Rubin, David and Hayden, Brian and Huang, Xiaosheng and Aldering, Greg and Amanullah, Rahman and Barbary, Kyle and Boone, Kyle and Brodwin, Mark and Deustua, Susana E. and Dixon, Sam and Eisenhardt, Peter and Fruchter, Andrew S. and Gonzalez, Anthony H. and Goobar, Ariel and Gupta, Ravi R. and Hook, Isobel and Jee, M. James and Kim, Alex G. and Kowalski, Marek and Lidman, Chris E. and Linder, Eric and Luther, Kyle and Nordin, Jakob and Pain, Reynald and Perlmutter, Saul and Raha, Zachary and Rigault, Mickael and Ruiz-Lapuente, Pilar and Saunders, Clare M. and Sofiatti, Caroline and Spadafora, Anthony L. and Stanford, S. Adam and Stern, Daniel and Suzuki, Nao and Williams, Steven C. (2018) The Discovery of a Gravitationally Lensed Supernova Ia at Redshift 2.22. The Astrophysical Journal, 866 (1): 65. ISSN 0004-637X
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Abstract
We present the discovery and measurements of a gravitationally lensed supernova (SN) behind the galaxy cluster MOO J1014+0038. Based on multi-band Hubble Space Telescope and Very Large Telescope (VLT) photometry of the supernova, and VLT spectroscopy of the host galaxy, we find a 97.5% probability that this SN is a SN Ia, and a 2.5% chance of a CC SN. Our typing algorithm combines the shape and color of the light curve with the expected rates of each SN type in the host galaxy. With a redshift of 2.2216, this is the highest redshift SN Ia discovered with a spectroscopic host-galaxy redshift. A further distinguishing feature is that the lensing cluster, at redshift 1.23, is the most distant to date to have an amplified SN. The SN lies in the middle of the color and light-curve shape distributions found at lower redshift, disfavoring strong evolution to z = 2.22. We estimate an amplification due to gravitational lensing of 2.8+0.6-0.5 (1.10 +- 0.23 mag)---compatible with the value estimated from the weak-lensing-derived mass and the mass-concentration relation from LambdaCDM simulations---making it the most amplified SN Ia discovered behind a galaxy cluster.