The Cosmic Telescope That Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing Model and Source Plane Analysis
Abstract
We present a strong-lensing analysis of the cluster PSZ1 G311.65-18.48, based on Hubble Space Telescope imaging, archival VLT/MUSE spectroscopy, and Chandra X-ray data. This cool-core cluster (z = 0.443) lenses the brightest lensed galaxy known, dubbed the "Sunburst Arc" (z = 2.3703), a Lyman continuum (LyC) emitting galaxy multiply imaged 12 times. We identify in this field 14 additional strongly lensed galaxies to constrain a strong-lens model and report secure spectroscopic redshifts of four of them. We measure a projected cluster core mass of M(<250 kpc) = ${2.93}_{-0.02}^{+0.01}\times {10}^{14}$ M ⊙. The two least magnified but complete images of the Sunburst Arc's source galaxy are magnified by ~13×, while the LyC clump is magnified by ~4-80×. We present time delay predictions and conclusive evidence that a discrepant clump in the Sunburst Arc, previously claimed to be a transient, is not variable, thus strengthening the hypothesis that it results from an exceptionally high magnification. A source plane reconstruction and analysis of the Sunburst Arc finds its physical size to be 1 × 2 kpc and that it is resolved in three distinct directions in the source plane, 0°, 40°, and 75° (east of north). We place an upper limit of r ≲ 50 pc on the source plane size of unresolved clumps and r ≲ 32 pc for the LyC clump. Finally, we report that the Sunburst Arc is likely in a system of two or more galaxies separated by ≲6 kpc in projection. Their interaction may drive star formation and could play a role in the mechanism responsible for the leaking LyC radiation. *Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO-15101, GO-15377, GO-15418, and GO-15949.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2022
- DOI:
- 10.3847/1538-4357/ac927a
- arXiv:
- arXiv:2209.03417
- Bibcode:
- 2022ApJ...941..203S
- Keywords:
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- Galaxy clusters;
- Strong gravitational lensing;
- Reionization;
- Star formation;
- 584;
- 1643;
- 1383;
- 1569;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 31 pages, 14 figures, 4 tables. Submitted to ApJ