SN Refsdal
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c_cld
Hubble Space Telescope discovery of a multiply imaged, gravitationally lensed supernova
(Atel 21 Nov 2014; 22:02 UT)
We report the discovery of a multiply imaged, gravitationally lensed supernova, forming an Einstein cross around a z=0.544 early-type galaxy in the galaxy cluster MACS J1149.6+2223. The redshift of the supernova host galaxy is 1.491.
http://archive.stsci.edu/pub/ffsn/macs1149/finder_lens_MACS1149.png
Lens Galaxy: 1237667782831702078
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c_cld
New paper: Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens arXiv:1411.6009 from Patrick L. Kelly (UCB), Steven A. Rodney (JHU), Tommaso Treu (UCLA), et al.
We report the discovery of the first multiply-imaged gravitationally-lensed supernova. The four images form an Einstein cross with over 2" diameter around a z=0.544 elliptical galaxy that is a member of the cluster MACSJ1149.6+2223. The supernova appeared in Hubble Space Telescope exposures taken on 3-20 November 2014 UT, as part of the Grism Lens-Amplified Survey from Space. The images of the supernova coincide with the strongly lensed arm of a spiral galaxy at z=1.491, which is itself multiply imaged by the cluster potential. A measurement of the time delays between the multiple images and their magnification will provide new unprecedented constraints on the distribution of luminous and dark matter in the lensing galaxy and in the cluster, as well as on the cosmic expansion rate.
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c_cld
New paper: Predicted properties of multiple images of the strongly lensed supernova SN Refsdal from Masamune Oguri (University of Tokyo)
We construct a mass model of the cluster MACS J1149.6+2223 to study the expected properties of SN Refsdal, the first example of a gravitationally lensed supernova with resolved multiple images recently reported by Kelly et al. We find that the best-fit model predicts six supernova images in total, i.e., two extra images in addition to the observed four Einstein cross supernova images S1--S4. One extra image is predicted to have appeared about 17 years ago, whereas the other extra image is predicted to appear in about one year from the appearance of S1--S4, which is a testable prediction with near future observations. The predicted magnification factors of individual supernova images range from $\sim 18$ for the brightest image to $\sim 4$ for the faint extra images. Confronting these predictions with future observations should provide an unprecedented opportunity to improve our understanding of cluster mass distributions.
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c_cld
Detection of a SN near the center of the galaxy cluster field MACS1149 consistent with predictions of a new image of Supernova Refsdal ; on 12 Dec 2015;
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c_cld
New paper: Deja Vu All Over Again: The Reappearance of Supernova Refsdal From: Patrick Kelly et al. (Submitted on 15 Dec 2015)
In Hubble Space Telescope (HST) imaging taken on 10 November 2014, four images of supernova (SN) 'Refsdal' (z = 1.49) appeared in an Einstein-cross--like configuration (images S1-S4) around an early-type galaxy in the cluster MACS J1149.5+2223 (z = 0.54). The gravitational potential of the cluster creates three full images of the star-forming host galaxy of the SN. Almost all lens models of the cluster have predicted that the SN should reappear within approximately one year in a second host-galaxy image, offset by ~8" from the previous images. In HST observations taken on 11 December 2015, we find a new source that we interpret as a new image of SN Refsdal. This marks the first time the appearance of a SN at a particular time and location in the sky was successfully predicted in advance! We use these data and the light curve from the first four observed images of SN Refsdal to place constraints on the relative time delay and magnification of the new image (SX), compared to images S1-S4. This enables us, for the first time, to test lens model predictions of both magnifications and time delays for a lensed SN. We find that the timing and brightness of the new image are consistent with the blind predictions of a fraction of the models. The reappearance illustrates the discriminatory power of this blind test and its utility to uncover sources of systematic uncertainty in the lens models. From planned HST photometry, we expect to reach a precision of 1-2% on the relative time delay between S1-S4 and SX.
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This is very impressive and interesting, thanks for posting!
So if i understand correctly images S1--S4 were still visible when SX appeared, +/- 13 months after they were detected?Posted
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c_cld
MACS J1149+2223 Hubble sees multiple images of a supernova for the very first time 5 March 2015
News Release Number: STScI-2015-08
Caught in the act, Hubble captures first-ever predicted exploding star ; 16 December 2015
News Release Number: STScI-2015-46
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c_cld
in response to Ghost_Sheep_SWR's comment.
This SN Refsdal has been ruled out as a type Ia.
The observations in 2014 began before the light peak and gave data for weeks. The light curve ressemblance was made with the closest nearby SN 1987A in LMC which is classified as a Type II supernova.
So you are right in viewing SX on dec 2015 with S1-S4, a year after detection of this Einstein's cross SN Refsdal ! 😃
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ElisabethB
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Amazing ! Thanks for posting Claude ! 😄
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c_cld
SN Refsdal Light curves 😃
SN Refsdal: Photometry and Time Delay Measurements of the First Einstein Cross Supernova From: Steven Rodney et al.
(Submitted on 17 Dec 2015)
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 20 April, 2015. Using a set of light curve templates constructed from the family of 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). We find, however, that 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 days (S2), 0.6+-3 days (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.
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So if the '1995' galaxy is the host galaxy of SN Refsdal, does this mean the '2015' galaxy near SX has a higher redshift then the '2014' / S1-S4 galaxy? I'm trying to build a mental picture here, but can't find the Z of the SX galaxy.
Or are these the actual lensed images of the host galaxy, which means the ellipticals near the 2015 SX image have a higher redshift than the elliptical near the 2014 S1-S4 images?
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c_cld
in response to Ghost_Sheep_SWR's comment.
Kelly, P. L., Rodney, S. A., Treu, T., et al. 2015, Science, 347,
The cluster’s gravitational potential also creates multiple images of the z = 1.49 spiral supernova host galaxy, and a future appearance of the supernova elsewhere in the cluster field is expected.Kelly, P. L., Rodney, S. A., Treu, T., et al. 2015a, ArXiv e-prints, arXiv:1512.04654
four images of supernova (SN) `Refsdal' (z = 1:49) appeared in an Einstein-cross like con guration (images S1-S4) around an early-type galaxy in the cluster MACS J1149.5+2223 (z = 0:54). The gravitational potential of the cluster creates three full images of the star-forming host galaxy of the SN.the color-composite image shows the red galaxy lens at z = 0.54 surrounded by an Einstein ring formed by light from the distorted spiral host galaxy with z = 1.49 (20 ), whose nucleus is offset by 3.3" from the center of the lensing elliptical galaxy.
"1995" and "2015 SX" are locations of lensed images of (arm of) the spiral galaxy at z=1.49, not of the lensing elliptical of the SN. 😃
SX http://arxiv.org/abs/1509.08914Posted
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c_cld
New paper: SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova (Submitted on 30 Dec 2015) from Patrick Kelly et al. arXiv:1512.09093 [astro-ph.GA]
We have acquired Hubble Space Telescope (HST) and Very Large Telescope
near-infrared spectra and images of supernova (SN) Refsdal after its
discovery as an Einstein cross in Fall 2014. The HST light curve of SN
Refsdal matches the distinctive, slowly rising light curves of SN
1987A-like supernovae (SNe), and we find strong evidence for a broad
H-alpha P-Cygni profile in the HST grism spectrum at the redshift (z =
1.49) of the spiral host galaxy. SNe IIn, powered by circumstellar interaction, could provide a good match to the light curve of SN
Refsdal, but the spectrum of a SN IIn would not show broad and strong
H-alpha absorption. From the grism spectrum, we measure an H-alpha
expansion velocity consistent with those of SN 1987A-like SNe at a
similar phase. The luminosity, evolution, and Gaussian profile of the
H-alpha emission of the WFC3 and X-shooter spectra, separated by ~2.5
months in the rest frame, provide additional evidence that supports
the SN 1987A-like classification. In comparison with other examples of
SN 1987A-like SNe, SN Refsdal has a blue B-V color and a high
luminosity for the assumed range of potential magnifications. If SN
Refsdal can be modeled as a scaled version of SN 1987A, we estimate it
would have an ejecta mass of 20+-5 solar masses. The evolution of the
light curve at late times will provide additional evidence about the
potential existence of any substantial circumstellar material (CSM).
Using MOSFIRE and X-shooter spectra, we estimate a subsolar
host-galaxy metallicity (8.3+-0.1 dex and lt 8.4 dex, respectively)
near the explosion site.Posted
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c_cld
Hubble Space Telescope Discovery of a Probable Caustic-Crossing Event in the MACS1149 Galaxy Cluster Field
ATel #9097; Patrick L. Kelly (UCB), on 29 May 2016;An HST image of the transient in the MACS1149 cluster field may be found here.
follow-up:
New paper: An individual star at redshift 1.5 extremely magnified by a galaxy-cluster lens arXiv:1706.10279v1 30 Jun 2017 Patrick L. Kelly et al.
Galaxy-cluster gravitational lenses can magnify background galaxies by a factor of up to ~50. An individual well-aligned background star, however, could potentially become much more highly magnified. Here we report an image of a star (dubbed "MACS J1149 Lensed Star 1 (LS1)") at redshift z=1.49 magnified by >2000. We measure fluctuations in the star's flux arising from microlensing by intracluster stars and compact objects, whose effective Einstein radii should become exaggerated by a factor of ~100 by the cluster's potential. LS1's light curve is sensitive to the mass function of intracluster stars and compact objects and provides evidence about binary fractions as well as specific stellar evolution and supernova models, and against a high abundance of ~30 solar-mass primordial black holes. A second event, separated by 0.26" from LS1, likely corresponds to LS1's counterimage demagnified for multiple years by a ~3 solar-mass object in the cluster. Additional monitoring should test the hypothesis that dark matter consists of extremely light bosons.
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https://arxiv.org/abs/1801.06546
https://arxiv.org/pdf/1801.06546.pdf
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Budgieye
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Here are two spacewarps discussions
https://talk.spacewarps.org/#/boards/BSW0000006/discussions/DSW0000enx
https://talk.spacewarps.org/#/boards/BSW0000006/discussions/DSW0000env
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