An Hα view of galaxy buildup in the first 2 Gyr: Luminosity functions at z ∼ 4−6.5 from NIRCam/grism spectroscopy

Article Article scientifique Article An Hα view of galaxy buildup in the first 2 Gyr: Luminosity functions at z ∼ 4−6.5 from NIRCam/grism spectroscopy eng 2025-02-12 2025-02 author Covelo Paz Alba 0000-0002-9672-3005 402623 Département d'astronomie (ASTRO) author Giovinazzo Emma 0009-0004-3835-0089 403264 Département d'astronomie (ASTRO) author Oesch Pascal 0000-0001-5851-6649 846811 Département d'astronomie (ASTRO) author Meyer Romain 0000-0001-5492-4522 406183 Département d'astronomie (ASTRO) author Weibel Andrea Daniel 0000-0001-8928-4465 970671 Département d'astronomie (ASTRO) author Brammer Gabriel author Fudamoto Yoshinobu author Kerutt Josephine 0000-0002-1273-2300 author Lin Jamie author Matharu Jasleen author Naidu Rohan P. author Velichko Anna 0000-0001-7512-1606 402570 author Bollo Victoria 0000-0002-9842-296X author Bouwens Rychard author Chisholm John author Illingworth Garth D. author Kramarenko Ivan author Magee Daniel author Maseda Michael author Matthee Jorryt author Nelson Erica author Reddy Naveen 0000-0001-9687-4973 author Schaerer Daniel Olivier 0000-0001-7144-7182 23688 Département d'astronomie (ASTRO) author Stefanon Mauro author Xiao Mengyuan 0000-0003-1207-5344 403902 Département d'astronomie (ASTRO) 15 A178 10.1051/0004-6361/202452363 0004-6361 https://www.aanda.org/10.1051/0004-6361/202452363 The H α nebular emission line is an optimal tracer for recent star formation in galaxies. With the advent of JWST , this line has recently become observable at z > 3 for the first time. We present a catalog of 1050 H α emitters at 3.7 < z < 6.7 in the GOODS fields obtained from a blind search in JWST NIRCam/grism data. We made use of the FRESCO survey’s 124 arcmin 2 of observations in GOODS-North and GOODS-South with the F444W filter, probing H α at 4.9 < z < 6.7, and the CONGRESS survey’s 62 arcmin 2 of observations in GOODS-North with F356W, probing H α at 3.8 < z < 5.1. We found an overdensity with 98 sources at z ∼ 4.4 in GOODS-N, and confirmed previously reported overdensities at z ∼ 5.2 in GOODS-N and at z ∼ 5.4 and z ∼ 5.9 in GOODS-S. We computed the observed H α luminosity functions (LFs) in three bins centered at z ∼ 4.45, 5.30, and 6.15, which are the first such measurements at z > 3 obtained based purely on spectroscopic data, robustly tracing galaxy star formation rates (SFRs) beyond the peak of the cosmic star formation history. We compared our results with theoretical predictions from three different simulations and found good agreement at z ∼ 4 − 6. The UV LFs of this spectroscopically confirmed sample are in good agreement with pre- JWST measurements obtained with photometrically selected objects. Finally, we derived SFR functions and integrated them to compute the evolution of the cosmic SFR densities across z ∼ 4 − 6, finding values in good agreement with recent UV estimates from Lyman-break galaxies, which imply a continuous decrease in SFR density by a factor of three over z ∼ 4 to z ∼ 6. Our work shows the power of NIRCam grism observations to efficiently provide new tests for early galaxy formation models based on emission line statistics. Dewey 520 Swiss State Secretariat for Education, Research, and Innovation MB22.00072 Danmarks Grundforskningsfond DNRF140 Swiss National Science Foundation A Revolutionary New Window on the First Galaxies 207349 CH Projects 26 Département d'astronomie 12 false 870 Direction de recherche "Galaxies et cosmologie observationnelle" Astronomy & astrophysics 694 d60b33e0-be1c-4746-90c9-728cb985e8df Article (Published version) Public Article_scientifique_from_crossref.pdf 1865856 application/pdf CC BY-4.0 4a76f489f3936de5624b4a8e517e1338fd73e1926fc81085de0f67e3237a3f9a openAccess Faculté des sciences / Département d'astronomie

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An Hα view of galaxy buildup in the first 2 Gyr: Luminosity functions at z ∼ 4−6.5 from NIRCam/grism spectroscopy	Astronomy & astrophysics			2025	24	279

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Velichko, Anna