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(abridged) We present a comprehensive study of a sample of 23 genuine radio-loud NLS1 galaxies which have the radio-loudness parameters greater than 100. The radio sources of the sample are ubiquitously compact. A significant fraction of…

Astrophysics · Physics 2009-11-13 W. Yuan , H. Y. Zhou , S. Komossa , X. B. Dong , T. G. Wang , H. L. Lu , J. M. Bai

We present X-ray spectral analyses of the three z>4 Active Galactic Nuclei (AGNs) thus far spectroscopically identified in the Chandra Deep Field-North Survey, at redshifts of 5.186, 4.424, and 4.137. These analyses are made possible by the…

Water and ice Cherenkov telescopes of the present and future aim for the detection of a neutrino signal from extraterrestrial sources at energies E>PeV. Some of the most promising extragalactic sources are Active Galactic Nuclei (AGN). In…

Astrophysics · Physics 2009-11-10 Julia K. Becker , Peter L. Biermann , Wolfgang Rhode

CGRaBS J0809+5341, a high redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by $\sim$5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Vaidehi S. Paliya , M. L. Parker , C. S. Stalin , A. C. Fabian , S. Ramya , S. Covino , G. Tagliaferri , S. Sahayanathan , C. D. Ravikumar

In its first three months of operations, the Fermi Gamma-Ray Observatory has detected approximately one quarter of the radio-flux-limited MOJAVE sample of bright flat-spectrum active galactic nuclei (AGNs) at energies above 100 MeV. We have…

Astrophysics of Galaxies · Physics 2011-02-11 M. L. Lister , D. C. Homan , M. Kadler , K. I. Kellermann , Y. Y. Kovalev , E. Ros , T. Savolainen , J. A. Zensus

Using the Urumqi 25m radio telescope, sources from the first three-month Fermi-LAT detected AGN catalog with declination >0 were observed in 2009 at 4.8 GHz. The radio flux density appears to correlate with the gamma-ray intensity.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Xiang Liu , Hua-Gang Song , Jun Liu , Zhen Ding , Nicola Marchili , Thomas P. Krichbaum , Lars Fuhrmann , Anton Zensus , Tao An

High redshift blazars are among the most powerful objects in the Universe. Although they represent a significant fraction of the extragalactic hard X-ray sky, they are not commonly detected in gamma-rays. High redshift (z>2) objects…

High Energy Astrophysical Phenomena · Physics 2015-03-03 M. Orienti , F. D'Ammando , M. Giroletti , D. Dallacasa , T. Venturi , J. Finke , M. Ajello

We present deep L-Band observations of the equatorial field centered on the z=6.3 SDSS QSO, reaching a 1 sigma sensitivity of ~2.5 uJy at the center of the field. We extracted a catalog of 1489 radio sources down to a flux density of ~12.5…

We present Very Large Array observations at 1.4 and 5 GHz of a sample of 16 quasi-stellar objects (QSOs) at z = 1.78 to 2.71. Half of the chosen quasars are bright at mm wavelengths (250 or 350 GHz) while the other half were not detected at…

Astrophysics · Physics 2008-11-26 A. Petric , C. L. Carilli , F. Bertoldi , A. Beelen , P. Cox , A. Omont

We applied image stacking on empty-field Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey maps centred on optically identified high-redshift quasars at $z\geq4$ to uncover the hidden $\mu$Jy radio emission in these active…

Astrophysics of Galaxies · Physics 2020-07-07 Krisztina Perger , Sándor Frey , Krisztina É. Gabányi , L. Viktor Tóth

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.…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Caitlin M. Casey , Scott C. Chapman , Tom W. B. Muxlow , Rob J. Beswick , David M. Alexander , Christopher J. Conselice

We present near-infrared spectra of young radio quasars [P(1.4GHz) ~ 26-27 W/Hz] selected from the Wide-Field Infrared Survey Explorer. The detected objects have typical redshifts of z ~ 1.6-2.5 and bolometric luminosities ~ 10^47 erg/s.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Minjin Kim , Luis C. Ho , Carol J. Lonsdale , Mark Lacy , Andrew W. Blain , Amy E. Kimball

The parsec-scale radio properties of 232 active galactic nuclei (AGNs), most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long…

High Energy Astrophysical Phenomena · Physics 2015-06-11 J. D. Linford , G. B. Taylor , F. K. Schinzel

We report the 888 MHz radio detection in the Rapid ASKAP Continuum Survey (RACS) of VIK J2318$-$3113, a $z$=6.44 quasar. Its radio luminosity (1.2 $\times 10^{26}$ W Hz$^{-1}$ at 5 GHz) compared to the optical luminosity (1.8 $\times…

Astrophysics of Galaxies · Physics 2021-03-24 L. Ighina , S. Belladitta , A. Caccianiga , J. W. Broderick , G. Drouart , A. Moretti , N. Seymour

Radio and gamma-ray emission from active galactic nuclei (AGN) are thought to share a common origin, related to the ejection phenomena in the vicinity of supermassive black holes. Thanks to its sensitivity, surveying capability, and broad…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-29 M. Giroletti , A. Reimer , L. Fuhrmann , V. Pavlidou , J. L. Richards

Non-blazar Active Galactic Nuclei (AGN) have emerged as a new gamma-ray emitting source class on the extragalactic sky and started to deepen our understanding of the physical processes and the nature of AGN in general. The detection of…

High Energy Astrophysical Phenomena · Physics 2017-07-10 Frank M. Rieger

We present a sample of 252 broad-line Active Galactic Nuclei (BLAGNs), incorporating 171 newly identified sources, spanning a redshift interval from $z$ = 0.8 to 7.2. We have analyzed spectroscopic data from the NIRSpec instrument aboard…

Astrophysics of Galaxies · Physics 2025-12-04 Caroline Baccus , Xinfeng Xu

Most $\gamma$-ray detected active galactic nuclei are blazars with one of their relativistic jets pointing towards the Earth. Only a few objects belong to the class of radio galaxies or misaligned blazars. Here, we investigate the nature of…

High Energy Astrophysical Phenomena · Physics 2024-01-17 H. E. S. S. Collaboration , F. Aharonian , F. Ait Benkhali , J. Aschersleben , H. Ashkar , M. Backes , A. Baktash , V. Barbosa Martins , J. Barnard , R. Batzofin , Y. Becherini , D. Berge , K. Bernlöhr , B. Bi , M. Böttcher , C. Boisson , J. Bolmont , M. de Bony de Lavergne , J. Borowska , F. Bradascio , M. Breuhaus , R. Brose , A. Brown , F. Brun , B. Bruno , T. Bulik , C. Burger-Scheidlin , T. Bylund , S. Caroff , S. Casanova , R. Cecil , J. Celic , M. Cerruti , T. Chand , S. Chandra , A. Chen , J. Chibueze , O. Chibueze , G. Cotter , J. Damascene Mbarubucyeye , I. D. Davids , J. Djuvsland , A. Dmytriiev , V. Doroshenko , K. Egberts , S. Einecke , J. -P. Ernenwein , G. Fontaine , M. Füßling , S. Funk , S. Gabici , S. Ghafourizadeh , G. Giavitto , D. Glawion , J. F. Glicenstein , J. Glombitza , P. Goswami , G. Grolleron , L. Haerer , J. A. Hinton , T. L. Holch , M. Holler , D. Horns , M. Jamrozy , F. Jankowsky , V. Joshi , I. Jung-Richardt , E. Kasai , K. Katarzyński , R. Khatoon , B. Kh'elifi , z , niak , Nu. Komin , K. Kosack , D. Kostunin , R. G. Lang , S. Le Stum , F. Leitl , A. Lemière , J. -P. Lenain , F. Leuschner , A. Luashvili , J. Mackey , R. Marx , A. Mehta , M. Meyer , A. Mitchell , R. Moderski , A. Montanari , E. Moulin , M. de Naurois , J. Niemiec , P. O'Brien , S. Ohm , L. Olivera-Nieto , E. de Ona Wilhelmi , M. Ostrowski , S. Panny , R. D. Parsons , S. Pita , D. A. Prokhorov , G. Pühlhofer , M. Punch , A. Quirrenbach , P. Reichherzer , A. Reimer , O. Reimer , H. Ren , F. Rieger , B. Rudak , V. Sahakian , H. Salzmann , D. A. Sanchez , M. Sasaki , F. Schüssler , H. M. Schutte , J. N. S. Shapopi , H. Sol , A. Specovius , S. Spencer , L. , Stawarz , R. Steenkamp , S. Steinmassl , K. Streil , I. Sushch , H. Suzuki , T. Takahashi , T. Tanaka , C. van Eldik , M. Vecchi , J. Veh , C. Venter , S. J. Wagner , A. Wierzcholska , M. Zacharias , D. Zargaryan , A. A. Zdziarski , A. Zech , S. Zouari , N. Żywucka

We present the results from the first large (>100 source) 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN). The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 I. Agudo , C. Thum , H. Wiesemeyer , T. P. Krichbaum
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