TY - JOUR

T1 - COALAS

T2 - I. ATCA CO(1-0) survey and luminosity function in the Spiderweb protocluster at z=2.16

AU - Jin, S.

AU - Dannerbauer, H.

AU - Emonts, B.

AU - Serra, P.

AU - Lagos, C. D. P.

AU - Thomson, A. P.

AU - Bassini, L.

AU - Lehnert, M.

AU - Allison, J. R.

AU - Champagne, J. B.

AU - Indermuehle, B.

AU - Norris, R. P.

AU - Seymour, N.

AU - Shimakawa, R.

AU - Casey, C. M.

AU - De Breuck, C.

AU - Drouart, G.

AU - Hatch, N.

AU - Kodama, T.

AU - Koyama, Y.

AU - Macgregor, P.

AU - Miley, G.

AU - Overzier, R.

AU - Perez-Martinez, J. M.

AU - Rodriguez-Espinosa, J. M.

AU - Roettgering, H.

AU - Sanchez Portal, M.

AU - Ziegler, B.

PY - 2021/8/4

Y1 - 2021/8/4

N2 - We report a detailed CO(1 0) survey of a galaxy protocluster field at z = 2:16, based on 475 h of observations with the Australia Telescope Compact Array. We constructed a large mosaic of 13 individual pointings, covering an area of 21 arcmin2 and similar to 6500 km s 1 range in velocity. We obtained a robust sample of 46 CO(1 0) detections spanning z = 2:09 2:22, constituting the largest sample of molecular gas measurements in protoclusters to date. The CO emitters show an overdensity at z = 2:12 2:21, suggesting a galaxy super-protocluster or a protocluster connected to large-scale filaments of similar to 120 cMpc in size. We find that 90% of CO emitters have distances >0:05 40 to the center galaxy, indicating that small area surveys would miss the majority of gas reservoirs in similar structures. Half of the CO emitters have velocities larger than escape velocities, which appears gravitationally unbound to the cluster core. These unbound sources are barely found within the R200 radius around the center, which is consistent with a picture in which the cluster core is collapsed while outer regions are still in formation. Compared to other protoclusters, this structure contains a relatively higher number of CO emitters with relatively narrow line widths and high luminosities, indicating galaxy mergers. We used these CO emitters to place the first constraint on the CO luminosity function and molecular gas density in an overdense environment. The amplitude of the CO luminosity function is 1.6 similar to 0.5 orders of magnitude higher than that observed for field galaxy samples at z similar to 2, and one order of magnitude higher than predictions for galaxy protoclusters from semi-analytical SHARK models. We derive a high molecular gas density of 0:6 1:3 similar to 109 M fi cMpc 3 for this structure, which is consistent with predictions for cold gas density of massive structures from hydro-dynamical DIANOGA simulations.

AB - We report a detailed CO(1 0) survey of a galaxy protocluster field at z = 2:16, based on 475 h of observations with the Australia Telescope Compact Array. We constructed a large mosaic of 13 individual pointings, covering an area of 21 arcmin2 and similar to 6500 km s 1 range in velocity. We obtained a robust sample of 46 CO(1 0) detections spanning z = 2:09 2:22, constituting the largest sample of molecular gas measurements in protoclusters to date. The CO emitters show an overdensity at z = 2:12 2:21, suggesting a galaxy super-protocluster or a protocluster connected to large-scale filaments of similar to 120 cMpc in size. We find that 90% of CO emitters have distances >0:05 40 to the center galaxy, indicating that small area surveys would miss the majority of gas reservoirs in similar structures. Half of the CO emitters have velocities larger than escape velocities, which appears gravitationally unbound to the cluster core. These unbound sources are barely found within the R200 radius around the center, which is consistent with a picture in which the cluster core is collapsed while outer regions are still in formation. Compared to other protoclusters, this structure contains a relatively higher number of CO emitters with relatively narrow line widths and high luminosities, indicating galaxy mergers. We used these CO emitters to place the first constraint on the CO luminosity function and molecular gas density in an overdense environment. The amplitude of the CO luminosity function is 1.6 similar to 0.5 orders of magnitude higher than that observed for field galaxy samples at z similar to 2, and one order of magnitude higher than predictions for galaxy protoclusters from semi-analytical SHARK models. We derive a high molecular gas density of 0:6 1:3 similar to 109 M fi cMpc 3 for this structure, which is consistent with predictions for cold gas density of massive structures from hydro-dynamical DIANOGA simulations.

KW - Galaxy: evolution

KW - galaxies: formation

KW - galaxies: clusters: individual: Spiderweb

KW - galaxies: high-redshift

KW - galaxies: ISM

KW - ISM: molecules

KW - ALMA SPECTROSCOPIC SURVEY

KW - PROBE WMAP OBSERVATIONS

KW - MASSIVE CLUSTER GALAXY

KW - MOLECULAR GAS CONTENT

KW - STAR-FORMATION

KW - HIGH-REDSHIFT

KW - PROTO-CLUSTER

KW - CO EMISSION

KW - STARBURST GALAXIES

KW - DUSTY STARBURSTS

U2 - 10.1051/0004-6361/202040232

DO - 10.1051/0004-6361/202040232

M3 - Journal article

VL - 652

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

M1 - A11

ER -