12381( 4) - 29-Sep-2010 14:23:00 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12381 Version: 4 Check-in Time: 29-Sep-2010 14:23:00 STScI Edit Number: 3 Title Imaging the Crab nebula while it is flaring in gamma-rays ------------------------------------------------------------------------------------ Type Cycle GO/DD 18 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Patrizia A. Caraveo CNR, Istituto di Astrofisica Spaziale CoI: Dr. Andrea De Luca CNR, Istituto di Astrofisica Spaziale N CoI: Dr. Roberto Mignani Mullard Space Science Laboratory Y ------------------------------------------------------------------------------------ Abstract The high energy gamma-ray flux from the Crab nebula doubled in a couple of days (from September 19 to September 21). Such enhancement, never seen before, is clearly detected both by Agile and Fermi, the two gamma-ray telescopes currently in operation. While such huge brightening is exciting the entire astrophysical community, TOOs are being scheduled by high energy space observatories such as Integral, Swift and Chandra. By imaging the status of the knots and wisps in the inner Crab nebula, HST could provide a unique piece of information, which may yield a clue to understand the source behavior. ------------------------------------------------------------------------------------ Observations Description ------------------------ We ask for straight imaging of the Crab Nebula. We will use the HST/ACS instrument in its WFC configuration (which will cover the entire field of interest). We propose to use the large-band F550M filter, well suited to sample the continuum emission from the system, with almost no contamination from line emission from the SNR filaments. Such a choice will also allow for an easy comparison of the new image with the large available database of HST images of the Crab collected with the WFPC2 instrument through the F547M filter, having a very similar bandpass to the F550M selected here. The observation (2200s integration; one single orbit) must be split in 4 frames (550s each) with a standard 4-point BOX dithering pattern (few pixel spacing). Real Time Justification ----------------------- The observation has to be performed as soon as possible (within 2 days maximum) to observe the target as close as possible to the peak of its variability Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12381( 4) - 29-Sep-2010 14:23:00 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CRAB-NEBULA- STAR, NEUTRON STAR, RA=05H34M31.9500S +/- 0.1", J2000 V = 16.65 +/- 0.05 AND-PULSAR PULSAR, SUPERNOVA DEC=+22D00'52.10" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 12381( 4) - 29-Sep-2010 14:23:00 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12381( 4) - 29-Sep-2010 14:23:00 - [ 4] Visit: 01 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 CRAB-NEBULA ACS/WFC ACCUM WFC1-FIX F550M 1 500 S PATTERN 1 1 -AND-PULSAR 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 | ------------------------------------------------------------------------------------------------------------------------------------ CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 1 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 2 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 3 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 4 none none none 1 500.0 S SAR 12381( 4) - 29-Sep-2010 14:23:00 - [ 5] Visit: 51 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 CRAB-NEBULA ACS/WFC ACCUM WFC1-FIX F550M 1 500 S PATTERN 1 1 -AND-PULSAR 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 | ------------------------------------------------------------------------------------------------------------------------------------ CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 1 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 2 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 3 none none none 1 500.0 S SAR CRAB-NEBULA-AND-PUL 1 ACS/WFC ACCUM WFC1-FIX F550M 4 none none none 1 500.0 S SAR 12381( 4) - 29-Sep-2010 14:23:00 - [ 6] Summary Form for Proposal 12381 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F550M ------------------------------------------------------------------------------------------------------------------------------------ Target Names CRAB-NEBULA-AND-PULSAR ------------------------------------------------------------------------------------------------------------------------------------