Starbursts with suppressed velocity dispersion revealed in a forming cluster at z & x2006;& x2004;=& x2004;& x2006;2.51
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Starbursts with suppressed velocity dispersion revealed in a forming cluster at z & x2006;& x2004;=& x2004;& x2006;2.51. / Xiao, M. -Y.; Wang, T.; Elbaz, D.; Iono, D.; Lu, X.; Bing, L. -J.; Daddi, E.; Magnelli, B.; Gomez-Guijarro, C.; Bournaud, F.; Gu, Q. -S.; Jin, S.; Valentino, F.; Zanella, A.; Gobat, R.; Martin, S.; Brammer, G.; Kohno, K.; Schreiber, C.; Ciesla, L.; Yu, X. -L.; Okumura, K.
In: Astronomy & Astrophysics, Vol. 664, A63, 04.08.2022.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Starbursts with suppressed velocity dispersion revealed in a forming cluster at z & x2006;& x2004;=& x2004;& x2006;2.51
AU - Xiao, M. -Y.
AU - Wang, T.
AU - Elbaz, D.
AU - Iono, D.
AU - Lu, X.
AU - Bing, L. -J.
AU - Daddi, E.
AU - Magnelli, B.
AU - Gomez-Guijarro, C.
AU - Bournaud, F.
AU - Gu, Q. -S.
AU - Jin, S.
AU - Valentino, F.
AU - Zanella, A.
AU - Gobat, R.
AU - Martin, S.
AU - Brammer, G.
AU - Kohno, K.
AU - Schreiber, C.
AU - Ciesla, L.
AU - Yu, X. -L.
AU - Okumura, K.
PY - 2022/8/4
Y1 - 2022/8/4
N2 - One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early Universe via starbursts. However, the role of dense environments and their detailed physical mechanisms in triggering starburst activities remain unknown. Here we report spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO J & x2004;=& x2004;3-2 emission line, with a resolution of about 2.5 kpc, toward a forming galaxy cluster core with starburst galaxies at z & x2004;=& x2004;2.51. In contrast to starburst galaxies in the field often associated with galaxy mergers or highly turbulent gaseous disks, our observations show that the two starbursts in the cluster exhibit dynamically cold (rotation-dominated) gas-rich disks. Their gas disks have extremely low velocity dispersion (sigma(0)& x2004;similar to & x2004;20-30 km s(-1)), which is three times lower than their field counterparts at similar redshifts. The high gas fraction and suppressed velocity dispersion yield gravitationally unstable gas disks, which enables highly efficient star formation. The suppressed velocity dispersion, likely induced by the accretion of corotating and coplanar cold gas, might serve as an essential avenue to trigger starbursts in massive halos at high redshifts.
AB - One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early Universe via starbursts. However, the role of dense environments and their detailed physical mechanisms in triggering starburst activities remain unknown. Here we report spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO J & x2004;=& x2004;3-2 emission line, with a resolution of about 2.5 kpc, toward a forming galaxy cluster core with starburst galaxies at z & x2004;=& x2004;2.51. In contrast to starburst galaxies in the field often associated with galaxy mergers or highly turbulent gaseous disks, our observations show that the two starbursts in the cluster exhibit dynamically cold (rotation-dominated) gas-rich disks. Their gas disks have extremely low velocity dispersion (sigma(0)& x2004;similar to & x2004;20-30 km s(-1)), which is three times lower than their field counterparts at similar redshifts. The high gas fraction and suppressed velocity dispersion yield gravitationally unstable gas disks, which enables highly efficient star formation. The suppressed velocity dispersion, likely induced by the accretion of corotating and coplanar cold gas, might serve as an essential avenue to trigger starbursts in massive halos at high redshifts.
KW - galaxies
KW - formation
KW - high-redshift
KW - clusters
KW - general
KW - evolution
KW - ISM
KW - COSMIC STAR-FORMATION
KW - MOLECULAR GAS MASSES
KW - INTERSTELLAR-MEDIUM
KW - MAIN-SEQUENCE
KW - SPECTROSCOPIC SURVEY
KW - SCALING RELATIONS
KW - DUSTY STARBURSTS
KW - MASSIVE GALAXIES
KW - ROTATION CURVES
KW - DEPLETION TIME
U2 - 10.1051/0004-6361/202142843
DO - 10.1051/0004-6361/202142843
M3 - Journal article
VL - 664
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
SN - 0004-6361
M1 - A63
ER -
ID: 317088143