A broad absorption line outflow associated with the broad emission line region in the quasar SDSS J075133.35+134548.3

We report on the discovery of unusual broad absorption lines (BALs) in the bright quasar SDSS J075133.35+134548.3 at z similar to 1, using archival and newly obtained optical and NIR spectroscopic data. The BALs are detected reliably in He I* lambda 3889, He I* lambda 10830 and tentatively in Al III, Mg II. These BALs show complex velocity structures consisting of two major components: a high-velocity component (HV), with a blueshifted velocity range of Delta v(HV) similar to -9300 - -3500 km s(-1), which can be reliably detected in He I* lambda 10830, and tentatively in Al III and Mg II, whereas it is undetectable in He I* lambda 3889; and a low-velocity component (LV), with Delta v(LV) similar to -3500 - -1800 km s(-1), is only detected in He I* lambda 3889 and He I* lambda 10830. With the BALs from different ions, the HV outflowing gas can be constrained to have a density of n(H)similar to 10(10.3)-10(11.4) cm(-3), a column density of N-H similar to 10(21) cm(-2) and an ionization parameter of U similar to 10(-1.83)-10(-1.72); inferring a distance of R-HV similar to 0.5 pc from the central continuum source with a monochromatic luminosity lambda L-lambda (5100)=7.0x10(45) erg s(-1) at 5100 angstrom. This distance is remarkably similar to that of the normal broad line region (BLR) estimated from reverberation experiments, suggesting association of the BLR and the HV BAL outflowing gas. Interestingly, a blueshifted component is also detected in Al III and Mg II broad emission lines (BELs), and the Al III/Mg II of such a BEL component can be reproduced by the physical parameters inferred from the HV BAL gas. The LV BAL gas likely has a larger column density, a higher ionization level and hence a smaller distance than the HV BAL gas. Further spectroscopy with a high S/N ratio and broader wavelength coverage is needed to confirm this to shed new light on the possible connection between BALs and BELs.