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arXiv · 1312.4526

Gas bulk motion in the Perseus cluster measured with SUZAKU

Takayuki Tamura·N. Yamasaki·R. Iizuka·Y. Fukazawa·K. Hayashida·S. Ueda·K. Matsushita·K. Sato·K. Nakazawa·N. Ota·M. Takizawa
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Abstract

We present the results from Suzaku observations of the Perseus galaxy 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, 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, relative to the main system was found at 2-4 arcmin (45-90kpc) 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 50-100kpc and within 200kpc radii of the center, the gas-radial-velocity variation is below 300 km/s, while over scales of 400 kpc within 600 kpc radii, the variation is below 600 km/s. 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. These results of gas dynamics in the core and larger scales in association with cluster merger activities are discussed and future potential of high-energy resolution spectroscopy with ASTRO-H is considered.

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Takayuki Tamura, N. Yamasaki, R. Iizuka, Y. Fukazawa, K. Hayashida, S. Ueda, K. Matsushita, K. Sato, K. Nakazawa, N. Ota, M. Takizawa. 2013-12-14. Gas bulk motion in the Perseus cluster measured with SUZAKU. https://doi.org/10.1088/0004-637x/782/1/38

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