THE MOST SLOWLY DECLINING TYPE Ia SUPERNOVA 2001ay

Journal Article · Thu Sep 15 00:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/142/3/74· OSTI ID:21582948

Krisciunas, Kevin; Gooding, Samuel D ^[1]

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1. Department of Physics and Astronomy, George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)

We present optical and near-infrared photometry, as well as ground-based optical spectra and Hubble Space Telescope ultraviolet spectra, of the Type Ia supernova (SN) 2001ay. At maximum light the Si II and Mg II lines indicated expansion velocities of 14,000 km s{sup -1}, while Si III and S II showed velocities of 9000 km s{sup -1}. There is also evidence for some unburned carbon at 12,000 km s{sup -1}. SN 2001ay exhibited a decline-rate parameter of {Delta}m{sub 15}(B) = 0.68 {+-} 0.05 mag; this and the B-band photometry at t {approx}> +25 day past maximum make it the most slowly declining Type Ia SN yet discovered. Three of the four super-Chandrasekhar-mass candidates have decline rates almost as slow as this. After correction for Galactic and host-galaxy extinction, SN 2001ay had M{sub B} = -19.19 and M{sub V} = -19.17 mag at maximum light; thus, it was not overluminous in optical bands. In near-infrared bands it was overluminous only at the 2{sigma} level at most. For a rise time of 18 days (explosion to bolometric maximum) the implied {sup 56}Ni yield was (0.58 {+-} 0.15)/{alpha} M{sub sun}, with {alpha} = L{sub max}/E{sub Ni} probably in the range 1.0-1.2. The {sup 56}Ni yield is comparable to that of many Type Ia SNe. The 'normal' {sup 56}Ni yield and the typical peak optical brightness suggest that the very broad optical light curve is explained by the trapping of {gamma} rays in the inner regions.

• OSTI ID: 21582948
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 142, Issue 3; Other Information: DOI: 10.1088/0004-6256/142/3/74; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BOLOMETERS
BRIGHTNESS
CARBON
GALAXIES
GAMMA RADIATION
NICKEL 56
PHOTOMETRY
PULSE RISE TIME
SUPERNOVAE
TELESCOPES
ULTRAVIOLET SPECTRA
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BINARY STARS
DAYS LIVING RADIOISOTOPES
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
ERUPTIVE VARIABLE STARS
EVEN-EVEN NUCLEI
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
MEASURING INSTRUMENTS
NICKEL ISOTOPES
NONMETALS
NUCLEI
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
RADIOISOTOPES
SPECTRA
STARS
TIMING PROPERTIES
VARIABLE STARS