Tracing the Evolution of the Cool Gas in CGM and IGM Environments through Mg <scp>ii</scp> Absorption from Redshift <i>z</i> = 0.75 to <i>z</i> = 1.65 Using DESI-Y1 Data
Abstract We present a measurement of the mean absorption of cool gas traced by Mg ii ( λλ 2796, 2803) around emission line galaxies (ELGs), spanning spatial scales from 20 kpc to 10 Mpc. The measurement is based on crossmatching the positions ELGs at z = 0.75–1.65 and the metal absorption in the spectra of background quasars with data provided by the Year 1 sample of the Dark Energy Spectroscopic Instrument. The ELGs are divided into two redshift intervals: 0.75 < z < 1.0 and 1.0 < z < 1.65. We find that the composite quasar spectra constructed by stacking the ELG-QSO pairs evolve with redshift, with z > 1 having a systematically higher signal of Mg ii absorption. Within 1 Mpc, the covering fraction of the cool gas at z > 1 is higher than that of z < 1. The enhancement becomes less apparent especially if the projected distance r p > 1 Mpc. ELGs with higher stellar mass and star formation rate (SFR) yield higher clustering of Mg ii absorbers at z < 1. For z > 1, the covering fractions with different SFRs show little difference. The higher Mg ii absorption at higher redshift supports the observations of higher star formation at cosmic noon. Converting the Mg ii absorbers to unsaturated Si ii , our estimate indicates that the metal abundance of Si ii ranges from 0.7 to 1.2 × 10 −6 from z = 0.9 to 1.3. The growth of low-ionization metal abundance strongly suggests a metal-enriched circumgalactic medium and an increased presence of cool gas in the intergalactic medium toward higher redshifts.
Authors
- Xuanyi Wu (ORCID: https://orcid.org/0000-0002-0744-8022)
- Ting-Wen Lan (ORCID: https://orcid.org/0000-0001-8857-7020)
- Abhijeet Anand (ORCID: https://orcid.org/0000-0003-2923-1585)
- D. Brooks (ORCID: https://orcid.org/0000-0002-8458-5047)
- A. Lambert
- S. Juneau (ORCID: https://orcid.org/0000-0002-0000-2394)
- Jeffrey A. Newman (ORCID: https://orcid.org/0000-0001-8684-2222)
- Gregory Tarlé (ORCID: https://orcid.org/0000-0003-1704-0781)
- Laurent Le Guillou (ORCID: https://orcid.org/0000-0001-7178-8868)
- David Sprayberry (ORCID: https://orcid.org/0000-0001-7583-6441)
- David J. Schlegel (ORCID: https://orcid.org/0000-0002-5042-5088)
- Axel de la Macorra (ORCID: https://orcid.org/0000-0002-1769-1640)
- Martin Landriau (ORCID: https://orcid.org/0000-0003-1838-8528)
- Simone Ferraro (ORCID: https://orcid.org/0000-0003-4992-7854)
- Siwei Zou (ORCID: https://orcid.org/0000-0002-3983-6484)
- Marc Manera (ORCID: https://orcid.org/0000-0003-4962-8934)
- J. Aguilar (ORCID: https://orcid.org/0000-0003-0822-452X)
- Eusebio Sanchez (ORCID: https://orcid.org/0000-0002-9646-8198)
- Satya Gontcho A Gontcho (ORCID: https://orcid.org/0000-0003-3142-233X)
- K. Honscheid (ORCID: https://orcid.org/0000-0002-6550-2023)
- M. Siudek (ORCID: https://orcid.org/0000-0002-2949-2155)
- Zheng Cai (ORCID: https://orcid.org/0000-0001-8467-6478)
- J. E. Forero-Romero (ORCID: https://orcid.org/0000-0002-2890-3725)
- Steven P. Ahlen (ORCID: https://orcid.org/0000-0001-6098-7247)
- Aaron Meisner (ORCID: https://orcid.org/0000-0002-1125-7384)
- R. Miquel (ORCID: https://orcid.org/0000-0002-6610-4836)
- Theodore S. Kisner (ORCID: https://orcid.org/0000-0003-3510-7134)
- Biprateep Dey (ORCID: https://orcid.org/0000-0002-5665-7912)
- R. Kehoe (ORCID: https://orcid.org/0000-0002-7101-697X)
- John Moustakas (ORCID: https://orcid.org/0000-0002-2733-4559)
- Zihao Li (ORCID: https://orcid.org/0000-0001-5951-459X)
- Hu Zou (ORCID: https://orcid.org/0000-0002-6684-3997)
- Graziano Rossi
- P. Doel (ORCID: https://orcid.org/0000-0002-6397-4457)
- M. Schubnell
- T. Claybaugh
- B. A. Weaver
- F. Prada (ORCID: https://orcid.org/0000-0001-7145-8674)
Institutions
- Boston University (US)
- Institució Catalana de Recerca i Estudis Avançats (ES)
- Universidad Complutense de Madrid (ES)
- Universitat Autònoma de Barcelona (ES)
- Centre National de la Recherche Scientifique (FR)
- Institute of Space Sciences (ES)
- Lawrence Berkeley National Laboratory (US)
- Universidad de Los Andes (CO)
- National Taiwan University (TW)
- University of Pittsburgh (US)
- Southern Methodist University (US)
- Institute for High Energy Physics (ES)
- Chinese Academy of Sciences (CN)
- University of Michigan (US)
- Sejong University (KR)
- Sorbonne Université (FR)
- Laboratoire de Physique Nucléaire et de Hautes Énergies (FR)
- Institut National de Physique Nucléaire et de Physique des Particules (FR)
- Community Science and Data Center (US)
- Peng Cheng Laboratory (CN)
- NSF NOIRLab (US)
- Instituto de Astrofísica de Andalucía (ES)
- National Astronomical Observatories (CN)
- Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES)
- University College London (GB)
- The Ohio State University (US)
- Universidad Nacional Autónoma de México (MX)
- Siena College (US)
- University of California, Berkeley (US)
- Tsinghua University (CN)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-04-18
- DOI
- https://doi.org/10.3847/1538-4357/adb28a
- Citations
- 4
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 4.62
Funders
- National Science Foundation
- U.S. Department of Energy
- Gordon and Betty Moore Foundation
- National Natural Science Foundation of China
- Tsinghua University
- Ministry of Education, India
- Ministerio de Ciencia e Innovación
- National Taiwan University
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives
- National Science and Technology Council
- Office of Science
- Science and Technology Facilities Council
- Division of Astronomical Sciences