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Mrk 1388 has an unusual Seyfert nucleus that shows narrow emission-line components without broad ones, but shows a strong featureless continuum and strong iron-forbidden high-ionization emission lines. The apparent coexistence of type-1/2…

星系天体物理 · 物理学 2015-06-23 Akihiro Doi

We have analyzed new, archival and published high resolution radio and X-ray observations of a sample of composite LINER/HII galaxies known to exhibit AGN-like properties. Five of the 16 AGN candidates have milliarcsecond-scale detections…

天体物理学 · 物理学 2009-11-10 M. E. Filho , F. Fraternali , S. Markoff , N. M. Nagar , P. D. Barthel , L. C. Ho , F. Yuan

We study the radio properties at 1.4 GHz of Seyfert galaxies with strong forbidden high-ionization lines (FHILs), selected from the Sloan Digital Sky Survey - a large-sized sample containing nearly equal proportion of diverse range of…

星系天体物理 · 物理学 2016-01-05 Dharam V. Lal

We present 115 compact radio point sources in three galaxies, NGC 5474, NGC 4631 and M51, taken in the most extended (A-)configuration of the Karl G. Jansky Very Large Array at 10GHz. Several of these compact radio point sources have…

Occupying the intermediate-mass regime of the accretion--jet parameter space, radio continuum emission from active galactic nuclei with black hole mass M_BH <~ 10^6 Msun (low-mass AGNs) is a valuable probe to the physics of relativistic…

星系天体物理 · 物理学 2024-01-30 Jin-Zhi Wu , Xiao-Bo Dong , Lei Qian , Wen-Juan Liu , Fu-Guo Xie , Bo Peng

We present new Giant Metrewave Radio Telescope observations at 235 MHz and 610 MHz of 18 X-ray bright galaxy groups. These observations are part of an extended project, presented here and in future papers, which combines low-frequency radio…

Results are presented of extended and refined optical identification of 181 radio/X-ray sources in the RASS-Green Bank (RGB) catalog which have been spectroscopically observed in the Sloan digital sky survey (SDSS) DR5. For 72 sources, the…

高能天体物理现象 · 物理学 2009-09-24 Deliang Wang , Jianguo Wang , Xiaobo Dong

Near-infrared spectroscopy (rest-frame 3700-6800 Angstroms) of eight high redshift powerful radio galaxies (HzPRGs) at z = 2.2-2.6 is presented. Strong forbidden lines and H-alpha emission were detected in all sources; the data show…

天体物理学 · 物理学 2009-10-30 A. S. Evans

We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN(1-0) and HCO$^+$(1-0) for 3 objects. In NGC 3079 the lines show complex profiles as a result of…

Although the properties of the narrow-line region (NLR) of active galactic nuclei(AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of…

宇宙学与河外天体物理 · 物理学 2015-06-11 L. Vaona , S. Ciroi , F. Di Mille , V. Cracco , G. La Mura , P. Rafanelli

Our understanding of the unification of jetted AGNs has advanced greatly as the size of extragalactic sources increased. In the present paper, based on the large sample of radio sources, we compiled 680 blazars (279 FSRQs and 401 BL Lacs)…

星系天体物理 · 物理学 2021-11-17 E. U. Iyida , I. O. Eya , F. C. Odo

We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio…

星系天体物理 · 物理学 2018-06-27 A. Lähteenmäki , E. Järvelä , V. Ramakrishnan , M. Tornikoski , J. Tammi , R. J. C. Vera , W. Chamani

We present here new VLBI observations of one FR-I radio galaxy (NGC2484) and two Broad Line FR-II radio galaxies (3C109 and 3C382). For 3C109 new VLA maps are also shown. These sources belong to a complete sample of radio galaxies under…

天体物理学 · 物理学 2009-10-22 G. Giovannini , L. Feretti , T. Venturi , L. Lara , J. Marcaide , M. Rioja , S. R. Spangler , A. E. Wehrle

Variable gamma-ray emission has been discovered in five Radio-loud Narrow Line Seyfert 1 (NLSy1) galaxies by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope. This has clearly demonstrated that these NLSy1 galaxies…

高能天体物理现象 · 物理学 2015-06-15 Vaidehi S. Paliya , C. S. Stalin , Amit Shukla , S. Sahayanathan

Less than $200$ radio-loud active galactic nuclei (AGN) are known above redshift $4$. Around $40$ of them have been observed at milliarcsecond (mas) scale resolution with very long baseline interferometry (VLBI) technique. Some of them are…

Among the large varieties of active galactic nuclei (AGN) known, narrow line Seyfert 1 (NLSy1) galaxies are a puzzling class, particularly after the discovery of $\gamma$-ray emission in a handful of them using observations from the Fermi…

星系天体物理 · 物理学 2019-01-09 Suvendu Rakshit , C. S. Stalin , Ananda Hota , Chiranjib Konar

This paper presents infrared spectra taken with the newly commissioned NIRSPEC spectrograph on the Keck II Telescope of the High Redshift Radio Galaxy MRC 2025-218 (z=2.63) These observations represent the deepest infrared spectra of a…

[Abridged] Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that have all the properties of type 1 Seyfert galaxies but show peculiar characteristics, including the narrowest Balmer lines, strongest Fe II…

宇宙学与河外天体物理 · 物理学 2015-05-28 A. Tarchi , P. Castangia , A. Columbano , F. Panessa , J. A. Braatz

We discuss the properties of compact nuclear radio components in Seyfert galaxies from the extended 12-micron AGN sample of Rush et al.(1993). Our main results can be summarised as follows. Type 1 and type 2 Seyferts produce compact radio…

天体物理学 · 物理学 2009-11-06 Andy Thean , Alan Pedlar , Marek J. Kukula , Stefi A. Baum , Christopher P. O'Dea

We present near-IR integral field spectroscopy of a sample of 31 Seyfert and LINER galaxies which were selected both to span a wide range of nuclear magnitudes and to possess roughly equal numbers of Seyfert type 1 and 2 nuclei. Moderate…

天体物理学 · 物理学 2009-11-06 R. M. Sosa-Brito , L. E. Tacconi-Garman , M. D. Lehnert , J. F. Gallimore