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Recent hydrodynamic simulations and observations of radio jets have shown that the surrounding environment has a large effect on their resulting morphology. To investigate this we use a sample of 50 Extended Radio Active Galactic Nuclei…

We present the results of a Spitzer search for obscured AGN in the Chandra Deep Field-North, using both radio-excess and mid-infrared power-law selection. AGN selected via the former technique tend to lie at z ~ 1, have SEDs dominated by…

天体物理学 · 物理学 2007-05-23 J. L. Donley , G. H. Rieke , P. G. Perez-Gonzalez , J. R. Rigby , A. Alonso-Herrero

We present an all-sky catalogue that aligns and overlays the ROSAT HRI, RASS, PSPC and WGA X-ray catalogues and the NVSS, FIRST and SUMSS radio catalogues onto the optical APM and USNO-A catalogues. Objects presented are those APM/USNO-A…

天体物理学 · 物理学 2009-11-10 E. Flesch , M. J. Hardcastle

We identify 85 variable galaxies in the GOODS North and South fields using 5 epochs of HST ACS V-band (F606W) images spanning 6 months. The variables are identified through significant flux changes in the galaxy's nucleus and represent ~2%…

We report the localization of the X-ray emission from two strongly lensed AGN, CLASS B0712+472 ($z=1.34$) and CLASS B1608+656 ($z=1.394$). We obtain milliarcsecond X-ray astrometry by developing a novel method that combines parametric lens…

高能天体物理现象 · 物理学 2022-06-01 C. Spingola , D. Schwartz , A. Barnacka

BL Lac Objects (BL Lacs) and Flat Spectrum Radio Quasars (FSRQs) are radio-loud active galaxies (AGNs) whose jets are seen at a small viewing angle (blazars), while Misaligned Active Galactic Nuclei (MAGNs) are mainly radiogalaxies of type…

高能天体物理现象 · 物理学 2018-08-20 G. Chiaro , M. Meyer , N. Alvarez Crespo , R. J. Britto , J. P. Marais , B. van Soelen , D. Salvetti , G. La Mura , D. J Thompson

By combining the 2-degree Field Galaxy Redshift Survey with the NRAO VLA Sky Survey at 1.4 GHz, the environments of radio loud AGN in the nearby Universe are investigated using both local projected galaxy densities and a friends-of-friends…

天体物理学 · 物理学 2009-11-10 P. N. Best

We present high spatial resolution MERLIN 1.4GHz radio observations of two high redshift (z~2) sources, RGJ123623 (HDF147) and RGJ123617 (HDF130), selected as the brightest radio sources from a sample of submillimetre-faint radio galaxies.…

宇宙学与河外天体物理 · 物理学 2009-11-13 Caitlin M. Casey , Scott C. Chapman , Tom W. B. Muxlow , Rob J. Beswick , David M. Alexander , Christopher J. Conselice

Since a large fraction of active galactic nuclei (AGN) is missed in common UV-excess surveys and is even hard to find in radio, near-IR and X-ray surveys, we have used a new AGN selection technique which is expected to be not affected by…

We use deep follow-up XMM-Newton observations of 6 clusters discovered in the XXL Survey at $z>1$ to gain robust measurements of their X-ray properties and to investigate the extent to which scaling relations at low redshift are valid at…

We investigate faint radio emission from low- to high-luminosity Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey (SDSS). Their radio properties are inferred by co-adding large ensembles of radio image cut-outs from…

天体物理学 · 物理学 2008-11-26 W. H. de Vries , J. A. Hodge , R. H. Becker , R. L. White , D. J. Helfand

Surveys above 10 keV represent one of the the best resources to provide an unbiased census of the population of Active Galactic Nuclei (AGN). We present the results of 60 months of observation of the hard X-ray sky with Swift/BAT. In this…

宇宙学与河外天体物理 · 物理学 2015-06-04 M. Ajello , D. M. Alexander , J. Greiner , G. M. Madejski , N. Gehrels , D. Burlon

We detect and study the properties of faint radio AGN in Luminous Red Galaxies (LRGs). The LRG sample comprises 760,000 objects from a catalog of LRG photometric redshifts constructed from the Sloan Digital Sky Survey (SDSS) imaging data,…

星系天体物理 · 物理学 2015-05-13 J. A. Hodge , G. R. Zeimann , R. H. Becker , R. L. White

This is the fifth paper in a series of investigations of the clustering properties of luminous, broad-emission-line active galactic nuclei (AGN) identified in the ROSAT All-Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). In this work…

Analysis of the frequency and physical properties of galaxies with star-formation and AGN activity in different environments in the local universe is a cornerstone for understanding structure formation and galaxy evolution. We have built a…

天体物理学 · 物理学 2008-11-26 Pietro Reviglio , David J. Helfand

Giant radio sources, including galaxies and quasars (hereafter GRGs), are active galactic nuclei (AGN) hosting relativistic jets with source sizes exceeding the projected length of 0.7 Mpc. They are crucial to understanding the evolution of…

高能天体物理现象 · 物理学 2025-07-08 Vaidehi S. Paliya , D. J. Saikia , Gabriele Bruni , Alberto Dominguez , C. S. Stalin

The XMM-XXL Survey spans two fields of $\rm 25$ deg$^2$ each observed for more than 6Ms with XMM, which provided a sample of tens of thousands of point sources with a flux limit of $\sim 2.2 \times 10^{-15}$ and $\sim 1.4 \times 10^{-14}$…

We investigate the properties of the environment around 20 powerful radio galaxies and quasars at redshifts between 0.45 and 1. Using XMM-Newton and Chandra observations we probe the spatial distribution and the temperature of the cluster…

天体物理学 · 物理学 2009-11-13 Elena Belsole , Diana M. Worrall , Martin J. Hardcastle , Judith H. Croston

The ROSAT ALL Sky Survey Bright Source Catalogue (RASS-BSC) has been correlated with the Catalogue of Principal Galaxies (PGC) to identify new extragalactic counterparts. 550 reliable optical counterparts have been detected. We took optical…

天体物理学 · 物理学 2009-11-13 W. Kollatschny , R. Kotulla , W. Pietsch , K. Bischoff , M. Zetzl

This paper presents a survey of X-ray selected active galactic nuclei (AGN) with optical spectroscopic follow-up in a $\sim 18\, \rm{deg^2}$ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by…