----- Attempting Submission 1 (Thu Apr 17 12:59:37 GMT 2008) ----- Phase II Proposal 11517 (hstAPTformsdither.apt) successfully submitted. ----- Attempting Submission 5 (Tue Apr 22 07:44:46 GMT 2008) ----- The X-ray source XMMUJ134736.6+173403 has recently been discovered serendipitously. Its X-ray position coincides with two interacting galaxies, one of which is a Seyfert II. The X-ray variability and spectrum rule out an association with the Seyfert II. Carpano et al. (2008) suggest that the source is a foreground quiescent low-mass X-ray binary (unrelated to the galaxy-pair). Our recent optical photometry rules out such a scenario since the counterpart to the low-mass X-ray binary should have been detected. Furthermore, we find an extended source in the XMM error circle. Optical spectroscopy shows emission lines, such as those found in ULX nebulae, redshifted to the same redshift as that of the pair of interacting galaxies. Swift/UVOT observations show that the spectrum of the emission nebula is very blue. If this emission nebula is indeed associated with the X-ray source it implies that the X-ray source is a ULX. We propose here to obtain an ACS/SBC image to accurately determine the magnitude and the extend of the nebula and to investigate if the ULX/nebula emission can be responsible for the observed X-ray emission by extending the SED to ~1300 angstrom.

We request a short HST ACS observation using the F122M filter in order to: -Extend the SED down to 1300 A. A further brightening of the nebula in comparison with the Seyfert II in the F122M band would strengthen the association of the X-ray source with a ULX and the nebula. -Determine the size of the nebula accurately. We determined the exposure time using the UVOT UVW2 flux estimate. We extrapolated the SED to 1300 A, from this we find that a 4x600 s exposure would give us a SN of >10. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 3 false 0.0 0.0 false false false false false SUPPORTED GALAXY EMISSION LINE NEBULA INTERACTING GALAXY F(1900)=8.6E-17 J2000 13 47 36.6000 +17 34 3.00 J2000 WFPC2 Imaging No F122M WFPC2 Imaging No F450W POS-TARG DITHER 0.179 LINE 0.116 false false 63.65 4 20.02 ACS-SBC-DITHER-BOX 2 false The scheduling data was generated by CASM 17.0. CASM was run in Phase II mode. /private/tmp/OPVisit7614.xml 1208850171251 (Tic-Visit :proposal-id 11517 :visit-id "01" :proposal-version -1 :trans-version "20071214" :date "22-Apr-2008 09:42:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11517 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11517 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2789 :al-overhead-at-end 0 :internal-dur-at-end 119 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3144 :pcs-gap 0 ) true 1 0