THE ABSOLUTE MAGNITUDES OF TYPE Ia SUPERNOVAE IN THE ULTRAVIOLET

Journal Article · Fri Oct 01 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/721/2/1608· OSTI ID:21464751

Brown, Peter J; Roming, Peter W. A.; Ciardullo, Robin; Gronwall, Caryl; Hoversten, Erik A; Pritchard, Tyler ^[1]; Milne, Peter ^[2]; Bufano, Filomena; Mazzali, Paolo ^[3]; Elias-Rosa, Nancy ^[4]; Filippenko, Alexei V; Weidong, Li ^[5]; Foley, Ryan J; Hicken, Malcolm; Kirshner, Robert P ^[6]; Gehrels, Neil; Holland, Stephen T; Immler, Stefan ^[7]; Phillips, Mark M ^[8]; Still, Martin ^[9]

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1. Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
2. Steward Observatory, University of Arizona, Tucson, AZ 85719 (United States)
3. INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy)
4. Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
5. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
6. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
7. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
8. Las Campanas Observatory, Casilla 601, La Serena (Chile)
9. Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom)

We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1{sub rc} covering {approx}2600-3300 A after removing optical light, and u {approx} 3000-4000 A) compared to a mid-UV filter (uvm2 {approx}2000-2400 A). The uvw1{sub rc} - b colors show a scatter of {approx}0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2 - uvw1 colors implies significantly larger spectral variability below 2600 A. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, {approx}1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.

• OSTI ID: 21464751
• Journal Information: Astrophysical Journal, Vol. 721, Issue 2; Other Information: DOI: 10.1088/0004-637X/721/2/1608; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
DUSTS
LUMINOSITY
MAGELLANIC CLOUDS
MILKY WAY
RED SHIFT
SUPERNOVAE
TELESCOPES
ULTRAVIOLET RADIATION
BINARY STARS
ELECTROMAGNETIC RADIATION
ERUPTIVE VARIABLE STARS
GALAXIES
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
STARS
VARIABLE STARS