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Post Info TOPIC: MACS J1149.6+2223


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MACS J1149 Lensed Star 1
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MACS J1149 Lensed Star 1, also known as Icarus, is a blue supergiant observed through a gravitational lens and the most distant individual star detected, at 9 billion light-years from Earth (redshift z=1.49; comoving distance of 14.4 billion light-years; lookback time of 9.34 billion years), as of April 2018. Light from the star was emitted 4.4 billion years after the Big Bang. According to co-discoverer Patrick Kelly, the star is at least a hundred times more distant than the next-farthest non-supernova star observed, SDSS J1229+1122, and is the first magnified individual star seen.
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RE: MACS J1149.6+2223
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Title: SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova
Author: P. L. Kelly, G. Brammer, J. Selsing, R. J. Foley, J. Hjorth, S. A. Rodney, L. Christensen, L.-G. Strolger, A. V. Filippenko, T. Treu, C. C. Steidel, A. Strom, A. G. Riess, A. Zitrin, K. B. Schmidt, M. Bradac, S. W. Jha, M. L. Graham, C. McCully, O. Graur, B. J. Weiner, J. M. Silverman

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 modelled 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 <8.4 dex, respectively) near the explosion site.

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Supernova Refsdal
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Title: SN Refsdal : Photometry and Time Delay Measurements of the First Einstein Cross Supernova 
Author: S. A. Rodney, L.-G. Strolger, P. L. Kelly, M. Bradac, G. Brammer, A. V. Filippenko, R. J. Foley, O. Graur, J. Hjorth, S. W. Jha, C. McCully, A. Molino, A. G. Riess, K. B. Schmidt, J. Selsing, K. Sharon, T. Treu, B. J. Weiner, A. Zitrin 

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 behaviour 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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RE: SN Refsdal
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ATel 8402: Detection of a SN near the center of the galaxy cluster field MACS1149 consistent with predictions of a new image of Supernova Refsdal



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RE: MACS J1149.6+2223
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Hubble Sees Supernova Split into Four Images by Cosmic Lens

Astronomers using NASA's Hubble Space Telescope have spotted for the first time a distant supernova split into four images. The multiple images of the exploding star are caused by the powerful gravity of a foreground elliptical galaxy embedded in a massive cluster of galaxies.
This unique observation will help astronomers refine their estimates of the amount and distribution of dark matter in the lensing galaxy and cluster. Dark matter cannot be seen directly but is believed to make up most of the universe's mass.

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SN Refsdal
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ATel 6729: Hubble Space Telescope discovery of a multiply imaged, gravitationally lensed supernova



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RE: MACS J1149.6+2223
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Infant galaxy offers peek at early universe

A Michigan State University astronomer is part of an international team of scientists that has discovered a galaxy so far, far away that its light was emitted not all that long after the Big Bang occurred.
The research of MSU's physics and astronomy professor Megan Donahue and colleagues is detailed in the recent issue of the journal Nature. They found that this galaxy began emitting light "just" 490 million years after the Big Bang, when the universe was only 3.6 percent of its present age.

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MACS1149-JD
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NASA Telescopes Spy Ultra-Distant Galaxy Amidst Cosmic 'Dark Ages'

With the combined power of NASA's Spitzer and Hubble space telescopes, as well as a cosmic magnification effect, astronomers have spotted what could be the most distant galaxy ever seen. Light from the young galaxy captured by the orbiting observatories first shone when our 13.7-billion-year-old universe was just 500 million years old. The far-off galaxy existed within an important era when the universe began to transit from the so-called cosmic dark ages. During this period, the universe went from a dark, starless expanse to a recognizable cosmos full of galaxies. The discovery of the faint, small galaxy opens a window onto the deepest, remotest epochs of cosmic history.
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Posts: 131287
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MACS1149-JD1
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 Infant galaxy offers tantalising peek at early Universe

Astronomers are claiming a new benchmark in the quest to see the Universes first galaxies. By taking advantage of a rare cosmic zoom lens - where the gravity of a large mass magnifies light from objects in the distant background - a team of US and European researcher has spotted a galaxy so remote its light was emitted just 490 million years after the Big Bang, when the Universe was a mere 3.6% of its current age.
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MACS J1149.6+2223
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Title: A highly magnified candidate for a young galaxy seen when the Universe was 500 Myrs old
Authors: Wei Zheng, Marc Postman, Adi Zitrin, John Moustakas, Xinwen Shu, Stephanie Jouvel, Ole Host, Alberto Molino, Larry Bradley, Dan Coe, Leonidas A. Moustakas, Mauricio Carrasco, Holland Ford, Narciso Bentez, Tod R. Lauer, Stella Seitz, Rychard Bouwens, Anton Koekemoer, Elinor Medezinski, Matthias Bartelmann, Tom Broadhurst, Megan Donahue, Claudio Grillo, Leopoldo Infante, Saurabh Jha, Daniel D. Kelson, Ofer Lahav, Doron Lemze, Peter Melchior, Massimo Meneghetti, Julian Merten, Mario Nonino, Sara Ogaz, Piero Rosati, Keiichi Umetsu, Arjen van der Wel

The early Universe at redshift z~6-11 marks the reionisation of the intergalactic medium, following the formation of the first generation of stars. However, those young galaxies at a cosmic age of \lesssim 500 million years (Myr, at z \gtrsim 10) remain largely unexplored as they are at or beyond the sensitivity limits of current large telescopes. Gravitational lensing by galaxy clusters enables the detection of high-redshift galaxies that are fainter than what otherwise could be found in the deepest images of the sky. We report the discovery of an object found in the multi-band observations of the cluster MACS1149+22 that has a high probability of being a gravitationally magnified object from the early universe. The object is firmly detected (12 sigma) in the two reddest bands of HST/WFC3, and not detected below 1.2 µm, matching the characteristics of z~9 objects. We derive a robust photometric redshift of z = 9.6 ±0.2, corresponding to a cosmic age of 490 ±15Myr (i.e., 3.6% of the age of the Universe). The large number of bands used to derive the redshift estimate make it one of the most accurate estimates ever obtained for such a distant object. The significant magnification by cluster lensing (a factor of ~15) allows us to analyse the object's ultra-violet and optical luminosity in its rest-frame, thus enabling us to constrain on its stellar mass, star-formation rate and age. If the galaxy is indeed at such a large redshift, then its age is less than 200 Myr (at the 95% confidence level), implying a formation redshift of zf \lesssim 14. The object is the first z>9 candidate that is bright enough for detailed spectroscopic studies with JWST, demonstrating the unique potential of galaxy cluster fields for finding highly magnified, intrinsically faint galaxies at the highest redshifts.

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Position (J2000):     R.A. 11 49 33.584  |  Dec. +22° 24' 45.78''



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