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相关论文: Accretion disk versus jet orientation in H$_{2}$O …

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We investigate the nuclear environment of galaxies with observed 22 GHz water megamaser in their subparsec edge-on accretion disks, using 33 GHz (9mm) radio continuum data from VLA, with a resolution of ~ 0.2-0.5 arcsecs, and relate the…

(abbreviated): This paper presents the results of a high resolution radio imaging survey of all known (96) low-luminosity active galactic nuclei (LLAGNs) at D<19Mpc. We find that almost half of all LINERs and low-luminosity Seyferts have…

天体物理学 · 物理学 2009-11-07 N. M. Nagar , H. Falcke , A. S. Wilson , J. S. Ulvestad

Accretion rates in radio galaxies are typically estimated from optical and total radio flux measurements, incorporating emission from the core, jets, and lobes. These estimates can be used to investigate the link between observed Active…

The 25 years following the serendipitous discovery of megamasers have seen tremendous progress in the study of luminous extragalactic H$_2$O emission. Single-dish monitoring and high resolution interferometry have been used to identify…

天体物理学 · 物理学 2009-11-10 C. Henkel , J. A. Braatz , A. Tarchi , A. B. Peck , N. M. Nagar , L. J. Greenhill , M. Wang , Y. Hagiwara

We study a sample of 44 low-luminosity radio-loud AGN, which represent a range of nuclear radio-power spanning 5 orders of magnitude, to unveil the accretion mechanism in these galaxies. We estimate the accretion rate of gas associated with…

天体物理学 · 物理学 2009-11-13 Barbara Balmaverde , Ranieri D. Baldi , Alessandro Capetti

We present the accretion disk size estimates for a sample of 19 active galactic nuclei (AGN) using the optical $g$, $r$, and $i$ band light curves obtained from the Zwicky Transient Facility (ZTF) survey. All the AGN have reliable…

星系天体物理 · 物理学 2022-01-14 Vivek Kumar Jha , Ravi Joshi , Hum Chand , Xue-Bing Wu , Luis C. Ho , Shantanu Rastogi , Qinchun Ma

A thorough study of radio emission in Active Galactic Nuclei (AGN) is of fundamental importance to understand the physical mechanisms responsible for the emission and the interplay between accretion and ejection processes. High frequency…

星系天体物理 · 物理学 2020-05-27 E. Chiaraluce , F. Panessa , G. Bruni , R. D. Baldi , E. Behar , F. Vagnetti , F. Tombesi , I. McHardy

We use HST broad band images, VLA and VLBI continuum data to study the three dimensional orientation of jets relative to nuclear dust disks in 20 radio galaxies. The comparison between the position angles of the jets with those of the dust…

天体物理学 · 物理学 2009-11-07 H. R. Schmitt , J. E. Pringle , C. J. Clarke , A. L. Kinney

Based on spectroscopic signatures, about one-third of known H$_2$O maser sources in active galactic nuclei (AGN) are believed to arise in highly inclined accretion disks around central engines. These "disk maser candidates" are of interest…

宇宙学与河外天体物理 · 物理学 2014-11-20 Lincoln J. Greenhill , Paul T. Kondratko , James M. Moran , Avanti Tilak

We examine the alignment between H_2O megamaser disks on sub-pc scales with circumnuclear disks and bars on <500 pc scales observed with HST/WFC3. The HST imaging reveals young stars, indicating the presence of gas. The megamaser disks are…

We review the latest attempts to determine the accretion geometry in radio-loud active galactic nuclei (AGN). These objects, which comprise ~10-20% of the AGN population, produce powerful collimated radio jets that can extend thousands of…

天体物理学 · 物理学 2008-11-26 D. R. Ballantyne

We present the study of arcsecond scale radio continuum and OH line emission of a sample of known OH megamaser galaxies with $z \geq$ 0.15 using archival Very Large Array (VLA) data. And also the results of our pilot Five hundred meter…

Active galactic nuclei jets are detected via their radio and/or gamma-ray emissions while the accretion disks are detected by their optical and UV radiation. Observations of the radio and optical luminosities show a strong correlation…

星系天体物理 · 物理学 2015-06-23 Vahe Petrosian , Jack Singal

We study the orientation of accretion disks, traced by the position angle of the jet, relative to the dust disk major axis in a sample of 20 nearby Radio Galaxies. We find that the observed distribution of angles between the jet and dust…

天体物理学 · 物理学 2007-05-23 Henrique R. Schmitt

The correlation between the jet power and accretion disk luminosity is investigated and analyzed with our model for 7 samples of low luminosity active galactic nuclei (LLAGNs). The main results are: (1) the power-law correlation index…

星系天体物理 · 物理学 2016-12-14 Renzhi Su , Xiang Liu , Zhen Zhang

Various studies have laid claim to finding an alignment of the polarization vectors or radio jets of active galactic nuclei (AGN) over large distances, but these results have proven controversial and so far, there is no clear explanation…

We analyze the broadband photometric light curves of Seyfert 1 galaxies from the Sergeev et al. (2005) sample and find that a) perturbations propagating across the continuum emitting region are a general phenomenon securely detected in most…

宇宙学与河外天体物理 · 物理学 2015-06-16 Doron Chelouche

The innermost regions of Active Galactic Nuclei (AGN) are critical for understanding galaxy evolution and the dynamics of matter near a Supermassive Black Hole (SMBH). Yet, due to smaller angular projections, it is very difficult to resolve…

星系天体物理 · 物理学 2024-02-07 Vivek Kumar Jha

We present the largest visually selected sample of extended ($>$60 arcsec) radio-loud active galactic nuclei (RLAGN) to date, based on the LOw-Frequency Array Two-Metre Sky Survey second data release (LoTSS DR2). From the broader LoTSS DR2…

The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion…

星系天体物理 · 物理学 2015-08-06 Ehud Behar , Ranieri D. Baldi , Ari Laor , Assaf Horesh , Jamie Stevens , Tasso Tzioumis
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