KECK/MOSFIRE SPECTROSCOPIC CONFIRMATION OF A VIRGO-LIKE CLUSTER ANCESTOR AT z = 2.095
- Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)
- Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia)
- George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)
- Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia)
- School of Physics, University of Melbourne, Parksville, VIC 3010 (Australia)
- Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands)
We present spectroscopic confirmation of a galaxy cluster at z = 2.095 in the COSMOS field. This galaxy cluster was first reported in the ZFOURGE survey as harboring evolved massive galaxies using photometric redshifts derived with deep near-infrared (NIR) medium-band filters. We obtain medium-resolution (R ∼ 3600) NIR spectroscopy with MOSFIRE on the Keck 1 telescope and secure 180 redshifts in a 12' × 12' region. We find a prominent spike of 57 galaxies at z = 2.095 corresponding to the galaxy cluster. The cluster velocity dispersion is measured to be σ{sub v1D} = 552 ± 52 km s{sup –1}. This is the first study of a galaxy cluster in this redshift range (z ≳ 2.0) with the combination of spectral resolution (∼26 km s{sup –1}) and the number of confirmed members (>50) needed to impose a meaningful constraint on the cluster velocity dispersion and map its members over a large field of view. Our ΛCDM cosmological simulation suggests that this cluster will most likely evolve into a Virgo-like cluster with M {sub vir} = 10{sup 14.4} {sup ±} {sup 0.3} M {sub ☉} (68% confidence) at z ∼ 0. The theoretical probability of finding such a cluster is ∼4%. Our results demonstrate the feasibility of studying galaxy clusters at z > 2 in the same detailed manner using multi-object NIR spectrographs as has been done in the optical in lower-redshift clusters.
- OSTI ID:
- 22364569
- Journal Information:
- Astrophysical Journal Letters, Vol. 795, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
ZFIRE: THE KINEMATICS OF STAR-FORMING GALAXIES AS A FUNCTION OF ENVIRONMENT AT z ∼ 2
Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z ≳ 2: high velocity dispersions in progenitors of compact quiescent galaxies