ﻻ يوجد ملخص باللغة العربية
We present high resolution, long-slit spectra of the jet-cloud interaction in the powerful southern radio galaxy PKS2250-41. We have resolved the emission lines into two main kinematic components: a broad component (FWHM geq 900 km/s) and a narrow component (FWHM leq 150 km/s). While the broad component is characterized by a low ionization level (with particular ly weak HeII$lambda$4686 emission) and is spatially associated with the radio lobe, the narrow component is characterized by a higher ionization level and extends well beyond the radio lobe. Crucially, we measure a higher electron temperature for the broad component (T sim 30,000 K) than for the narrow component (T sim 15,000 K). The general line ratios and physical conditions of the two components are consistent with a model in which the broad component r epresents gas cooling behind the shock front driven by the radio jets, while the narrow component represents the AGN- or shock-photoionized precursor gas. However, uncertainties remain about the gas acceleration mechanism behind the shock front: unless the radio components are expanding unusually fast in this source, it is likely that entrainment of the warm clouds in the hot post-shock wind or radio plasma is required. The similarities between the kinematic properties of PKS2250-41 and some high redshift radio galaxies suggest that the ambient and the shocked gas have also been resolved in the more distant objects. Given the evidence that the emission line processes are affected by the interactions between the radio and the optical structures, care must be taken when interpreting the UV spectra of high redshift radio galaxies.
We present the results of a multiwavelength study of the z = 0.31 radio source PKS2250-41. Integral field unit and long-slit spectroscopy obtained using VIMOS and FORS1 on the VLT, and archival HST optical imaging observations are used to study the m
There is now unequivocal evidence that the jets in FR I radio galaxies are initially relativistic, decelerating flows. On the assumption that they are axisymmetric and intrinsically symmetrical (a good approximation close to the nucleus), we can make
We compare the kinetic energy and momentum injection rates from intense star formation, bolometric AGN radiation, and radio jets with the kinetic energy and momentum observed in the warm ionized gas in 24 powerful radio galaxies at z~2. These galaxie
The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large
Massive outflows of neutral atomic hydrogen (HI) have been observed in absorption in a number of radio galaxies and are considered a signature of AGN feedback. These outflows on kpc-scales have not been investigated in great detail as they require hi