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HI Mass Fraction as a Measure of Physical Processes Efficiency in Cluster Environment of A262

Hassan M. S. R., Abidin Z. Z., Ibrahim U. F. S. U., Hashim N.

Acta Astronomica

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2023

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Vol. 73, No. 1

87--104

EN

We present our results on measurements of the neutral hydrogen (HI) mass fraction in galaxy cluster environment of a nearby cluster Abell 262 (A262), and investigate the possible physical processes that lead to our estimation of HI mass fraction in this cluster. We conduct a spectroscopic analysis to define a true cluster membership around Abell radius of the cluster, from which we estimate the virial mass of the whole cluster based on the velocity dispersion analysis, and later use data from a 21-cm single-pointing observation to deduce the global HI mass fraction in the cluster. It is found that the HI mass, MHI, and HI mass fraction, FHI, of A262 are equal to be about (4.33±0.32)×1011M☉ and (1.01±0.09)×10-3, respectively, in which the latter agrees with previous findings. We have also shown that the fraction of stellar mass in A262 is about (8.25±0.14)×10-3, and falls within the range of the widely accepted value. We discuss several physical mechanisms that contribute to the derived HI mass fraction of A262. We also emphasize that the FHI can be used as a proxy of efficiency of physical processes in clusters, if we have a large sample of galaxy clusters with available HI data.

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J1145-0033 - The Most Distant Giant Radio Source?

Kuźmicz A., Kuligowska E., Jamrozy M.

Acta Astronomica

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2011

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Vol. 61, No. 1

71--82

EN

We present J1145-0033, a candidate for the most distant (z=2.055) lobe-dominated giant radio quasar, with a projected linear size of 1.34 Mpc. This quasar has both FRII-type radio morphology and broad absorption lines in its optical spectrum. Some physical characteristics (e.g., black hole mass, accretion rate, equipartition magnetic field, energy density and particle density of ambient medium) based on the optical and radio data are provided. We have also found that the quasar has a relatively large central black hole mass and a very small accretion rate in comparison with similar objects.

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Giant Radio Sources as a Probe of the Cosmological Evolution of the IGM. II. The Observational Constraint on the Model of Radio-Jets Propagation through the X-ray Halo-IGM Interface

Kuligowska E., Jamrozy M., Koziel-Wierzbowska D., Machalski J.

Acta Astronomica

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2009

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Vol. 59, No. 4

431--455

EN

Three limited samples of high-redshift radio sources of FRII-type are used to constrain the dynamical model for the jets' propagation through the two-media environment: the X-ray emitting halo with the power-law density profile surrounding the parent galaxy and the much hotter intergalactic medium (IGM) of a constant density. The model, originally developed by Gopal-Krishna and Wiita, is modified adopting modern values of its free parameters taken from recent X-ray measurements with the XMM-Newton and Chandra Observatories. We find that (i) giant-sized radio sources (≈1 Mpc) exist at redshifts up to z≈2, (ii) all newly identified the largest radio sources with 1

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Giant Radio Galaxies as a Probe of the Cosmological Evolution of the IGM I. Preliminary Deep Detections and Low-Resolution Spectroscopy with SALT

Machalski J., Kozieł-Wierzbowska D., Jamrozy M.

Acta Astronomica

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2007

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Vol. 57, No. 3

227--248

EN

A problem of the cosmological evolution of the intergalactic medium (IGM) is recalled and a necessity to find distant (z>0.5) "giant" radio galaxies (GRGs) with the lobe energy densities lower than about 10-14 J/m3 to solve this problem is emphasized. Therefore we undertake a search for such GRGs on the southern sky hemisphere using SALT. In this paper we present a selected sample of the GRG candidates and the first deep detections of distant host galaxies, as well as the low-resolution spectra of the galaxies identified on the DSS frames. The data collected during the Performance Verification (P-V) phase show that 21 of 35 galaxies with the spectroscopic redshift have the projected linear size greater than 1 Mpc (for H0=71 km/s Mpc). However their redshifts do not exceed the value of 0.4 and the energy density in only two of them is less than 10-14 J/m3. A photometric redshift estimate of one of them (J1420-0545) suggests a linear extent larger than 4.8 Mpc, i.e., larger than that of 3C236, the largest GRG known up to now.