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Broad Absorption Line, Radio, and Optical Quasars: A SDSS View Xinyu Dai (Univ. of Oklahoma), Francesco Shankar (MPI), Gregory R. Sivakoff (Univ. of Virginia), Marianne Vestergaard (Copenhagen Univ.) Abstract Relative Growth between Optical and Radio Quasars It is a main theme in AGN studies to understanding various sub-samples of quasars within coherent schemes. We study the origin of the broad absorption line quasars, radio quasars, and optical quasars, based on the parent SDSS quasar catalog. We find the intrinsic fractions of BALQSOs, LoBALs, and FeLoBals are 2, 5, and 7 Fig. 7. The distributions of times the observed fractions in the optical bands by studying the infrared and radio optical and radio quasars in properties of these quasars. In particular, the intrinsic fraction of BALQSOs can be the L-z, M-z, and M-L as high as 43% when using a less strict BAL definition. We also find that the planes. We use the black hole fractions of quasars with BAL features are functions of radio luminosity, where in mass and bolometric the low radio luminosity range, the BAL fractions are consistent with their intrinsic luminosity reported in fractions, and the BAL fractions are significantly smaller at high radio luminosities. Vestergaard et al. (2008). These observations can be explained under a geometric model of BALQSOs for the There is no significant majority of the BALQSOs. We argue that a small portion of LoBALs and difference between the optical FeLoBALs with excess infrared luminosity may be explained under the and radio quasar distributions evolutionary model. We also present the relative growth of radio and optical in the three panels. quasars, based on the relative evolution of Eddington ratios between radio and Fig. 4. The increase of BAL fractions from optical to NIR band can be modeled using an obscuration optical quasars. We find complex growth history for radio and optical quasars, and model for BALs (Dai, Shankar, Sivakoff 2008, ApJ, 672, 108). that the radio emission is not apparently associated with the BH mass or Eddington radio. Dependence of BALQSO Fractions on Radio Luminosity Intrinsic Fraction of BALQSOs We match the SDSS BALQSO catalog (Trump et al. 2006) with the FIRST survey (Becker et al. 1995), and measure the BAL fractions as a function of radio luminosity. Using the SDSS, 2MASS, and FIRST surveys, we are able to measure the intrinsic fraction of BALQSOs. We find the raw BALQSO fractions from optical surveys are significantly biased, and the intrinsic fraction is about two times the optical fraction. Fig. 8. (left) Mean Eddington ratio as a function of BH mass for sources at z < 1.5 (upper plot) and at z ≥ 1.5 (lower plot). (right) Mean Eddington ratio as a function of redshift for BHs with mass logM < 9.0 (upper panel) and logM ≥ 9.0 (lower panel). With respect to optical quasars, massive radio quasars tend to have higher Eddington Fig. 5. (left) The BAL fractions decreases with increasing radio luminosity. At the low/moderate ratios at higher z and lower or comparable Eddington ratios at lower z. Also, radio radio luminosity regime, the BAL fractions are consistent with the intrinsic BAL fractions measured quasars tend to have higher Eddington ratios at z≥1.5, and lower Eddington ratios at in NIR bands. This confirms our claim that the NIR fractions are close to the intrinsic fraction, lower z. Fig. 1. 2MASS K mag vs. SDSS i mag Fig. 2. K-i color distribution of since there is also little absorption in the radio band. The drop of BAL fractions at high radio for BALQSOs (red circles) and non- BALQSOs (dashed line) and non-BALs luminosity end can be explained using a geometric model for BALQSOs. (right) A geometric BALs (black squares) detected in all of (solid line). The inset shows the model for BALQSOs, where BALs are located close the the equatorial plane. The radio emission the J, H, and K bands in the redshift cumulative distribution of the two are composed of two components, one strong beamed emission close to the jet direction and one range of 1.7 < z < 4.38. samples. The BALQSOs are redder than weak isotropic component (Shankar, Dai, Sivakoff 2008, ApJ, 687, 859). the non-BALs based on the K-S test. Low-Ionization Borad Absorption Line Quasars The increase of BAL fractions from optical to NIR bands can be explained if Since LoBALs are more obscured compared to HiBALs, we expect that the optical fractions are even one considers the spectral difference more biased. Fig. 9. (left) Mean BH mass as a function of redshift for sources accreting with an between BALs and non-BALs (extra dust Eddington ratio logλ < −0.6 (upper plot) and logλ > −0.6 (lower plot). (right) same extinction and absorption lines in BALs). pattern as left-hand panel considering only the subsample of sources with BH mass higher than 108.7Msun, for which no strong luminosity bias should be present. Radio The NIR fractions are close the intrinsic sources with high λ have lower masses with respect to optical ones at z > 1.5, but fraction, and the optical fractions are have a tendency for higher BH masses at lower redshifts. significantly biased. The intrinsic fraction of BI-BALs is 20±2%. Fig. 3. BALQSO (circles for BI- BALs and squares for AI-BALs) Fig. 6. (left) The fractions of LoBALs increases from optical to NIR bands, similar to HiBALs. We The intrinsic fraction of AI-BALs is fractions increase from the g to K obtain intrinsic fractions of 4.0±0.5%, 7.2±0.6%, and 3.6±1.0% for BI-LoBALs, AI-LoBALs, and 43±2%. bands. The fitting results from our FeLoBALs, respectively. (middle) The fraction of LoBALs decrease with increasing radio models (solid lines). The thick and luminosity, again, similar to HiBALs. At the low/moderate radio luminosity range, the LoBAL BALQSOs are not the minority of the thin dashed lines show the true fractions are consistent with the intrinsic fractions measured in the NIR bands. The analogy between Fig. 10. Mean accretion growth curves for BHs of different mass from z = 4 to 0 for QSO population. The larger fraction of fraction of AI-BALs (43±2%) and LoBALs and HiBALs in the NIR and radio properties indicates that the majority of LoBALs and radio quasars (left panel) and optical quasars (right panel). While radio sources only out-flowing AGNs makes wind a more BI-BALs (20±2%) that satisfy HiBALs can be unified under the same physical scheme, either geometric or evolutionary, but not grow by a factor of ~2, at the most, optical quasars grow more and at later times. prominsing candidate responsible for Weymann et al. (1991) definition. belong to separate schemes. Using a geometric model, we can successfully fit the LoBAL fractions in carrying the feedback energy to the host the radio band (lines in the middle panel). We find that no clear correlation between radio activity and BH mass and/or accretion galaxy. Fig. 6. (right) The fractions of LoBALs increase with NIR luminosity. This behavior is the only rate is evident from our data, pointing to other BH properties, possibly the spin, as the difference we find between LoBALs and HiBALs. This suggests that LoBALs with excess IR driver of radio activity (Shankar, Sivakoff, Vestergaard, Dai 2010, MNRAS, 401, luminosity may be at the early stages of quasar evolution (Dai et al. 2010, in preparation). 1869).
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