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We present new millimetre 43 GHz observations of a sample of radio-bright Planetary Nebulae. Such observations were carried out to have a good determination of the high-frequency radio spectra of the sample in order to evaluate, together…

Astrophysics · Physics 2009-11-13 G. Umana , P. Leto , C. Trigilio , C. S. Buemi , P. Manzitto , S. Toscano , S. Dolei , L. Cerrigone

We analyze the long-term evolution of the fluxes of six active galactic nuclei (AGN) - 0923+392, 3C 111, 3C 273, 3C 345, 3C 454.3, and 3C 84 - in the frequency range 80-267 GHz using archival calibration data of the IRAM Plateau de Bure…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 S. Trippe , M. Krips , V. Pietu , R. Neri , J. M. Winters , F. Gueth , M. Bremer , P. Salome , R. Moreno , J. Boissier , F. Fontani

We show the combined spectral analysis of \emph{Chandra} high energy transmission grating (HETG) and \emph{XMM-Newton} reflection grating spectrometer (RGS) observations of the broad-line radio galaxy 3C 111. The source is known to show…

High Energy Astrophysical Phenomena · Physics 2017-06-28 F. Tombesi , C. S. Reynolds , R. F. Mushotzky , E. Behar

We present a combined Suzaku and Swift BAT broad-band E=0.6-200keV spectral analysis of three 3C 111 observations obtained in 2010. The data are well described with an absorbed power-law continuum and a weak (R~0.2) cold reflection…

High Energy Astrophysical Phenomena · Physics 2015-06-16 F. Tombesi , J. N. Reeves , C. S. Reynolds , J. Garcia , A. Lohfink

We determine the characteristics of the 7mm to 20cm wavelength radio variability in Sgr A* on time scales from days to three decades. The amplitude of the intensity modulation is between 30 and 39% at all wavelengths. Analysis of uniformly…

Astrophysics · Physics 2009-11-13 Jean-Pierre Macquart , Geoff Bower

We study the dynamic changes of electron energy distribution (EED) through systematically analysing the quasi-simultaneous spectral energy distributions (SEDs) of the flat spectrum radio quasar 3C 279 in different states. With Markov chain…

High Energy Astrophysical Phenomena · Physics 2016-01-27 Dahai Yan , Jianjian He , Jinyuan Liao , Li Zhang , Shuang-Nan Zhang

We report the results of decade-long (2008-2018) $\gamma$-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, $\it{Fermi}$ and $\it{Swift}$ data, as well as polarimetric and spectroscopic data. The X-ray and…

The recent detection of the "cosmic dawn" redshifted 21 cm signal at 78 MHz by the EDGES experiment differs significantly from theoretical predictions. In particular, the absorption trough is roughly a factor of two stronger than the most…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Jayce Dowell , Greg B. Taylor

We present coronal density profiles derived from low-frequency (80-240 MHz) imaging of three type III solar radio bursts observed at the limb by the Murchison Widefield Array (MWA). Each event is associated with a white light streamer at…

Solar and Stellar Astrophysics · Physics 2018-10-17 Patrick I. McCauley , Iver H. Cairns , John Morgan

We present the results of a long-look monitoring of 3C273 with RXTE between 1996 and 2000. A total of 230 observations amounts to a net exposure of 845ksec, with this spectral and variability analysis of 3C273 covering the longest…

We report the results from a 200 ks Chandra observation of the z=1.786 radio galaxy 3C294 and its cluster environment, increasing by tenfold our earlier observation. The diffuse emission, extending about 100 kpc around the nucleus, has a…

Astrophysics · Physics 2009-09-17 A. C. Fabian , J. S. Sanders , C. S. Crawford , S. Ettori

We report on the second round of Chandra observations of the 3C snapshot survey developed to observe the complete sample of 3C radio sources with z<0.3 for 8 ksec each. In the first paper, we illustrated the basic data reduction and…

In this paper, the third and final of a series, we present complete K-band imaging and some complementary I-band imaging of the filtered 6C* sample. We find no systematic differences between the K-z relation of 6C* radio galaxies and those…

In this letter we report the discovery of a z=4.88 radio galaxy discovered with a new technique which does not rely on pre-selection of a sample based on radio properties such as steep-spectral index or small angular size. This radio galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Matt J. Jarvis , Hanifa Teimourian , Chris Simpson , Daniel J. B. Smith , Steve Rawlings , David Bonfield

We present Very Long Baseline Array polarimetric observations of the innermost jet of 3C$\sim$84 (NGC$\sim$1275) at 43$\sim$GHz. A significant polarized emission is detected at the hotspot of the innermost re-started jet, which is located…

High Energy Astrophysical Phenomena · Physics 2017-11-08 H. Nagai , Y. Fujita , M. Nakamura , M. Orienti , M. Kino , K. Asada , G. Giovannini

We have conducted a deep radio survey with the Very Large Array at 1.4 GHz of a region containing the Hubble Deep Field. This survey overlaps previous observations at 8.5 GHz allowing us to investigate the radio spectral properties of…

Astrophysics · Physics 2009-10-31 E. A. Richards

The temporal smearing of impulsive radio events at cosmological redshifts probes the properties of the ionized Inter-Galactic Medium (IGM). We relate the degree of temporal smearing and the profile of a scattered source to the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jean-Pierre Macquart , Jun-Yi Koay

We present a survey for transient and variable sources, on timescales from 28 seconds to $\sim$1 year, using the Murchison Widefield Array (MWA) at 182 MHz. Down to a detection threshold of 0.285 Jy, no transient candidates were identified,…

Quantifying how the baryonic matter traces the underlying dark matter distribution is key to both understanding galaxy formation and our ability to constrain the cosmological model. Using the cross-correlation function of radio and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 S. N. Lindsay , M. J. Jarvis , K. McAlpine

An 80 ksec Chandra ACIS observation of the radio galaxy 3C 452 is reported. A diffuse X-ray emission associated with the lobes has been detected with high statistical significance, together with the X-ray nucleus of the host galaxy. The…

Astrophysics · Physics 2009-11-07 N. Isobe , M. Tashiro , K. Makishima , N. Iyomoto , M. Suzuki , M. M. Murakami , M. Mori , K. Abe