15667( 4) - 08-Jul-2019 23:11:02 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15667 Version: 4 Check-in Time: 08-Jul-2019 23:11:02 STScI Edit Number: 2 Title VLA & HST Monitoring of Sgr A* in July 2019 with Spitzer and Chandra ------------------------------------------------------------------------------------ Type Cycle GO 26 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Farhad Yusef-Zadeh Northwestern University Y CoI: Dr. Howard A. Bushouse Space Telescope Science Institute N CoI: Dr. Lorant Sjouwerman Associated Universities, Inc. N CoI: Dr. Joseph L. Hora Smithsonian Institution Astrophysical N Observatory CoI: Dr. Steven P. Willner Smithsonian Institution Astrophysical N Observatory CoI: Mr. Marc Royster Northwestern University N CoI: Dr. Mark Wardle Macquarie University N CoI: Dr. William Cotton Associated Universities, Inc. N CoI: Dr. Douglas A. Roberts Northwestern University N ------------------------------------------------------------------------------------ Abstract We propose to use the VLA and WFC3/HST as part of an observing campaign led by Spitzer and Chandra for continuous monitoring of Sgr A* in July 2019. The Chandra (2x24h) and Spitzer (2x24h) have already been approved. The Spitzer mission is scheduled to end in November 2019, the last chance for Spitzer monitoring, which is unique in terms of its continuous coverage in the mid-IR. It is well established that an expanding synchrotron source model can explain flare emission from Sgr A* at radio wavelengths. However, it is not clear if radio, submm and IR flare emission are related to each other. If there is a relationship between low and high frequency emission, our measurements will test a predication in which a time delay between radio and IR tells us about the importance of opacity in the adiabatic expansion of plasma ejected from Sgr A*. In addition, they provide insight into particle acceleration of relativistic particles by determining the synchrotron cooling time scale at mid and near-IR by using Spitzer and HST. In particular, the adiabatic expansion model can explain the simultaneity of peak flare emission at mid-IR and submm in terms of of optical depth effects. ------------------------------------------------------------------------------------ Observations Description ------------------------ The 8 orbits of this proposal need to be scheduled in coordination with the Spitzer, Chandra, and VLA observations of Sgr A* that will be taking place between 12 July 2019 and 4 August 2019. We intend to split the 8 HST orbits allocated to this program into 2 visits of 4 back-to-back orbits each, to 15667( 4) - 08-Jul-2019 23:11:02 - [ 2] obtain monitoring of Sgr A* over a time period of ~6 hours during each of those 2 visits. The 2 visits will be scheduled to overlap as much as possible with the simultaneous observations by the other observatories. We will obtain WFC3/IR observations with the F153M filter and the SPARS-25 readout sequence. This readout sequence not only gives us equally-spaced readout intervals of 25 secs to keep the detector stable, but also results in exposures of 5-6 min duration, which is long enough to perform WFC3 buffer dumps in parallel with the exposures, thus maximizing our on-source time. We will embed the exposures within 4-point dither pattern, in order to mitigate the effects of bad pixels, flat-field uncertainties, and persistence from bright stars. A total of 8 such exposures can be obtained within each orbit, giving us nearly constant coverage of Sgr A* over a span of about 50 mins per orbit. As of 9 Jan 2019, the exact dates and times of the coordinated Spitzer and Chandra observations have not yet been determined. They will be determined from the following list of candidate orbital periods: Orbit Begin UT End UT 2753 12 JUL 10:01 14 JUL 05:29 2754 15 JUL 01:29 16 JUL 20:57 2755 17 JUL 16:57 19 JUL 12:24 2756 20 JUL 08:24 22 JUL 03:52 2757 22 JUL 23:52 24 JUL 19:20 2758 25 JUL 15:20 27 JUL 10:48 2759 28 JUL 06:48 30 JUL 02:16 2760 30 JUL 22:16 01 AUG 17:45 2761 02 AUG 13:45 04 AUG 09:14 A preliminary schedule should be available in March 2019 and a final schedule perhaps in late May 2019. Once those dates are released, we will pick two of them on which to schedule the HST visits. For now, we have simply set the BETWEEN times for the HST visits to be within the above range of 12 JUL 2019 through 04 AUG 2019. ------------------------------------------------------------------------------------ 15667( 4) - 08-Jul-2019 23:11:02 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SGR-A STELLAR CLUSTER, RA=17H45M40.0360S, J2000 V = 35 0.15 mJy in H-band ACCRETION DISK DEC=-29D00'28.17" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 15667( 4) - 08-Jul-2019 23:11:02 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.572 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 15667( 4) - 08-Jul-2019 23:11:02 - [ 5] Visit: 01 Visit Requirements: BETWEEN 12-JUL-2019:10:01:00 AND 04-AUG-2019:09:00:00 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SGR-A WFC3/IR MULTIAC IR F153M SAMP-SEQ=SPARS25, NSAMP=12 9 DEF PATTERN 1 1 CUM (10005.766 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SGR-A WFC3/IR MULTIAC IR F153M SAMP-SEQ=SPARS25, NSAMP=12 9 DEF PATTERN 2 2 CUM (5002.883 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 1 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 2 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 3 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 4 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 5 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 6 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 7 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 8 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 9 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 1 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 2 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 3 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 4 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 5 none 2 N/A CUM 15667( 4) - 08-Jul-2019 23:11:02 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 6 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 7 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 8 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 9 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 1 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 2 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 3 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 4 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 5 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 6 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 7 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 8 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 3 none 9 none 3 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 1 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 2 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 3 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 4 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 5 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 6 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 7 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 8 none 4 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 4 none 9 none 4 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 1 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 2 none 5 N/A CUM 15667( 4) - 08-Jul-2019 23:11:02 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 3 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 4 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 5 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 6 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 7 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 8 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 1 none 9 none 5 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 1 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 2 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 3 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 4 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 5 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 6 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 7 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 8 none 6 N/A CUM SGR-A 2 WFC3/IR MULTIAC IR F153M 2 none 9 none 6 N/A CUM 15667( 4) - 08-Jul-2019 23:11:02 - [ 8] Visit: 02 Visit Requirements: BETWEEN 12-JUL-2019:10:01:00 AND 04-AUG-2019:09:00:00 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SGR-A WFC3/IR MULTIAC IR F153M SAMP-SEQ=SPARS25, NSAMP=12 5 DEF PATTERN 2 1 CUM (2779.38 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 1 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 2 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 3 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 4 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 1 none 5 none 1 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 1 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 2 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 3 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 4 none 2 N/A CUM SGR-A 1 WFC3/IR MULTIAC IR F153M 2 none 5 none 2 N/A CUM 15667( 4) - 08-Jul-2019 23:11:02 - [ 9] Summary Form for Proposal 15667 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=12, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 12-JUL-2019:10:01:00 AND 04-AUG-2019:09:00:00, PATTERN 1 1, PATTERN 2 1, PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F153M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SGR-A ------------------------------------------------------------------------------------------------------------------------------------