0.8-2.5um spectra of 2 red quasars

However, alternative mechanisms also exist to explain their red colors: (i) an intrinsically red continuum; (ii) an unusual high covering factor of the hot dust component, that is, CF_HD_=L_HD_/L_bol_, where the L_HD_ is the luminosity from the hot dust component and the L_bol_ is the bolometric luminosity; and (iii) a moderate viewing angle.

In order to investigate why red quasars are red, we studied optical and NIR spectra of 20 red quasars at z~0.3 and 0.7, where the usage of the NIR spectra allowed us to look into red quasar properties in ways that are little affected by dust extinction. The Paschen to Balmer line ratios were derived for 13 red quasars and the values were found to be ~10 times higher than unobscured type 1 quasars, suggesting a heavy dust extinction with A_V_>2.5mag.