RIOJA. Complex Dusty Starbursts in a Major Merger B14-65666 at z=7.15
Artikel i vetenskaplig tidskrift, 2025
We present JWST NIRCam imaging of B14-65666 ("Big Three Dragons"), a bright Lyman-break galaxy system (MUV = -22.5 mag) at z = 7.15. The high angular resolution of NIRCam reveals the complex morphology of two galaxy components: galaxy E has a compact core (E-core), surrounded by diffuse, extended, rest-frame optical emission, which is likely to be tidal tails; and galaxy W has a clumpy and elongated morphology with a blue UV slope (beta UV = -2.2 +/- 0.1). The flux excess, F356W - F444W, peaks at the E-core ( 1.05-0.09+0.08 mag), tracing the presence of strong [O iii] lambda lambda 4960,5008 emission. Atacama Large Millimeter/submillimeter Array archival data show that the bluer galaxy W is brighter in dust continua than the redder galaxy E, while the tails are bright in [O iii] 88 mu m. The UV/optical and submillimeter spectral energy distribution (SED) fitting confirms that B14-65666 is a major merger in a starburst phase as derived from the stellar mass ratio (3:1 to 2:1) and the star formation rate, similar or equal to 1 dex higher than the star formation main sequence at the same redshift. Galaxy E is a dusty (AV = 1.2 +/- 0.1 mag) starburst with a possible high dust temperature (>= 63-68 K). Galaxy W would have a low dust temperature (<= 27-33 K) or patchy stellar-and-dust geometry, as suggested by the IR excess and beta UV diagram. The high optical-to-far-IR [O iii] line ratio of the E-core shows its lower gas-phase metallicity (similar or equal to 0.2-0.4 Z circle dot) than galaxy W. These results agree with a scenario where major mergers disturb morphology and induce nuclear dusty starbursts triggered by less-enriched inflows. B14-65666 shows a picture of complex stellar buildup processes during major mergers in the epoch of reionization.
Star-forming galaxy
Stellar feedback
Luminosity function
Ionized-gas
Mass-metallicity relation
Infrared-emission
Lyman-break galaxy
High-redshift
Line ratios
Big 3 dragons
Författare
Yuma Sugahara
Waseda University
National Astronomical Observatory of Japan
Javier Álvarez-Márquez
Consejo Superior de Investigaciones Científicas (CSIC)
Takuya Hashimoto
University of Tsukuba
Luis Colina
Consejo Superior de Investigaciones Científicas (CSIC)
Akio K. Inoue
Waseda University
Luca Constantin
Consejo Superior de Investigaciones Científicas (CSIC)
Yoshinobu Fudamoto
Chiba University
National Astronomical Observatory of Japan
Waseda University
Ken Mawatari
University of Tsukuba
Yi W. Ren
Waseda University
Santiago Arribas
Consejo Superior de Investigaciones Científicas (CSIC)
Tom Bakx
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Carmen Blanco-Prieto
Consejo Superior de Investigaciones Científicas (CSIC)
Daniel Ceverino
Universidad Autonoma de Madrid (UAM)
Alejandro Crespo Gomez
Consejo Superior de Investigaciones Científicas (CSIC)
Masato Hagimoto
Nagoya University
Takeshi Hashigaya
Kyoto University
Rui Marques-Chaves
Université de Genève
Hiroshi Matsuo
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
Yurina Nakazato
University of Tokyo
Miguel Pereira-Santaella
Consejo Superior de Investigaciones Científicas (CSIC)
Yoichi Tamura
Nagoya University
Mitsutaka Usui
University of Tsukuba
Naoki Yoshida
University of Tokyo
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 981 2 135Ämneskategorier (SSIF 2025)
Astronomi, astrofysik och kosmologi
DOI
10.3847/1538-4357/adb02a