TY - JOUR
T1 - Megaparsec-scale structure around the protocluster core SPT2349-56 at z=4.3
AU - Hill, Ryley
AU - Chapman, Scott
AU - Scott, Douglas
AU - Apostolovski, Yordanka
AU - Aravena, Manuel
AU - Bethermin, Matthieu
AU - Bradford, C. M.
AU - Canning, Rebecca E. A.
AU - De Breuck, Carlos
AU - Dong, Chenxing
AU - Gonzalez, Anthony
AU - Greve, Thomas R.
AU - Hayward, Christopher C.
AU - Hezaveh, Yashar
AU - Litke, Katrina
AU - Malkan, Matt
AU - Marrone, Daniel P.
AU - Phadke, Kedar
AU - Reuter, Cassie
AU - Rotermund, Kaja
AU - Spilker, Justin
AU - Vieira, Joaquin D.
AU - Weiss, Axel
PY - 2020/7/2
Y1 - 2020/7/2
N2 - We present an extensive ALMA spectroscopic follow-up programme of the z = 4.3 structure SPT2349-56, one of the most actively star-forming protocluster cores known, to identify additional members using their [C] 158 mu m and CO(4-3) lines. In addition to robustly detecting the 14 previously published galaxies in this structure, we identify a further 15 associated galaxies at z = 4.3, resolving 55 +/- 5 per cent of the 870 mu m flux density at 0.5 arcsec resolution compared to 21 arcsec single-dish data. These galaxies are distributed into a central core containing 23 galaxies extending out to 300 kpc in diameter, and a northern extension, offset from the core by 400 kpc, containing three galaxies. We discovered three additional galaxies in a red Herschel-SPIRE source 1.5 Mpc from the main structure, suggesting the existence of many other sources at the same redshift as SPT2349-56 that are not yet detected in the limited coverage of our data. An analysis of the velocity distribution of the central galaxies indicates that this region may be virialized with a mass of (9 +/- 5) x 10(12) M-circle dot, while the two offset galaxy groups are about 30 and 60 per cent less massive and show significant velocity offsets from the central group. We calculate the [CI] and far-infrared number counts, and find evidence for a break in the [CII] luminosity function. We estimate the average SFR density within the region of SPT2349-56 containing single-dish emission (a proper diameter of 720 kpc), assuming spherical symmetry, to be roughly 4 x 10(4) M-circle dot yr(-1) Mpc(-3); this may be an order of magnitude greater than the most extreme examples seen in simulations.
AB - We present an extensive ALMA spectroscopic follow-up programme of the z = 4.3 structure SPT2349-56, one of the most actively star-forming protocluster cores known, to identify additional members using their [C] 158 mu m and CO(4-3) lines. In addition to robustly detecting the 14 previously published galaxies in this structure, we identify a further 15 associated galaxies at z = 4.3, resolving 55 +/- 5 per cent of the 870 mu m flux density at 0.5 arcsec resolution compared to 21 arcsec single-dish data. These galaxies are distributed into a central core containing 23 galaxies extending out to 300 kpc in diameter, and a northern extension, offset from the core by 400 kpc, containing three galaxies. We discovered three additional galaxies in a red Herschel-SPIRE source 1.5 Mpc from the main structure, suggesting the existence of many other sources at the same redshift as SPT2349-56 that are not yet detected in the limited coverage of our data. An analysis of the velocity distribution of the central galaxies indicates that this region may be virialized with a mass of (9 +/- 5) x 10(12) M-circle dot, while the two offset galaxy groups are about 30 and 60 per cent less massive and show significant velocity offsets from the central group. We calculate the [CI] and far-infrared number counts, and find evidence for a break in the [CII] luminosity function. We estimate the average SFR density within the region of SPT2349-56 containing single-dish emission (a proper diameter of 720 kpc), assuming spherical symmetry, to be roughly 4 x 10(4) M-circle dot yr(-1) Mpc(-3); this may be an order of magnitude greater than the most extreme examples seen in simulations.
KW - galaxies: evolution
KW - galaxies: formation
KW - ULTRALUMINOUS INFRARED GALAXIES
KW - STAR-FORMING GALAXIES
KW - DARK-MATTER HALOS
KW - SUBMILLIMETER GALAXIES
KW - ENVIRONMENTAL DEPENDENCE
KW - MOLECULAR GAS
KW - HIGH-REDSHIFT
KW - RADIO GALAXIES
KW - BOLOMETER CAMERA
KW - FORMATION RATES
U2 - 10.1093/mnras/staa1275
DO - 10.1093/mnras/staa1275
M3 - Journal article
SN - 0035-8711
VL - 495
SP - 3124
EP - 3159
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -