We present measurements of the spectral properties for a total of 526,265 quasars, out of which 63% have a continuum signal-to-noise ratio > 3 pixel−1, selected from the fourteenth data release of the Sloan Digital Sky Survey (SDSS-DR14) quasar catalog. We performed a careful and homogeneous analysis of the SDSS spectra of these sources to estimate the continuum and line properties of several emission lines such as Hα, Hβ, Hγ, Mg ii, C iii], C iv, and Lyα. From the derived emission line parameters, we estimated single-epoch virial black hole masses (M BH) for the sample using Hβ, Mg ii, and C iv emission lines. The sample covers a wide range in bolometric luminosity ( erg s−1) between 44.4 and 47.3 and between 7.1 and 9.9 M ⊙. Using the ratio of L bol to the Eddington luminosity as a measure of the accretion rate, the logarithm of the accretion rate is found to be in the range between −2.06 and 0.43. We performed several correlation analyses between different emission line parameters and found them to match the correlation known earlier using smaller samples. We note that strong Fe ii sources with a large Balmer line width and highly accreting sources with large M BH are rare in our sample. We make an extended and complete catalog available online that contains various spectral properties of 526,265 quasars derived in this work along with other properties culled from the SDSS-DR14 quasar catalog.

Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 10 erg at infrared and radio wavelengths but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.

A B S T R A C TWe present near-infrared 1:5-2:5 mm moderate-resolution long-slit spectra of two Seyfert 1 galaxies (NGC 1097 and 1566), three Seyfert 2s (NGC 1386, 4945 and 5128) and one Seyfert 1.5 (NGC 3227), both parallel to an ionization cone or jet and perpendicular to it. The spectra are used to study the spatial extent of the line emission, integrated masses of excited H 2 and the excitation mechanisms of interstellar gas. In all three Seyfert 2 galaxies, [Fe II] is found to be stronger than Brg or H 2 1 -0 S(1), while in the Seyfert 1 NGC 1566 and the Seyfert 1.5 NGC 3227 Brg is the strongest line. Broad Brg originating from the broad-line region (BLR) is detected in three galaxies (NGC 1386, 1566 and 3227), of which NGC 1386 is optically classified as Seyfert 2. In these galaxies [Fe II] is narrow and may be X-ray excited. In all galaxies except in NGC 5128, the spatial full width at half-maximum (FWHM) size of the H 2 1 -0 S(1) nuclear core is larger perpendicular to the cone or jet than parallel to it, in agreement with active galactic nucleus (AGN) unified models. The values of nuclear N H 2 are higher in Seyfert 2s than in Seyfert 1s, with the Seyfert 1.5 NGC 3227 lying between them. The exception to this is the Seyfert 2 NGC 1386, where two extended regions are detected parallel to the cone. Coronal lines are detected in two galaxies, NGC 1386 and 3227.