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arXiv · 2203.11957

COOL-LAMPS II. Characterizing the Size and Star Formation History of a Bright Strongly Lensed Early-Type Galaxy at Redshift 1.02

Ezra Sukay·Gourav Khullar·Michael D. Gladders·Keren Sharon·Guillaume Mahler·Kate Napier·Lindsey E. Bleem·Håkon Dahle·Michael K. Florian·Katya Gozman·Jason J. Lin·Michael N. Martinez·Owen S. Matthews Acuña·Elisabeth Medina·Kaiya Merz·Jorge A. Sanchez·Emily E. Sisco·Daniel J. Kavin Stein·Kiyan Tavangar·Katherine E. Whitaker
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Abstract

We present COOL J1323+0343, an early-type galaxy at $z = 1.0153 \pm 0.0006$, strongly lensed by a cluster of galaxies at z = $z = 0.353 \pm 0.001$. This object was originally imaged by DECaLS and noted as a gravitational lens by COOL-LAMPS, a collaboration initiated to find strong-lensing systems in recent public optical imaging data, and confirmed with follow-up data. With ground-based grzH imaging and optical spectroscopy from the Las Campanas Observatory and the Nordic Optical Telescope, we derive a stellar mass, metallicity, and star-formation history from stellar-population synthesis modeling. The lens modeling implies a total magnification of $\mu \sim $113. The median remnant stellar mass in the source plane is M$_* \sim 10.63$ $M_\odot$ and the median star-formation rate in the source plane is SFR $\sim 1.55 \times 10^{-3}$ M$_\odot$ yr$^{-1}$ (log sSFR = -13.4 yr$^{-1}$) in the youngest two age bins (0-100 Myr), closest to the epoch of observation. Our measurements place COOL J1323+0343 below the characteristic mass of the stellar mass function, making it an especially compelling target that could help clarify how intermediate mass quiescent galaxies evolve. We reconstruct COOL J1323+0343 in the source plane and fit its light profile. This object is below the expected size-evolution of early-type galaxy at this mass with an effective radius r$_e \sim$ 0.5 kpc. This extraordinarily magnified and bright lensed early-type galaxy offers an exciting opportunity to study the morphology and star formation history of an intermediate mass early-type galaxy in detail at $z \sim $1 .

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Ezra Sukay, Gourav Khullar, Michael D. Gladders, Keren Sharon, Guillaume Mahler, Kate Napier, Lindsey E. Bleem, Håkon Dahle, Michael K. Florian, Katya Gozman, Jason J. Lin, Michael N. Martinez, Owen S. Matthews Acuña, Elisabeth Medina, Kaiya Merz, Jorge A. Sanchez, Emily E. Sisco, Daniel J. Kavin Stein, Kiyan Tavangar, Katherine E. Whitaker. 2022-03-22. COOL-LAMPS II. Characterizing the Size and Star Formation History of a Bright Strongly Lensed Early-Type Galaxy at Redshift 1.02. https://doi.org/10.3847/1538-4357/ac9974

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