Wednesday, February 13, 2013

1302.2785 (Robert M. Quimby et al.)

Extraordinary Magnification of the Ordinary Type Ia Supernova PS1-10afx    [PDF]

Robert M. Quimby, Marcus C. Werner, Masamune Oguri, Surhud More, Anupreeta More, Masayuki Tanaka, Ken'ichi Nomoto, Takashi J. Moriya, Gaston Folatelli, Keiichi Maeda, Melina Bersten
Recently, Chornock and co-workers announced the Pan-STARRS discovery of a transient source reaching an apparent peak luminosity of ~4x10^44 erg/s. We show that the spectra of this transient source are well fit by normal Type Ia supernova (SNIa) templates. The multi-band colors and light curve shapes are also consistent with a normal SNIa at the spectroscopically determined redshift of z=1.3883; however, the observed flux is a constant factor of 20 times too bright in each band over time as compared to the templates. At a minimum, this shows that the peak luminosities inferred from the light curve widths of some SNeIa will deviate significantly from the established, empirical relation used by cosmologists. We argue on physical grounds that the observed fluxes do not reflect an intrinsically luminous SNIa, but rather PS1-10afx is a normal SNIa whose flux has been amplified by an external source. The only known astrophysical source capable of such magnification is a gravitational lens. Given the lack of obvious lens candidates, such as galaxy clusters, in the vicinity, we further argue that the lens is a supermassive black hole or a comparatively low-mass dark matter halo. In this case, the lens continues to amplify the underlying host galaxy light, and similar lensing may be observable in other quiescent galaxies. If confirmed, this discovery could impact a broad range of topics, from the selection of gamma-ray bursts, to measuring cosmology, to constraints on the nature and distribution of dark matter halos.
View original: http://arxiv.org/abs/1302.2785

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