DIRECT CONFIRMATION OF THE ASYMMETRY OF THE CAS A SUPERNOVA WITH LIGHT ECHOES

Journal Article · Sun May 01 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/1/3· OSTI ID:21574674

Rest, A; Narayan, G ^[1]; Foley, R J; Kirshner, R P ^[2]; Sinnott, B; Welch, D L ^[3]; Badenes, C ^[4]; Filippenko, A V ^[5]; Bergmann, M ^[6]; Bhatti, W A; Huber, M E ^[7]; Blondin, S ^[8]; Challis, P; Damke, G ^[9]; Finley, H ^[10]; Kasen, D ^[11]; Matheson, T ^[12]; Mazzali, P ^[13]; Minniti, D ^[14]; Nakajima, R ^[15]

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1. Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)
4. Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, 76100 Rehovot (Israel)
5. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
6. 6530 E. Clinton St., Scottsdale, AZ 85254 (United States)
7. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, 3400 North Charles Street, MD 21218 (United States)
8. Centre de Physique des Particules de Marseille (CPPM), Aix-Marseille Universite, CNRS/IN2P3, 163 Avenue de Luminy, 13288 Marseille Cedex 9 (France)
9. Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)
10. Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)
11. UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
12. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719-4933 (United States)
13. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching (Germany)
14. Vatican Observatory, V00120 Vatican City State (Italy)
15. Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)

We report the first detection of asymmetry in a supernova (SN) photosphere based on SN light echo (LE) spectra of Cas A from the different perspectives of dust concentrations on its LE ellipsoid. New LEs are reported based on difference images, and optical spectra of these LEs are analyzed and compared. After properly accounting for the effects of finite dust-filament extent and inclination, we find one field where the He I {lambda}5876 and H{alpha} features are blueshifted by an additional {approx}4000 km s{sup -1} relative to other spectra and to the spectra of the Type IIb SN 1993J. That same direction does not show any shift relative to other Cas A LE spectra in the Ca II near-infrared triplet feature. We compare the perspectives of the Cas A LE dust concentrations with recent three-dimensional modeling of the SN remnant (SNR) and note that the location having the blueshifted He I and H{alpha} features is roughly in the direction of an Fe-rich outflow and in the opposite direction of the motion of the compact object at the center of the SNR. We conclude that Cas A was an intrinsically asymmetric SN. Future LE spectroscopy of this object, and of other historical SNe, will provide additional insight into the connection of the explosion mechanism to SN then to SNR, as well as give crucial observational evidence regarding how stars explode.

• OSTI ID: 21574674
• Journal Information: Astrophysical Journal, Vol. 732, Issue 1; Other Information: DOI: 10.1088/0004-637X/732/1/3; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASYMMETRY
DUSTS
SIMULATION
SPECTRA
STELLAR ATMOSPHERES
SUPERNOVA REMNANTS
SUPERNOVAE
THREE-DIMENSIONAL CALCULATIONS
ATMOSPHERES
BINARY STARS
COSMIC RADIO SOURCES
ERUPTIVE VARIABLE STARS
STARS
VARIABLE STARS