Galaxy Mergers in the Epoch of Reionization II: Major Merger-Triggered Star Formation and AGN Activities at $z =$ 4.5-8.5

Fuente: arXiv
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Autori principali: Duan, Qiao, Li, Qiong, Conselice, Christopher J., Harvey, Thomas, Austin, Duncan, Adams, Nathan J., Ferreira, Leonardo, Duncan, Kenneth J., Trussler, James, Pascalau, Robert G., Windhorst, Rogier A., Holwerda, Benne W., Broadhurst, Thomas J., Coe, Dan, Cohen, Seth H., Du, Xiaojing, Driver, Simon P., Frye, Brenda, Grogin, Norman A., Hathi, Nimish P., Jansen, Rolf A., Koekemoer, Anton M., Marshall, Madeline A., Nonino, Mario, Ortiz III, Rafael, Pirzkal, Nor, Robotham, Aaron, Ryan Jr, Russell E., Summers, Jake, D'Silva, Jordan C. J., Willmer, Christopher N. A., Yan, Haojing
Natura: Preprint
Pubblicazione: 2024
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author Duan, Qiao
Li, Qiong
Conselice, Christopher J.
Harvey, Thomas
Austin, Duncan
Adams, Nathan J.
Ferreira, Leonardo
Duncan, Kenneth J.
Trussler, James
Pascalau, Robert G.
Windhorst, Rogier A.
Holwerda, Benne W.
Broadhurst, Thomas J.
Coe, Dan
Cohen, Seth H.
Du, Xiaojing
Driver, Simon P.
Frye, Brenda
Grogin, Norman A.
Hathi, Nimish P.
Jansen, Rolf A.
Koekemoer, Anton M.
Marshall, Madeline A.
Nonino, Mario
Ortiz III, Rafael
Pirzkal, Nor
Robotham, Aaron
Ryan Jr, Russell E.
Summers, Jake
D'Silva, Jordan C. J.
Willmer, Christopher N. A.
Yan, Haojing
author_facet Duan, Qiao
Li, Qiong
Conselice, Christopher J.
Harvey, Thomas
Austin, Duncan
Adams, Nathan J.
Ferreira, Leonardo
Duncan, Kenneth J.
Trussler, James
Pascalau, Robert G.
Windhorst, Rogier A.
Holwerda, Benne W.
Broadhurst, Thomas J.
Coe, Dan
Cohen, Seth H.
Du, Xiaojing
Driver, Simon P.
Frye, Brenda
Grogin, Norman A.
Hathi, Nimish P.
Jansen, Rolf A.
Koekemoer, Anton M.
Marshall, Madeline A.
Nonino, Mario
Ortiz III, Rafael
Pirzkal, Nor
Robotham, Aaron
Ryan Jr, Russell E.
Summers, Jake
D'Silva, Jordan C. J.
Willmer, Christopher N. A.
Yan, Haojing
contents Galaxy mergers are a key driver of galaxy formation and evolution, including the triggering of AGN and star formation to a still unknown degree. We thus investigate the impact of galaxy mergers on star formation and AGN activity using a sample of 3,330 galaxies at $z = [4.5, 8.5]$ from eight JWST fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, and MACS-0416), collectively covering an unmasked area of 189 arcmin$^2$. We focuses on star formation rate (SFR) enhancement, AGN fraction, and AGN excess in major merger ($μ> 1/4$) close-pair samples, defined by $Δz < 0.3$ and projected separations $r_p < 100$ kpc, compared to non-merger samples. We find that SFR enhancement occurs only at $r_p < 20$ kpc, with values of $0.25 \pm 0.10$ dex and $0.26 \pm 0.11$ dex above the non-merger medians for $z = [4.5, 6.5]$ and $z = [6.5, 8.5]$. No other statistically significant enhancements in galaxy sSFR or stellar mass are observed at any projected separation or redshift bin. We also compare our observational results with predictions from the SC-SAM simulation and find no evidence of star formation enhancement in the simulations at any separation range. Finally, we examine the AGN fraction and AGN excess, finding that the fraction of AGNs in AGN-galaxy pairs, relative to the total AGN population, is $3.25^{+1.50}_{-1.06}$ times greater than the fraction of galaxy pairs relative to the overall galaxy population at the same redshift. We find that nearly all AGNs have a companion within 100 kpc and observe an excess AGN fraction in close-pair samples compared to non-merger samples. This excess is found to be $1.26 \pm 0.06$ and $1.34 \pm 0.06$ for AGNs identified via the inferred BPT diagram and photometric SED selection, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2411_04944
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Galaxy Mergers in the Epoch of Reionization II: Major Merger-Triggered Star Formation and AGN Activities at $z =$ 4.5-8.5
Duan, Qiao
Li, Qiong
Conselice, Christopher J.
Harvey, Thomas
Austin, Duncan
Adams, Nathan J.
Ferreira, Leonardo
Duncan, Kenneth J.
Trussler, James
Pascalau, Robert G.
Windhorst, Rogier A.
Holwerda, Benne W.
Broadhurst, Thomas J.
Coe, Dan
Cohen, Seth H.
Du, Xiaojing
Driver, Simon P.
Frye, Brenda
Grogin, Norman A.
Hathi, Nimish P.
Jansen, Rolf A.
Koekemoer, Anton M.
Marshall, Madeline A.
Nonino, Mario
Ortiz III, Rafael
Pirzkal, Nor
Robotham, Aaron
Ryan Jr, Russell E.
Summers, Jake
D'Silva, Jordan C. J.
Willmer, Christopher N. A.
Yan, Haojing
Astrophysics of Galaxies
Galaxy mergers are a key driver of galaxy formation and evolution, including the triggering of AGN and star formation to a still unknown degree. We thus investigate the impact of galaxy mergers on star formation and AGN activity using a sample of 3,330 galaxies at $z = [4.5, 8.5]$ from eight JWST fields (CEERS, JADES GOODS-S, NEP-TDF, NGDEEP, GLASS, El-Gordo, SMACS-0723, and MACS-0416), collectively covering an unmasked area of 189 arcmin$^2$. We focuses on star formation rate (SFR) enhancement, AGN fraction, and AGN excess in major merger ($μ> 1/4$) close-pair samples, defined by $Δz < 0.3$ and projected separations $r_p < 100$ kpc, compared to non-merger samples. We find that SFR enhancement occurs only at $r_p < 20$ kpc, with values of $0.25 \pm 0.10$ dex and $0.26 \pm 0.11$ dex above the non-merger medians for $z = [4.5, 6.5]$ and $z = [6.5, 8.5]$. No other statistically significant enhancements in galaxy sSFR or stellar mass are observed at any projected separation or redshift bin. We also compare our observational results with predictions from the SC-SAM simulation and find no evidence of star formation enhancement in the simulations at any separation range. Finally, we examine the AGN fraction and AGN excess, finding that the fraction of AGNs in AGN-galaxy pairs, relative to the total AGN population, is $3.25^{+1.50}_{-1.06}$ times greater than the fraction of galaxy pairs relative to the overall galaxy population at the same redshift. We find that nearly all AGNs have a companion within 100 kpc and observe an excess AGN fraction in close-pair samples compared to non-merger samples. This excess is found to be $1.26 \pm 0.06$ and $1.34 \pm 0.06$ for AGNs identified via the inferred BPT diagram and photometric SED selection, respectively.
title Galaxy Mergers in the Epoch of Reionization II: Major Merger-Triggered Star Formation and AGN Activities at $z =$ 4.5-8.5
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2411.04944