ﻻ يوجد ملخص باللغة العربية
(Abridged) We present a spectral analysis of a deep (220 ks) XMM-Newton observation of the Phoenix cluster (SPT-CL J2344-4243), which we also combine with Chandra archival ACIS-I data. We extract CCD and RGS X-ray spectra from the core region to search for the signature of cold gas, and constrain the mass deposition rate in the cooling flow which is thought to be responsible of the massive star formation episode observed in the BCG. We find an average mass deposition rate of $dot M = 620 (-190 +200)_{stat} (-50 +150)_{syst} M_odot$/yr in the temperature range 0.3-3.0 keV from MOS data. A temperature-resolved analysis shows that a significant amount of gas is deposited only above 1.8 keV, while upper limits of the order of hundreds of $M_odot$/yr can be put in the 0.3-1.8 keV temperature range. From pn data we obtain $dot M = 210 (-80 +85)_{stat} ( -35 +60)_{syst} M_odot$/yr, and the upper limits from the temperature-resolved analysis are typically a factor of 3 lower than MOS data. In the RGS spectrum, no line emission from ionization states below Fe XXIII is seen above $12 AA$, and the amount of gas cooling below $sim 3$ keV has a best-fit value $dot M = 122_{-122}^{+343}$ $M_{odot}$/yr. In addition, our analysis of the FIR SED of the BCG based on Herschel data provides $SFR = (530 pm 50) M_odot$/yr, significantly lower than previous estimates by a factor 1.5. Current data are able to firmly identify substantial amount of cooling gas only above 1.8 keV in the core of the Phoenix cluster. While MOS data analysis is consistent with values as high as $dot M sim 1000$ within $1 sigma$, pn data provide $dot M < 500 M_odot$ yr$^{-1}$ at $3sigma$ c.l. at temperature below 1.8 keV. At present, this discrepancy cannot be explained on the basis of known calibration uncertainties or other sources of statistical noise.
Cool core galaxy clusters are considered to be dynamically relaxed clusters with regular morphology and highly X-ray luminous central region. However, cool core clusters can also be sites for merging events that exhibit cold fronts in X-ray and mini-
A brief Chandra observation of the ultraluminous quasar, SDSS J010013.02+280225.8 at redshift 6.326, showed it to be a relatively bright, soft X-ray source with a count rate of about 1 ct/ks. In this paper we present results for the quasar from a 65k
Although absorbed quasars are extremely important for our understanding of the energetics of the Universe, the main physical parameters of their central engines are still poorly known. In this work we present and study a complete sample of 14 quasars
An XMM-Newton imaging spectroscopy analysis of the galaxy cluster A1644 is presented. A1644 is a complex merging system consisting of a main and a sub cluster. A trail of cool, metal-rich gas has been discovered close to the sub cluster. The combinat
Abell 3667 is the archetype of a merging cluster with radio relics. The NW radio relic is the brightest cluster relic or halo known, and is believed to be due to a strong merger shock. We have observed the NW relic for 40 ksec of net XMM time. We obs