SIMBAD references

We present results of a study of 12 dust-reddened quasars with 0.4<z<2.21 and reddenings in the range 0.15<E(B-V)<1.7. We obtained ACIS-S X-ray spectra of these quasars, estimated the column densities toward them, and hence obtained the gas:dust ratios in the material obscuring the quasar. We detect all but one of the red quasars in the X-rays. Even though there is no obvious correlation between the X-ray-determined column densities of our sources and their optical color or reddening, all of the sources show absorbed X-ray spectra. When we correct the luminosity for absorption, they can be placed among luminous quasars; therefore, our objects belong to the group of high-luminosity analogs of the sources contributing to the X-ray background seen in deep X-ray observations. Such sources are also found in serendipitous shallow X-ray surveys. There is a hint that the mean spectral slope of the red quasar is higher than that of normal, unobscured quasars, which could be an indication for higher accretion rates and/or an evolutionary effect. We investigate the number density of these sources compared to type 2 AGNs based on the X-ray background and estimate how many moderate-luminosity red quasars may be found in deep X-ray fields.