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The Centaurus A radio galaxy, due to its proximity, presents itself as one of the few systems that allow the study of relativistic jet outflows at sub-parsec distances from the central supermassive black holes, with high signal to noise. We…

高能天体物理现象 · 物理学 2024-12-03 Steve Prabu , Steven J Tingay , Arash Bahramian , James C. A. Miller-Jones , Callan M. Wood , Shane P. O'Sullivan

We present a multiwavelength study of the nucleus, environment, jets, and hotspots of the nearby FRII radio galaxy 3C 321, using new and archival data from MERLIN, the VLA, Spitzer, HST, and Chandra. An initially collimated radio jet…

Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When…

天体物理学 · 物理学 2011-02-11 L. Stawarz , C. C. Cheung , D. E. Harris , M. Ostrowski

We present a detailed study of the X-ray, optical and radio emission from the jet, lobes and core of the quasar PKS 2101-490 as revealed by new Chandra, HST and ATCA images. We extract the radio to X-ray spectral energy distributions from…

We present new results on the shock around the southwest radio lobe of Centaurus A using data from the Chandra Very Large Programme observations. The X-ray spectrum of the emission around the outer southwestern edge of the lobe is well…

The {\gamma}-ray data of Fermi-LAT on the giant lobes of Centaurus A are analysed together with the high frequency radio data obtained with the Planck satellite. The large {\gamma}-ray photon statistics, accumulated during seven years of…

高能天体物理现象 · 物理学 2017-08-09 Xiao-na Sun , Rui-zhi Yang , Benjamin Mckinley , Felix Aharonian

The recent discovery of the gamma-ray emission from the lobes of the closest radio galaxy Centaurus A by Fermi implies the presence of high-energy electrons at least up to gamma ~ 10^5 - 10^6. These high-energy electrons are required to…

高能天体物理现象 · 物理学 2015-05-27 F. Massaro , M. Ajello

We have mapped the powerful radio galaxy Hercules A at six frequencies spanning 1295 to 8440 MHz using the VLA in all four configurations. Here we discuss the structure revealed in total intensity, spectral index, polarization, and…

天体物理学 · 物理学 2009-11-07 Nectaria A. B. Gizani , J. P. Leahy

Centaurus A, at a distance of less than 4 Mpc, is the nearest radio-loud AGN. Its emission is detected from radio to very-high energy gamma-rays. Despite the fact that Cen A is one of the best studied extragalactic objects the origin of its…

高能天体物理现象 · 物理学 2015-05-14 H. Steinle

We report on the very first radio detection associated with the peculiar hourglass-morphology X-rays surrounding 3C 294 at z=1.8. Using International Low Frequency Array (LOFAR) data at 144 MHz and Chandra data at 0.3-6 keV, we find that…

星系天体物理 · 物理学 2025-12-19 Vijay H. Mahatma , Andrew C. Fabian , Leah K. Morabito

This paper presents observations of Cygnus A at 74 and 327 MHz at angular resolutions of approximately 10" and 3", respectively. These observations are among the highest angular resolutions obtained below 1000 MHz for this object. While the…

天体物理学 · 物理学 2009-11-11 T. J. W. Lazio , A. S. Cohen , N. E. Kassim , R. A. Perley , W. C. Erickson , C. L. Carilli , P. C. Crane

We present evidence for the presence of a weak compact jet during a soft X-ray state of Cygnus X-1. Very-high-resolution radio observations were taken with the VLBA, EVN and MERLIN during a hard-to-soft spectral state change, showing the…

Centaurus A is the closest radio-loud active galaxy. Very Long Baseline Interferometry (VLBI) enables us to study the jet-counterjet system on milliarcsecond (mas) scales, providing essential information for jet emission and propagation…

We present simultaneous dual-frequency radio observations of Cygnus X-3 during a phase of low-level activity. We constrain the minimum variability timescale to be 20 minutes at 43 GHz and 30 minutes at 15 GHz, implying source sizes of 2 to…

We present high sensitivity radio observations of the merging cluster A521, at a mean redsfhit z=0.247. The observations were carried out with the GMRT at 610 MHz and cover a region of $\sim$1 square degree, with a sensitivity limit of…

天体物理学 · 物理学 2009-11-11 S. Giacintucci , T. Venturi , S. Bardelli , G. Brunetti , R. Cassano , D. Dallacasa

We model the observed size and brightness of the VLBA radio core of the jet in Cygnus X-1 to derive an expression for the jet power as a function of basic jet parameters. We apply this expression to recent constraints on the jet power from…

天体物理学 · 物理学 2009-11-13 Sebastian Heinz

A sub-parsec scale radio counterjet has been detected in the nucleus of the closest radio galaxy, Centaurus A (NGC 5128), with VLBI imaging at 2.3 and 8.4 GHz. This is one of the first detections of a VLBI counterjet and provides new…

We report the discovery of a putative radio relic, 830 kpc in length and found toward the outskirts of galaxy cluster Abell 1697 ($z=0.181$), using the LOFAR Two Meter Sky Survey (LoTSS) at 144 MHz. With an X-ray-inferred mass of…

星系天体物理 · 物理学 2020-01-15 Surajit Paul , Sameer Salunkhe , Satish Sonkamble , Prateek Gupta , Tony Mroczkowski , Somak Raychaudhury

We present new radio observations of the brighter region of the northern lobe (the Northern Middle Lobe, NML) of Centaurus A obtained at 20 cm with the Australia Telescope Compact Array. The angular resolutions are ~50 and ~130 arcsec,…

天体物理学 · 物理学 2009-10-31 R. Morganti , N. E. B. Killeen , R. D. Ekers , T. A. Oosterloo