Radio-loud Narrow-Line Type 1 Quasars

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dc.creatorKomossa, S.
dc.creatorVoges, W.
dc.creatorXu, D.
dc.creatorMathur, S.
dc.creatorAdorf, H. -M.
dc.creatorLemson, G.
dc.creatorDuschl, W.
dc.creatorGrupe, D.
dc.date2006-03-24
dc.date.accessioned2026-07-07T11:25:24Z
dc.date.available2026-07-07T11:25:24Z
dc.descriptionWe present the first systematic study of (non-radio-selected) radio-loud narrow-line Seyfert 1 (NLS1) galaxies. Cross-correlation of the `Catalogue of Quasars and Active Nuclei' with several radio and optical catalogues led to the identification of 11 radio-loud NLS1 candidates including 4 previously known ones. Most of the radio-loud NLS1s are compact, steep spectrum sources accreting close to, or above, the Eddington limit. The radio-loud NLS1s of our sample are remarkable in that they occupy a previously rarely populated regime in NLS1 multi-wavelength parameter space. While their [OIII]/H_beta and FeII/H_beta intensity ratios almost cover the whole range observed in NLS1 galaxies, their radio properties extend the range of radio-loud objects to those with small widths of the broad Balmer lines. Among the radio-detected NLS1 galaxies, the radio index R distributes quite smoothly up to the critical value of R ~ 10 and covers about 4 orders of magnitude in total. Statistics show that ~7% of the NLS1 galaxies are formally radio-loud while only 2.5% exceed a radio index R > 100. Several mechanisms are considered as explanations for the radio loudness of the NLS1 galaxies and for the lower frequency of radio-louds among NLS1s than quasars. While properties of most sources (with 2-3 exceptions) generally do not favor relativistic beaming, the combination of accretion mode and spin may explain the observations. (abbreviated)
dc.descriptionAstronomical Journal (first submitted in Dec. 2005); 45 pages incl. 1 colour figure
dc.identifierhttps://arxiv.org/abs/astro-ph/0603680
dc.identifierhttp://arxiv.org/abs/astro-ph/0603680
dc.identifierAstron.J.132:531-545,2006
dc.identifierdoi:10.1086/505043
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195500
dc.subjectAstrophysics
dc.titleRadio-loud Narrow-Line Type 1 Quasars
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