Related papers: Seyfert's Sextet: where is the gas?
We present optical broad band B-I colour maps of a further sample of 10 Seyfert 2 galaxies. In these bands, the contribution from emission lines to the total flux is small, and hence the images predominantly trace the continuum…
We have conducted a high-resolution ``3D'' imaging survey of the CO(1--0), HCN(1--0), and HCO$^+$(1--0) lines toward the central a few kpc regions of the Seyfert and starburst galaxies in the local universe using the Nobeyama Millimeter…
The Spitzer IRS high resolution spectra of about 90 Seyfert galaxies from the 12um Galaxy Sample are presented and discussed. These represent about 70% of the total complete sample of local Seyfert galaxies. The presence of starburst…
We report here the results of high-resolution and spectral imaging X-ray observations, with both the ROSAT HRI and PSPC, of the field surrounding the nearby Seyfert galaxy IC4329A. Many point sources are detected, the brightest being…
We use a new fiber spectroscopic survey of 12 nearby, poor groups of galaxies to examine the dynamics and evolution of galaxies in these common, but poorly studied, environments. Some of our conclusions are: (1) The nine groups in our…
We have undertaken a multiwavelength project to study the relatively unknown properties of groups and poor clusters of galaxies at intermediate redshifts. In this paper, we describe the XMM-Newton observations of six X-ray selected groups…
The EPIC detectors on XMM-Newton provide the most sensitive broad band (0.3-12 keV) X-ray spectra to date. Observations of 6 Seyfert 1 galaxies, covering a wide luminosity range, are examined with the aim of identifying the primary X-ray…
In a matched sample of Seyfert and quiescent galaxies we simultaneously probe the stellar and molecular gas kinematics from 1 kpc down to 50 pc with the aim of identifying the dynamical processes dictating black hole accretion rates. This…
We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN(1-0) and HCO$^+$(1-0) for 3 objects. In NGC 3079 the lines show complex profiles as a result of…
The prototype compact group known as Stephan's Quintet (SQ) was observed with XMM-Newton in order to complement the excellent resolution of Chandra with high sensitivity to extended emission. SQ is a dynamic environment whose main effect,…
Seyfert-type AGN that exhibit unusually strong and steep soft X-ray spectra are reviewed, building on observations made during the ROSAT all-sky survey. Two individual cases are described in brief detail, both being identified initially in…
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…
We present the discovery of an isolated compact group of galaxies that is extremely dense (median projected galaxy separation: 6.9 kpc), has a very low velocity dispersion ($\sigma_{\rm 2D}$ = 67 km s$^{-1}$), and where all observed members…
In the course of an extensive campaign to measure radial velocities of galaxies in a selected sample of compact groups photometrically studied by de Carvalho et al. (1994), we report the discovery of a system very rich in starburst galaxies…
We present an X-ray analysis of the rich cluster ABCG 85 based on ROSAT PSPC data. By applying an improved wavelet analysis, we show that our view of this cluster is notably changed from what was previously believed (a main region and a…
Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As…
We present a study of the hard X-ray spectrum (>15 keV) of different classes of Seyfert galaxies observed with BeppoSAX/PDS. Using hard X-ray data, we avoid absorption effects modifying the Seyfert emission and have direct access to the…
We use Chandra observations of 13 nearby groups of galaxies to investigate the hot gas content of their member galaxies. We find that a large fraction of near-IR bright, early-type galaxies in groups have extended X-ray emission, indicating…
Far-infrared flux densities are newly extracted from the IRAS database for the RSA and CfA complete samples of Seyfert galaxies. These data are used to classify the Seyfert galaxies into those where the far-infrared continuum emission is…
Galaxy groups contain the majority of bound mass with a significant portion of baryons due to the combination of halo mass and abundance (Cui 2024). Hence they serve as a crucial missing piece in the puzzle of galaxy formation and the…