Early Results from GLASS-JWST. VIII. An Extremely Magnified Blue Supergiant Star at Redshift 2.65 in the A2744 Cluster Field
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- Chen_2022_ApJL_940_L54
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We report the discovery of an extremely magnified star at redshift z = 2.65 in the James Webb Space Telescope (JWST) NIRISS pre-imaging of the A2744 galaxy-cluster field. The star’s background host galaxy lies on a fold caustic of the foreground lens, and the cluster creates a pair of images of the region close to the lensed star. We identified the bright transient in one of the merging images at a distance of ∼0.″15 from the critical curve by subtracting the JWST F115W and F150W imaging from coadditions of archival Hubble Space Telescope (HST) F105W and F125W images and F140W and F160W images, respectively. Since the time delay between the two images should be only hours, the transient must be the microlensing event of an individual star, as opposed to a luminous stellar explosion that would persist for days to months. Analysis of individual exposures suggests that the star’s magnification is not changing rapidly during the observations. From photometry of the point source through the F115W, F150W, and F200W filters, we identify a strong Balmer break, and modeling allows us to constrain the star’s temperature to be approximately 7000-12,000 K.
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | L54 |
| Tidsskrift | Astrophysical Journal Letters |
| Vol/bind | 940 |
| Udgave nummer | 2 |
| Antal sider | 8 |
| ISSN | 2041-8205 |
| DOI | |
| Status | Udgivet - 1 dec. 2022 |
Bibliografisk note
Funding Information:
This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. The specific observations analyzed can be accessed via 10.17909/y6dh-6g16. We acknowledge financial support from NASA through grant JWST-ERS-1324. Archival images from the Hubble Space Telescope were also used. We would like to thank Dr. Pietro Bergamini, Prof. Piero Rosati, Prof. Claudio Grillo, Dr. Ana Acebron, and Dr. Eros Vanzella for their helpful comments on our paper and for sharing the predictions of their lens model.
Funding Information:
This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. The specific observations analyzed can be accessed via 10.17909/y6dh-6g16 . We acknowledge financial support from NASA through grant JWST-ERS-1324. Archival images from the Hubble Space Telescope were also used. We would like to thank Dr. Pietro Bergamini, Prof. Piero Rosati, Prof. Claudio Grillo, Dr. Ana Acebron, and Dr. Eros Vanzella for their helpful comments on our paper and for sharing the predictions of their lens model.
Funding Information:
W.C. acknowledges support from NASA HST grant AR-15791. P.L.K. is supported by NSF grant AST-1908823 and NASA/Keck JPL RSA 1644110. R.A.W. acknowledges support from NASA JWST Interdisciplinary Scientist grants NAG5-12460, NNX14AN10G, and 80NSSC18K0200 from GSFC. J.M.D. acknowledges the support of project PGC2018-101814-B-100 (MCIU/AEI/MINECO/FEDER, UE) Ministerio de Ciencia, Investigación y Universidades. This project was funded by the Agencia Estatal de Investigación, Unidad de Excelencia María de Maeztu, ref. MDM-2017-0765. A.K. is supported by scientist grants NAG5-12460, NNX14AN10G, and 80NSSC18K0200 from GSFC. A.Z. and A.K.M. acknowledge support by Grant No. 2020750 from the United States-Israel Binational Science Foundation (BSF) and grant No. 2109066 from the United States National Science Foundation (NSF), and by the Ministry of Science & Technology, Israel. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
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