We present results from a multiwavelength IR–to–X-ray campaign of the infrared bright ( but highly optical-UV extincted ) QSO IRAS 13349+2438 obtained with the Chandra High Energy Transmission Grating Spectrometer ( HETGS ) , the Hubble Space Telescope Space Telescope Imaging Spectrograph ( STIS ) , the Hobby-Eberly Telescope ( HET ) 8-meter , and the Spitzer Infrared Spectrometer ( IRS ) .
Based on HET optical spectra of [ O iii ] , we refine the redshift of IRAS 13349 to be z = 0.10853 .
The weakness of the [ O iii ] in combination with strong Fe ii in the HET spectra reveal extreme Eigenvector-1 characteristics in IRAS 13349 , but the 2468 { \thinspace km } { \thinspace s } ^ { -1 } width of the H \beta line argues against a narrow-line Seyfert 1 classification ; on average , IR , optical and UV spectra show IRAS 13349 to be a typical QSO .
Independent estimates based on the H \beta line width and fits to the IRAS 13349 SED both give a black hole mass of M _ { BH } = 10 ^ { 9 } ~ { } M _ { \odot } .
The heavily reddened STIS UV spectra reveal for the first time blue-shifted absorption from Ly \alpha , N v and C iv , with components at systemic velocities of -950 ~ { } \hbox { $ { \thinspace km } { \thinspace s } ^ { -1 } $ } and -75 ~ { } \hbox { $ { \thinspace km } { \thinspace s } ^ { -1 } $ } .
The higher velocity UV lines are coincident with the lower-ionisation ( \xi \sim 1.6 ) WA-1 warm absorber lines seen in the X-rays with the HETGS .
In addition , a \xi \sim 3.4 WA-2 is also required by the data , while a \xi \sim 3 WA-3 is predicted by theory , and seen at less significance ; all detected X-ray absorption lines are blueshifted by \sim 700 - 900 { \thinspace km } { \thinspace s } ^ { -1 } .
Theoretical models comparing different ionising SEDs reveal that including the UV ( i.e. , the accretion disc ) as part of the ionising continuum has strong implications for the conclusions one would draw about the thermodynamic stability of the warm absorber .
Specific to IRAS 13349 , we find that an X-ray-UV ionising SED favors a continuous distribution of ionisation states in a smooth flow ( this paper ) , versus discrete clouds in pressure equilibrium ( previous work by other authors ) .
Direct detections of dust are seen in both the IR and X-rays .
We see weak PAH emission at 7.7 \mu { m } and 11.3 \mu { m } which may also be blended with forsterite , and 10 \mu { m } and 18 \mu { m } silicate emission , as well as an Fe L edge at 700 eV indicative of iron-base dust with a dust-to-gas ratio > 90 % .
We develop a geometrical model in which we view the nuclear regions of the QSO along a line of sight that passes through the upper atmosphere of an obscuring torus .
This sight line is largely transparent in X-rays since the gas is ionised , but it is completely obscured by dust that blocks a direct view of the UV/optical emission region .
In the context of our model , 20 % of the intrinsic UV/optical continuum is scattered into our sight line by the far wall of an obscuring torus .
An additional 2.4 % of the direct light , which likely dominates the UV emission , is Thomson-scattered into our line-of-sight by another off-plane component of highly ionized gas .