Star Formation at the Epoch of Reionization with CANUCS: The ages of stellar populations in MACS1149-JD1

• DOI: 10.48550/arxiv.2308.13288
• Publication Date: 2023-01-01
• Authors: Maruša Bradač; Victoria Strait; Lamiya Mowla; Kartheik G. Iyer; Gaël Noirot; Chris J. Willott; Gabriel Brammer; Roberto Abraham; Yoshihisa Asada; G. Desprez; Vicente Estrada-C...; Anishya Harshan; Nicholas Martis; Jasleen Matharu; Adam Muzzin; Gregor Rihtaršič; Ghassan T. E. Sar...; Marcin Sawicki
• Keywords: Grism; Gravitational microlensing; Balmer series; Stellar mass

We present measurements of stellar populations properties a z = 9.1 gravitationally lensed galaxy MACS1149-JD1 using deep JWST NIRISS slitless spectroscopy as well and NIRCam imaging from the CAnadian Unbiased Cluster Survey (CANUCS). The is split into four components. Three magnified (${\mu}$ ~ 17) star-forming components are unresolved, giving intrinsic sizes < 50pc. In addition, underlying extended component contains bulk mass, formed majority its stars 50Myr earlier than other three not site most active star formation currently. resolved photometry does confirm strong Balmer break previously seen in Spitzer. grism spectrum has been extracted for entire shows clear continuum Lyman-break, with no Lyman-${\alpha}$ detected.