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Narrow-Line Seyfert 1 (NLS1) galaxies show extreme properties with respect to the other Seyfert galaxies. Indeed, they are thought to be accreting at Eddington rates and to possess low mass black holes. Therefore, they may represent a key…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 G. Orban de Xivry , R. Davies , M. Schartmann , S. Komossa , A. Marconi , E. Hicks , H. Engel , L. Tacconi

We have identified 1027 star forming complexes in a sample of 46 galaxies from the Spirals, Bridges, and Tails (SB&T) sample of interacting galaxies, and 693 star forming complexes in a sample of 38 non-interacting spiral (NIS) galaxies in…

The Spitzer high resolution spectra of 72 Seyfert galaxies from the 12$\mu$m Galaxy Sample are presented and discussed. The presence of starburst components in these galaxies can be quantified by powerful mid-IR diagnostics tools (i.e.…

Astrophysics · Physics 2008-07-31 S. Tommasin , L. Spinoglio , K. Hainline , M. A. Malkan , H. Smith

Recent observations have shown that the Fe Kalpha line profile of the Seyfert~1 galaxy MCG-06-30-15 is strongly variable. We attempt accretion disk model fits to the Fa Kalpha line profiles in a high, low and medium continuum luminosity…

Astrophysics · Physics 2015-06-24 J. W. Sulentic , P. Marziani , M. Calvani

The galaxy integrated star-formation rate (SFR) surface density ($\Sigma_{\rm SFR}$) has been proposed as a valuable diagnostic of the mass accumulation in galaxies as being more tightly related to the physics of star-formation (SF) and…

We present Star Formation Histories (SFHs) for a sample of 104 massive (stellar mass M > 10$^{10}$ M$_{\odot}$) quiescent galaxies (MQGs) at $z$=1.0-1.5 from the analysis of spectro-photometric data from the SHARDS and HST/WFC3 G102 and…

Although episodic star formation (SF) had been suggested for nearby SF regions, a panoramic view to the latest episodic SF history in the solar neighborhood is still missing. By uniformly constraining the slope $\alpha$ of infrared spectral…

Solar and Stellar Astrophysics · Physics 2023-02-01 Mingchao Liu , Jinhua He , Jixing Ge , Tie Liu , Yuping Tang , Xuzhi Li

During the last decade, studies about highly attenuated and massive red star-forming galaxies (RedSFGs) at $z \sim 4$ have suggested that they could constitute a crucial population for unraveling the mechanisms driving the transition from…

We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated…

We present analysis of the long-term X-ray spectral variability of Seyfert galaxies as observed by Swift, which provides well-sampled observations over a much larger flux range and a much longer timescale than any other X-ray observatory.…

High Energy Astrophysical Phenomena · Physics 2015-02-27 S. D. Connolly , I. M. McHardy , T. Dwelly

We aim at defining homogeneous selection criteria of small galaxy systems in order to build catalogues suitable to compare main properties of pairs, triplets, and groups with four or more members. To this end we use spectroscopic and…

Astrophysics of Galaxies · Physics 2020-03-06 F. Duplancic , G. V. Coldwell , S. Alonso. , D. G. Lambas

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 present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the…

Astrophysics of Galaxies · Physics 2015-05-13 Y. Revaz , P. Jablonka , T. Sawala , V. Hill , B. Letarte , M. Irwin , G. Battaglia , A. Helmi , M. D. Shetrone , E. Tolstoy , K. A. Venn

(abridged) It has been suggested that Narrow-Line Seyfert 1 (NLS1) galaxies are evolutionarily young objects, powered by the accretion of gas onto central black holes that are lower in mass than those found in typical broad-line Seyferts.…

Astrophysics · Physics 2008-11-26 C. J. Ryan , M. M. De Robertis , S. Virani , A. Laor , P. C. Dawson

We present the first results of the hard (5-10 keV) ASCA GIS survey SHEEP (Search for the High Energy Extragalactic Population). We have analysed 149 fields covering an area of 39 sq. deg detecting 69 sources. Several of these appear to be…

Astrophysics · Physics 2007-05-23 I. Georgantopoulos , K. Nandra , A. Ptak

AIMS: Compact groups of galaxies are excellent laboratories for studying galaxy interactions and their effects on the evolution of galaxies. In particular, dynamically young systems, with a large fraction of interacting, late type galaxies,…

Astrophysics · Physics 2009-11-13 G. Trinchieri , A. Iovino , E. Pompei , M. Dahlem , J. Reeves , R. Coziol , S. Temporin

The merging of supermassive black holes (SMBHs) is a direct consequence of our hierarchical picture of galaxy evolution. It is difficult to track the merging process of SMBHs during mergers of galaxies as SMBHs are naturally difficult to…

Astrophysics of Galaxies · Physics 2020-07-22 B. Husemann , J. Heidt , A. De Rosa , C. Vignali , S. Bianchi , T. Bogdanović , S. Komossa , Z. Paragi

We have conducted a study of optical and HI properties of spiral galaxies (size, luminosity, H-alpha flux distribution, circular velocity, HI gas mass) to explore the role of gas stripping as a driver of morphological evolution in clusters.…

Astrophysics · Physics 2009-11-10 Nicole P. Vogt , Martha P. Haynes , Riccardo Giovanelli , Terry Herter

We present new broad-band optical images of some merging Seyfert galaxies that were earlier considered to be non-interacting objects. On our deep images obtained at the Russian 6-m telescope we have detected elongated tidal envelopes…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-01 A. A. Smirnova , A. V. Moiseev , V. L. Afanasiev

Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an…

Astrophysics of Galaxies · Physics 2014-11-20 Hannah B. Krug , David S. N. Rupke , Sylvain Veilleux