0 ----- Attempting Submission 1 (Thu Aug 30 13:34:52 GMT 2012) ----- The only errors are about the (failed) visit 01, that cannot be modified here. The relevant visit for this phase 2 resubmission is visit 51. Constraining the irradiated disk and the nature of the companion star in an ultraluminous X-ray source Previous HST observations of the ultraluminous X-ray source Holmberg IX X-1 show that its optical emission may be dominated at short wavelengths by an irradiated accretion disk and at long wavelengths by a late-type (super)giant star which would be the donor star in the system. This makes of Holmberg IX X-1 one of the few ULXs where we have a direct, observational hint about the presence of a companion star. We propose X-ray and UV to NIR observations with Chandra and HST/WFC3. The X-ray spectrum will be essential at modeling the disk emission and, combined with UV/optical measurements, will allow us to constrain the irradiation in the disk. Longer wavelengths will enable us to definitely identify the red excess emission as coming from the donor star or from some structure from the disk. The observations consist of one simultaneous Chandra/HST observation. We will observe using the WFC3/UVIS instrument in the F225W, F336W,F438W, F547M, F621M, F689M, F763M, F845M filters. We will also make use of WFC3/IR to perform observations in the F098M, F125W and F160W filters. Holmberg IX X-1 is known to be variable in X-rays and in the optical, on timescales of days (and less). Thus, for a reliable modeling of the spectral energy distribution, we need the HST observations to be simultaneous with the 15 ks Chandra observation (Chandra proposal 13400775). RESOLVED STELLAR POPULATIONS 12 false 15.0 0.0 false false false false SUPPORTED EXT-STAR ACCRETION DISK J2000 J2000 WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F547M WFC3/UVIS Imaging No No F621M WFC3/UVIS Imaging No No F689M WFC3/UVIS Imaging No No F763M WFC3/UVIS Imaging No No F845M WFC3/IR Imaging No No F098M WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. /home/grise/Work/Proposal/HST/Cycle19/PhaseII/OP-cache/phase2_sub1k_revised-v01.xml This visit should be scheduled to occur during the 15,000 second duration of the corresponding Chandra observation (Chandra Seq: 401413 ObsId: 13728, see Chandra proposal 13400775). 1342725211000 37.47027126277041 (Tic-Visit :proposal-id 12747 :visit-id "01" :proposal-version -1 :trans-version "20120802" :date "30-Aug-2012 12:11:45.0" :trans-errors '(:WARNINGS 3 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1209424 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12747 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12747 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3265 :al-overhead-at-end 74 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12747 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3370 :al-overhead-at-end 76 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12747 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3371 :al-overhead-at-end 0 :internal-dur-at-end 677 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) true 3 3 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. /home/grise/Work/Proposal/HST/Cycle19/PhaseII/OP-cache/phase2_sub1k_revised-v51.xml This visit should be scheduled to occur during the 15,000 second duration of the corresponding Chandra observation (Chandra Seq: 401436 ObsId: 14471, see Chandra proposal 13400775). (Tic-Visit :proposal-id 12747 :visit-id "51" :proposal-version -1 :trans-version "20120802" :date "30-Aug-2012 12:59:02.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1209424 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12747 :visit-id "51" :obset-id "51" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12747 :visit-id "51" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3248 :al-overhead-at-end 80 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12747 :visit-id "51" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3351 :al-overhead-at-end 82 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12747 :visit-id "51" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3359 :al-overhead-at-end 0 :internal-dur-at-end 677 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3582 :pcs-gap 0 ) true 3 0