The Nature of the UV/X-Ray Absorber in PG 2302+029
| Authors:
|
Sabra, B.M.1,
Hamann, F.W.1
Jannuzi, B.T.2,
George, I.M.3,4,
Shields, J.C.5,
|
| Affiltns:
|
1 Univ. Florida
2 NOAO,
3 LHEA,
NASA/GSFC,
4 JCA, UMBC,
5 Ohio Univ.
|
| Journal:
|
ApJ in press
|
| Publn Date:
|
2003
|
Summary
We present Chandra X-ray observations of the radio-quiet QSO
PG2302+029. This quasar has a rare system of ultra-high velocity
(-56,000 km s-1) UV
absorption lines that form in an outflow from the
active nucleus (Jannuzi et al. 2003). The Chandra data indicate that
soft X-ray absorption is also present. We perform a joint UV and X-ray
analysis, using photoionization calculations, to detemine the nature of
the absorbing gas. The UV and X-ray datasets were not obtained simultaneously.
Nonetheless,
our analysis suggests that the X-ray absorption occurs at high velocities
in the same general region as the UV absorber. There are not enough
constraints to rule out multi-zone models. In fact, the distinct broad and
narrow UV line profiles clearly indicate that multiple zones are present.
Our preferred estimates of the ionization and total column density in
the X-ray absorber
(log U=1.6, NH=1022.4 cm-2)
over predict the O VI (lambda 1032,1038) absorption
unless
the X-ray absorber is also outflowing at
56,000$ km s-1, but they
over predict the
Ne VIII (lambda 770, 780) absorption at
all
velocities. If we assume that the X-ray absorbing gas is outflowing
at the same velocity of the UV-absorbing wind and that the wind
is radiatively accelerated, then the outflow must be launched at a radius of
<=1015 cm from the central continuum source. The smallness
of this radius casts doubts on the assumption of radiative acceleration.
Figures:
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See Also
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