ﻻ يوجد ملخص باللغة العربية
We present radio observations for 29 southern Seyfert galaxies selected from a volume limited sample with cz<3600 km s^-1, and declination delta<0degr. Objects with declination -30degr<delta<0degr were observed with the Very Large Array (VLA) at 6 cm (4.9 GHz) and objects with delta<-30degr were observed with the Australia Telescope Compact Array (ATCA) at 3.5 cm (8.6 GHz). Both the VLA and the ATCA observations have a resolution of ~1arcsec. These new observations cover more than 50% of the southern sample with all but two of the 29 objects detected above our limit of 0.15 mJy. Combining these data with data available from the literature gives almost 85% coverage of the southern sample and further expands the radio observations of a distance limited sample by 22%. Collecting additional sources from the literature, consisting of known Seyferts with cz < 4600 km s^-1, we find that 38% of the sources are unresolved at arcsecond resolution, and 34% have linear radio structure. Our results expand upon and are consistent with earlier studies. We confirm a correlation between the size of the radio structure and the radio luminosity. A comparison between Seyfert types 1 and 2 finds that type 2s tend to have a larger linear size. There is no statistically significant difference in radio power between types 1 and 2, although all the most powerful objects appear to be Seyfert 2s. No significant difference has been found in the spectral indices.
We present the results of new radio observations carried out with the Karl G. Jansky Very Large Array C-configuration at 5.5 GHz for a sample of southern narrow-line Seyfert 1 galaxies (NLS1s). This work increases the number of known radio-detected N
This is the first of two papers in which a study is made of a sample of 12 southern radio-luminous Seyfert galaxies. Our aim is to investigate possible correlations between radio morphology and nuclear/circumnuclear emission-line properties. In this
JHKLM (1-5 micron) imaging of a sample of Seyfert (Sy) 2 galaxies is presented. We confirm that the 1-2.2 micron nuclear continuum of some Sy 2s is dominated by stellar emission, whereas the continuum emission at longer wavelengths (3-5 micron) is al
This paper aims to understand the continuum of Seyfert 2 galaxies. By fitting the single galaxies in the sample of Heckman et al. (1995) with composite models (shock+ photoionization from the active center), we show that five main components characte
We present a new accurate catalog of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS) final data release, which is currently the most extensive spectroscopic survey available in the sou