Joana S. Santos, Paolo Tozzi, Piero Rosati, Mario Nonino, Gabriele Giovannini
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 \AA, 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.
View original:
http://arxiv.org/abs/1111.3642
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