SN Refsdal : Photometry and Time Delay Measurements of the First Einstein Cross Supernova
Abstract
We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) "Refsdal," a gravitationally lensed SN at z = 1.488 ± 0.001 with multiple images behind the galaxy cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1–S4) exhibited a slow rise (over ~150 days) to reach a broad peak brightness around 2015 April 20. Using a set of light curve templates constructed from SN 1987A-like peculiar Type II SNe, we measure time delays for the four images relative to S1 of 4 ± 4 (for S2), 2 ± 5 (S3), and 24 ± 7 days (S4). The measured magnification ratios relative to S1 are 1.15 ± 0.05 (S2), 1.01 ± 0.04 (S3), and 0.34 ± 0.02 (S4). None of the template light curves fully captures the photometric behavior of SN Refsdal, so we also derive complementary measurements for these parameters using polynomials to represent the intrinsic light curve shape. These more flexible fits deliver fully consistent time delays of 7 ± 2 (S2), 0.6 ± 3 (S3), and 27 ± 8 days (S4). The lensing magnification ratios are similarly consistent, measured as 1.17 ± 0.02 (S2), 1.00 ± 0.01 (S3), and 0.38 ± 0.02 (S4). We compare these measurements against published predictions from lens models, and find that the majority of model predictions are in very good agreement with our measurements. Finally, we discuss avenues for future improvement of time delay measurements—both for SN Refsdal and for other strongly lensed SNe yet to come.
Additional Information
© 2016 The American Astronomical Society. Received 2015 December 19; accepted 2016 January 15; published 2016 March 17. The authors thank Stefano Casertano, Armin Rest, Piero Rosati, and Claudio Grillo for helpful discussion of this paper. Financial support for this work was provided to S.A.R. by NASA through grant HST-GO-13386 from the Space Telescope Science Instittute (STScI), which is operated by Associated Universities for Research in Astronomy, Inc. (AURA), under NASA contract NAS 5-26555. R.J.F. gratefully acknowledges support from NSF grant AST-1518052 and the Alfred P. Sloan Foundation. This supernova research at Rutgers University is supported by NSF CAREER award AST- 0847157, and NASA/Keck JPL RSA 1508337 and 1520634 to SWJ. T.T. acknowledges support from NASA through grant HST-GO-13459 for the GLASS program. A.Z. is supported by NASA through Hubble Fellowship grant #HST-HF2- 51334.001-A awarded by STScI.Attached Files
Published - apj_820_1_50.pdf
Submitted - 1512.05734v4.pdf
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Additional details
- Eprint ID
- 66490
- Resolver ID
- CaltechAUTHORS:20160426-150938741
- HST-GO-13386
- NASA
- NAS 5-26555
- NASA
- AST-1518052
- NSF
- Alfred P. Sloan Foundation
- AST-0847157
- NSF
- 1508337
- NASA/Keck JPL
- 1520634
- NASA/Keck JPL
- HST-GO-13459
- NASA
- HST-HF2- 51334.001-A
- NASA Hubble Fellowship
- Created
-
2016-04-26Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field