TY - JOUR
T1 - The most slowly declining type Ia supernova 2001ay
AU - Krisciunas, Kevin
AU - Li, Weidong
AU - Matheson, Thomas
AU - Howell, D. Andrew
AU - Stritzinger, Maximilian
AU - Aldering, Greg
AU - Berlind, Perry L.
AU - Calkins, M.
AU - Challis, Peter
AU - Chornock, Ryan
AU - Conley, Alexander
AU - Filippenko, Alexei V.
AU - Ganeshalingam, Mohan
AU - Germany, Lisa
AU - Gonzlez, Sergio
AU - Gooding, Samuel D.
AU - Hsiao, Eric
AU - Kasen, Daniel
AU - Kirshner, Robert P.
AU - Howie Marion, G. H.
AU - Muena, Cesar
AU - Nugent, Peter E.
AU - Phelps, M.
AU - Phillips, Mark M.
AU - Qiu, Yulei
AU - Quimby, Robert
AU - Rines, K.
AU - Silverman, Jeffrey M.
AU - Suntzeff, Nicholas B.
AU - Thomas, Rollin C.
AU - Wang, Lifan
PY - 2011/9
Y1 - 2011/9
N2 - 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 14,000kms-1, while Si III and S II showed velocities of 9000kms-1. There is also evidence for some unburned carbon at 12,000kms-1. SN 2001ay exhibited a decline-rate parameter of Δm 15(B)= 0.68 ± 0.05mag; this and the B-band photometry at t ≳ +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 MB = -19.19 and MV = -19.17mag at maximum light; thus, it was not overluminous in optical bands. In near-infrared bands it was overluminous only at the 2σ level at most. For a rise time of 18 days (explosion to bolometric maximum) the implied 56Ni yield was (0.58 ± 0.15)/α M, with α = L max/E Ni probably in the range 1.0-1.2. The 56Ni yield is comparable to that of many Type Ia SNe. The "normal" 56Ni yield and the typical peak optical brightness suggest that the very broad optical light curve is explained by the trapping of γ rays in the inner regions.
AB - 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 14,000kms-1, while Si III and S II showed velocities of 9000kms-1. There is also evidence for some unburned carbon at 12,000kms-1. SN 2001ay exhibited a decline-rate parameter of Δm 15(B)= 0.68 ± 0.05mag; this and the B-band photometry at t ≳ +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 MB = -19.19 and MV = -19.17mag at maximum light; thus, it was not overluminous in optical bands. In near-infrared bands it was overluminous only at the 2σ level at most. For a rise time of 18 days (explosion to bolometric maximum) the implied 56Ni yield was (0.58 ± 0.15)/α M, with α = L max/E Ni probably in the range 1.0-1.2. The 56Ni yield is comparable to that of many Type Ia SNe. The "normal" 56Ni yield and the typical peak optical brightness suggest that the very broad optical light curve is explained by the trapping of γ rays in the inner regions.
KW - supernovae: individual (SN 2001ay)
KW - techniques: photometric
KW - techniques: spectroscopic
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U2 - 10.1088/0004-6256/142/3/74
DO - 10.1088/0004-6256/142/3/74
M3 - Article
AN - SCOPUS:80052714783
SN - 0004-6256
VL - 142
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 74
ER -