Innovación y Universidades (MCIU)RTI2018-096228-B-C31
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
European Research Council (ERC)725161
Ministry of Science (Israel)UNSPECIFIED
German-Israeli Foundation for Research and DevelopmentUNSPECIFIED
Benoziyo Endowment Fund for the Advancement of ScienceUNSPECIFIED
Deloro Institute for Advanced Research in Space and OpticsUNSPECIFIED
Veronika A. Rabl Physics Discretionary FundUNSPECIFIED
Paul and Tina GardnerUNSPECIFIED
Weizmann Institute of ScienceUNSPECIFIED
Helen and Martin Kimmel AwardUNSPECIFIED
European Research Council (ERC)759194
Heising-Simons Foundation2018-0907
ZTF partner institutionsUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
University of CambridgeUNSPECIFIED
University of OxfordUNSPECIFIED
European Research Council (ERC)307215
Subject Keywords:Supernovae ; Type Ic supernovae ; Core-collapse supernovae ; Radio transient sources ; Radio observatories ; Optical observation ; X-ray transient sources ; Transient sources
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Supernovae (1668); Type Ic supernovae (1730); Core-collapse supernovae (304); Radio transient sources (2008); Radio observatories (1350); Optical observation (1169); X-ray transient sources (1852)
Record Number:CaltechAUTHORS:20200916-112923664
Persistent URL:
Official Citation:Assaf Horesh et al 2020 ApJ 903 132
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105421
Deposited By: George Porter
Deposited On:17 Sep 2020 20:53
Last Modified:16 Nov 2021 18:42

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