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相关论文: Low Power Compact Radio Galaxies at High Angular R…

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The statistical study of the parsec scale properties of radio sources is crucial to get information on the nature of the central engine and to provide the foundations of the current unified theories, suggesting that the appearance of active…

星系天体物理 · 物理学 2015-04-14 Elisabetta Liuzzo , Gabriele Giovannini , Marcello Giroletti

We present full polarization Very Long Baseline Array (VLBA) observations at 5 GHz and 15 GHz of 24 compact active galactic nuclei (AGN). These sources were observed as part of a pilot project to demonstrate the feasibility of conducting a…

Context: Until now, there have only been seven quasars at z>4.5 whose the high-resolution radio structure had been studied in detail with Very Long Baseline Interferometry (VLBI) imaging. Aims: We almost double the number of VLBI-imaged…

宇宙学与河外天体物理 · 物理学 2010-11-30 S. Frey , Z. Paragi , L. I. Gurvits , D. Cseh , K. E. Gabanyi

We present sub-arcsecond ($\theta\sim0.1^{\prime\prime}$) resolution VLA 1.3 cm continuum and 22.2 GHz H$_2$O maser observations toward 15 compact radio continuum sources with rising spectral index and 8 string-like radio continuum…

太阳与恒星天体物理 · 物理学 2026-01-19 Tatiana M. Rodriguez , Peter Hofner , Emmanuel Momjian , Esteban D. Araya , Ananay Sethi , Viviana Rosero

We observed 20 Palomar-Green (PG) quasars at low redshift ($z<0.5$) with total flux density > 1 mJy, including 4 radio-loud quasars (RLQs) and 16 radio-quiet quasars (RQQs), using the Very Long Baseline Array (VLBA) at 5 GHz. Ten RQQs are…

星系天体物理 · 物理学 2022-11-01 Ailing Wang , Tao An , Xiaopeng Cheng , Luis C. Ho , Kenneth I. Kellermann , Willem A. Baan , Jun Yang , Yingkang Zhang

We present results from 4.8 GHz VLA and Global-VLBI observations of the northern half of the moderate FIR luminosity (median L_IR = 10^11.01 L_Sol) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90)…

宇宙学与河外天体物理 · 物理学 2015-05-19 R. Parra , J. E. Conway , S. Aalto , P. N. Appleton , R. P. Norris , Y. M. Pihlstroem , L. J. Kewley

We present the analysis of VLA and VLBA observations of the radio source 3C 338, associated with the cD galaxy NGC 6166, the central dominant galaxy of the cluster Abell 2199. The VLBA observations were done at 8.4 and 15.4 GHz, while the…

天体物理学 · 物理学 2011-02-11 G. Gentile , C. Rodriguez , G. B. Taylor , G. Giovannini , S. W. Allen , W. M. Lane , N. E. Kassim

We investigate the nature of low-luminosity radio-loud active galactic nuclei (RLAGN) selected from the LOFAR Two-metre Sky Survey (LoTSS) first data release (DR1). Using optical, mid-infrared, and radio data, we have conservatively…

A significant fraction of compact radio-loud quasars display most of the characteristics of relativistically beamed, high-optical polarization blazars, yet are weakly polarized in the optical regime. We have used the VLBA at 22 and 43 GHz…

天体物理学 · 物理学 2009-10-31 Matthew L. Lister , Paul S. Smith

The first Fermi-LAT High-energy source catalog (1FHL), containing gamma-ray sources detected above 10 GeV, is an ideal sample to characterize the physical properties of the most extreme gamma-ray sources. We investigate the pc scale…

高能天体物理现象 · 物理学 2016-10-19 R. Lico , M. Giroletti , M. Orienti , F. D'Ammando

VLBA observations are presented for 6 compact radio sources selected from the Peacock & Wall catalogue. From the new morphological and spectral information 2 objects that in the Peacock and Wall catalogue are flat spectrum (alpha < 0.5)…

天体物理学 · 物理学 2009-11-10 A. Rossetti , F. Mantovani , D. Dallacasa , C. Fanti , R. Fanti

The NRAO Very Long Baseline Array (VLBA) was used at 1.4 GHz to image 20 compact sources in the inner 1-degree radius of the Spitzer VLA First-Look Survey. Twelve sources were detected with the VLBA, with peak flux densities above 2 mJy at…

天体物理学 · 物理学 2009-11-10 J. M. Wrobel , M. A. Garrett , J. J. Condon , R. Morganti

Using the JVLA, we explored the Galactic center (GC) with a resolution of 0.05" at 33.0 and 44.6 GHz. We detected 64 hyper-compact radio sources (HCRs) in the central parsec. The dense group of HCRs can be divided into three spectral types:…

星系天体物理 · 物理学 2022-03-09 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

Multifrequency Very Long Baseline Array (VLBA) observations were performed to study the radio morphology and the synchrotron spectra of four high frequency peaking radio sources. They are resolved in several compact components and the radio…

宇宙学与河外天体物理 · 物理学 2015-06-17 M. Orienti , D. Dallacasa

The radio bright zone (RBZ) at the Galactic center has been observed with the JVLA in the A, B and C array configurations at 5.5 and 9 GHz. With a procedure for high-dynamic range imaging developed on CASA, we constructed deep images a…

高能天体物理现象 · 物理学 2020-10-26 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

Low-luminosity active galactic nuclei (LLAGNs) often host weak radio jets whose propagation is shaped by the surrounding interstellar medium. We investigate the nearby LLAGN NGC7213 to assess its ability to launch collimated outflows beyond…

星系天体物理 · 物理学 2026-05-12 G. Bruni , F. Panessa , E. Kammoun , A. L. Thakur , C. Reynolds , R. Ricci , M. Wieringa , S. Bianchi , A. De Rosa , G. Matt , F. Nicastro , F. Ursini

We report the results of high-resolution 5 GHz Very Long Baseline Array and European VLBI Network observations of 36 nearby galaxies, an extension of the Legacy e-MERLIN Multi-band Imaging of Nearby Galaxies (LeMMINGs) survey. Our sample…

We present archival high spatial resolution VLA and VLBA data of the nuclei of seven of the nearest and brightest Seyfert galaxies in the Southern Hemisphere. At VLA resolution (~0.1 arcsec), the nucleus of the Seyfert galaxies is…

宇宙学与河外天体物理 · 物理学 2015-05-14 M. Orienti , M. A. Prieto

Among radio galaxies, compact sources are a class of objects not yet well understood, and most of them cannot be included in classical populations of compact radio sources (flat spectrum AGN or compact steep spectrum sources). Our main goal…

宇宙学与河外天体物理 · 物理学 2015-06-11 E. Liuzzo , S. Buttiglione , G. Giovannini , M. Giroletti , S. Capetti , G. B. Taylor

Compact Symmetric Objects (CSOs) are small (less than 1 kpc) radio sources which have symmetric double lobes or jets. The dominant theory for the small size of these objects is that they are young radio sources which could grow into larger…

星系天体物理 · 物理学 2010-11-11 S. E. Tremblay , G. B. Taylor , J. F. Helmboldt , C. D. Fassnacht , R. W. Romani