相关论文: Ionization of large-scale absorbing haloes and fee…

A search for HI absorption has been made in 23 radio galaxies using the ATCA, the VLA and the WSRT. In five galaxies HI absorption was detected. We investigate how the detection rate is distributed among galaxies with different radio and…

We use the observed cumulative statistics of CIV absorbers and dark matter halos to infer the distribution of CIV-absorbing gas relative to galaxies at redshifts $0\!\leq\!z\!\leq\!5$. We compare the cosmic incidence $dN/dX$ of CIV absorber…

We present Chandra observations of two radio-quiet QSOs, PG 2302+029 and PG 1254+047. PG 2302+029 has an ultra high-velocity UV absorption system -56,000 km/s, while PG 1254+047 is a Broad Absorption Line (BAL) QSO with detached troughs.…

Recent observations of Broad Absorption Line (BAL) quasars demonstrated that the soft X-ray emission of these objects is extremely weak and convincing evidence for very strong absorption by a high column density (~ 10^23.5 cm^-2) was…

Star-forming galaxies are considered to be the leading candidate sources that dominate the cosmic reionization at z>7, and the search for analogs at moderate redshift showing Lyman continuum (LyC) leakage is currently a active line of…

We have examined radial velocities and fluxes of ultraviolet emission lines at different epochs, deduced from archival IUE and GRHS/HST spectra. The line fluxes give electron densities and were in addition used to calculate emission…

The VLBA and the VLA have been used to image the continuum radio emission from Mrk 231, a Seyfert 1 galaxy and the brightest infrared galaxy in the local universe. The smallest scales reveal a double source less than 2 pc in extent. The…

We present optical and near-IR imaging and spectroscopy of SGAS J105039.6$+$001730, a strongly lensed galaxy at z $=$ 3.6252 magnified by $>$30$\times$, and derive its physical properties. We measure a stellar mass of…

We examine halo gas cross sections and covering fractions, f_c, of intermediate redshift MgII absorption selected galaxies. We computed statistical absorber halo radii, R_x, using current values of dN/dz and Schechter luminosity function…

We present analysis of two O VI absorbers at redshift z_{abs} = 0.227, detected in the spectra of two closely spaced QSO sightlines (Q 0107-025 A and B), observed with the Cosmic Origins Spectrograph (COS) on board the Hubble Space…

Aim of this work is a broad-band study with INTEGRAL, Swift and XMM-Newton satellites of a sample of 9 blazars (7 FSRQ and 2 BL Lac) with redshift up to about 4. The spectral analysis has shown clear evidence of a flattening of the…

The study of both neutral and ionized gas in young radio sources is providing key information on the effect the radio plasma has on the ISM of these objects. We present results obtained for the compact radio sources PKS1549-79, 4C12.50 and…

We present observations of the O VI system at z_abs = 0.495096 toward PKS 0405-123 (z_em = 0.5726) obtained with FUSE and STIS. In addition to strong O VI, with log N(O VI) = 14.47+/-0.02, and moderate H I this absorber shows C III, N IV, O…

(Abridged) Using ab initio cosmological Eulerian adaptive mesh refinement radiation hydrodynamical calculations, we discuss how very massive stars start the process of cosmological reionization. The models include non-equilibrium primordial…

The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic HI and HeII Ly-alpha forest spectra, constructed from…

Outflows of photoionized gas are commonly detected in the X-ray spectra of Seyfert 1 galaxies. However, the evidence for this phenomenon in broad line radio galaxies, which are analogous to Seyfert 1 galaxies in the radio-loud regime, has…

We have used the 610 MHz receivers of the Giant Metrewave Radio Telescope (GMRT) to detect associated HI 21cm absorption from the $z = 1.2230$ blazar TXS1954+513. The GMRT HI 21cm absorption is likely to arise against either the…

We study the effect of inclination on the apparent brightness of star-forming galaxies in spectral passbands that are commonly used as star-formation indicators. As diagnostics we use mass-to-light ratios in three passbands: the UV…

Using a sample of 38 radio-loud galaxy mergers at z<=0.2, we confirm the high detection rate (~84%) of HI 21-cm absorption in mergers, which is significantly higher (~4 times) than in non-mergers. The distributions of the HI column density…

We report the detection of 21-cm HI absorption towards the core of the Fanaroff-Riley II radio galaxy 3C452 (J2245+3941). The absorption profile is well resolved into three components; the strongest and narrowest component being coincident…