BAL Outflows In Quasars

The famous relationship MBH-? between the mass of black hole and the veloc-ity dispersion of galaxy bulge suggests that the growth of Supper-Massive Black Hole(SMBH)is closely related to the evolution of galaxies.Active Galactic Nuclei(AGN)outflows carry mass,momentum and energy into the surrounding environment,and have long been considered to play an important role in regulating the growth of supermassive black holes(SMBHs)and the evolution of their host galaxies.Due to the complexity of outflows and the limit of current facilties,we have little knowledge of the physical properties of outflows and their influences on galaxy evolution.A crucial parameter for understanding the origin of these outflows and measuring their influences on their host galaxies is the distance(R)between the outflow gas and the central source.During the last decade or so,R have been measured for only a number of individual quasars using density-sensitive absorption lines from excited levels(such as S iv*,Fe ?*).Due to line blending,the method can not apply to broad absorption line(BAL).During my pursuit of a PhD degree,I first studied the mechanism of the BAL vari-ability for a large sample.On this basis,we have developed a new method to determine the distance and power of outflow in a statistical sense,so as to determine the ability of outflow to influence Galaxy evolution.At the same time,we propose a simple geo-metric model to limit the distance of some very special outflows.In addition,I use the morphology of AGN narrow line region to test the AGN unification model.We present a statistical analysis of the variability of BAL in quasars using the large multi-epoch spectroscopic dataset of the Sloan Digital Sky Survey Data Release 12(SDSS DR12).We divide the sample into two groups according to the pattern of the variation of C iv BAL with respect to that of continuum:the equivalent widths(EW)of the BAL decreases(increases)when the continuum brightens(dims)as group T1;and the variation of EW and continuum in the opposite relation as group T2.We find that T2 has significantly higher EW ratios(R)of Si iv to C iv BAL than T1.Our result agrees with the prediction of photoionization models that C+3 column density increases(decreases)if there is a(or no)C+3 ionization front while R decreases with the incident continuum.We show that BAL variabilities in at least 80%quasars are driven by the variation of ionizing continuum.As known that the variation of ionizing continuum is the main driver of BAL vari-ability,we propose that the fraction curve of BAL variability detection can be used to constrain the the distribution of the recombination timescales.Then we can obtain other properties of BAL outflows.Using the statistical properties of BAL variability in a sam-ple of 915 quasars from SDSS DR14,the distributions of R and the kinetic luminosities of outflow gas are obtained.The mean and standard deviation of the distribution of R are 101.4±0.5 parsec(pc).The typical outflow distance in this sample is tens of pc,which is greater than the theoretically predicted sizes(0.01?0.1 pc)of the accretion disc line-driven winds The typical value of the mass-flow rate Mout is tens of M(?)yr-1,which is several times of the accretion rate Macc.The typical value of the ratio of the kinetic to bolometric luminosity Ek/Lbol is a few percents,indicating that outflows have a significant feedback effect on their host galaxies.Secondly,we searched out 58 vary deep and broad N v BAL from SDSS database,and found Ly? emission lines with a line width of about 2000km s-1 in three of them.Assuming that the emission line at the bottom of N v BAL originates from the Viridized emission line region which is not blocked by the BAL outflow region.The outflow scales of these three sources are estimated to be in the range of 3-26 pc according to the mass of the black hole.The results of the three sources are consistent with those obtained by the method of BAL variability.This method can be used as a supplement to other methods of outflow measurement.Finally,we use the morphology of AGN ionization region to test the AGN unified model.Extended narrow-line regions(NLRs)around active galactic nuclei(AGN)are shaped by the distribution of gas in the host galaxy and by the geometry of the circumnu-clear obscuration,and thus they can be used to test the AGN unification model.We quan-tify the morphologies of the NLR in 308 nearby AGNs(z = 0-0.14,Lbpl?1042 4-44 1 erg s-1)from the MaNGA survey.Based on the NLR maps,we find that a large fraction(81%)of these AGN have bi-conical NLR morphology.The distribution of their mea-sured opening angles suggests that the intrinsic opening angles of the ionization cones has a mean value of 85-98° with a finite spread of 39-44°(1-?).Our inferred opening angle distribution implies a number ratio of type I to type II AGN of 1:1.6-2.3,con-sistent with other measurements of the type I/type II ratio at low AGN luminosities.Combining these measurements with the WISE photometry data,we find that redder mid-IR color(lower effective temperature of dust)corresponds to stronger and NLR.This relation is in agreement with the unification model that suggests that the bi-conical NLR are shaped by a toroidal dusty structure within a few pc from the AGN.Further-more,we find a significant alignment between the minor axis of host galaxy disks and AGN ionization cones.Together,these findings suggest that obscuration on both cir-cumnuclear(Npc)and galactic(?kpc)scales are important in shaping and orienting the AGN NLR.