SPT-CL J2040−4451—spectroscopically confirmed at z = 1.478—is the highest-redshift galaxy cluster yet discovered via the Sunyaev–Zel’dovich effect. SPT-CL J2040−4451 was a candidate galaxy cluster identified in the first 720 deg2 of the South Pole Telescope Sunyaev–Zel’dovich (SPT-SZ) survey, and has been confirmed in follow-up imaging and spectroscopy. From multi-object spectroscopy with Magellan-I/Baade+IMACS we measure spectroscopic redshifts for 15 cluster member galaxies, all of which have strong [O ii] λλ3727 emission. SPT-CL J2040−4451 has an SZ-measured mass of M500,SZ = 3.2 ± 0.8 × 1014 M h−1 70 , corresponding to M200,SZ = 5.8 ± 1.4 × 1014 M h−1 70 . The velocity dispersion measured entirely from blue star-forming members is σv = 1500 ± 520 km s−1. The prevalence of star-forming cluster members (galaxies with >1.5 M yr−1) implies that this massive, high-redshift cluster is experiencing a phase of active star formation, and supports recent results showing a marked increase in star formation occurring in galaxy clusters at z 1.4. We also compute the probability of finding a cluster as rare as this in the SPT-SZ survey to be >99%, indicating that its discovery is not in tension with the concordance ΛCDM cosmological model.
SPT-CL J2040-4451: An SZ-selected galaxy cluster at z = 1.478 with significant ongoing star formation / Bayliss, M. B.; Ashby, M. L. N.; Ruel, J.; Brodwin, M.; Aird, K. A.; Bautz, M. W.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Carlstrom, J. E.; Chang, C. L.; Cho, H. M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dobbs, M. A.; Dudley, J. P.; Foley, R. J.; Forman, W. R.; George, E. M.; Gettings, D.; Gladders, M. D.; Gonzalez, A. H.; De Haan, T.; Halverson, N. W.; High, F. W.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hrubes, J. D.; Jones, C.; Joy, M.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; Mawatari, K.; Mcdonald, M.; Mcmahon, J. J.; Mehl, J.; Meyer, S. S.; Miller, E. D.; Mocanu, L.; Mohr, J. J.; Montroy, T. E.; Murray, S. S.; Padin, S.; Plagge, T.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Song, J.; Stalder, B.; Šuhada, R.; Spieler, H. G.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K.; Stubbs, C. W.; Van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 794:1(2014), pp. 12.12-12.-. [10.1088/0004-637X/794/1/12]
SPT-CL J2040-4451: An SZ-selected galaxy cluster at z = 1.478 with significant ongoing star formation
Saro, A.;
2014-01-01
Abstract
SPT-CL J2040−4451—spectroscopically confirmed at z = 1.478—is the highest-redshift galaxy cluster yet discovered via the Sunyaev–Zel’dovich effect. SPT-CL J2040−4451 was a candidate galaxy cluster identified in the first 720 deg2 of the South Pole Telescope Sunyaev–Zel’dovich (SPT-SZ) survey, and has been confirmed in follow-up imaging and spectroscopy. From multi-object spectroscopy with Magellan-I/Baade+IMACS we measure spectroscopic redshifts for 15 cluster member galaxies, all of which have strong [O ii] λλ3727 emission. SPT-CL J2040−4451 has an SZ-measured mass of M500,SZ = 3.2 ± 0.8 × 1014 M h−1 70 , corresponding to M200,SZ = 5.8 ± 1.4 × 1014 M h−1 70 . The velocity dispersion measured entirely from blue star-forming members is σv = 1500 ± 520 km s−1. The prevalence of star-forming cluster members (galaxies with >1.5 M yr−1) implies that this massive, high-redshift cluster is experiencing a phase of active star formation, and supports recent results showing a marked increase in star formation occurring in galaxy clusters at z 1.4. We also compute the probability of finding a cluster as rare as this in the SPT-SZ survey to be >99%, indicating that its discovery is not in tension with the concordance ΛCDM cosmological model.Pubblicazioni consigliate
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