Using the deepest (370 ksec) Chandra observation of a high-redshift galaxy cluster, we perform a detailed characterization of the intra-cluster medium (ICM) of WARPJ1415.1+3612 at z=1.03. We also explore the connection between the ICM core properties and the radio/optical properties of the brightest cluster galaxy (BCG). We perform a spatially resolved analysis of the ICM to obtain temperature, metallicity and surface brightness profiles. Using the deprojected temperature and density profiles we accurately derive the cluster mass at different overdensities. In addition to the X-ray data, we use archival radio VLA imaging and optical GMOS spectroscopy of the central galaxy to investigate the feedback between the central galaxy and the ICM. The X-ray spectral analysis shows a significant temperature drop towards the cluster center, with a projected value of Tc = 4.6 \pm 0.4 keV, and a remarkably high central iron abundance peak, Zc= 3.6 Zsun. The central cooling time is shorter than 0.1 Gyr and the entropy is equal to 9.9 keV cm2. We detect a strong [OII] emission line in the optical spectra of the BCG with an equivalent width of -25 Å, for which we derive a star formation rate within the range 2 - 8 Msun/yr. The VLA data reveals a central radio source coincident with the BCG and a faint one-sided jet-like feature with an extent of 80 kpc. The analysis presented shows that WARPJ1415 has a well developed cool core with ICM properties similar to those found in the local Universe. Its properties and the clear sign of feedback activity found in the central galaxy in the optical and radio bands, show that feedback processes are already established at z~1. In addition, the presence of a strong metallicity peak shows that the central regions have been promptly enriched by star formation processes in the central galaxy already at z > 1.
Deep Chandra Observations of the z = 1.16 Relaxed, Cool-core Galaxy Cluster SPT-CL J2215-3537
Stanford University(斯坦福大学);Kavli Institute for Particle Astrophysics and Cosmology, Stanford University(斯坦福大学卡弗里粒子天体物理与宇宙学研究所);SLAC National Accelerator Laboratory(SLAC国家加速器实验室);Rutgers University(罗格斯大学)
We present the results of a joint analysis of $Chandra$ X-ray and South Pole Telescope (SPT) SZ observations targeting the first sample of galaxy clusters at $0.3 < z < 1.3$, selected to be the progenitors of well-studied nearby clusters based on their expected accretion rate. We develop a new procedure in order to tackle the analysis challenge that is estimating the intracluster medium (ICM) properties of low-mass and high-redshift clusters with ${\sim}150$ X-ray counts. One of the dominant sources of uncertainty on the ICM density profile estimated with a standard X-ray analysis with such sh…
We present a multi-wavelength analysis of the galaxy cluster A1668, performed by means of new EVLA and Chandra observations and archival H$α$ data. The radio images exhibit a small central source ($\sim$14 kpc at 1.4 GHz) with L$_{\text{1.4 GHz}}$ $\sim$6 $\cdot$ 10$^{23}$ W Hz$^{-1}$. The mean spectral index between 1.4 GHz and 5 GHz is $\sim$ -1, consistent with the usual indices found in BCGs. The cooling region extends for 40 kpc, with bolometric X-ray luminosity L$_{\text{cool}} = 1.9\pm 0.1 \cdot$ 10$^{43}$ erg s$^{-1}$. We detect an offset of $\sim$ 6 kpc between the cluster BCG and the…
SPT-CL J0417-4748: A Deep Chandra Study of a Relaxed Galaxy Cluster Without Central Star Formation
Chulalongkorn University(朱拉隆功大学);Kavli Institute for Particle Astrophysics and Cosmology, Stanford University(斯坦福大学卡弗里粒子天体物理与宇宙学研究所);Department of Physics, Stanford University(斯坦福大学物理系);SLAC National Accelerator Laboratory(斯坦福直线加速器中心);Department of Physics and Astronomy, Rutgers University(罗格斯大学物理与天文系)
We carry out a test of the radial acceleration relation (RAR) for a sample of 10 dynamically relaxed and cool-core galaxy clusters imaged by the Chandra X-ray telescope, which was studied in Giles et al. For this sample, we observe that the best-fit RAR shows a very tight residual scatter equal to 0.09 dex. We obtain an acceleration scale of $1.59 \times 10^{-9} m/s^2$, which is about an order of magnitude higher than that obtained for galaxies. Furthermore, the best-fit RAR parameters differ from those estimated from some of the previously analyzed cluster samples, which indicates that the ac…
We present the first X-ray dedicated study of the galaxy cluster A795 and of the Fanaroff-Riley Type 0 hosted in its brightest cluster galaxy. Using an archival 30 ks \textit{Chandra} observation we study the dynamical state and cooling properties of the intracluster medium, and we investigate whether the growth of the radio galaxy is prevented by the surrounding environment. We discover that A795 is a weakly cool core cluster, with an observed mass deposition rate $\lessapprox 14\,$ M$_{\odot}$yr$^{-1}$ in the cooling region (central $\sim$66 kpc). In the inner $\sim$ 30 kpc we identify two p…
How the cool-core population transitions from galaxy groups to massive clusters: A comparison of the largest Magneticum simulation with eROSITA, XMM-Newton, Chandra and LOFAR observations
We present deep ($205 \rm ks$), \Chandra observations of the \ab295 binary merging cluster ($z=0.30$). In the X-ray image, the secondary component is clearly visible as a surface brightness peak, while the primary cluster has a flatter distribution. We found cool gas ($\sim 6 \rm keV$) associated with the secondary, while the central temperature of the primary does not deviate significantly from the mean temperature of the cluster of $\sim 9.5 \rm keV$. In the vicinity of the primary's core we found the hottest region in the cluster accompanied by a surface brightness discontinuity. We propose…
We present new, deep (245 ks) Chandra observations of the galaxy cluster Abell 1664 ($z = 0.1283$). These images reveal rich structure, including elongation and accompanying compressions of the X-ray isophotes in the NE-SW direction, suggesting that the hot gas is sloshing in the gravitational potential. This sloshing has resulted in cold fronts, at distances of 55, 115 and 320 kpc from the cluster center. Our results indicate that the core of A1664 is highly disturbed, as the global metallicity and cooling time flatten at small radii, implying mixing on large scales. The central AGN appears t…