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Title: A mid-life crisis? Sudden changes in radio and X-ray emission from supernova 1970G

Supernovae (SNe) provide a backdrop from which we can probe the end state of stellar evolution in the final years before the progenitor star explodes. As the shock from the SN expands, the timespan of mass-loss history we are able to probe also extends, providing insight to rapid timescale processes that govern the end state of massive stars. While SNe transition into remnants on timescales of decades to centuries, observations of this phase are currently limited. Here, we present observations of SN 1970G, serendipitously observed during the monitoring campaign of SN 2011fe, which shares the same host galaxy. Utilizing the new Jansky Very Large Array (VLA) upgrade and a deep X-ray exposure taken by Chandra, we are able to recover this middle-aged SN and distinctly resolve it from the H II cloud with which it is associated. We find that the flux density of SN 1970G has changed significantly since it was last observed—the X-ray luminosity has increased by a factor of ∼3, while we observe a significantly lower radio flux of only 27.5 μJy at 6.75 GHz, a level only detectable through the upgrades now in operation at the Jansky VLA. These changes suggest that SN 1970G has enteredmore » a new stage of evolution toward an SN remnant, and we may be detecting the turn-on of the pulsar wind nebula. Deep radio observations of additional middle-aged SNe with the improved radio facilities will provide a statistical census of the delicate transition period between SN and remnant.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
  2. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
  3. National Radio Astronomy Observatory, Domenici Science Operations Center, Socorro, NM 87801 (United States)
  4. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
Publication Date:
OSTI Identifier:
22356680
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; FLUX DENSITY; GALAXIES; LUMINOSITY; MASS TRANSFER; NEBULAE; STAR EVOLUTION; STELLAR WINDS; SUPERNOVAE; X RADIATION