10811( 6) - 05/09/07 14:59 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10811 Version: 6 Check-in Time: 09-May-2007 18:59:04 STScI Edit Number: 0 Title Morphology of a most spectactular Spitzer selected galaxy ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 15 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Colin J.K. Borys University of Toronto CoI: Dr. Baruch T. Soifer California Institute of Technology N CoI: Dr. Emeric Le Floc'h University of Arizona N CoI: Dr. Arjun Dey National Optical Astronomy Observatories, N AURA CoI: Dr. Buell T. Jannuzi National Optical Astronomy Observatories, N AURA CoI: Dr. Andrew Blain California Institute of Technology N ------------------------------------------------------------------------------------ Abstract By using ground based sub-millimeter observations to followup Spitzer-selected galaxies, we have discovered a starburst dominated hyperluminous infrared galaxy. A mid-infrared spectrum obtained with Spitzer-IRS provides a redshift of z=1.325, which has been subsequently confirmed using both NIR spectroscopy at Keck, and sub- mm spectroscopy with IRAM and the CSO. By combining the Spitzer and ground based sub-mm data, we measure an integrated IR luminosity of 4 x 10^13 Lsun. This is the only such object found in the 9 square degree NDWFS survey, and hence is incredibly rare. The only other dusty galaxies this bright show strong evidence of AGN activity, but this source does not. One reason this object could be so bright is due to lensing, and indeed a foreground source spectroscopically confirmed at z=1.034 seems directly aligned with the target. However it is unlikely that the geometry of this galaxy-galaxy lensing system could support an amplification more than a factor of a few. Our IRAC images reveal very faint and red satellite systems near our target, hence another possibility is that the galaxy is so luminous because of merging induced star-formation activity. Morphology is the best way to discriminate between these hypotheses, and hence HST observations are essential since the scales on which the merging or lensing are occuring are much smaller than what can be resolved from the ground. ------------------------------------------------------------------------------------ 10811( 6) - 05/09/07 14:59 - [ 2] Observations Description ------------------------ Simple 2 orbit observation (1 with ACS, one with NICMOS) to investigate the morphology of a unique, luminous, Spitzer selected galaxy. Based on previous experience with high-redshift IR luminous galaxies, we request LOWSKY conditions, and want to avoid the SAA. There is no constraint between when the ACS and NICMOS orbits are scheduled. ACS observations: We use a simple 4 point dither pattern (BOX). The object is centered in the middle of one the two ACS chips to ensure we get it and its immediate environment well away from the interchip gap. Since the 4 points should be sufficient to remove cosmic-rays, we set CR-SPLIT to "no". 4x437s exposures are used to fill the available time while avoiding the low-sky cutoff. NICMOS observations: We use the NIC2 aperture and a standard spiral dither pattern, with a spacing of 0.6375 arcseconds (8.5 pixels). We found that by setting NSAMP=6 and SAMP- SEQ=SPARS128, we could fill up most of the orbit while still avoiding the low- sky limit. We note that NSAMP=19, SPARS32 would result in 120 extra seconds of exposure time, but at the expense of potentially higher noise given the increased readout frequency. To avoid the SAA, we used (on advice from STSCI), the "GS ACQ SCENARIO: BASE1TNS" setting. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- Note: The nearest GSC2.2 guidestar (N13322216746) to the object we are studying does not overlap with our most recent I-band imaging. Likely proper motion is to blame. Although perhaps difficult to manage, the scientific impact of these observations would be strongest if made during the early June 2006 window, rather than waiting until February 2007 when it opens again. This would allow us to immediately publish it and other followup data we have collected using ground-based telescopes this past semester. ------------------------------------------------------------------------------------ 10811( 6) - 05/09/07 14:59 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MIPSJ142824. GALAXY, GRAVITATIONAL RA=14H28M24.0700S +/- 0.3", J2000 Z = V = 24.0 0+352619 LENS, STARBURST, DEC=+35D26'19.40" +/- 0.3" 1.325 I=21 ULTRALUMINOUS IR GAL K=17 (Vega) Reference Frame: ICRS 10811( 6) - 05/09/07 14:59 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFPC2-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.559017 Line_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.56505 Angle_Between_Sides 143.130102 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type NIC-SPIRAL-DITH Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.6735 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 0.0 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 10811( 6) - 05/09/07 14:59 - [ 5] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: This updated phase II converts the ACS observation originally planned for this target into a WFPC2 observation. We choose the PC camera for resolution, and apply a standard box-dither pattern. Each of the four orbits are identical except for modest (11 pixel on the PC CCD) shift to further mitigate bad pixel issues. Orientation is not a concern since we are concerned with the circular area within 15 arcsec of the target. Also, the PC coverage is more than sufficient to cover the NICMOS image already obtained as part of this project. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MIPSJ142824 WFPC2 IMAGE PC1 F814W 1 260 S LOW-SKY; PATTERN 1 1 .0+352619 ------------------------------------------------------------------------------------------------------------------------------------ 2 MIPSJ142824 WFPC2 IMAGE PC1 F814W 1 260 S POS TARG 0.498, 0; .0+352619 LOW-SKY; PATTERN 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 MIPSJ142824 WFPC2 IMAGE PC1 F814W 1 260 S POS TARG 0.498, 0.498; .0+352619 LOW-SKY; PATTERN 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 MIPSJ142824 WFPC2 IMAGE PC1 F814W 1 260 S POS TARG 0, 0.498; .0+352619 PATTERN 1 4 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ MIPSJ142824.0+3526 1 WFPC2 IMAGE PC1 F814W 1 none none none 1 N/A 19 MIPSJ142824.0+3526 1 WFPC2 IMAGE PC1 F814W 2 none none none 1 N/A 19 MIPSJ142824.0+3526 1 WFPC2 IMAGE PC1 F814W 3 none none none 1 N/A 19 MIPSJ142824.0+3526 1 WFPC2 IMAGE PC1 F814W 4 none none none 1 N/A 19 MIPSJ142824.0+3526 2 WFPC2 IMAGE PC1 F814W 1 none none none 2 N/A 19 MIPSJ142824.0+3526 2 WFPC2 IMAGE PC1 F814W 2 none none none 2 N/A 19 MIPSJ142824.0+3526 2 WFPC2 IMAGE PC1 F814W 3 none none none 2 N/A 19 MIPSJ142824.0+3526 2 WFPC2 IMAGE PC1 F814W 4 none none none 2 N/A 19 10811( 6) - 05/09/07 14:59 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ MIPSJ142824.0+3526 3 WFPC2 IMAGE PC1 F814W 1 none none none 3 N/A 19 MIPSJ142824.0+3526 3 WFPC2 IMAGE PC1 F814W 2 none none none 3 N/A 19 MIPSJ142824.0+3526 3 WFPC2 IMAGE PC1 F814W 3 none none none 3 N/A 19 MIPSJ142824.0+3526 3 WFPC2 IMAGE PC1 F814W 4 none none none 3 N/A 19 MIPSJ142824.0+3526 4 WFPC2 IMAGE PC1 F814W 1 none none none 4 N/A 19 MIPSJ142824.0+3526 4 WFPC2 IMAGE PC1 F814W 2 none none none 4 N/A 19 MIPSJ142824.0+3526 4 WFPC2 IMAGE PC1 F814W 3 none none none 4 N/A 19 MIPSJ142824.0+3526 4 WFPC2 IMAGE PC1 F814W 4 none none none 4 N/A 19 10811( 6) - 05/09/07 14:59 - [ 7] Visit: 02 Visit Priority: Visit Requirements: 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 MIPSJ142824 NIC2 MULTIAC NIC2 F160W NSAMP=6,SAMP-SEQ=SPARS128 1 DEF LOW-SKY; GS ACQ SCENARIO .0+352619 CUM BASE1TNS; PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ MIPSJ142824.0+3526 1 NIC2 MULTIAC NIC2 F160W 1 none none none 1 N/A 19 CUM MIPSJ142824.0+3526 1 NIC2 MULTIAC NIC2 F160W 2 none none none 1 N/A 19 CUM MIPSJ142824.0+3526 1 NIC2 MULTIAC NIC2 F160W 3 none none none 1 N/A 19 CUM MIPSJ142824.0+3526 1 NIC2 MULTIAC NIC2 F160W 4 none none none 1 N/A 19 CUM 10811( 6) - 05/09/07 14:59 - [ 8] Summary Form for Proposal 10811 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=6 SAMP-SEQ=SPARS128 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements LOW-SKY; PATTERN 1 1; POS TARG 0.498, 0; PATTERN 1 2; POS TARG 0.498, 0.498; PATTERN 1 3; POS TARG 0, 0.498; PATTERN 1 4; GS ACQ SCENARIO BASE1TNS; PATTERN 2 1; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names MIPSJ142824.0+352619 ------------------------------------------------------------------------------------------------------------------------------------