Discovery of Strong Balmer Line Absorption in Two Luminous LoBAL Quasars at z similar to 1.5

作者：Schulze, Andreas^*; Misawa, Toru; Zuo, Wenwen; Wu, Xue-Bing

来源：Astrophysical Journal, 2018, 853(2): 167.

DOI：10.3847/1538-4357/aaa7f0

• galaxies: active
• galaxies: nuclei
• quasars: general

We present the discovery of strong Balmer line absorption in H alpha to H gamma in two luminous low-ionization broad absorption line quasars at z similar to 1.5, with black hole masses around 10(10) M-circle dot from near-IR spectroscopy. There are only two previously known quasars at z > 1.0 showing Balmer line absorption. SDSS. J1019+0225 shows blueshifted absorption by similar to 1400 km s(-1) with an H alpha rest-frame equivalent width of 13 angstrom. In SDSS. J0859+4239, we find redshifted absorption by similar to 500 km s(-1) with an Ha rest-frame equivalent width of 7 angstrom. The redshifted absorption could indicate an inflow of high-density gas onto the black hole, though we cannot rule out alternative interpretations. The Balmer line absorption in both objects appears to be saturated, indicating partial coverage of the background source by the absorber. We estimate the covering fractions and optical depth of the absorber and derive neutral hydrogen column densities, N-HI similar to 1.3 x 10(18) cm(-2) for SDSS. J1019+0225 and N-HI similar to 9 x 10(17) cm(-2) for SDSS. J0859+4239. In addition, the optical spectra reveal also absorption troughs in He I* lambda 3889 and lambda 3189 in both objects.

• 出版日期2018-2-1
• 单位北京大学; 中国科学院国家天文台; 中国科学院上海天文台