_version_ 1866908990563155968
author Fox, Ori D.
Rest, Armin
Pierel, Justin D. R.
Coulter, David A.
Casey, Caitlin M.
Kartaltepe, Jeyhan S.
Akins, Hollis B.
Franco, Maximilien
Engesser, Mike
Larison, Conor
Moriya, Takashi J.
Quimby, Robert M.
Shuntov, Marko
Siebert, Matthew R.
DeCoursey, Christa
Angulo, Rodrigo
DerKacy, James M.
Drakos, Nicole E.
Egami, Eiichi
Finkelstein, Steven L.
Flayhart, Carter
Fujimoto, Seiji
Gonzalez, Estefania Padilla
Griggio, Massimo
Harish, Santosh
Ilbert, Olivier
Inayoshi, Kohei
Koekemoer, Anton M.
Kokorev, Vasily
Laigle, Clotilde
Lambrides, Erini
Larson, Rebecca L.
Li, Xiaolong
Liu, Daizhong
Magdis, Georgios E.
McCleary, Jacqueline E.
McCracken, Henry J.
McMahon, Nicolas
McKinney, Jed
Moore, Thomas
Paquereau, Louise
Rhodes, Jason
Robertson, Brant E.
Sanders, David B.
Sanjaripour, Sogol
Shukawa, Koji
Strolger, Louis-Gregory
Toft, Sune
Wang, Qinan
Williams, Robert E.
Zenati, Yossef
author_facet Fox, Ori D.
Rest, Armin
Pierel, Justin D. R.
Coulter, David A.
Casey, Caitlin M.
Kartaltepe, Jeyhan S.
Akins, Hollis B.
Franco, Maximilien
Engesser, Mike
Larison, Conor
Moriya, Takashi J.
Quimby, Robert M.
Shuntov, Marko
Siebert, Matthew R.
DeCoursey, Christa
Angulo, Rodrigo
DerKacy, James M.
Drakos, Nicole E.
Egami, Eiichi
Finkelstein, Steven L.
Flayhart, Carter
Fujimoto, Seiji
Gonzalez, Estefania Padilla
Griggio, Massimo
Harish, Santosh
Ilbert, Olivier
Inayoshi, Kohei
Koekemoer, Anton M.
Kokorev, Vasily
Laigle, Clotilde
Lambrides, Erini
Larson, Rebecca L.
Li, Xiaolong
Liu, Daizhong
Magdis, Georgios E.
McCleary, Jacqueline E.
McCracken, Henry J.
McMahon, Nicolas
McKinney, Jed
Moore, Thomas
Paquereau, Louise
Rhodes, Jason
Robertson, Brant E.
Sanders, David B.
Sanjaripour, Sogol
Shukawa, Koji
Strolger, Louis-Gregory
Toft, Sune
Wang, Qinan
Williams, Robert E.
Zenati, Yossef
contents Transient astronomy in the early Universe (z > 2) remains largely unexplored, lying beyond the rest-frame optical spectroscopic reach of most current observatories. Yet this regime promises transformative insights, with high-redshift transients providing direct access to the early Universe and enabling studies of how stellar populations and cosmology evolve over cosmic time. JWST is uniquely equipped to probe these redshifts efficiently in the rest-frame optical and near-IR. We present results from an initial pathfinder search, covering an area of ~133 arcmin^2 (~0.037 deg^2) independently imaged by the PRIMER and COSMOS-Web (hereafter COSMOS) extragalactic surveys. Although neither program was designed for time-domain astronomy, combining their data results in difference images separated by roughly one year, leading to the discovery of 68 supernovae (SNe) with host photometric redshifts reaching z < 5. For most SNe, only a single epoch is available, but the combination of host redshift, classification, color, and magnitude enables us to prioritize candidates for detailed photometric and spectroscopic follow-up. Among the most notable sources are a relatively bright, blue CCSN at z > 3 (SN 2023aeab) and a young, normal SN Ia at z > 2 (SN 2023aeax). The sample distribution highlights the increasing likelihood that a wide-area JWST program can uncover younger, bluer, and potentially more extreme explosions. While this pathfinder effort is limited in cadence and number of filters, it demonstrates the strong potential of a dedicated, well-planned time-domain survey with JWST to obtain the sample sizes and rate measurements needed to chart SN populations deep into the early Universe.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08931
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Expanding the High-z Supernova Frontier: "Wide-Area" JWST Discoveries from the First Two Years of COSMOS-Web
Fox, Ori D.
Rest, Armin
Pierel, Justin D. R.
Coulter, David A.
Casey, Caitlin M.
Kartaltepe, Jeyhan S.
Akins, Hollis B.
Franco, Maximilien
Engesser, Mike
Larison, Conor
Moriya, Takashi J.
Quimby, Robert M.
Shuntov, Marko
Siebert, Matthew R.
DeCoursey, Christa
Angulo, Rodrigo
DerKacy, James M.
Drakos, Nicole E.
Egami, Eiichi
Finkelstein, Steven L.
Flayhart, Carter
Fujimoto, Seiji
Gonzalez, Estefania Padilla
Griggio, Massimo
Harish, Santosh
Ilbert, Olivier
Inayoshi, Kohei
Koekemoer, Anton M.
Kokorev, Vasily
Laigle, Clotilde
Lambrides, Erini
Larson, Rebecca L.
Li, Xiaolong
Liu, Daizhong
Magdis, Georgios E.
McCleary, Jacqueline E.
McCracken, Henry J.
McMahon, Nicolas
McKinney, Jed
Moore, Thomas
Paquereau, Louise
Rhodes, Jason
Robertson, Brant E.
Sanders, David B.
Sanjaripour, Sogol
Shukawa, Koji
Strolger, Louis-Gregory
Toft, Sune
Wang, Qinan
Williams, Robert E.
Zenati, Yossef
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
Transient astronomy in the early Universe (z > 2) remains largely unexplored, lying beyond the rest-frame optical spectroscopic reach of most current observatories. Yet this regime promises transformative insights, with high-redshift transients providing direct access to the early Universe and enabling studies of how stellar populations and cosmology evolve over cosmic time. JWST is uniquely equipped to probe these redshifts efficiently in the rest-frame optical and near-IR. We present results from an initial pathfinder search, covering an area of ~133 arcmin^2 (~0.037 deg^2) independently imaged by the PRIMER and COSMOS-Web (hereafter COSMOS) extragalactic surveys. Although neither program was designed for time-domain astronomy, combining their data results in difference images separated by roughly one year, leading to the discovery of 68 supernovae (SNe) with host photometric redshifts reaching z < 5. For most SNe, only a single epoch is available, but the combination of host redshift, classification, color, and magnitude enables us to prioritize candidates for detailed photometric and spectroscopic follow-up. Among the most notable sources are a relatively bright, blue CCSN at z > 3 (SN 2023aeab) and a young, normal SN Ia at z > 2 (SN 2023aeax). The sample distribution highlights the increasing likelihood that a wide-area JWST program can uncover younger, bluer, and potentially more extreme explosions. While this pathfinder effort is limited in cadence and number of filters, it demonstrates the strong potential of a dedicated, well-planned time-domain survey with JWST to obtain the sample sizes and rate measurements needed to chart SN populations deep into the early Universe.
title Expanding the High-z Supernova Frontier: "Wide-Area" JWST Discoveries from the First Two Years of COSMOS-Web
topic High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2601.08931