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Post Info TOPIC: Quasar Ton 34


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Posts: 131433
Date:
BALQSO Ton 34
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Title: Hubble Space Telescope Observations of BALQSO Ton 34 Reveal a Connection between the Broad Line Region and the BAL Outflow
Author: Y. Krongold, L. Binette, R. Bohlin, L. Bianchi, A. L. Longinotti, S. Mathur, F. Nicastro, A. Gupta, C. A. Negrete, F. Hernandez-Hibarra

Ton 34 recently transitioned from non-absorbing quasar into a BALQSO.Here, we report new HST-STIS observations of this quasar. Along with CIV absorption, we also detect absorption by NV+Ly alpha and possibly OVI+Ly beta. We follow the evolution of the CIV BAL, and find that, for the slower outflowing material, the absorption trough varies little (if at all) on a rest-frame timescale of 2 yr. However, we detect a strong deepening of the absorption in the gas moving at larger velocities (-20,000 - -23,000 km s-1). The data is consistent with a multistreaming flow crossing our line of sight to the source. The transverse velocity of the flow should be few thousand km s-1, similar to the rotation velocity of the BLR gas (2,600 km s-1). By simply assuming Keplerian motion, these two components must have similar locations, pointing to a common outflow forming the BLR and the BAL. We speculate that BALs, mini-BALs, and NALs, are part of a common, ubiquitous, accretion-disk outflow in AGN, but become observable depending on the viewing angle towards the flow. The absorption troughs suggest a wind covering only 20% of the emitting source, implying a maximum size of 10^-3 pc for the clouds forming the BAL/BLR medium. This is consistent with constraints of the BLR clouds from X-ray occultations. Finally, we suggest that the low excitation broad emission lines detected in the spectra of this source lie beyond the wind, and this gas is probably excited by the shock of the BAL wind with the surrounding medium.

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Posts: 131433
Date:
Quasar Ton 34
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Title: The unusual UV continuum of quasar Ton 34 and the possibility of crystalline dust absorption
Authors: Luc Binette, Yair Krongold

Luminous quasars are known to display a sharp steepening of the continuum near 1100A. This spectral feature is not well fitted by current accretion disk models, unless comptonisation of the disk emission is invoked. Absorption by carbon crystalline dust has been proposed to account for this feature. Ton 34 (z=1.928) exhibits the steepest far-UV decline (F_nu prop nu^{-5.3}) among the 183 quasar HST-FOS spectra analysed by Telfer et al. It is an ideal object to test the crystalline dust hypothesis as well as alternative interpretations of the UV break. We reconstruct the UV spectral energy distribution of Ton 34 by combining HST, IUE and Palomar spectra. The far-UV continuum shows a very deep continuum trough, which is bounded by a steep far-UV rise. We fit the trough assuming nanodiamond dust grains. Extinction by carbon crystalline dust reproduces the deep absorption trough of Ton 34 reasonably well, but not the observed steep rise in the extreme UV. We also study the possibility of an intrinsic continuum rollover. The dust might be part of a high velocity outflow (13000 km/s), which is observed in absorption in the lines of CIV, OVI, NV and Ly_alpha.

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