ﻻ يوجد ملخص باللغة العربية
Double-peaked Balmer lines have been observed in about 150 AGNs and were interpreted preferably as emission from relativistic accretion disks. In this paper, we report the discovery of extreme double-peaked lines in SDSS J0942+0900 and SDSS J1417+6141. The FWHM of the Halpha line ~40,600 km/s in the first object is almost twice as large as the broadest one previously known. By comparing the line profile with accretion disk models, we find that most of the line flux is emitted from a narrow annulus around 100Rg in SDSS J0942+0900, and from a disk of radii between 100 and 400Rg in SDSS J1417+6141. This is the first time that an accretion disk at radii below 100Rg can be directly probed through optical emission lines. A certain asymmetry in the disk is required for both objects. Another much weaker broad Halpha component (EW~20A, and FWHM 4000km/s) is also detected in both objects. Both objects show weak radio emission and strong high-ionization narrow lines.
We present spectroscopic observations with the 3.6m ESO telescope of two emission-line galaxies, J2104-0035 and J0113+0052, selected from the Data Release 4 (DR4) of the Sloan Digital Sky Survey (SDSS). From our data we determine the oxygen abundance
We present AGN from the Sloan Digital Sky Survey (SDSS) having double-peaked profiles of [OIII] 5007,4959 and other narrow emission-lines, motivated by the prospect of finding candidate binary AGN. These objects were identified by means of a visual e
We have combined a sample of 44984 quasars, selected from the Sloan Digital Sky Survey (SDSS) Data Release 3, with the FIRST radio survey. Using a novel technique where the optical quasar position is matched to the complete radio environment within 4
Two newly identified magnetic cataclysmic variables discovered in the Sloan Digital Sky Survey (SDSS), SDSSJ155331.12+551614.5 and SDSSJ132411.57+032050.5, have spectra showing highly prominent, narrow, strongly polarized cyclotron humps with amplitu
We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We identified ~100