DOE OSTI · 3010027
PAC in DESI. I. Galaxy stellar mass function into the 10 6 M ⊙ frontier
Abstract
The Photometric objects Around Cosmic webs (PAC) method integrates cosmological photometric and spectroscopic surveys, offering valuable insights into galaxy formation. PAC measures the excess surface density of photometric objects, $\bar{n}_2w_{{\rm {p}}}$, with specific physical properties around spectroscopic tracers. In this study, we improve the PAC method to make it more rigorous and eliminate the need for redshift bins. We apply the enhanced PAC method to the DESI Y1 BGS Bright spectroscopic sample and the deep Dark Energy Camera Legacy Survey (DECaLS) photometric sample, obtaining $\bar{n}_2w_{{\mathrm {p}}}$ measurements across the complete stellar mass range, from $10^{5.3}$ to $10^{11.5}\,{\rm M}_{\odot }$ for blue galaxies, and from $10^{6.3}$ to $10^{11.9}\,{\rm M}_{\odot }$ for red galaxies. We combine $\bar{n}_2w_{{\rm {p}}}$ with $w_{{\rm {p}}}$ measurements from the BGS sample, which is not necessarily complete in stellar mass. Assuming that galaxy bias is primarily determined by stellar mass and colour, we derive the galaxy stellar mass functions (GSMFs) down to $10^{5.3}\,{\rm M}_{\odot }$ for blue galaxies and $10^{6.3}\,{\rm M}_{\odot }$ for red galaxies, while also setting lower limits for smaller masses. The blue and red GSMFs are well described by single and double Schechter functions, respectively, with low-mass end slopes of $\alpha _{\rm {blue}}=-1.54^{+0.02}_{-0.02}$ and $\alpha _{\rm {red}}=-2.50^{+0.08}_{-0.08}$, resulting in the dominance of red galaxies below $10^{7.6}\,{\rm M}_{\odot }$. Stage-IV cosmological photometric surveys, capable of reaching 2–3 mag deeper than DECaLS, present an opportunity to explore the entire galaxy population in the local universe with PAC. This advancement allows us to address critical questions regarding the nature of dark matter, the physics of reionization, and the formation of dwarf galaxies.
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Xu, Kun [Univ. of Pennsylvania, Philadelphia, PA (United States); Durham Univ. (United Kingdom); Shanghai Jiao Tong Univ. (China)] (ORCID:0000000276973306), Jing, Y. P. [Shanghai Jiao Tong Univ. (China)], Cole, S. [Durham Univ. (United Kingdom)], Frenk, C. S. [Durham Univ. (United Kingdom)], Bose, S. [Durham Univ. (United Kingdom)] (ORCID:0000000209745266), Elbers, W. [Durham Univ. (United Kingdom)] (ORCID:0000000222076108), Wang, W. [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000257627571), Wang, Yirong [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000332033299), Moore, S. [Durham Univ. (United Kingdom)], Aguilar, J. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Ahlen, S. [Boston Univ., MA (United States)], Bianchi, D. [Univ. degli Studi di Milano (Italy); Istituto Nazionale di Astrofisica (INAF) (Italy)], Brooks, D. [Univ. College London (United Kingdom)], Claybaugh, T. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], de la Macorra, A. [Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)], Dey, Arjun [National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)], Forero-Romero, J. E. [Univ. of the Andes (Colombia)], Gaztañaga, E. [Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona (Spain); Univ. of Portsmouth (United Kingdom); Institute of Space Sciences, Barcelona (Spain)], Gontcho, S. Gontcho A [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Gutierrez, G. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)], Honscheid, K. [The Ohio State Univ., Columbus, OH (United States)], Ishak, M. [Univ. of Texas at Dallas, Richardson, TX (United States)], Kisner, T [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Koposov, S. E. [Univ. of Edinburgh, Scotland (United Kingdom); Univ. of Cambridge (United Kingdom)], Landriau, M. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Le Guillou, L. [Sorbonne Univ., Paris (France)], Miquel, R. [Univ. Autonoma de Barcelona (Spain). Inst. Catalana de Recerca i Estudis Avancats (ICREA) and Inst. de Fisica d'Altes Energies (IFAE); Barcelona Institute of Science and Technology (BIST) (Spain)], Moustakas, J. [Siena College, Loudonville, NY (United States)], Poppett, C. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)], Prada, F. [Spanish National Research Council (CSIC) (Spain)], Pérez-Ràfols, I. [Univ. Politecnica de Catalunya (Spain)], Rossi, G. [Sejong Univ., Seoul (Korea, Republic of)], Sanchez, E. [Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain)], Sprayberry, D. [National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)], Tarlé, G. [Univ. of Michigan, Ann Arbor, MI (United States)], Weaver, B. A. [National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)], Zou, H. [Chinese Academy of Sciences (CAS), Beijing (China)]. 2025-05-13. PAC in DESI. I. Galaxy stellar mass function into the 10 6 M ⊙ frontier. https://doi.org/10.1093/mnras%2Fstaf782
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