Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/56644

Title

Optical and near-infrared observations of the peculiar Type la supernova 1999ac

Author(s)

Phillips, Mark M.;  Krisciunas, Kevin;  Suntzeff, Nicholas B.;  Abraham, R. G.;  Beckett, M. G.;  Bonati, Marco;  Candia, Pablo;  Corwin, T. Michael;  Depoy, Darren L.;  Espinoza, Juan;  Firth, Andrew E.;  Freedman, Wendy L.;  Galaz, Gaspar;  Germany, Lisa;  Gonzalez, David;  Hamuy, Mario;  Hastings, N. C.;  Hungerford, Aimee L.;  Ivanov, Valentin D.;  Labbé, Erika;  Marzke, Ronald O.;  McCarthy, Patrick J.;  McMahon, Richard G.;  McMillan, Russet;  Muena, Cesar;  Persson, S. E.;  Roth, Miguel;  Ruiz, Maria Teresa;  Smith, R. Chris;  Smith, Roger;  Strolger, Louis-Gregory;  Stubbs, Christopher

Abstract

We present 39 nights of optical photometry, 34 nights of IR photometry, and 4 nights of optical spectroscopy of the Type la supernova 1999ac. This supernova was discovered 2 weeks before maximum light, and observations were begun shortly thereafter. At early times its spectra resembled the unusual SN 1999aa and were characterized by very high velocities in the Ca II H and K lines but very low velocities in the Si II λ6355 line. The optical photometry showed a slow rise to peak brightness but, quite peculiarly, was followed by a more rapid decline from maximum. Thus, the B- and V-band light curves cannot be characterized by a single stretch factor. We argue that the best measure of the nature of this object is not the decline rate parameter Δm15 (B). The B - V colors were unusual from 30 to 90 days after maximum light in that they evolved to bluer values at a much slower rate than normal Type Ia supernovae. The spectra and bolometric light curve indicate that this event was similar to the spectroscopically peculiar slow decliner SN 1999aa.

Publication type

Journal article

Source

Astronomical Journal, Vol. 131, no. 5 (2006), pp. 2615-2627

Publication year

2006

FOR Code(s)

0201 Astronomical and Space Sciences;  020110 Stellar Astronomy and Planetary Systems

Keyword(s)

Astronomy;  Cosmology;  Near-infrared photometry;  Optical photometry;  Supernovae;  Type la supernova

Publisher

University of Chicago Press

ISSN

0004-6256

Publisher URL

http://dx.doi.org/10.1086/503108

Copyright

Copyright © 2006 The American Astronomical Society. All rights reserved. Publisher does not officially support author/institution self-archiving of either the postprint (final, revised accepted draft) or published version of full text.

Peer reviewed