We will study a transient ultraluminous X-ray source (ULX) in M83, which went into outburst in 2010 and is now evolving towards the luminosity range of ordinary stellar-mass black holes. We propose an XMM-Newton and HST study: a) to model the spectral state evolution during the decline, and discover how the ULX regime is linked to the sub-Eddington accretion states of Galactic BHs; b) to determine or constrain the mass of the BH, from X-ray spectroscopy; c) to quantify the properties of the irradiated disk, and its response to variable X-ray illumination from new HST WFC3 imagery. This HST program was accepted as part of a joint XMM-HST proposal with Roberto Soria (Curtin University, Australia) as PI. Blair is administrative PI and contact for this phase II submission. The program is very straightforward, to obtain WFC3 U, B, V, I imagery of a field in the galaxy M83 that contains an Ultraluminous X-ray source (ULX). The ULX was detected in DD program 12683 (Winkler, PI) in 2011. This is another observation of the field in these four bands, using 3 orbits and deeper exposures, both to go deeper in the surrounding field to characterize the nearby stellar populations and to ensure a solid detection of the optical source that corresponds with the ULX, which may have faded somewhat from the previous observation. Hence, any apparent duplication with earlier data is intentional. The ULX position is placed at the UVIS aperture position and full-field data are requested to maximize the secondary utility of the data for ancillary science. The WFC3-UVIS-MOS-DITH-LINE dither pattern is requested to ensure coverage of the chip gap region while maintaining reasonable sub-pixel dithering. FLASH has been added on the U abd B-band data to ensure the CTE-mitigation level of 12 electrons is reached. 12 Regular false false false false false SUPPORTED EXT-STAR ACCRETION DISK IRREGULAR VARIABLE X-RAY TRANSIENT Source is likely variable at the 0.5 mag level as the X-ray flux varies. (The light arises from reprocessing of the X-ray emission in an accretion disk around a black hole.) J2000 WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W POS-TARG MOSAIC DITHER 2 2.4 WFC3-UVIS-MOS-DITH-LINE false true 0.119 2 85.754 POS-TARG WFC3-UVIS-MOS-DITH-LINE 33.606 1 true 1430407749167 The scheduling data was generated by CASM 23.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14059 :visit-id "01" :proposal-version -1 :trans-version "20150128" :date "30-Apr-2015 11:29:09.0" :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 4620016 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14059 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14059 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2903 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14059 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3016 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14059 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3018 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) false 3 0