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Related papers: Are young radio sources in equipartition?

200 papers

We present an extensive synthetic observational analysis of numerically- simulated radio galaxies designed to explore the effectiveness of conventional observational analyses at recovering physical source properties. These are the first…

Astrophysics · Physics 2009-11-10 I. L. Tregillis , T. W. Jones , Dongsu Ryu

Regular magnetic field structures can be derived from the Faraday rotation measures (RM) of polarized background sources observable at 1.4 GHz with the SKA. At lower frequencies ($<250$ MHz) polarimetry of radio sources with the Low…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-20 Tigran G. Arshakian , Rainer Beck

Extreme high-synchrotron peaked blazars (EHSPs) are rare high-energy sources characterised by synchrotron peaks beyond 10$^{17}$ Hz in their spectral energy distributions (SEDs). Their extreme properties challenge conventional blazar…

High Energy Astrophysical Phenomena · Physics 2025-08-26 M. Láinez , M. Nievas-Rosillo , A. Domínguez , J. L. Contreras , J. Becerra González , A. Dinesh , V. S. Paliya

We aim at clarifying the nature of the emission of two spatially related unidentified X-ray sources detected with XMM-Newton telescope at intermediate-low Galactic latitude. Observations reveal a point-like source aligned with elongated…

High Energy Astrophysical Phenomena · Physics 2015-11-25 Federico García , Jorge A. Combi , María C. Medina , Gustavo E. Romero

We present polarization measurements at 8.4, 22, and 43 GHz made with the VLA of a complete sample of extragalactic sources stronger than 1 Jy in the 5-year WMAP catalogue and with declinations north of -34 degrees. The observations were…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 N. Jackson , I. W. A. Browne , R. A. Battye , D. Gabuzda , A. C. Taylor

We review estimates of small scale fluctuations due to extragalactic point sources in the Planck Surveyor frequency bands. While our undestanding of the spectral and evolutionary properties of these sources is far from complete,…

Astrophysics · Physics 2007-05-23 G. De Zotti , L. Toffolatti , G. L. Granato

Global VLBI observations at 5 GHz have been performed to study the source morphology in 10 compact steep-spectrum (CSS) sources selected from the Peacock & Wall catalogue with the aim of finding asymmetric structures produced by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 D. Dallacasa , M. Orienti , C. Fanti , R. Fanti , C. Stanghellini

WSRT observations have been used to investigate the presence of neutral hydrogen in extremely young radio galaxies. These objects were selected from a sample of High-Frequency Peakers (HFPs). We detect 2 of the 6 observed galaxies…

Astrophysics · Physics 2009-11-11 M. Orienti , R. Morganti , D. Dallacasa

LS 5039 is an X-ray binary that presents non-thermal radio emission. The radiation at $\sim 5$ GHz is quite steady and optically thin, consisting on a dominant core plus an extended jet-like structure. There is a spectral turnover around 1…

Astrophysics · Physics 2009-11-13 V. Bosch-Ramon

The polarisation properties of the intrinsically small (< 20 kpc) radio sources are briefly discussed. At centimetric and decimetric wavelengths, substantial polarised emission is often detected in quasars and, at a lower level, in radio…

Astrophysics · Physics 2007-05-23 D. Dallacasa

The Planck-ATCA Co-eval Observations (PACO) project has yielded observations of 464 sources with the Australia Telescope Compact Array (ATCA) between 4.5 and 40 GHz. The main purpose of the project was to investigate the spectral properties…

We propose a morphological classification based on the parsec scale structure of fifty-one High Frequency Peakers (HFPs) from the ``bright'' HFP sample. VLBA images at two adjacent frequencies (chosen among 8.4, 15.3, 22.2 and 43.2 GHz)…

Astrophysics · Physics 2009-11-11 M. Orienti , D. Dallacasa , S. Tinti , C. Stanghellini

We present the first results of a systematic search for the rare extragalactic radio sources showing an inverted (integrated) spectrum, with spectral index $\alpha \ge +2.0$, a previously unexplored spectral domain. The search is expected…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Gopal-Krishna , S. K. Sirothia , Mukul Mhaskey , Pritesh Ranadive , Paul J. Wiita , A. Goyal , N. G. Kantharia , C. H. Ishwara-Chandra

I extract the radio spectral index, $\alpha$, from 541,195 common sources observed in the 150 MHz TIFR GMRT Sky Survey (TGSS) and the 1.4 GHz NRAO VLA Sky Survey (NVSS). This large common source catalogue covers about $80\%$ of the sky. The…

Astrophysics of Galaxies · Physics 2019-07-26 Prabhakar Tiwari

We have determined detailed radio spectra for 26 compact sources in the starburst nucleus of M82, between 74 and 1.3 cm. Seventeen show low-frequency turnovers. One other has a thermal emission spectrum, and we identify it as an HII region.…

Astrophysics · Physics 2009-10-30 Michael L. Allen , Philipp P. Kronberg

We present VLBA observations at 15 GHz of ten GHz Peaked Spectrum (GPS) radio sources. The cores are often difficult or impossible to locate. When likely cores are found, they account for a small fraction of the flux density in GPS galaxies…

Astrophysics · Physics 2009-11-07 C. Stanghellini , D. Dallacasa , C. P. O'Dea , S. A. Baum , R. Fanti , C. Fanti

(abridged)Prompt GRB emission is often interpreted as synchrotron radiation from high-energy electrons accelerated in internal shocks. Fast synchrotron cooling predicts that the photon index below the spectral peak is alpha=-3/2. This…

High Energy Astrophysical Phenomena · Physics 2015-05-19 F. Daigne , Z. Bosnjak , Guillaume Dubus

We present the first targeted measurement of the power spectrum of anisotropies of the radio synchrotron background, at 140 MHz where it is the overwhelmingly dominant photon background. This measurement is important for understanding the…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-06 A. R. Offringa , J. Singal , S. Heston , S. Horiuchi , D. M. Lucero

Some rapidly variable extra-galactic radio sources show very high brightness temperatures T_B>10^{12}K and high degrees of circular polarisation (1%). Standard synchrotron models that assume a power-law electron distribution cannot produce…

Astrophysics · Physics 2009-11-11 J. G. Kirk , O. Tsang

To increase the number of sources with Very Long Baseline Interferometry (VLBI) astrometry available for comparison with the Gaia results, we have observed 31 young stars with recently reported radio emission. These stars are all in the…

Solar and Stellar Astrophysics · Physics 2024-06-12 Sergio A. Dzib , Laurent Loinard , Ralf Launhardt , Jazmín Ordóñez-Toro