Subaru Telescope | National Astronomical Observatory of Japan | 2015 Apr 20
Ongoing studies of distant galaxy protoclusters using the Multi-Object Infrared Camera and Spectrograph (MOIRCS) instrument on the Subaru Telescope is giving astronomers a closer look at the characteristics of star-forming regions in galaxies in the early universe. A team of astronomers from the National Astronomical Observatory of Japan (NAOJ) and SOKENDAI (Graduate University of Advanced Studies, Japan) are tracking velocity structures and gaseous metallicities in galaxies in two protoclusters located in the direction of the constellation Serpens. These appear around the radio galaxies PKS 1138-262 (at a redshift of 2.2, Figure 1) and USS 1558-003 (at a redshift of 2.5). The clusters appear as they would have looked 11 billion years ago, and the team concluded that they are in the process of cluster formation that has led to present-day galaxy clusters.
The MOIRCS near-infrared spectrograph is very effective for studies focused on the distant, early universe because strong emission lines from star-forming galaxies are redshifted from the optical to the near-infrared regime. This gives astronomers unique insights into these activities. (Note 1)
Based on the MOIRCS data, the team estimated that both protoclusters have a weight of about 10^14 solar masses (Figure 2). These follow the typical mass growth history of the today's most massive clusters, such as the 'Coma Cluster.' That makes the two protoclusters ideal laboratories for exploring early phasesof galaxy formation in a unique clustered environment. ...
An early phase of environmental effects on galaxy properties unveiled
by near-infrared spectroscopy of protocluster galaxies at z>2 - Rhythm Shimakawa et al
- Monthly Notices of the RAS 448(1) 666 (2015 Mar 21) DOI: 10.1093/mnras/stv051
arXiv.org > astro-ph > arXiv:1406.5219 > 19 Jun 2014 (v1), 07 Feb 2015 (v3)
- Monthly Notices of the RAS 441(1) L1 (2014 June 11) DOI: 10.1093/mnras/slu029
arXiv.org > astro-ph > arXiv:1402.3568 > 14 Feb 2014 (v1), 31 Mar 2014 (v3)
http://asterisk.apod.com/viewtopic.php?t=34615