11553( 4) - 14-Aug-2008 15:38:06 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11553 Version: 4 Check-in Time: 14-Aug-2008 15:38:06 STScI Edit Number: 0 Title HST Imaging of the Luminous Transient in NGC 300 ------------------------------------------------------------------------------------ Type Cycle GO/DD 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Howard E. Bond Space Telescope Science Institute CoI: Dr. Luigi R. Bedin Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract A luminous optical transient discovered in the nearby (~2.2 Mpc) Sculptor Group spiral NGC 300 in May 2008 appears to be a new member of the V838 Monocerotis class of stars that expand in a few weeks to become red supergiants. Spectroscopic observations show that the NGC 300 OT is categorically not a classical nova, supernova, or luminous blue variable. At an absolute magntude of -12.5, it is by far the brightest star at present in NGC 300, but if it follows the pattern of V838 Mon and the similar object M31 RV, it will fade away rapidly in about 3 months. Before it fades, we propose to obtain WFPC2 images in order to locate the position of the object to within a few milliarcsec. This will allow us to identify the progenitor object, based on a superb set of pre-outburst ACS and WFPC2 images of NGC 300 available in the archive. We also propose a second observation in September 2008, in order to search for emergence of a light echo similar to the spectacular one that surrounds V838 Mon. If a light echo does appear, follow-up ACS polarimetry after SM4 offers the possibility of a direct geometric distance determination, allowing a fundamental calibration of the rich variety of standard candles that exist in NGC 300 (Cepheids, red-giant tip, planetary nebulae, etc.). ------------------------------------------------------------------------------------ Observations Description ------------------------ We will obtain WFPC2 images in B (F450W) and I (F814W) in early June 2008, for the purpose of identifying the progenitor of the NGC 300 optical transient (OT) in archival ACS images. At each of 3 dither positions, we will obtain short exposures in both filters that will not saturate the image of the OT (expected to be at about magnitude 14) and longer exposures at the same pointing that will show enough background stars for registration with the ACS images. We will also make the same set of observations (possibly with longer exposure times if the star has faded) in September 2008 to search for emergence of a light echo, similar to that seen around the Galactic star V838 Mon. Real Time Justification ----------------------- Calibration Justification ------------------------- 11553( 4) - 14-Aug-2008 15:38:06 - [ 2] Additional Comments ------------------- ------------------------------------------------------------------------------------ 11553( 4) - 14-Aug-2008 15:38:06 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC300-TRANS EXT-STAR, CIRCUMSTELLAR RA=00H54M34.5090S +/- 0.4", J2000 V = 14 +/- 1 IENT MATTER, IRREGULAR DEC=-37D38'31.43" +/- 0.4" VARIABLE Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11553( 4) - 14-Aug-2008 15:38:06 - [ 4] Visit: 01 Visit Requirements: BEFORE 15-JUN-2008:00:00:00 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 10 S POS TARG -7, -7 SIENT ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 240 S POS TARG -7, -7 SIENT see below ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 5 S POS TARG -7, -7 SIENT ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 80 S POS TARG -7, -7 SIENT ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 5 S POS TARG -6.886075, SIENT -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 80 S POS TARG -6.886075, SIENT -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 10 S POS TARG -6.886075, SIENT -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 240 S POS TARG -6.886075, SIENT see below -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 10 S POS TARG -6.8291125, SIENT -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC300-TRAN WFPC2 IMAGE PC1-FIX F450W ATD-GAIN=7, CR-SPLIT=NO 1 240 S POS TARG -6.8291125, SIENT see below -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 5 S POS TARG -6.8291125, SIENT -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 80 S POS TARG -6.8291125, SIENT -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 11553( 4) - 14-Aug-2008 15:38:06 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC300-TRANSIENT 1 WFPC2 IMAGE PC1-FIX F450W none none none none 1 N/A NGC300-TRANSIENT 2 WFPC2 IMAGE PC1-FIX F450W none none none none 1 160.0 S NGC300-TRANSIENT 3 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 4 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 5 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 6 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 7 WFPC2 IMAGE PC1-FIX F450W none none none none 1 N/A NGC300-TRANSIENT 8 WFPC2 IMAGE PC1-FIX F450W none none none none 1 160.0 S NGC300-TRANSIENT 9 WFPC2 IMAGE PC1-FIX F450W none none none none 1 N/A NGC300-TRANSIENT 10 WFPC2 IMAGE PC1-FIX F450W none none none none 1 260.0 S NGC300-TRANSIENT 11 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 12 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A 11553( 4) - 14-Aug-2008 15:38:06 - [ 6] Visit: 02 Visit Requirements: BETWEEN 01-SEP-2008:00:00:00 AND 30-SEP-2008:00:00:00 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -7, -7 SIENT ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -7, -7 SIENT ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -6.886075, SIENT -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -6.886075, SIENT -6.9430375 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -6.8291125, SIENT -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 160 S POS TARG -6.8291125, SIENT -6.8291125 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 180 S POS TARG -6.9430375, SIENT -6.886075 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC300-TRAN WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7, CR-SPLIT=NO 1 180 S POS TARG -6.9430375, SIENT -6.886075 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC300-TRANSIENT 1 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 2 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 3 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 4 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 5 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 6 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 7 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A NGC300-TRANSIENT 8 WFPC2 IMAGE PC1-FIX F814W none none none none 1 N/A 11553( 4) - 14-Aug-2008 15:38:06 - [ 7] Summary Form for Proposal 11553 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN=7, CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 15-JUN-2008:00:00:00, BETWEEN 01-SEP-2008:00:00:00 AND 30-SEP-2008:00:00:00, POS TARG -6.8291125, -6.8291125, POS TARG -6.886075, -6.9430375, POS TARG -6.9430375, -6.886075, POS TARG -7, -7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F450W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC300-TRANSIENT ------------------------------------------------------------------------------------------------------------------------------------