arXiv subjects

Murat Hudaverdi

Publications and source records attributed to Murat Hudaverdi.

5 recordsLinked to original sources

arXiv2026

Weak cool core, weak turbulence: XRISM, XMM-Newton and Chandra spectroscopy of the core of Abell 1413

We present the first XRISM spectroscopy of the core of Abell 1413 (z = 0.143), combining 104.7 ks of Resolve with archival XMM-Newton and Chandra spectra of a matched sky region. A1413 is hot, massive and relaxed but lacks a strong cool core (t_cool = 6.4 Gyr), a regime in which the low turbulence reported to date has been tested only once, in A3571. The Resolve spectrum requires a single velocity-broadened component with kT = 7.06 (+0.33, -0.43) keV and a line-of-sight velocity dispersion sigma_v = 170 (+25, -24) km/s (M_3D = 0.217). The bulk velocity relative to the brightest cluster galaxy, v_bulk = -24 +/- 26 (z_ICM) +/- 71 (z_BCG) km/s, is limited by the optical redshift rather than by Resolve, and disfavours coherent line-of-sight sloshing. The non-thermal pressure fraction, 2.5 +/- 0.7 per cent, implies a hydrostatic mass bias b < 2.5 per cent, comparable to the strong cool-core cluster A2029 (2.6 +/- 0.3 per cent) and, at matched sampling scale, if anything below it. With A3571 (1.3 +/- 0.3 per cent), to which A1413 rescales within 0.2 sigma, two weak cool cores now show that this quiescence does not require central cooling. The resolved Fe-K He-alpha complex gives Fe = 0.38 +/- 0.03 (stat) +/- 0.04 (sys) solar; Ni/Fe, separated from Fe K-beta for the first time, is solar, as is the pattern as a whole. The Ne, Mg and Si lines that set Ne/Fe, Mg/Fe and Si/Fe lie below 2 keV, where our instruments disagree by 10-20 per cent; we therefore do not regard the SNIa fraction as constrained.

astro-ph.GA↗

arXiv2019

Chandra observation of a cold front in Abell 2554

We present the evidence for the existence of substructure in the cold front cluster A2554 based on a 20.14 ks Chandra observation. Using centroid shift and X-ray brightness concentration parameters, we confirm that A2554 is a dynamically disturbed system. We detect two dominant structures; a main cluster at z = 0.1108 and a foreground northern substructure at z = 0.1082. The analysis reveals an X-ray surface brightness edge at r \simeq 60 kpc from the cluster core. The thermodynamical profiles across the edge are ruling out the shock scenario. The temperature jump (from \sim 6 keV to \sim 10 keV), and pressure equilibrium (P0/P1 = 1.01 \pm 0.23) across the edge, are consistent with the definition of a cold front with a Mach number M=0.94^{+0.13}_{-0.17} also observed a weak bow-shock at \sim 100 kpc in front of the cold cloud, corresponding an upper limit to the Mach number M \sim 1.1. If the northern substructure was not related to the cold front, we conclude that the transonic motion of the cloud is caused by a merger, which was weak or occurred long ago.

astro-ph.CO↗

arXiv2017

Dynamical history of a binary cluster: Abell 3653

We study the dynamical structure of a bimodal galaxy cluster Abell 3653 at z=0.1089 by using combined optical and X-ray data. Observations include archival data from Anglo-Australian Telescope and X-ray observatories of XMM-Newton and Chandra. We draw a global picture for A3653 using galaxy density, X-ray luminosity and temperature maps. Galaxy distribution has a regular morphological shape at the 3 Mpc size. Galaxy density map shows an elongation EW direction, which perfectly aligns with the extended diffuse X-ray emission. We detect two dominant grouping around two brightest cluster galaxies (BCGs). The BCG1 (z=0.1099) can be associated with the main cluster A3653E, and a foreground subcluster A3563W concentrated at the BCG2 (z=0.1075). Both X-ray peaks are dislocated from BCGs by ($\sim$35 kpc), which suggest an ongoing merger process. We measure the subclusters' gas temperatures 4.67 and 3.66 keV, respectively. Two-body dynamical analysis shows that A3653E & A3653W are very likely (93.5% probability) gravitationally bound. The highly favoured scenario suggests that two subclusters with the mass ratio of 1.4 are colliding close to the plane of sky ($α$=17$^\circ$.61) with 2400 km $s^{-1}$, and will undergo core passage in 380 Myr. Temperature map also significantly shows a shock-heated gas (6.16 keV) in between the subclusters, which confirms the supersonic infalling scenario.

astro-ph.HE↗

arXiv2017

XMM-Newton view of X-ray overdensities from nearby galaxy clusters: the environmental dependencies

In this work, we studied ten nearby ($z$$ \leq$0.038) galaxy clusters to understand possible interactions between hot plasma and member galaxies. A multi-band source detection was applied to detect point-like structures within the intra-cluster medium. We examined spectral properties of a total of 391 X-ray point sources within cluster's potential well. Log $N$ - Log $S$ was studied in the energy range of 2-10 keV to measure X-ray overdensities. Optical overdensities were also calculated to solve suppression/triggering phenomena for nearby galaxy clusters. Both X-ray to optical flux/luminosity properties, ($X/O$, $L_{X}$/$L_{B}$, $L_{X}$/$L_{K}$), were investigated for optically identified member galaxies. X-ray luminosity values of our point sources are found to be faint (40.08 $\leq$ log($L_{X}$) $\leq$ 42.39 erg s$^{-1}$). The luminosity range of point sources reveals possible contributions to X-ray emission from LLAGNs, X-ray Binaries and star formation. We estimated $\sim$ 2 times higher X-ray overdensities from galaxies within galaxy clusters compared to fields. Our results demonstrate that optical overdensities are much higher than X-ray overdensities at the cluster's centre, whereas X-ray overdensities increase through the outskirts of clusters. We conclude that high pressure from the cluster's centre affects the balance of galaxies and they lose a significant amount of their fuels; as a result, clustering process quenches X-ray emission of the member galaxies. We also find evidence that the existence of X-ray bright sources within cluster environment can be explained by two main phenomena: contributions from off-nuclear sources and/or AGN triggering caused by galaxy interactions rather than AGN fuelling.

astro-ph.HE↗

arXiv2008

Overdensity of X-ray Sources in the Field of Nearby Clusters of Galaxies

Two nearby clusters of galaxies: A194 (z=0.018) and A1060 (z=0.0114) have been analyzed for their X-ray point source properties with XMM-Newton EPIC-PN data. A multi-band source detection technique was applied to both of the clusters, resulting in 46 sources from the A194 field and 32 sources from the A1060 field, respectively. The cumulative log(N)-log(S) for a flux limit of Fx~10E-14 ergs cm-2 s-1 is calculated and compared with that of the Lockman Hole. A ~3 sigma excess of X-ray sources is found for the cluster regions. Considering the higher fraction observed in optical studies from the clusters, we estimate that the cluster source density is 6 times higher than the blank field source density, and 15 times higher than the local group. Our X-ray selected sources have luminosity values between 10E(39.6) 10E(40.5) ergs/s, at which point the source density becomes comparable to that of the blank-field level. Considering this confined low luminosity range and the X-ray to optical luminosity ratios (L_X/L_B), the observed overdensity is ascribed to AGN fueling by its infall into cluster environment for Lx < 10E(40.5) ergs/s in the X-ray luminosity function. Whereas, the quenching of AGN activity by the deep cluster potential explains why the excess of the source density vanishes for the brighter sources.

astro-ph↗