Related papers: Seyfert's Sextet: where is the gas?
We present an estimate of the local X-ray luminosity function and emissivity for different subsamples of galaxies namely Seyferts, LINERS, star-forming and passive (no-emission-line) galaxies. This is performed by convolving their optical…
We have obtained $H_{\alpha}$ fluxes and luminosities for a sample of 95 accordant galaxies from observations of 31 Hickson Compact Groups (HCGs) in the North hemisphere. This sample is the largest $H_{\alpha}$ selected catalogue of…
We discuss the properties of the Seyfert 1.5 galaxy LB 1727, also known as 1H 0419-577, from X-ray observations obtained by ASCA and ROSAT along with optical observations from earlier epochs. ASCA shows only modest (< 20%) variations in…
We have reanalysed the ASCA X-ray spectrum of the bright symbiotic star CH Cyg, which exhibits apparently distinct hard and soft X-ray components. Our analysis demonstrates that the soft X-ray emission can be interpreted as scattering of…
ACO 3627 is a rich, nearby cluster of galaxies at the core of the Great Attractor. At the low galactic latitude of b = -7.2 the galactic extinction is significant. Nevertheless, its proximity makes it a prime target for studies of…
The diffuse light within galaxy groups and clusters provides valuable insight into the growth of massive cosmic structures. Groups are particularly interesting in this context, because they represent the link between galactic haloes and…
We summarize recent results on the infrared (IR) nuclear properties of Seyfert galaxies. 100% of all Seyfert 1-1.9$ and ~50% of all Seyfert 2s in the CfA and RSA samples observed with HST/NICMOS show nuclear point sources at 1.6micron. We…
Stephan's Quintet (SQ) is a compact group of galaxies that has been well studied since its discovery in 1877 but is mysterious using cold dark matter hierarchical clustering cosmology (CDMHCC). Anomalous red shifts z = (0.0027,0.019, 0.022,…
Francis & Hewett (1993) identified two 10-Mpc scale regions of the high redshift universe that were seemingly very overdense in neutral hydrogen. Subsequent observations showed that at least one of these gas-rich regions enveloped a cluster…
X-ray luminosities and spectral indices of 97 bright Seyfert 1 galaxies from XMM archive are analyzed in this article. Distribution of these values is random so we conclude that the model of emission should be at least two-parametric.…
We obtain R-band photometry for galaxies in six nearby poor groups for which we have spectroscopic data, including 328 new galaxy velocities. For the five groups with luminous X-ray halos, the composite group galaxy luminosity function…
We performed an analysis of the mid-infared properties of the 12micron Seyfert sample, a complete unbiased 12micron flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog, based on low resolution spectra…
We present the results of the classification of spectral activity types for 193 galaxies from a new sample of 49 compact groups of galaxies in the southern hemisphere (SCGs). This sample was selected in automated fashion from a digitized…
We present new important results about the intermediate-type Seyfert galaxy Mrk 315, recently observed through optical imaging and integral-field spectroscopy. Broad-band images were used to study the morphology of the host galaxy,…
We present results from a systematic investigation of the X-ray properties of a sample of moderate redshift (0.3<z<0.6) galaxy groups. These groups were selected not by traditional X-ray or optical search methods, but rather by an…
Hickson Compact Groups (HCGs) are dense configurations of 4 to 10 galaxies, whose HI (neutral gas) morphology appears to follow an evolutionary sequence of three phases, with gas initially confined to galaxies, then significant amounts…
Aims. The synthesis of the cosmic X-ray background (CXB) requires a large population of Compton-thick active galactic nuclei that have not been detected so far. We probe whether bright infrared galaxies could harbor a population of…
Compact galaxy groups are at the extremes of the group environment, with high number densities and low velocity dispersions that likely affect member galaxy evolution. To explore the impact of this environment in detail, we examine the…
We present the first Chandra X-ray observations of H72.97-69.39, a highly-embedded, potential super-star cluster (SSC) in its infancy located in the star-forming complex N79 of the Large Magellanic Cloud. We detect particularly hard,…
We report the discovery of a remarkable concentration of massive galaxies with extended X-ray emission at $z_{spec} = 2.506$, which contains 11 massive ($M_{*} \gtrsim 10^{11} M_{\odot}$) galaxies in the central 80kpc region (11.6$\sigma$…