11620( 3) - 30-Jun-2009 18:40:50 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11620 Version: 3 Check-in Time: 30-Jun-2009 18:40:50 STScI Edit Number: 1 Title A Quasar Light Echo in the Local Universe? ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. William C. Keel University of Alabama CoI: Dr. Chris J. Lintott University of Oxford N CoI: Dr. Kevin Schawinski Yale University N CoI: Dr. Nicola Bennert University of California - Riverside N CoI: Dr. Daniel Thomas University of Portsmouth N CoI: Ms. Hanny van Arkel Netherlands school system N ------------------------------------------------------------------------------------ Abstract The time history and duty cycle of individual AGN is an important part of their evolution and the growth history of massive black holes, but almost unconstrained on scales between galaxy-interaction timescales (hundreds of Myr) and the scales of years probed by variability measurements. We propose a detailed study of an object which seems to be a large-scale light echo from a QSO-level episode in a nearby galaxy. The Galaxy Zoo morphological survey of SDSS objects has uncovered a peculiar emission-line structure whose spectrum matches the narrow-line region of AGN, despite lying at least 20 kpc from a galaxy whose activity is currently very weak. This is best explained if the nucleus has faded dramatically on time scales of several tens of thousands of years. We propose a suite of imaging and spectroscopic observations to probe its properties, and the time history of this episode of nuclear activity, measuring time scales hitherto unavailable. ------------------------------------------------------------------------------------ Observations Description ------------------------ We examine the nature and energy source of a newly-found cloud near the galaxy IC 2497 ("Hanny's Voorwerp") in several ways. STIS spectroscopy of the IC 2497 nucleus will seek highly-ionized AGN gas, and measure the stellar velocity dispersion. ACS ramp-filter exposures will map [O III] and H-alpha, comparison of which might show past fluctuations in the ionizing luminosity of the AGN, and include the central part of IC 2497 to seek highly ionized structures near the core. Finally, WFC3 exposures in the UV, I, and F160W bands will be used to look for star clusters in the cloud itself, to see whether it was originally a dwarf galaxy which was later disrupted. Real Time Justification ----------------------- Calibration Justification ------------------------- 11620( 3) - 30-Jun-2009 18:40:50 - [ 2] Additional Comments ------------------- ------------------------------------------------------------------------------------ 11620( 3) - 30-Jun-2009 18:40:50 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ094103. GALAXY, EMISSION LINE RA=09H41M4.0449S +/- 0.1", J2000 g=18.3 80+344334.2 NEBULA DEC=+34D43'39.82" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 2 IC2497 GALAXY, NUCLEUS RA=09H41M4.1500S +/- 0.1", J2000 V = 14 g(nucleus)=16.9 DEC=+34D43'58.30" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11620( 3) - 30-Jun-2009 18:40:50 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 47.23 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.636 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 11620( 3) - 30-Jun-2009 18:40:50 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: STIS spectroscopy of the nucleus of IC 2497, seeking evidence of ongoing (even if obscured) nuclear actvity. The 0.2" slit is a compromise between rejection of the surounding starlight and throughput (plus speed of acquisition). Setups in blue and red (with fring flats) are used for one orbit each. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IC2497 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=DIFFUSE, 1 100 S DIFFUSE-CENTER=FLUX-CENTROID, CHECKBOX=9 ------------------------------------------------------------------------------------------------------------------------------------ 2 IC2497 STIS/CCD ACCUM 52X0.2 G750L 7751 1 2000 S ------------------------------------------------------------------------------------------------------------------------------------ 3 CCDFLAT STIS/CCD ACCUM 52X0.2 G750L 7751 2 DEF ------------------------------------------------------------------------------------------------------------------------------------ 4 IC2497 STIS/CCD ACCUM 52X0.2 G430L 4300 1 2750 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 | ------------------------------------------------------------------------------------------------------------------------------------ IC2497 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A IC2497 2 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 1 1 N/A IC2497 2 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 2 1 N/A CCDFLAT 3 STIS/CCD ACCUM 52X0.2 G750L 7751 none none 1 none 1 N/A CCDFLAT 3 STIS/CCD ACCUM 52X0.2 G750L 7751 none none 2 none 1 N/A IC2497 4 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 1 2 N/A IC2497 4 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 2 2 N/A 11620( 3) - 30-Jun-2009 18:40:50 - [ 6] Visit: 02 Visit Requirements: ORIENT 305D TO 335 D; ORIENT 117D TO 149 D On Hold Comments: Additional Comments: Narrowband images in [O III] and H-alpha at z=0.05. 2-point dither pattern, 2x2 pixels to reject hot pixels and keep the whole ramp-filter field. To keep two targets in monochromatic fields, orientation is restricted to two ranges and center point is offset from target cordinates (to maximize rangle of usable angles). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ094103 ACS/WFC ACCUM WFC1-MRAM FR505N 5240.0 1 1285 S PATTERN 1 1 .80+344334. P 2 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ094103 ACS/WFC ACCUM WFC1-IRAM FR716N 6921.0 1 1375 S PATTERN 1 2 .80+344334. P 2 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ094103.80+3443 1 ACS/WFC ACCUM WFC1-MRA FR505N 5240. 1 none none none 1 N/A 34.2 MP 0 SDSSJ094103.80+3443 1 ACS/WFC ACCUM WFC1-MRA FR505N 5240. 2 none none none 1 N/A 34.2 MP 0 SDSSJ094103.80+3443 2 ACS/WFC ACCUM WFC1-IRA FR716N 6921. 1 none none none 2 N/A 34.2 MP 0 SDSSJ094103.80+3443 2 ACS/WFC ACCUM WFC1-IRA FR716N 6921. 2 none none none 2 N/A 34.2 MP 0 11620( 3) - 30-Jun-2009 18:40:50 - [ 7] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Broadband continuum images (UVIS and IR) of the cloud known as Hanny's Voorwerp are used to seek underlying stelar populations, to tell whether it was originally a dwarf galaxy later disrupted and illuminated by IC 2497. Simple 2- and 3-pont linear dithers are used for hot-pixel rejection. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ094103 WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=STEP100, NSAMP=15 1 DEF PATTERN 3 1 .80+344334. CUM 2 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ094103 WFC3/UVI ACCUM UVIS1 F225W CR-SPLIT=NO 1 1200 S PATTERN 2 2 .80+344334. S see below 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ094103 WFC3/UVI ACCUM UVIS1 F814W CR-SPLIT=NO 1 1300 S PATTERN 2 3 .80+344334. S see below 2 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ094103.80+3443 1 WFC3/IR MULTIAC IR-FIX F160W 1 none none none 1 N/A 34.2 CUM SDSSJ094103.80+3443 1 WFC3/IR MULTIAC IR-FIX F160W 2 none none none 1 N/A 34.2 CUM SDSSJ094103.80+3443 1 WFC3/IR MULTIAC IR-FIX F160W 3 none none none 1 N/A 34.2 CUM SDSSJ094103.80+3443 2 WFC3/UVI ACCUM UVIS1 F225W 1 none none none 2 1476.0 S 34.2 S SDSSJ094103.80+3443 2 WFC3/UVI ACCUM UVIS1 F225W 2 none none none 2 1476.0 S 34.2 S SDSSJ094103.80+3443 3 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 3 1652.0 S 34.2 S SDSSJ094103.80+3443 3 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 3 N/A 34.2 S 11620( 3) - 30-Jun-2009 18:40:50 - [ 8] Summary Form for Proposal 11620 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP, IR-FIX, UVIS1, WFC1-IRAMP, WFC1-MRAMP ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, STIS/CCD, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=DIFFUSE, CHECKBOX=9, CR-SPLIT=NO, DIFFUSE-CENTER=FLUX-CENTROID, NSAMP=15, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 117D TO 149 D, ORIENT 305D TO 335 D, PATTERN 1 1, PATTERN 1 2, PATTERN 2 2, PATTERN 2 3, PATTERN 3 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F225W, F814W, FR505N, FR716N, G430L, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, IC2497, SDSSJ094103.80+344334.2 ------------------------------------------------------------------------------------------------------------------------------------