A Broad Absorption Line Outflow Associated with the Broad Emission Line
  Region in the Quasar SDSS J075133.35+134548.3
  We report the discovery of unusual broad absorption lines (BALs) in the
bright quasar SDSS J075133.35+134548.3 at z~1, and present a detailed study of
BAL and emission lines using the archived and newly obtained optical and NIR
spectroscopic data. The BALs are detected tentatively in Mg II, Al III and
reliably in HeI*3889, HeI*10830, which show complexed velocity structures
splitting into two components: a high-velocity component (HV), with a
blueshifted velocity range of -9300 ~ -3500 km/s, can be reliably detected
tentatively in Mg II, Al III and reliably in HeI* 10830, whereas it is
undetectable in HeI* 3889; and low-Velocity component (LV), with the velocity
of -3500 ~ -1800 km/s, is only detected in HeI*3889 and HeI* 10830. With the
BALs from different ions, the HV outflowing gas can be constrained to have a
density n_H~10^10.3-10^11.4 cm^-3, a column density N_H~10^21 cm^-2 and an
ionization parameter U~10^-1.83 - 10^-1.72; and thus inferring a distance of
R_HV~0.5 pc from the central continuum source with a monochromatic luminosity
of 7.0*10^45 erg/s at 5100 A. This distance is remarkable similar to that of
normal broad emission line region (BLR) estimated according to the
luminosity-distance from the reverberation experiments, suggesting the
association between the BLR and the HV BAL outflowing gas. Interestingly
enough, a blueshifted component is also significantly detected in Mg II and Al
III 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 very likely have a larger column density and a higher ionization
level than the HV BAL gas, and hence a smaller distance than that of the
latter. Further spectroscopy with high S/N ratio and broader wavelength
coverage is needed to confirm this and shed new light on the possible
connection between BALs and BELs.
