13935( 8) - 05-Sep-2014 17:19:02 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13935 Version: 8 Check-in Time: 05-Sep-2014 17:19:02 STScI Edit Number: 0 Title The Nature of SPIRITS Intermediate-Luminosity Mid-IR Transients ------------------------------------------------------------------------------------ Type Cycle GO/DD 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Howard E. Bond The Pennsylvania State University Y CoI: Dr. Mansi Kasliwal California Institute of Technology N CoI: Dr. Lee Armus California Institute of Technology N CoI: Prof. John Bally University of Colorado at Boulder N CoI: Mr. Yi Cao California Institute of Technology N CoI: Dr. Robert D. Gehrz University of Minnesota - Twin Cities N CoI: Dr. George Helou California Institute of Technology N CoI: Dr. Emily Levesque University of Colorado at Boulder N CoI: Dr. Shazrene Mohamed South African Astronomical Observatory N CoI: Dr. Mudumba Parthasarathy Indian Institute of Astrophysics N CoI: Dr. Nathan Smith University of Arizona N CoI: Mr. Samaporn Tinyanont Harvey Mudd College N CoI: Dr. Schuyler D. Van Dyk California Institute of Technology N CoI: Dr. Patricia A. Whitelock South African Astronomical Observatory N CoI: Dr. Robert E. Williams Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract SPIRITS--the SPitzer InfraRed Intensive Transients Survey--is an ongoing search for mid-IR (MIR) variables and transients in nearly 200 nearby galaxies, being carried out with the warm Spitzer telescope at 3.6 and 4.5 microns. It is the first large-scale search for luminous MIR transients in the local universe. Among the many variables that SPIRITS has discovered is a puzzling new class of luminous MIR transients which lack conspicuous optical, or in most cases even near-IR, counterparts in our deepest ground-based followup images. We suggest the name SMIRTs for these objects--Spitzer Mid-IR Transients. The luminosities of SMIRTs exceed those of classical novae, but they are not as bright as any known classes of supernovae. Lying in spiral arms, they appear to be associated with young populations. The properties of SMIRTs are somewhat similar to the recently discovered, but still mysterious, class of intermediate-luminosity red transients, as well as LBVs and "supernova impostors." However, these known types of objects all have bright optical counterparts. We propose a small program of HST imaging, using the WFC3 IR channel at J and H, and the WFC3 UVIS channel at I, to explore the nature of SMIRTs. We have selected 2 representatives, all in outburst at the time of writing, with a range of eruption timescales. Both have archival pre-explosion HST optical imaging, and one also has archival WFC3/IR. Our aims are: search for faint optical and NIR counterparts while they are still in eruption; extend the SEDs to shorter wavelengths to refine dust temperatures and search for faint photospheres/outflows; and attempt to identify progenitor stars in the archival HST images. ------------------------------------------------------------------------------------ 13935( 8) - 05-Sep-2014 17:19:02 - [ 2] Observations Description ------------------------ For both of the two targets, we will devote one HST orbit each to imaging with the WFC3 UVIS and IR channels. We will use 3-point dither patterns and the UVIS F814W filter and the IR F110W and F160W filters. ------------------------------------------------------------------------------------ 13935( 8) - 05-Sep-2014 17:19:02 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SPIRITS-14AX EXT-STAR, CIRCUMSTELLAR RA=09H56M1.5200S, J2000 V = 30 A MATTER, EJECTA, DEC=+69D03'12.40" IRREGULAR VARIABLE, NOVA-LIKE, SUPERNOVA Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 SPIRITS-14AJ EXT-STAR, CIRCUMSTELLAR RA=14H02M55.5100S, J2000 V = 30 E MATTER, EJECTA, DEC=+54D23'18.50" IRREGULAR VARIABLE, NOVA-LIKE, SUPERNOVA Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13935( 8) - 05-Sep-2014 17:19:02 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.605 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 13935( 8) - 05-Sep-2014 17:19:02 - [ 5] Visit: 01 Visit Requirements: BEFORE 06-OCT-2014:00:00:00; VISIBILITY INTERVAL 54.1 M 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 SPIRITS-14A WFC3/UVI ACCUM UVIS2-C51 F814W CR-SPLIT=NO 1 525 S GS ACQ SCENARIO BASE1B3; XA S 2C-SUB (1575 S) PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 SPIRITS-14A WFC3/IR MULTIAC IRSUB256 F110W NSAMP=12, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 2-3 XA CUM (738.253 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SPIRITS-14A WFC3/IR MULTIAC IRSUB256 F160W NSAMP=9, SAMP-SEQ=SPARS10 1 DEF XA CUM (177.149 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 | ------------------------------------------------------------------------------------------------------------------------------------ SPIRITS-14AXA 1 WFC3/UVI ACCUM UVIS2-C5 F814W 1 none none none 1 N/A S 12C-SUB SPIRITS-14AXA 1 WFC3/UVI ACCUM UVIS2-C5 F814W 2 none none none 1 N/A S 12C-SUB SPIRITS-14AXA 1 WFC3/UVI ACCUM UVIS2-C5 F814W 3 none none none 1 N/A S 12C-SUB SPIRITS-14AXA 2 WFC3/IR MULTIAC IRSUB256 F110W 1 none none none 1 N/A CUM SPIRITS-14AXA 2 WFC3/IR MULTIAC IRSUB256 F110W 2 none none none 1 N/A CUM SPIRITS-14AXA 2 WFC3/IR MULTIAC IRSUB256 F110W 3 none none none 1 N/A CUM SPIRITS-14AXA 3 WFC3/IR MULTIAC IRSUB256 F160W 1 none none none 1 N/A CUM SPIRITS-14AXA 3 WFC3/IR MULTIAC IRSUB256 F160W 2 none none none 1 N/A CUM SPIRITS-14AXA 3 WFC3/IR MULTIAC IRSUB256 F160W 3 none none none 1 N/A CUM 13935( 8) - 05-Sep-2014 17:19:02 - [ 6] Visit: 02 Visit Requirements: BEFORE 06-OCT-2014:00:00:00; VISIBILITY INTERVAL 54 M 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 SPIRITS-14A WFC3/UVI ACCUM UVIS2-C51 F814W CR-SPLIT=NO 1 553 S GS ACQ SCENARIO BASE1B3; JE S 2C-SUB (1659 S) PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 SPIRITS-14A WFC3/IR MULTIAC IRSUB256 F110W NSAMP=11, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 2-3 JE CUM (671.215 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SPIRITS-14A WFC3/IR MULTIAC IRSUB256 F160W NSAMP=8, SAMP-SEQ=SPARS10 1 DEF JE CUM (155.11 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 | ------------------------------------------------------------------------------------------------------------------------------------ SPIRITS-14AJE 1 WFC3/UVI ACCUM UVIS2-C5 F814W 1 none none none 1 N/A S 12C-SUB SPIRITS-14AJE 1 WFC3/UVI ACCUM UVIS2-C5 F814W 2 none none none 1 N/A S 12C-SUB SPIRITS-14AJE 1 WFC3/UVI ACCUM UVIS2-C5 F814W 3 none none none 1 N/A S 12C-SUB SPIRITS-14AJE 2 WFC3/IR MULTIAC IRSUB256 F110W 1 none none none 1 N/A CUM SPIRITS-14AJE 2 WFC3/IR MULTIAC IRSUB256 F110W 2 none none none 1 N/A CUM SPIRITS-14AJE 2 WFC3/IR MULTIAC IRSUB256 F110W 3 none none none 1 N/A CUM SPIRITS-14AJE 3 WFC3/IR MULTIAC IRSUB256 F160W 1 none none none 1 N/A CUM SPIRITS-14AJE 3 WFC3/IR MULTIAC IRSUB256 F160W 2 none none none 1 N/A CUM SPIRITS-14AJE 3 WFC3/IR MULTIAC IRSUB256 F160W 3 none none none 1 N/A CUM 13935( 8) - 05-Sep-2014 17:19:02 - [ 7] Summary Form for Proposal 13935 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IRSUB256, UVIS2-C512C-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, NSAMP=11, NSAMP=12, NSAMP=8, NSAMP=9, SAMP-SEQ=SPARS10, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 06-OCT-2014:00:00:00, GS ACQ SCENARIO BASE1B3, PATTERN 1 1, PATTERN 2 2-3, VISIBILITY INTERVAL 54 M, VISIBILITY INTERVAL 54.1 M ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SPIRITS-14AJE, SPIRITS-14AXA ------------------------------------------------------------------------------------------------------------------------------------