A few quasars are known to exhibit associated absorption lines with opaque partial covering. These are the lines which are clearly saturated but not completely dark, so that these absorbing clouds are opaquely and partially covering the quasar light. In some cases, ionization parameter and density arguments indicate that the absorbers are on kpc scale. This implies that at least in some cases, the residual, unabsorbed optical (rest-UV) continuum component originates from ~kpc scales, rather than microscopic scales (such as ~100 Schwarzschild radii). This could be a superluminous host galaxy or starbursting core, and could be resolved by HST. We address the nature of these opaquely and partially covered quasars with a simple and robust ACS imaging.

We image the quasar Q0449-135 with ACS/HRC using the narrow band filter F502N, which accidentally falls at the opaque partial covering absorption doublet lines NV1240. This will greatly enhance the contrast of the underlying ``residual'' continuum at these lines to the other component of the quasar light which is thought to be compact. We will use the HRC to get critical spatial sampling. Since we want to measure the quasar's PSF core to look for any extension, we will take a short exposure image of a star to measure the size of the core of the PSF just before and after the quasar observation. While the HST focus vary within the observation of three orbits, the PSF core FWHM will not change significantly (the larger effect is a change in the core/wing flux ratio; John Krist, p.c.). The two sets of the PSF star observations will be combined to achieve the necessary S/N, but also will be used to double-check the stability of the PSF core. The PSF star will be the one with B=15.2mag at ~80'' from the target. Since the slew from the star to the target is small, pointing-dependent focus change will be insignificant (John Krist, p.c.). We use the same narrow-band filter (F502N) for the PSF star observation, so that the color difference between the star and target will not be a problem. In the first orbit, we will take a 13min exposure with 2 integer-pixel dither positions (for removing CR hits and hot pixels) for the PSF star and a 29min exposure with 2 integer-pixel dither positions for the target, with 13min overhead out of the visibility period 55min. Then in the second orbit, we will take a 45min exposure with 3 integer-pixel dither positions for the target, with the overhead 10min. The third orbit will be essentially idential with the first orbit except that the exposure for the PSF star will be at the end of the orbit: 30min for the target, 13min exposure for the star, 12min overhead. (Total exposure time for the target = 104min; PSF star = 26min; overhead = 35min.) We estimate that the target gives 26 cts/sec. The PSF star is ~16 times brighter than this. AGN/QUASARS 12 false 0.0 false false false false false SUPPORTED GALAXY STARBURST HIGH REDSHIFT GALAXY QSO J2000 04 51 42.6000 -13 20 46.00 J2000 CALIBRATION POINT SPREAD FUNCTION GSC0532800598 J2000 00 00 0.0000 +00 00 0.00 J2000 GALAXY STARBURST HIGH REDSHIFT GALAXY QSO J2000 04 51 42.6000 -13 20 46.00 J2000 CALIBRATION POINT SPREAD FUNCTION GSC0532800598 J2000 00 00 0.0000 +00 00 0.00 J2000 ACS/HRC Imaging No No F502N POS-TARG DITHER 0.198 LINE false false 2 44.279999 ACS-HRC-DITHER-LINE 1 false POS-TARG DITHER 0.198 LINE false false 3 44.279999 ACS-HRC-DITHER-LINE 2 false (Tic-Visit :proposal-id 10570 :visit-id "01" :proposal-version -1 :trans-version "20051113" :date "21-Apr-2006 09:52:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2077536 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10570 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10570 :visit-id "01" :orbit-number 1 :pcs-time 339 :si-vis-utilization 2875 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3251 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10570 :visit-id "01" :orbit-number 2 :pcs-time 339 :si-vis-utilization 2901 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3251 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10570 :visit-id "01" :orbit-number 3 :pcs-time 339 :si-vis-utilization 2863 :al-overhead-at-end 0 :internal-dur-at-end 79 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3251 :pcs-gap 0 ) false 3 0 This is for the repeat of the orbit 1 of Visit 01. (Tic-Visit :proposal-id 10570 :visit-id "51" :proposal-version -1 :trans-version "20051113" :date "21-Apr-2006 12:20:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 609360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10570 :visit-id "51" :obset-id "51" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10570 :visit-id "51" :orbit-number 1 :pcs-time 339 :si-vis-utilization 2855 :al-overhead-at-end 0 :internal-dur-at-end 351 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3251 :pcs-gap 0 ) false 1 0 This is for the repeat of the orbit 1 of Visit 01. (Tic-Visit :proposal-id 10570 :visit-id "A1" :proposal-version -1 :trans-version "20060619" :date "01-Dec-2006 09:47:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 609360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10570 :visit-id "A1" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10570 :visit-id "A1" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2855 :al-overhead-at-end 0 :internal-dur-at-end 351 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3251 :pcs-gap 0 ) true 1 0