10579( 6) - 08/17/05 11:41 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10579 Version: 6 Check-in Time: 17-Aug-2005 15:40:39 Title ULX counterparts: the key to finding intermediate-mass black holes ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 14 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Timothy Paul Roberts University of Leicester CoI: Dr. Michael R. Goad University of Leicester N CoI: Mr. Andrew J. Levan University of Leicester N ------------------------------------------------------------------------------------ Abstract The origin and formation mechanism for supermassive black holes (SMBHs) found in the centres of most, if not all, galaxies remains one of the outstanding questions in astrophysics. Most scenarios involve the presence of massive black holes in the early universe, formed by the collapse of primordial Population III stars. It is predicted that a relic of this population could still be present in galactic halos in the current epoch, possessing masses from a few hundred times solar mass upwards. However, to date no CONCLUSIVE evidence for such a class of "intermediate-mass" black holes has been found. The most likely current candidates are the ultraluminous X-ray sources (ULXs), which show tantalising evidence for IMBHs (e.g. the extreme X- ray luminosities and low disk temperatures expected from accreting IMBHs). We propose to address this issue by identifying optical counterparts for six of the nearest ULXs. We will use this programme as a pathfinder for future radial velocity measurements, which will allow the orbital parameters and hence the first undisputed mass constraints for these systems to be determined. ------------------------------------------------------------------------------------ 10579( 6) - 08/17/05 11:41 - [ 2] Observations Description ------------------------ For each of our six targets we will obtain two orbits of imaging. One of these will utilize the ACS/WFC for B (F435W) and V-R (F606W) observations (note that we choose F606W over F555W, which is closer in coverage to the classic V filter, due to its superior throughput which allows far higher sensitivity observations). We will perform two exposures in each of the filters to enable cosmic ray rejection, these exposures will have a typical length of ~500s. This will allow us to reach 5-sigma magnitude limits of F435W = 26.6 and F606W = 27.2 corresponding to$M_B =-2.6 and Mv = -2.0 at a distance of 7 Mpc (the mean distance of our sample), and is sufficiently deep to observe B-stars on the main sequence. Our second orbit will use the ACS/HRC to obtain U-band (F330W) observations of the same targets. We will perform four exposures within the orbit utilising a small dither pattern to aid with cosmic-ray rejection and PSF recovery via the drizzle algorithm. The depth of the subsequently combined image will be F330W = 24.5 (equivalent to a B star with F606W = 26). This will provide a second colour (U-B), allowing the spectral type of any faint blue stellar companions to be constrained. The use of the HRC will also utilise the unmatched PSF of HST to its maximum effect, providing the highest resolution observations available to resolve potentially complex regions of the underlying galaxy. To precisely position our ULXs onto the celestial frame of the HST images we will perform relative astrometry between the ACS/WFC and Chandra frames. The increased field of view of ACS/WFC with respect to WFPC2 means that we can expect a larger number of X-ray sources to fall within our field of view. In the event that insufficient sources are unambigously identified on the ACS frame we will use ground-based images as intermediates to aid the alignment. We will align the ACS/HRC field to that of the WFC utilising common point source in each field. Via this method we will be able to recover the positions of ULXs on our ACS frames to positional accuracies of < 0."3. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 10579( 6) - 08/17/05 11:41 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2403-X1 UNIDENTIFIED, ACCRETION RA=07H36M25.5500S +/- 0.1", J2000 fx = 7.1e-13 erg/cm^2/s (0.5 - 2 keV) DISK, X-RAY EMITTER DEC=+65D35'40.00" +/- 0.1" Coordinate Source: Other_Source: Chandra location 4 NGC4485-X1 UNIDENTIFIED, ACCRETION RA=12H30M30.5600S +/- 0.1", J2000 fx = 1.8e-13 erg/cm^2/s (0.5 - 2 keV) DISK, X-RAY EMITTER DEC=+41D41'42.30" +/- 0.1" Coordinate Source: Other_Source: Chandra location 5 NGC5055-X2 UNIDENTIFIED, ACCRETION RA=13H15M19.5000S +/- 0.1", J2000 fx = 7.3e-13 erg/cm^2/s (0.5 - 2 keV) DISK, X-RAY EMITTER DEC=+42D03'2.20" +/- 0.1" Coordinate Source: Other_Source: Chandra location 6 M83-IXO82 UNIDENTIFIED, ACCRETION RA=13H37M20.1000S +/- 0.1", J2000 fx = 3.8e-13 erg/cm^2/s (0.5 - 2 keV) DISK, X-RAY EMITTER DEC=-29D53'46.00" +/- 0.1" Coordinate Source: Other_Source: Chandra location Comments: We would prefer to have the Chandra observation of this source taken (and analysed) before these observations are performed, so that we have the most accurate X-ray position of the ULX to point HST at. However, as the X-ray position is already good to < 5 arcsec, this is not an absolute necessity. 7 IC-342-X1 UNIDENTIFIED, ACCRETION RA=03H45M55.6800S +/- 0.1", J2000 V = 25.0+/-2.0 DISK, X-RAY EMITTER DEC=+68D04'54.90" +/- 0.1" Coordinate Source: Other_Source: Chandra 8 IC-342-X2 UNIDENTIFIED, ACCRETION RA=03H46M15.7300S +/- 0.1", J2000 V = 25.0+/-2.0 DISK, X-RAY EMITTER DEC=+68D11'12.60" +/- 0.1" Coordinate Source: Other_Source: Chandra 10579( 6) - 08/17/05 11:41 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.15 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 34.13 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.15 Line_Spacing 0.098 Coordinate_Frame POS-TARG Pattern_Orient 19.89 Angle_Between_Sides 63.5 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 10579( 6) - 08/17/05 11:41 - [ 5] Visit: 03 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2403-X1 ACS/WFC ACCUM WFC1 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2403-X1 ACS/WFC ACCUM WFC1 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 see below ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2403-X1 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 728 S PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC2403-X1 1 ACS/WFC ACCUM WFC1 F435W 1 none none none 1 624.0 S NGC2403-X1 1 ACS/WFC ACCUM WFC1 F435W 2 none none none 1 624.0 S NGC2403-X1 2 ACS/WFC ACCUM WFC1 F606W 1 none none none 1 624.0 S NGC2403-X1 2 ACS/WFC ACCUM WFC1 F606W 2 none none none 1 624.0 S NGC2403-X1 3 ACS/HRC ACCUM HRC F330W 1 none none none 2 N/A NGC2403-X1 3 ACS/HRC ACCUM HRC F330W 2 none none none 2 N/A NGC2403-X1 3 ACS/HRC ACCUM HRC F330W 3 none none none 2 N/A NGC2403-X1 3 ACS/HRC ACCUM HRC F330W 4 none none none 2 N/A 10579( 6) - 08/17/05 11:41 - [ 6] Visit: 07 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4485-X1 ACS/WFC ACCUM WFC1 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4485-X1 ACS/WFC ACCUM WFC1 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 see below ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4485-X1 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 663 S PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC4485-X1 1 ACS/WFC ACCUM WFC1 F435W 1 none none none 1 558.0 S NGC4485-X1 1 ACS/WFC ACCUM WFC1 F435W 2 none none none 1 558.0 S NGC4485-X1 2 ACS/WFC ACCUM WFC1 F606W 1 none none none 1 558.0 S NGC4485-X1 2 ACS/WFC ACCUM WFC1 F606W 2 none none none 1 558.0 S NGC4485-X1 3 ACS/HRC ACCUM HRC F330W 1 none none none 2 N/A NGC4485-X1 3 ACS/HRC ACCUM HRC F330W 2 none none none 2 N/A NGC4485-X1 3 ACS/HRC ACCUM HRC F330W 3 none none none 2 N/A NGC4485-X1 3 ACS/HRC ACCUM HRC F330W 4 none none none 2 N/A 10579( 6) - 08/17/05 11:41 - [ 7] Visit: 09 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5055-X2 ACS/WFC ACCUM WFC1 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC5055-X2 ACS/WFC ACCUM WFC1 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC5055-X2 1 ACS/WFC ACCUM WFC1 F435W 1 none none none 1 558.0 S NGC5055-X2 1 ACS/WFC ACCUM WFC1 F435W 2 none none none 1 558.0 S NGC5055-X2 2 ACS/WFC ACCUM WFC1 F606W 1 none none none 1 558.0 S NGC5055-X2 2 ACS/WFC ACCUM WFC1 F606W 2 none none none 1 558.0 S 10579( 6) - 08/17/05 11:41 - [ 8] Visit: 10 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5055-X2 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 663 S PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC5055-X2 1 ACS/HRC ACCUM HRC F330W 1 none none none 1 N/A NGC5055-X2 1 ACS/HRC ACCUM HRC F330W 2 none none none 1 N/A NGC5055-X2 1 ACS/HRC ACCUM HRC F330W 3 none none none 1 N/A NGC5055-X2 1 ACS/HRC ACCUM HRC F330W 4 none none none 1 N/A 10579( 6) - 08/17/05 11:41 - [ 9] Visit: 11 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M83-IXO82 ACS/WFC ACCUM WFC1 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 M83-IXO82 ACS/WFC ACCUM WFC1 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 M83-IXO82 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 642 S PATTERN 2 3 Comments: We would prefer to have the Chandra observation of this source taken (and analysed) before these observations are performed, so that we have the most accurate X-ray position of the ULX to point HST at. However, as the X-ray position is already good to < 5 arcsec, this is not an absolute necessity. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M83-IXO82 1 ACS/WFC ACCUM WFC1 F435W 1 none none none 1 N/A M83-IXO82 1 ACS/WFC ACCUM WFC1 F435W 2 none none none 1 N/A M83-IXO82 2 ACS/WFC ACCUM WFC1 F606W 1 none none none 1 N/A M83-IXO82 2 ACS/WFC ACCUM WFC1 F606W 2 none none none 1 N/A M83-IXO82 3 ACS/HRC ACCUM HRC F330W 1 none none none 2 N/A M83-IXO82 3 ACS/HRC ACCUM HRC F330W 2 none none none 2 N/A M83-IXO82 3 ACS/HRC ACCUM HRC F330W 3 none none none 2 N/A M83-IXO82 3 ACS/HRC ACCUM HRC F330W 4 none none none 2 N/A 10579( 6) - 08/17/05 11:41 - [ 10] Visit: 13 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IC-342-X1 ACS/WFC ACCUM WFC2 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 IC-342-X1 ACS/WFC ACCUM WFC2 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 see below ------------------------------------------------------------------------------------------------------------------------------------ 3 IC-342-X1 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 725 S PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ IC-342-X1 1 ACS/WFC ACCUM WFC2 F435W 1 none none none 1 624.0 S IC-342-X1 1 ACS/WFC ACCUM WFC2 F435W 2 none none none 1 624.0 S IC-342-X1 2 ACS/WFC ACCUM WFC2 F606W 1 none none none 1 624.0 S IC-342-X1 2 ACS/WFC ACCUM WFC2 F606W 2 none none none 1 624.0 S IC-342-X1 3 ACS/HRC ACCUM HRC F330W 1 none none none 2 N/A IC-342-X1 3 ACS/HRC ACCUM HRC F330W 2 none none none 2 N/A IC-342-X1 3 ACS/HRC ACCUM HRC F330W 3 none none none 2 N/A IC-342-X1 3 ACS/HRC ACCUM HRC F330W 4 none none none 2 N/A 10579( 6) - 08/17/05 11:41 - [ 11] Visit: 15 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IC-342-X2 ACS/WFC ACCUM WFC2 F435W CR-SPLIT=NO 1 500 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 IC-342-X2 ACS/WFC ACCUM WFC2 F606W CR-SPLIT=NO 1 500 S PATTERN 1 2 see below ------------------------------------------------------------------------------------------------------------------------------------ 3 IC-342-X2 ACS/HRC ACCUM HRC F330W CR-SPLIT=NO 1 725 S PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ IC-342-X2 1 ACS/WFC ACCUM WFC2 F435W 1 none none none 1 624.0 S IC-342-X2 1 ACS/WFC ACCUM WFC2 F435W 2 none none none 1 624.0 S IC-342-X2 2 ACS/WFC ACCUM WFC2 F606W 1 none none none 1 624.0 S IC-342-X2 2 ACS/WFC ACCUM WFC2 F606W 2 none none none 1 624.0 S IC-342-X2 3 ACS/HRC ACCUM HRC F330W 1 none none none 2 N/A IC-342-X2 3 ACS/HRC ACCUM HRC F330W 2 none none none 2 N/A IC-342-X2 3 ACS/HRC ACCUM HRC F330W 3 none none none 2 N/A IC-342-X2 3 ACS/HRC ACCUM HRC F330W 4 none none none 2 N/A 10579( 6) - 08/17/05 11:41 - [ 12] Summary Form for Proposal 10579 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1 HRC WFC2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1 PATTERN 1 2 PATTERN 2 3 PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F435W F606W F330W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC2403-X1 NGC4485-X1 NGC5055-X2 M83-IXO82 IC-342-X1 IC-342-X2 ------------------------------------------------------------------------------------------------------------------------------------