Results 21 to 30 of about 39,820 (206)

Deciphering Radio Emissions from Accretion Disk Winds in Radio-quiet Active Galactic Nuclei

The Astrophysical Journal
Unraveling the origins of radio emissions from radio-quiet active galactic nuclei (RQ AGNs) remains a pivotal challenge in astrophysics. One potential source of this radiation is the shock interaction between AGN disk winds and the interstellar medium ...
Tomoya Yamada, Nobuyuki Sakai, Yoshiyuki Inoue, Tomonari Michiyama   +3 more
doaj   +3 more sources

Identifying Radio-active Galactic Nuclei among Radio-emitting Galaxies [PDF]

The Astrophysical Journal, 2021
Abstract Basing our analysis on ROGUE I, a catalog of over 32,000 radio sources associated with optical galaxies, we provide two diagnostics to select the galaxies where the radio emission is dominated by an active galactic nucleus (AGN), referred to in the paper as radio-AGNs. Each of these diagnostics can be applied independently.
D. Kozieł-Wierzbowska, N. Vale Asari, G. Stasińska, F. R. Herpich, M. Sikora, N. Żywucka, A. Goyal   +6 more
openaire   +4 more sources

The Contribution of Active Galactic Nuclei to the Microjansky Radio Population [PDF]

The Astrophysical Journal, 2009
A X-ray background synthesis model is used to calculate the contribution of Active Galactic Nuclei (AGNs) to the 1.4 GHz number counts between 100 nJy and 10 mJy.
Ballantyne, Ballantyne, Ballantyne, Barger, Bell, Benn, Blundell, Bondi, Brinkmann, D. R. Ballantyne, Donley, Fomalont, Gabor, Grogin ., Heckman, Hickox, Hopkins, Hopkins, Hopkins, Hopkins, Huynh, Kellermann, Kellermann, Kim, La Franca, Lawrence, Longair, Moran, Mushotzky, Napier, Padovani, Pierce, Richards, Schawinski, Schinnerer, Serjeant, Shi, Sikora, Silverman, Silverman, Smolčić, Solomon, Spergel, Terashima, Thompson, Tozzi, Treister, Treister, Tueller, Ueda, Wada, Watabe, White, Wilman, Winter, Yun, Zakamska   +56 more
core   +2 more sources

The radio emission from active galactic nuclei [PDF]

Astronomy & Astrophysics, 2021
Context. For nearly seven decades, astronomers have been studying active galaxies, that is to say, galaxies with actively accreting central supermassive black holes: active galactic nuclei (AGN). A small fraction are characterized by luminous, powerful radio emission: This class is known as radio-loud AGN.
J. F. Radcliffe, P. D. Barthel, M. A. Garrett, R. J. Beswick, A. P. Thomson, T. W. B. Muxlow   +5 more
openaire   +5 more sources

The radio dichotomy of active galactic nuclei [PDF]

Publications of the Astronomical Society of Japan, 2022
Abstract The question of radio dichotomy in active galactic nuclei (AGNs) is still in debate, even though it has been discussed for more than 40 years. In order to solve this old riddle, we collect a sample of AGNs with optical B band and radio 6 cm wavelength data to analyze the radio loudness log R. Our results indicate a separation of
Xiao, Hubing, Zhu, Jingtian, Fu, Liping, Zhang, Shaohua, Fan, Junhui   +4 more
openaire   +2 more sources

Low-luminosity radio-loud active galactic nuclei [PDF]

Proceedings of 8th European VLBI Network Symposium — PoS(8thEVN), 2007
I review observational properties of low power radio loud AGN. High resolution VLBI observations allow the estimate of the jet velocity and orientation with respect to the line of sight and the determination of the Doppler factor. These data reveal rich structures, including two-sided jets and secondary components. New results on 1144+35, a giant radio
Giovannini, Gabriele, Giroletti, Marcello   +1 more
openaire   +3 more sources

Ultrafast outflows in radio-loud active galactic nuclei [PDF]

Monthly Notices of the Royal Astronomical Society, 2014
Recent X-ray observations show absorbing winds with velocities up to mildly-relativistic values of the order of ~0.1c in a limited sample of 6 broad-line radio galaxies. They are observed as blue-shifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultra-fast outflows (UFOs) reported in Seyferts and quasars.
Tombesi F., Tazaki F., Mushotzky R. F., Ueda Y., Cappi M., Gofford J., Reeves J. N., Guainazzi M.   +7 more
openaire   +4 more sources

Compact radio cores in radio-quiet active galactic nuclei [PDF]

Astronomy & Astrophysics, 2016
Context. The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGNs) is still debated and might arise from the central AGN, from star formation activity in the host, or from either of these sources. A direct detection of compact and bright radio cores embedded in sources that are classified as RQ can unambiguously determine ...
MAINI, ALESSANDRO, Prandoni, I., Norris, R. P., GIOVANNINI, GABRIELE, Spitler, L. R.   +4 more
openaire   +4 more sources

BeppoSAXView of Radio‐loud Active Galactic Nuclei [PDF]

The Astrophysical Journal, 2006
ApJ accepted, 33 pages, 6 ...
Grandi, Paola, Malaguti, Giuseppe, Fiocchi, Mariateresa   +2 more
openaire   +2 more sources

ENERGETICS AND LIFETIMES OF LOCAL RADIO ACTIVE GALACTIC NUCLEI [PDF]

The Astrophysical Journal, 2015
We present a model describing the evolution of Fanaroff-Riley type I and II radio AGN, and the transition between these classes. We quantify galaxy environments using a semi-analytic galaxy formation model, and apply our model to a volume-limited low redshift ($0.03 \leqslant z \leqslant 0.1$) sample of observed AGN to determine the distribution of jet
Ross J. Turner, Stanislav S. Shabala
openaire   +2 more sources