相关论文: Magnetic Field Structures In and Around Seyfert Ga…

We present here uGMRT band 4 (~650MHz) polarization images of 8 BL~Lac objects belonging to the Palomar-Green (PG) `blazar' sample. A large fraction of the sources (~63%) reveal core-halo radio structures with most of the polarization…

Despite the increasing prevalence of RL sources at cosmic noon, our understanding of the underlying physics that governs the accretion disc outflows in these particular sources and its dissimilarity with RQ quasars remains somewhat limited.…

The nucleus of the Milky Way is known to harbour regions of intense star formation activity as well as a super-massive black hole. Recent Fermi space telescope observations have revealed regions of \gamma-ray emission reaching far above and…

We argue that the narrow line regions of Seyfert galaxies are powered by the transport of energy and momentum by the radio-emitting jets and consequently that the ratio of the radio power to jet energy flux is much smaller than is usually…

The advent of the Very Long Baseline Array and its phase-referencing capability have enabled milliarcsecond-scale imaging of radio sources at sub-millijansky sensitivity, opening the door to high-resolution imaging of Seyfert galaxies. Over…

We have carried out an analysis of the radio and optical properties of a statistical sample of 45 Seyfert galaxies from the Palomar spectroscopic survey of nearby galaxies. We find that the space density of bright galaxies (-22 mag <=…

We investigate the optical emission-line flux ratios of narrow-line regions, in order to determine whether the formation of AGN jets requires specific accretion conditions. We find that bright compact radio galaxies, which are powerful…

The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion…

Narrow-line Seyfert 1 (NLS1) galaxies provide us with unique insights into the drivers of AGN activity under extreme conditions. Given their low black hole (BH) masses and near-Eddington accretion rates, they represent a class of galaxies…

Hard X-ray emission in radio-quiet active galactic nuclei (AGNs) is believed to be produced via inverse Compton scattering by hot and compact coronae near the super massive black hole. However the origin and physical properties of the…

Seyfert galaxies and quasars were first discovered through optical and radio techniques, but in recent years high-energy emission, that can penetrate central gas and dust, has become essentially the defining characteristic of an AGN. AGNs…

Regular magnetic field structures can be derived from the Faraday rotation measures (RM) of polarized background sources observable at 1.4 GHz with the SKA. At lower frequencies ($<250$ MHz) polarimetry of radio sources with the Low…

We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7).…

(Abridged) Spiral galaxies often have extended outflows that permeate beyond the region of the disk. Such outflows have been seen both in starburst galaxies, actively star forming galaxies and galaxies with an AGN. In the latter galaxies it…

We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array (VLA). We find all sources show two-sided, mildly…

We estimate black hole masses and Eddington ratios for a sample of 81 young radio galaxies (42 CSS +39 GPS). We find that the average black hole (BH) mass of these young radio galaxies is <log Mbh>~8.3, which is less than that of radio loud…

We present a study of the extended radio emission in a sample of 8434 low redshift (z < 0.35) broad line active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). To calculate the jet and lobe contributions to the total radio…

We report on a multiwavelength survey of a sample of 42 flat-spectrum radio-loud narrow-line Seyfert 1 galaxies (RLNLS1s). This is the largest known sample of this type of active galactic nucleus (AGN) to date. We found that 17% of sources…

In order to analyze the importance of the star formation rate in generating and amplifying magnetic fields in the interstellar medium we obtained deep total power and polarization maps at 4.85 GHz of three late type spiral galaxies NGC4236,…

The Fermi-LAT satellite has recently discovered a small group of radio galaxies and steep spectrum radio sources: the misaligned AGNs (MAGNs) sample. We present the X-ray analysis of all the sources of this sample (7 FRIs and 3 FRIIs) with…