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Title: Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material Around <10-Day-Old Type II Supernovae

Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. In this paper, by searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11more » SNe in our sample are either BF events or show FI signatures. Finally and interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M R = -18.2 belong to the FI or BF groups, and that all FI events peaked above M R = -17.6 mag, significantly brighter than average SNe II.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [2] ;  [2] ;  [4] ;  [1] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] more »;  [4] ;  [4] ;  [12] ;  [12] ;  [13] ;  [14] ;  [15] « less
  1. Weizmann Inst. of Science, Rehovot (Israel). Benoziyo Center for Astrophysics. Faculty of Physics
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States). Astronomy Dept.
  3. Las Cumbres Observatory Global Telescope Network, Goleta, CA (United States); Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics
  4. Stockholm Univ. (Sweden). The Oskar Klein Centre. Dept. of Astronomy
  5. Univ. of Southampton (United Kingdom). School of Physics and Astronomy
  6. Univ. of California, Berkeley, CA (United States). Dept. of Astronomy
  7. Univ. of California, Berkeley, CA (United States). Dept. of Astronomy; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division
  8. Las Cumbres Observatory Global Telescope Network, Goleta, CA (United States); Univ. of California, Santa Barbara, CA (United States). Dept. of Physics
  9. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Astrophysics Science Division
  10. Univ. of Texas, Austin, TX (United States). Dept. of Astronomy
  11. Univ. of Hawaii, Honolulu, HI (United States). Inst. for Astronomy
  12. California Inst. of Technology (CalTech), Pasadena, CA (United States). Spitzer Science Center
  13. California Inst. of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab.
  14. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  15. National Optical Astronomy Observatory, Tucson, AZ (United States)
Publication Date:
Report Number(s):
LA-UR-15-24643
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-06NA25396; AST-1302771; AST-1211916; 307260; 615929; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 818; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States); Weizmann Inst. of Science, Rehovot (Israel); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program; National Aeronautic and Space Administration (NASA); National Science Foundation (NSF); European Commission (EC); USDOE Office of Science (SC)
Contributing Orgs:
Stockholm Univ. (Sweden); Univ. of Southampton (United Kingdom); Weizmann Inst. of Science, Rehovot (Israel); Univ. of California, Berkeley, CA (United States); Univ. of Texas, Austin, TX (United States); Univ. of Hawaii, Honolulu, HI (United States); Univ. of California, Santa Barbara, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Astronomy and Astrophysics; Supernovae
OSTI Identifier:
1329868
Alternate Identifier(s):
OSTI ID: 1393026