Gas Bulk Motion in the Perseus Cluster Measured with Suzaku
Abstract
We present the results from Suzaku observations of the Perseus Cluster, which is relatively close, the brightest in the X-ray sky, and a relaxed object with a cool core. A number of exposures of central regions and offset pointing with the X-ray Imaging Spectrometer cover a region within radii of 20'-30'. The central data are used to evaluate the instrumental energy-scale calibration with accuracy confirmed to within around 300 km s-1 by the spatial and temporal variation of the instruments. These deep and well-calibrated data are used to measure X-ray redshifts of the intracluster medium. A hint of gas bulk motion, with radial velocity of about -(150-300) km s-1 relative to the main system, was found at 2'-4' (45-90 kpc) west of the cluster center, where an X-ray excess and a cold front were found previously. No other velocity structure was discovered. Over spatial scales of 50-100 kpc and within 200 kpc radii of the center, the gas-radial-velocity variation is below 300 km s-1, while over scales of 400 kpc within 600 kpc radii, the variation is below 600 km s-1. These X-ray redshift distributions are compared spatially with those of optical member galaxies for the first time in galaxy clusters. Based on X-ray line widths, gas turbulent velocities within these regions are also constrained within 1000-3000 km s-1. These results of gas dynamics in the core and larger scales in association with cluster merger activities are discussed, and the future potential of high-energy resolution spectroscopy with ASTRO-H is considered.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2014
- DOI:
- 10.1088/0004-637X/782/1/38
- arXiv:
- arXiv:1312.4526
- Bibcode:
- 2014ApJ...782...38T
- Keywords:
-
- galaxies: clusters;
- individual: Perseus;
- X-rays: galaxies: clusters;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted to ApJ