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We derive Galactic continuum spectra from 5-96/cm from COBE/FIRAS observations. The spectra are dominated by warm dust emission, which may be fit with a single temperature in the range 16-21 K (for nu^2 emissivity) along each line of sight.…

Using stellar luminosity functions derived from ROSAT data, the contributions of Galactic stars to the diffuse X-ray background are calculated for ROSAT PSPC energy bands. The model follows that of Guillout et al. (1996), but uses ROSAT…

天体物理学 · 物理学 2009-11-06 K. D. Kuntz , S. L. Snowden

We discuss the main uncertainties affecting estimates of small scale fluctuations due to extragalactic sources in the Planck Surveyor frequency bands. Conservative estimates allow us to confidently conclude that, in the frequency range…

天体物理学 · 物理学 2007-05-23 G. De Zotti , L. Toffolatti

The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic instrument observing at balloon altitudes with no emissive windows between the beam-forming…

宇宙学与河外天体物理 · 物理学 2016-10-05 D. J. Fixsen , A. Kogut , S. Levin , M. Limon , P. Lubin , P. Mirel , M. Seiffert , J. Singal , E. Wollack , T. Villela , C. A. Wuensche

We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies, to constrain models of extragalactic emission. Such emission is a…

宇宙学与河外天体物理 · 物理学 2009-01-21 M. Seiffert , D. J. Fixsen , A. Kogut , S. M. Levin , M. Limon , P. M. Lubin , P. Mirel , J. Singal , T. Villela , E. Wollack , C. A. Wuensche

Diffuse radio sources in galaxy clusters are unique signposts of cluster assembly in the Universe. Our knowledge of their observational properties has considerably improved over the past decade, and the long standing questions concerning…

宇宙学与河外天体物理 · 物理学 2015-03-18 Tiziana Venturi , INAF , Istituto di Radioastronomia

We make a new estimate of the extragalactic radio background down to kHz frequencies based on the observed luminosity functions and radio spectra of normal galaxies and radio galaxies. We have constructed models for the spectra of these two…

天体物理学 · 物理学 2010-11-30 R. J. Protheroe , P. L. Biermann

We present a detailed analysis of the radio synchrotron emission induced by WIMP dark matter annihilations and decays in extragalactic halos. We compute intensity, angular correlation, and source counts and discuss the impact on the…

宇宙学与河外天体物理 · 物理学 2012-03-27 N. Fornengo , R. Lineros , M. Regis , M. Taoso

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the…

天体物理学 · 物理学 2007-05-23 Martin Pohl

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…

天体物理学 · 物理学 2009-11-11 J. G. Kirk , O. Tsang

A wealth of new data from upgraded and new radio interferometers are rapidly improving and transforming our understanding of the faint extra-galactic radio sky. Indeed the mounting statistics at sub-mJy and uJy flux levels is finally…

星系天体物理 · 物理学 2018-10-15 Isabella Prandoni

Using the excellent observed correlations among various infrared wavebands with 12 and 60 micron luminosities, we calculate the 2-300 micron spectra of galaxies as a function of luminosity. We then use 12 micron and 60 micron galaxy…

天体物理学 · 物理学 2014-10-13 M. A. Malkan , F. W. Stecker

The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey…

天体物理仪器与方法 · 物理学 2018-01-10 F. de Gasperin , H. T. Intema , D. A. Frail

We present high-resolution radio observations of a sample of 65 radio sources at low Galactic latitudes. The sources were all observed at 5 GHz with the Very Large Array A-array. MERLIN observations at 5 GHz of the ultracompact HII region…

天体物理学 · 物理学 2009-11-10 D. J. Saikia , P. Thomasson , S. Roy , A. Pedlar , T. W. B. Muxlow

After the jets have switched off, radio galaxies undergo a fading phase which is often named the dying phase. The luminosity evolution of the remnant plasma during this period is still poorly constrained because of the paucity of objects…

星系天体物理 · 物理学 2016-10-05 Marisa Brienza , Elizabeth Mahony , Raffaella Morganti , Isabella Prandoni , Leith Godfrey

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,…

天体物理学 · 物理学 2007-05-23 G. De Zotti , L. Toffolatti , G. L. Granato

The solar corona is a highly-structured plasma which can reach temperatures of more than ~2 MK. At low frequencies (decimetric and metric wavelengths), scattering and refraction of electromagnetic waves are thought to considerably increase…

I present simple but robust estimates of the types of sources making up the faint, sub-microJy radio sky. These include, not surprisingly, star-forming galaxies and radio-quiet AGN but also two "new" populations, that is low radio power…

宇宙学与河外天体物理 · 物理学 2015-05-20 Paolo Padovani

We report on the discovery of a source which exhibits over 300% amplitude changes in radio flux density on the period of hours. This source, J1819+3845, is the most extremely variable extragalactic source known in the radio sky. We believe…

天体物理学 · 物理学 2009-10-31 J. Dennett-Thorpe , A. G. de Bruyn

The Lockman Hole is a well-studied extragalactic field with extensive multi-band ancillary data covering a wide range in frequency, essential for characterising the physical and evolutionary properties of the various source populations…