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Detection of a SN near the center of the galaxy cluster field MACS1149 consistent with predictions of a new image of Supernova Refsdal

ATel #8402; P. L. Kelly (UC Berkeley), S. A. Rodney (USC), G. Brammer (STScI), L. G. Strolger (STScI/WKU), R. J. Foley (Illinois), T. Treu (UCLA), A. Zitrin (Caltech), A. V. Filippenko (UC Berkeley), S. W. Jha (Rutgers), A. G. Riess (JHU/STScI), J. Hjorth (DARK), K. B. Schmidt (UC Santa Barbara), O. Graur (NYU/AMNH), M. Bradac (UC Davis), B. J. Weiner (Arizona), A. von der Linden (KIPAC), C. McCully (LCOGT/UC Santa Barbara), A. Molino (IAA-CSIC), J. Selsing (DARK), M. Nonino (IAG/USP), D. Coe (STScI)
on 12 Dec 2015; 07:35 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Patrick Kelly (pkelly@astro.berkeley.edu)

Subjects: Supernovae

In Hubble Space Telescope (HST) WFC3-IR exposures taken on UT 2015 December 10 (GO-14199; PI: Kelly), we discovered a new transient source in the MACS J1149.6+2223 (Ebeling et al. 2003) galaxy cluster field.

The new source was not detected in WFC3-IR exposures taken during a previous visit to the field on UT 2015 October 30.8 nor in earlier imaging from the FrontierSN program (GO-13790; PI: Rodney), Frontier Fields (GO/DD-13504; PI: Lotz), or Grism Lens-Amplified Survey from Space (GLASS, GO-14095; PI: Treu) programs. The new image is marginally detected in data taken in November 2015.

This new image coincides with a multiply imaged background galaxy at z = 1.49. This same galaxy, but seen as a different image, is the host galaxy of SN Refsdal, a SN discovered in November 2014 as four separate images in an Einstein cross configuration around an early-type cluster member (Kelly et al. 2015). Multiple lensing models consistently predicted that SN Refsdal would re-appear, within several years, at the position of the other image of the host galaxy closer to the galaxy center (Kelly et al. 2015 [using Zitrin et al. 2009]; see also Oguri et al. 2015; Sharon & Johnson 2015; Diego et al. 2015; Jauzac et al. 2015; Treu et al. 2015). The new SN, which we denote as 'SX,' is significantly fainter than images S1-S3 of the SN Refsdal Einstein cross when they were discovered in images taken on UT 2014 November 10.

The new SN position is both approximately spatially and temporally coincident with predictions for the location and timing of the delayed image of SN Refsdal. Moreover, the brightness differences are also approximately consistent with relative magnification predictions.

We conclude that this new SN is likely the re-appearance of SN Refsdal.

The J2000 position of image SX is as follows:

ID RA DEC RA_dd DEC_dd SX: 11:49:36.02 +22:23:48.1

From difference images of SN Refsdal constructed using template imaging from the CLASH program (PI: Postman, GO-12068), we measure the following AB magnitudes:

ID F125W F160W SX: 26.5 +- 0.2 26.3 +- 0.2

An image of the new multiply imaged system is posted online at http://astro.berkeley.edu/~pkelly/refsdal_redux.png