Related papers: The large-scale ionization cones in the Galaxy
The Fermi satellite discovery of the gamma-ray emitting bubbles extending 50 deg (10 kpc) from the Galactic Centre has revitalized earlier claims that our Galaxy has undergone an explosive episode in the recent past. We now explore a new…
Active galaxies are often associated with starbursts, which are possible sources of fuelling for the nuclear black holes. By means of optical (3500-7500 A) spectroscopic and narrow-band photometric data (H_alpha+[NII]6548,6583 and…
The Magellanic Stream and the Leading Arm form a massive, filamentary system of gas clouds surrounding the Large and Small Magellanic Clouds. Here we present a new component-level analysis of their ultraviolet (UV) kinematic properties…
We present the results of X-ray imaging and spectroscopic analysis of a sample of Seyfert 2 galaxies that contain starbursts, based on their optical and UV characteristics. These composite galaxies exhibit extended, soft, thermal X-ray…
CSS J102913+404220 is a peculiar narrow line Seyfert 1 galaxy with an energetic nuclear optical outburst. We present a detailed analysis of its multi-wavelength photometric and spectroscopic observations covering a period of decade since…
MeerKAT radio continuum and XMM-Newton X-ray images have recently revealed a spectacular bipolar channel at the Galactic Center that spans several degrees ($\sim$0.5 kpc). An intermittent jet likely formed this channel and is consistent…
New high variability extragalactic sources may be identified by comparing the flux of sources seen in the XMM-Newton Slew Survey with detections and upper limits from the ROSAT All Sky Survey. In November 2012, X-ray emission was detected…
The Fermi Gamma-ray Space Telescope reveals two large gamma-ray bubbles in the Galaxy, which extend about 50 degrees (~ 10 kpc) above and below the Galactic center (GC) and are symmetric about the Galactic plane. Using axisymmetric…
We analyze X-ray spectra and images of a sample of Seyfert 2 galaxies that unambiguously contain starbursts, based on their optical and UV characteristics. Although all sample members contain active galactic nuclei (AGNs), supermassive…
Large-amplitude, high-luminosity soft X-ray flares were detected by the ROSAT All-Sky Survey in several galaxies with no evidence of Seyfert activity in their ground-based optical spectra. These flares had the properties predicted for a…
We used narrowband interference filters with the CCD imaging camera on the Nickel 1.0 meter telescope at Lick Observatory to observe 31 nearby (z < 0.03) Seyfert galaxies in the 12 {\mu}m Active Galaxy Sample. We obtained pure emission line…
The Seyfert 1 galaxy 1E1615+061 was observed to display a very steep and intense soft X-ray spectrum during a HEAO-1 A2 observation in the 1978. Such an exceptionally soft X-ray state has never been observed subsequently, but the source has…
Large amplitude, high luminosity soft X-ray flares were detected by the ROSAT All-Sky Survey in several galaxies with no evidence for Seyfert activity in their ground-based optical spectra. These flares had the properties predicted for a…
Mid-resolution spectra are used to deduce the size and kinematics of the coronal gas in a sample of Seyfert galaxies by means of observations of the [FeXI], [FeX], [FeVII], [SiVI] and [SiVII] lines. These coronal lines (CL) extend from the…
Since its discovery in 1996, the source of the bright H-alpha emission (up to 750 mR) along the Magellanic Stream has remained a mystery. There is no evidence of ionising stars within the HI stream, and the extended hot halo is far too…
The Magellanic Stream and several high velocity clouds have now been detected in optical line emission. The observed emission measures and kinematics are most plausibly explained by photoionization due to hot, young stars in the Galactic…
We report the results from a six-year, multi-epoch very long baseline interferomertry monitoring of the Seyfert galaxy NGC3079. We have observed NGC3079 during eight epochs between 1999 and 2005 predominantly at 5GHz, but covering the…
We present sub-arcsec near-infrared 1.5 - 2.5 micron moderate resolution long-slit spectra of eight nearby Seyfert galaxies (z<0.01), both parallel to the ionization cone and perpendicular to it. These spectra complement similar data on six…
Recently evidence has emerged for enormous features in the gamma-ray sky observed by the Fermi-LAT instrument: bilateral `bubbles' of emission centered on the core of the Galaxy and extending to around 10 kpc above and below the Galactic…
We examine the 10\m\ emission of the central regions of 281 spiral galaxies, after having compiled all ground-based, small-aperture ($\sim$5") broad-band photometric observations at \l$\sim$10\m\ (N magnitudes) published in the literature.…