The BoRG-JWST Survey: Abundance and Mass-to-light Ratio of Luminous z = 7–9 Galaxies from Independent Sight Lines with NIRSpec

• DOI: 10.3847/1538-4357/adc67d
• Publication Date: 2025-05-15T11:08:21Z
• Authors: Sofía Rojas-Ruiz; Micaela Bagley; Guido Roberts-Bor...; Tommaso Treu; Steven L. Finkels...; Takahiro Morishita; Nicha Leethochawalit; Charlotte Mason; Eduardo Bañados; Michele Trenti; Massimo Stiavelli; L. Y. Aaron Yung; Pablo Arrabal Haro; Rachel S. Somerville; Christian Soto
• Keywords: Luminous intensity

Abstract We present new results on the rest-frame UV luminosity function (UVLF) and stellar mass-to-light ( M / L ) ratio of bright ≲ −20 mag) spectroscopically confirmed galaxies at z = 7–9 derived from BoRG-JWST survey, a unique data set NIRSpec prism follow-up Hubble Space Telescope (HST)–selected sources random-pointing imaging. By selecting over 300 independent sight lines, survey minimizes cosmic variance, ensuring statistically robust sample bright-galaxy population during epoch reionization. The are used to constrain, for first time, end UVLF eight fields. find that is higher than found using imaging JWST legacy fields, suggesting latter may be significantly affected by thus reducing tension with recent findings &gt; 10 comparable models invoking little dust attenuation bursty star formation. Additionally, we use galaxies’ spectra infer their masses ratios relative other HST studies. show mass scales almost linearly <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mo>*</mml:mo> </mml:mrow> </mml:msub> <mml:mo>∝</mml:mo> <mml:msubsup> <mml:mi>L</mml:mi> <mml:mi mathvariant="normal">UV</mml:mi> <mml:mn>0.85</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.12</mml:mn> </mml:msubsup> </mml:math> ), albeit large (∼0.5 dex) intrinsic scatter, consistent stochastic bursts formation in early galaxy