A Multiwavelength study of NLS1s galaxies from the Second Byurakan Survey

In this work we present a multiwavelength study of narrow-line Seyfert 1 galaxies (NLS1s) discovered in the Second Byurakan Survey (SBS). The sample consists of 26 objects, which have MB ≥ −23.0, or −19.9 > MB > −23.0, 0.0243 < z < 0.317 and 15.2 < B < 19.0. For these objects, we present accurate coordinates, magnitudes, redshifts and the identification of optical objects with X-ray, IR and radio sources. Several galaxies are identified as X-ray or radio sources for the first time. We also report spectroscopic and photometric data, the spectral energy distribution, αox indices and other data. Our study shows that SBS NLS1s are strong or moderately strong soft X-ray sources with log Lx = 42.8−45.4. Soft X-ray luminous sources in our sample do not tend to be luminous in the infrared. All SBS NLS1s are radio quiet objects ( log LR < 40.0), and 52% of them are strong FeII emitters (FeIIλ4570/Hβ > 1). The traditional linear correlation Lx and Lop, which seems to hold for AGN in ge neral, is found for SBS NLS1s. An anticorrelation between FWHM of Hβ and the ratio of FeIIλ4570/Hβ is also observed. A weak correlation is found between αox slope and Lop. One of our main findings is that almost all SBS NLS1s may not have a FIR bump. Their SED suggest that they may also possess a BBB. The absence of IR bump in most of SBS NLS1s and the weakness of X-ray radiation in some of them, may argue against the presence of a BLR. The surface density of SBS NLS1s is < 0.015 per deg. (B < 17.5, z < 0.16). Subject headings: Galaxies:Seyferts — Galaxies:NLSy1 — Quasars Instituto de Astronomı́a, UNAM, Apartado Postal 70-264, 04510 México DF. e-mail: [email protected],[email protected], [email protected] Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge,MA02138;e-mail: [email protected] Instituto Nacional de Astrof́ısica, Optica y Electronica,INAOE,Apartado Postal 512 y 216, 7200, Puebla, Pue., México. e-mail: [email protected], [email protected]