VERY EARLY ULTRAVIOLET AND OPTICAL OBSERVATIONS OF THE TYPE Ia SUPERNOVA 2009ig

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/744/1/38· OSTI ID:22004321

Foley, Ryan J; Challis, P J; Marion, G H; Kirshner, R P ^[1]; Filippenko, A V; Ganeshalingam, M; Li, W; Silverman, J M; Cenko, S B ^[2]; Landsman, W ^[3]; Beaton, R L ^[4]; Bennert, V N ^[5]; Childress, M ^[6]; Guhathakurta, P ^[7]; Jiang, L ^[8]; Kalirai, J S ^[9]; Stockton, A ^[10]; Tollerud, E J ^[11]; Vinko, J ^[12]; others, and

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
3. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
4. Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)
5. Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States)
6. Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
7. UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
8. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
9. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
10. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
11. Center for Cosmology, Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States)
12. Department of Optics and Quantum Electronics, University of Szeged, Dom ter 9, Szeged H-6720 (Hungary)

Supernova (SN) 2009ig was discovered 17 hr after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, making it one of the foremost SNe for intensive study in the last decade. Here, we present ultraviolet (UV) and optical observations of SN 2009ig, starting about 1 day after explosion until around maximum brightness. Our data include excellent UV and optical light curves, 25 premaximum optical spectra, and 8 UV spectra, including the earliest UV spectrum ever obtained of an SN Ia. SN 2009ig is a relatively normal SN Ia, but does display high-velocity ejecta-the ejecta velocity measured in our earliest spectra (v Almost-Equal-To -23, 000 km s{sup -1} for Si II {lambda}6355) is the highest yet measured in an SN Ia. The spectral evolution is very dramatic at times earlier than 12 days before maximum brightness, but slows after that time. The early-time data provide a precise measurement of 17.13 {+-} 0.07 days for the SN rise time. The optical color curves and early-time spectra are significantly different from template light curves and spectra used for light-curve fitting and K-corrections, indicating that the template light curves and spectra do not properly represent all SNe Ia at very early times. In the age of wide-angle sky surveys, SNe like SN 2009ig that are nearby, bright, well positioned, and promptly discovered will still be rare. As shown with SN 2009ig, detailed studies of single events can provide significantly more information for testing systematic uncertainties related to SN Ia distance estimates and constraining progenitor and explosion models than large samples of more distant SNe.

• OSTI ID: 22004321
• Journal Information: Astrophysical Journal, Vol. 744, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
EXPLOSIONS
PULSE RISE TIME
STAR EVOLUTION
SUPERNOVAE
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA