AGN duty cycle estimates for the ultra-steep spectrum radio relic VLSS J1431.8+1331
نویسندگان
چکیده
منابع مشابه
Spectroscopy of Ultra Steep Spectrum Radio Sources
We present optical spectroscopy of 62 objects selected from several samples of ultra steep spectrum (USS) radio sources. 46 of these are from our primary catalog, consisting of 669 sources with radio spectral indices α < −1.30 (Sν ∝ ν); this first spectroscopic sub-sample was selected on the basis of their faint optical and near-IR identifications. Most are identified as narrow-lined radio gala...
متن کاملUltra–Steep Spectrum Radio Galaxies at Hy Redshifts
Radio sources have traditionally provided convenient beacons for probing the early Universe. Hy Spinrad was among the first of the tenacious breed of observers who would attempt to obtain optical identifications and spectra of the faintest possible ‘radio galaxies’ to investigate the formation and evolution of galaxies at hy redshift. Modern telescopes and instruments have made these tasks much...
متن کاملMultiwavelength characterization of faint ultra steep spectrum radio sources: A search for high-redshift radio galaxies ⋆
Context. Ultra steep spectrum (USS) radio sources are one of the efficient tracers of powerful high-z radio galaxies (HzRGs). In contrast to searches for powerful HzRGs from radio surveys of moderate depths, fainter USS samples derived from deeper radio surveys can be useful in finding HzRGs at even higher redshifts and in unveiling a population of obscured weaker radio-loud AGN at moderate red...
متن کاملA Sample of 669 Ultra Steep Spectrum Radio Sources to Find High Redshift Radio Galaxies ⋆
Since radio sources with Ultra Steep Spectra (USS; α ∼ < −1.30;S ∝ ν) are efficient tracers of high redshift radio galaxies (HzRGs), we have defined three samples of such USS sources using the recently completed WENSS, TEXAS, MRC, NVSS and PMN radiosurveys. Our combined sample contains 669 sources with S1400 > 10 mJy and covers virtually the entire sky outside the Galactic plane (|b| > 15). For...
متن کاملOn the redshift cut-off for steep-spectrum radio sources
We use three samples (3CRR, 6CE and 6C*) selected at low radio frequency to constrain the cosmic evolution in the radio luminosity function (RLF) for the ‘most luminous’ steep-spectrum radio sources. Although intrinsically rare, such sources give the largest possible baseline in redshift for the complete flux-density-limited samples currently available. Using parametric models to describe the R...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2015
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201525632