Orientation effects on the near-infrared broad band emission of quasars

Feb 14, 2019
8 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 485 (2019) 1405
e-Print:
DOI:

Citations per year

201920202021012
Abstract: (arXiv)
We recently proposed the equivalent width (EW) of the narrow [OIII]5007{\AA} emission line as an orientation indicator for active galactic nuclei. We tested this method on about 12,30012,300 optically selected broad line quasars from the SDSS 7th Data Release at redshift z<0.8z < 0.8 and with full width at half-maximum values of broad emission lines (Hα\alpha, Hβ\beta, and MgII) larger than 20002000 km/s. We now examine their spectral energy distributions (SEDs) using broad band photometry from the near-infrared to the ultraviolet to look for variations in the overall shape as a function of the EW[OIII]. We find that quasars with low EW[OIII] values (close to face-on position) have flatter near-infrared SEDs with respect to sources with high EW[OIII] values (almost edge-on). Moreover, quasars with high EW[OIII] values show a factor of 2\sim 2 lower emission in the UV to quasars with low EW[OIII] values. Our findings indicate that the torus is clumpy and, on average, co-axial with the accretion disc and broad line region, in agreement with the most recent theoretical models for the obscuring torus.
Note:
  • Accepted for publication in MNRAS (8 pages, 4 figures and 2 tables)