scholarly journals The role of the central stellar cluster in active galactic nuclei

2002 ◽  
Vol 387 (3) ◽  
pp. 804-817 ◽  
Author(s):  
E. Y. Vilkoviskij ◽  
B. Czerny
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Stellar Cluster

scholarly journals Wolf-Rayet stars in Active Galactic Nuclei

1999 ◽  
Vol 193 ◽  
pp. 760-761
Author(s):  
Robin J.R. Williams ◽  
John E. Dyson ◽  
Judith J. Perry
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
Emission Lines ◽  
Supply Rate ◽  
Stellar Cluster ◽  
Uv Emission ◽  
Ram Pressure

Starbursts, black holes and AGN have strong observational links, as discussed elsewhere in these proceedings. Perry & Dyson (1985 (PD), see also Perry 1994) studied the role of shocks around supernovae and stellar wind bubbles in the nuclei of active galaxies. Both the ejecta and the ambient ISM are initially shocked to high temperatures. PD found that while the shocked gas is maintained at high pressure by ram pressure, it cools rapidly, to then produce the observed optical and UV emission lines. The mass supply rate from the nuclear starburst, inferred from the strength of the emission lines, tallies well with that required by an accreting black hole to generate the observed luminosity. A symbiosis between a starburst stellar cluster and an accreting black hole naturally generates the observational features associated with QSOs.

scholarly journals Understanding the origin of radio outflows in Seyfert galaxies using radio polarimetry

2019 ◽  
Vol 15 (S356) ◽  
pp. 247-251
Author(s):  
Biny Sebastian ◽  
Preeti Kharb ◽  
Christopher P. O’ Dea ◽  
Jack F. Gallimore ◽  
Stefi A. Baum ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Seyfert Galaxies ◽  
Starburst Galaxies ◽  
Galactic Magnetic Fields ◽  
5 Ghz

AbstractThe role of starburst winds versus active galactic nuclei (AGN) jets/winds in the formation of the kiloparsec scale radio emission seen in Seyferts is not yet well understood. In order to be able to disentangle the role of various components, we have observed a sample of Seyfert galaxies exhibiting kpc-scale radio emission suggesting outflows, along with a comparison sample of starburst galaxies, with the EVLA B-array in polarimetric mode at 1.4 GHz and 5 GHz. The Seyfert galaxy NGC 2639, shows highly polarized secondary radio lobes, not observed before, which are aligned perpendicular to the known pair of radio lobes. The additional pair of lobes represent an older epoch of emission. A multi-epoch multi-frequency study of the starburst-Seyfert composite galaxy NGC 3079, reveals that the jet together with the starburst superwind and the galactic magnetic fields might be responsible for the well-known 8-shaped radio lobes observed in this galaxy. We find that many of the Seyfert galaxies in our sample show bubble-shaped lobes, which are absent in the starburst galaxies that do not host an AGN.

scholarly journals The Role of Active Galactic Nuclei in the Quenching of Massive Galaxies in the SQuIGG$\vec{L}$E Survey

2020 ◽  
Vol 899 (1) ◽  
pp. L9
Author(s):  
Jenny E. Greene ◽  
David Setton ◽  
Rachel Bezanson ◽  
Katherine A. Suess ◽  
Mariska Kriek ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Massive Galaxies

scholarly journals MAGNETIC FIELD EFFECTS NEAR THE LAUNCHING REGION OF ASTROPHYSICAL JETS

2010 ◽  
Vol 19 (06) ◽  
pp. 729-739 ◽  
Author(s):  
E. M. DE GOUVEIA DAL PINO ◽  
G. KOWAL ◽  
L. H. S. KADOWAKI ◽  
P. PIOVEZAN ◽  
A. LAZARIAN
Keyword(s):  
Magnetic Field ◽  
Active Galactic Nuclei ◽  
Magnetic Energy ◽  
Galactic Nuclei ◽  
Young Stellar Objects ◽  
Magnetic Field Effects ◽  
Astrophysical Jets ◽  
Stellar Objects ◽  
Fundamental Properties

One of the fundamental properties of astrophysical magnetic fields is their ability to change topology through reconnection and in doing so, to release magnetic energy, sometimes violently. In this work, we review recent results on the role of magnetic reconnection and associated heating and particle acceleration in jet/accretion disk systems, namely young stellar objects (YSOs), microquasars, and active galactic nuclei (AGNs).

scholarly journals Polarization Properties of Active Galactic Nuclei

1997 ◽  
Vol 163 ◽  
pp. 600-609
Author(s):  
J. H. Hough
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Size Scale ◽  
Direct View ◽  
Made In

AbstractOne of the main uses of polarimetry over the last decade, has been to identify the nature of AGN that are normally hidden from direct view by an optically and geometrically thick torus, and thereby to unify different classes of AGN. Of growing importance is the role that polarimetry can play in our understanding of the properties and structure of AGN on a size scale which cannot be resolved directly. We review the progress being made in understanding the role of disks, extended scattering regions, and the obscuring torus in AGN.

scholarly journals Collimated Bipolar Outflow and the Formation of Nuclear Spirals; Possible Role of Magnetic Fields

1990 ◽  
Vol 140 ◽  
pp. 447-448
Author(s):  
P. Pismis ◽  
E. Moreno ◽  
A. Garcia-Barreto
Keyword(s):  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Radio Galaxies ◽  
The Past ◽  
Bipolar Outflow ◽  
The Difference ◽  
Observational Techniques ◽  
Quasars And Radio Galaxies

The existence of non–steady phenomena, namely activity in the form of radial motions (outflow) of matter from the nuclei of galaxies is well established at present. Active Galactic Nuclei (AGN) constitute a topic of great interest and are intensively studied by all existing observational techniques. Conventionally objects classified as AGN span a range from quasars, radio galaxies to Seyferts 1 and 2. It appears, however, that there exist galaxies which exhibit somewhat milder activity which does not qualify their inclusion in the AGN group. The designation of MAGN (M for mildly) was suggested in the past (Pismis, 1986) to cover the less energetic nuclei. It may be reasonable to consider that active nuclei form a sequence, the difference along it being due to the energetics of the nuclei, from the most active quasars and radio galaxies down to the mildest ones like M31 or our Galaxy. The phenomenon underlying the activity may thus be universal, subject to the intrinsic energetics of the nuclei (Pismis, 1987).

scholarly journals On the radio image of relativistic jets – I. Internal structure, Doppler boosting, and polarization maps

2019 ◽  
Vol 488 (1) ◽  
pp. 224-233 ◽  
Author(s):  
A V Chernoglazov ◽  
V S Beskin ◽  
V I Pariev
Keyword(s):  
Active Galactic Nuclei ◽  
Internal Structure ◽  
Linear Polarization ◽  
Ambient Pressure ◽  
Galactic Nuclei ◽  
Synchrotron Emission ◽  
Relativistic Jets ◽  
Radio Image ◽  
Radial Profiles

ABSTRACT In this first paper from forthcoming series of works devoted to radio image of relativistic jets from active galactic nuclei the role of internal structure of a flow is discussed. We determine the radial profiles of all physical values for reasonable Michel magnetization parameter σM and ambient pressure Pext. Maps of Doppler boosting factor δ and observed directions of linear polarization of synchrotron emission are also constructed.

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