14276( 2) - 22-Jul-2015 17:57:11 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14276 Version: 2 Check-in Time: 22-Jul-2015 17:57:11 STScI Edit Number: 0 Title Understanding the star formation environment of a very low redshift, low luminosity, long Gamma Ray Burst ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Elizabeth R. Stanway The University of Warwick Y CoI: Prof. Andrew J. Levan The University of Warwick N CoI: Prof. Nial R. Tanvir University of Leicester N CoI: Dr. Klaas Wiersema University of Leicester N ------------------------------------------------------------------------------------ Abstract Gamma ray bursts (GRBs) are potentially observable to the highest redshift, but their interpretation relies on a knowledge of their hosts and environment. GRB hosts are identified by a single stellar explosion which allows strong statistical statements on the global star formation distribution. However making these relies on local, low redshift exemplars in which the conditions giving rise to bursts can be studied. Unfortunately such sources are rare. We have identified an unusual, dusty GRB host in the local universe (host of low-luminosity GRB 080517 at z=0.09) which shows strong star formation and is exceptionally luminous in the infrared. It is also within 25 kpc and a few hundred km/s of a neighbouring galaxy, itself undergoing a merger. In this programme we wish to map this system in the ultraviolet and infrared. We will evaluate evidence for clumpy star formation and tidal interactions between the two galaxies, determining whether galaxy interactions may have contributed to the starbursts in both galaxies, and assessing whether this may have played a role in triggering the burst. If so, it is likely that the role of clustering and larger scale environment needs to be reassessed in inferences drawn from the redshift distribution of GRBs. ------------------------------------------------------------------------------------ Observations Description ------------------------ We requested 1 orbit, to include WFC3 observations in UVIS/F275W (~1235s on target), IR/F098M (200s) and IR/F160W (200s) of a single target field which is centred on the host galaxy of GRB 080517. We were allocated the 1 orbit requested. While the GRB host (on which our pointing is centered) is the primary target, we are also interested in a neighbouring source, 17 arcsec to the North-East, with which we believe it to be interacting. Both are visible in DSS imaging. In Phase II, we have updated the integration times to allow for dithering of the telescope (using standard dither patterns), and to pack the orbit in order to maximise science. The F275W observation is divided into three dithered sub-exposures, each flashing the chip to minimise background. These are specified in the UVIS2 aperture, while placing the target near the corner of the chip for charge transfer efficiency (which previous experience by our team 14276( 2) - 22-Jul-2015 17:57:11 - [ 2] suggests is important). This choice of aperture and target placement restricts our range of roll angles in order to ensure both sources are comfortably on the chip. The two IR observations are each divided into two dithered sub-exposures. These are centred on the IR chip to allow for any roll angle and have had total integration times increased to improve depth and prevent downtime due to buffer dump. We would appreciate careful checking of our programme, since the PI is relatively inexperienced at specifying a Hubble Phase II. ------------------------------------------------------------------------------------ 14276( 2) - 22-Jul-2015 17:57:11 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 FIELD080517 GALAXY, INTERACTING RA=06H48M57.9860S, J2000 Z = 0.09 V = 17.5 +/- 0.1 GALAXY, STARBURST DEC=+50D44'6.82" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14276( 2) - 22-Jul-2015 17:57:11 - [ 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 NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.636 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14276( 2) - 22-Jul-2015 17:57:11 - [ 5] Visit: 01 Visit Requirements: ORIENT 150D TO 270 D 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 FIELD080517 WFC3/UVI ACCUM UVIS2 F275W CR-SPLIT=NO, FLASH=12 1 415 S POS TARG -60, -30; S (1245 S) PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 FIELD080517 WFC3/IR MULTIAC IR F098M NSAMP=8, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 2 CUM (705.871 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 FIELD080517 WFC3/IR MULTIAC IR F160W NSAMP=10, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 3 CUM (455.874 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 | ------------------------------------------------------------------------------------------------------------------------------------ FIELD080517 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S FIELD080517 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S FIELD080517 1 WFC3/UVI ACCUM UVIS2 F275W 3 none none none 1 N/A S FIELD080517 2 WFC3/IR MULTIAC IR F098M 1 none none none 1 N/A CUM FIELD080517 2 WFC3/IR MULTIAC IR F098M 2 none none none 1 N/A CUM FIELD080517 3 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM FIELD080517 3 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM 14276( 2) - 22-Jul-2015 17:57:11 - [ 6] Summary Form for Proposal 14276 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, FLASH=12, NSAMP=10, NSAMP=8, SAMP-SEQ=SPARS25, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 150D TO 270 D, PATTERN 1 1, PATTERN 2 2, PATTERN 2 3, POS TARG -60, -30 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F098M, F160W, F275W ------------------------------------------------------------------------------------------------------------------------------------ Target Names FIELD080517 ------------------------------------------------------------------------------------------------------------------------------------