CHANDRA OBSERVATION OF 3C 212: A NEW LOOK AT THE X-RAY AND ULTRAVIOLET ABSORBERS

摘要

The red quasar 3C 212 (z = 1.049) is one of the most distant and most luminous active galactic nuclei that have shown evidence of an X-ray warm absorber. In order to further investigate this unusual quasar, we used Chandra/ACIS-S to observe 3C 212 for 19.5 ks, resulting in a net detection of ～4000 counts. The Chandra data confirm the presence of an excess absorbing column N_H ≈ 4 x 10~(21) cm~(-2) at the quasar redshift, but we find no compelling evidence for a warm absorber. Using both the Chandra and archival ROSAT PSPC data, we obtain very good fits for both a partially covered neutral absorber and a low-ionization (U = 0.03) photoionized absorber. In the ultraviolet, 3C 212 shows a strong associated Mg Ⅱ absorber. Based on a moderate-resolution (80 km s~(-1)) MMT spectrum we show that the absorber is highly saturated and has a covering fraction less than 60%, implying that the absorber is truly intrinsic to the quasar. Photoionization modeling of the Mg Ⅱ absorber yields a constraint on the ionization parameter of U < 0.03, inconsistent with a warm UV/X-ray absorber. In addition to our spectral analysis, we find evidence in the ACIS image data for weak extended emission surrounding the quasar as well as emission corresponding to the radio lobes at a distance of 5″ from 3C 212. The statistical significance of these features is low, but we briefly explore the implications if the detections are valid.