SN 2011dh: DISCOVERY OF A TYPE IIb SUPERNOVA FROM A COMPACT PROGENITOR IN THE NEARBY GALAXY M51

Journal Article · Thu Dec 15 00:00:00 EST 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/742/2/L18· OSTI ID:22047344

Arcavi, Iair; Gal-Yam, Avishay; Yaron, Ofer; Sternberg, Assaf; Rabinak, Itay; Waxman, Eli ^[1]; Kasliwal, Mansi M; Quimby, Robert M; Ofek, Eran O; Horesh, Assaf; Kulkarni, Shrinivas R ^[2]; Filippenko, Alexei V; Silverman, Jeffrey M; Cenko, S Bradley; Li, Weidong; Bloom, Joshua S; Nugent, Peter E; Poznanski, Dovi ^[3]; Sullivan, Mark ^[4]; Gorbikov, Evgeny ^[5] ; others, and

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1. Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel)
2. Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
3. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
4. Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom)
5. The Wise Observatory and the Raymond and Beverly Sackler School of Physics and Astronomy, the Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

On 2011 May 31 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras and also detected it with the Palomar Transient Factory survey, rapidly confirming it to be a Type II SN. Here, we present multi-color ultraviolet through infrared photometry which is used to calculate the bolometric luminosity and a series of spectra. Our early-time observations indicate that SN 2011dh resulted from the explosion of a relatively compact progenitor star. Rapid shock-breakout cooling leads to relatively low temperatures in early-time spectra, compared to explosions of red supergiant stars, as well as a rapid early light curve decline. Optical spectra of SN 2011dh are dominated by H lines out to day 10 after explosion, after which He I lines develop. This SN is likely a member of the cIIb (compact IIb) class, with progenitor radius larger than that of SN 2008ax and smaller than the eIIb (extended IIb) SN 1993J progenitor. Our data imply that the object identified in pre-explosion Hubble Space Telescope images at the SN location is possibly a companion to the progenitor or a blended source, and not the progenitor star itself, as its radius ({approx}10{sup 13} cm) would be highly inconsistent with constraints from our post-explosion spectra.

• OSTI ID: 22047344
• Journal Information: Astrophysical Journal Letters, Vol. 742, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
BOLOMETERS
CAMERAS
CHARGE-COUPLED DEVICES
COLOR
COOLING
DIAGRAMS
EMISSION SPECTRA
GALAXIES
IMAGES
LUMINOSITY
PHOTOMETRY
SUPERGIANT STARS
SUPERNOVAE
TELESCOPES
ULTRAVIOLET RADIATION
VISIBLE RADIATION