9174( 6) - 03/14/01 07:59 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9174 Version: 6 Check-in Date: 14-Mar-2001 07:58:27 1.Proposal Title: Using Optically Faint Radio Sources to Pinpoint Dusty Proto-galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Scott Chapman Carnegie Institution of Washington CoI: Dr. Eric Richards Arizona State University N CoI: Dr. Rogier Windhorst Arizona State University N ------------------------------------------------------------------------------------ 5. Abstract vspace-3mm Deep radio and submillimeter surveys show that at least one-half of the star-formation in the distant Universe remains hidden from optical surveys. We have recently isolated a number of high redshift, dusty starburst galaxies that remain invisible in ground based images to I_AB=25 and I_AB=28.5 in the Hubble Deep Field. These galaxies appear as faint radio sources with bright submillimeter counterparts (S_850>5 mJy), demonstrating they are very dusty systems. The luminosities of these galaxies (10^12-13 L(sun) ) suggest they are in the process of converting the bulk of their gas mass into stars, and will likely evolve into present day massive ellipticals. We propose to obtain deep STIS imaging for 7 of our high redshift (1< z <3) optically `invisible' ultraluminous galaxies, chosen from amongst our submillimeter- detected sample to display some hint of optical flux in our present ground-based imagery (I~26, 2Sigma). The STIS images will thereby identify their dust obscured optical counterparts, and allow comparison of their optical and radio morphology in matching 0"pt 1 images. Do these distant ultraluminous galaxies resemble local analogs (e.g., Arp 220)? Are the optical counterparts to sub-mm/radio selected sources isolated collapsing spheroids or merger driven starbursts? ------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 2] Observations Description ------------------------ We propose to obtain deep STIS imaging complete to an equivalent R ~ 28 for our seven (of 20) optically faint radio/sub-mm sources which show some sign of optical emission in our ground based images (limited to I=25, 5Sigma). These radio sources all have extended radio morphology and steep radio spectra (Alpha > 0.5; S \propto Nu ^-Alpha), indicating the presence of diffuse synchrotron emission. Although this is consistent with emission from a radio starburst, without the galaxy identification, some uncertainty remains. Through deep STIS imaging, it will be possible to classify morphologies to R ~ 27 and search for galaxy mergers, interactions, and distorted disk systems, as we expect if these are indeed major starbursts at 1 < z < 3. Because of our excellent astrometry, accurate to 0"pt 1 to 0"pt 2 (rms) across the HDF and flanking field region, we will be able to search for very faint optical counterparts in the STIS images (R ~ 28) with good reliability. Since these seven galaxies are very likely at z> 1, then they are effectively at the same angular-size distance. We want to perform surface photometry to an integrated R mag of 27. Thus if they have the same observed scale length as the lower redshift radio selected samples, r_e = 0"pt 2 -0"pt 4, then their surface brightness will range from 27.3 mag/arcsec to 28.4 mag/arcsec. Achieving a minimum signal to noise ratio of 0.5 per pixel suggests a 8000 sec exposure at minimum, critically dependent on the scale length of the galaxy from the www- STIS-ETC. Thus we request 3 orbits per object (21 orbits in all). In the event that our presently detected traces of optical emission are dominated by noise, we will still have a chance of recovering the true counterpart with the ability to detect point sources to R ~eq 28-9 at a snr = 10-5, in the event the surface brightness is too faint for surface photometry. If some of the optically faint radio sources are like the HDF source VLA J123646+621226 at IJH > 28.5, then we must have 3 orbits in STIS to have any hope of detecting their optical counterparts. During our primary STIS exposures, we also request parallel F814W images be taken. Some of these 3 orbit exposures will lie in the existing HFFs, deepening the exposures by 1 mag. and allowing for better identification of the radio sources contained in the HFFs. Depending on the orient when the primary STIS program is scheduled, several of WFPC2 parallels will likely fall outside the existing HST images, thereby increasing the effective area of the HFFs by as much as 50\ immediately. Real Time Justification ----------------------- none Calibration Justification ------------------------- Additional Comments ------------------- In some cases where more than one OFRS can potentially be imaged by the STIS field of view, adjustments will be made to the pointing center once the roll angle has been fixed. A few of our targets have changed from those in the original proposal, as they were discovered after the cycle 10 submission in subsequent surveys for optically faint radio sources. These new target selections represent the best possible objects from our greatly expanded complete catalog. We emphasize that (1) no one else has already done these observations in the past; (2) no one else has already had this observation apporved for Cycle 10; and (3) it does not change the original science intent of the proposal. ------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL- galaxy, radio galaxy, RA=22H 17M 25.20S +/- 0S, J2000 V = 27 221725+00124 ultraluminous ir gal DEC=00D 12' 40.0" +/- 0" 0 Coordinate Source: OTHER_SOURCE Comments: S850=20mJy, This source was discovered in one of our other radio fields after the cycle 10 proposal was submitted. This is the most luminous submm source in our radio sample and is now the highest priority HST followup source. Source position 221725.2+001240 2 GAL- galaxy, radio galaxy, RA=13H 12M 33.31S +/- 0S, J2000 V = 27 131231+42443 ultraluminous ir gal DEC=42D 44' 26.7" +/- 0" 0 Coordinate Source: OTHER_SOURCE Comments: S850=10mJy, 12mJy. These two sources were found in our SSA13 radio field after the cycle 10 proposal was submitted. They are separated by only 36" and as such both fit on the STIS field. Actual source positions: 13 12 31.9161, 42 44 29.752 13 12 35.2283, 42 44 23.559 3 GAL- galaxy, radio galaxy, RA=12H 36M 0.06S +/- 0S, DEC=62D J2000 V = 27 123600+62025 ultraluminous ir gal 2' 53.4" +/- 0" I = 24.7 3 Coordinate Source: OTHER_SOURCE Comments: S850=6.9, source #93 4 GAL- galaxy, radio galaxy, RA=12H 36M 17.27S +/- 0S, J2000 V = 27 123621+62170 ultraluminous ir gal DEC=62D 15' 32.1" +/- 0" I = 25.8 9 Coordinate Source: OTHER_SOURCE Comments: Barger S850=7.5 #141 : we are able to fit 3 optically faint radio sources into the STIS field at this slightly offset position 5 GAL- galaxy, radio galaxy, RA=12H 36M 21.96S +/- 0S, J2000 V = 27 123625+62174 ultraluminous ir gal DEC=62D 16' 48.8" +/- 0" 4 Coordinate Source: OTHER_SOURCE Comments: Barger S850=10.5 : we are able to fit 3 optically faint radio sources into the STIS field at this slightly offset position 6 GAL- galaxy, radio galaxy, RA=12H 37M 10.02S +/- 0S, J2000 V = 27 123610+62265 ultraluminous ir gal DEC=62D 26' 50.3" +/- 0" I = 25.3 0 Coordinate Source: OTHER_SOURCE Comments: S850=7.40 #254 7 GAL- galaxy, radio galaxy, RA=14H 18M 9.73S +/- 0S, DEC=52D J2000 V = 25 141809+52220 ultraluminous ir gal 22' 1.3" +/- 0" I = 24.0 1 Coordinate Source: OTHER_SOURCE Comments: S850=5.5mJy. This source was uncovered in our W14 radio field, after the cycle 10 was submitted. It is amongst the brightest of our OFRS sample, with the added advantage of a measured near-IR redshift (z=2.98) which suggests a peculiar morphology in the line profile. 9174( 6) - 03/14/01 07:59 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 8 GAL- galaxy, radio galaxy, RA=12H 37M 13.87S +/- 0S, J2000 V = 27 123714+62182 ultraluminous ir gal DEC=62D 18' 26.5" +/- 0" I = 26.5 7 Coordinate Source: OTHER_SOURCE Comments: S850=15.70, #260 9 GAL- galaxy, radio galaxy, RA=12H 35M 53.28S +/- 0S, J2000 V = 27 123553+62133 ultraluminous ir gal DEC=62D 13' 37.8" +/- 0" I = 24 8 Coordinate Source: OTHER_SOURCE Comments: S850=8.8, #83 9174( 6) - 03/14/01 07:59 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-CCD-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.565051 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type STIS-SPIRAL-DITH Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.565051 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 6] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures for the field are split into four half-orbit exposures each with a shift introduced using the STIS-CCD-BOX PATTERN for the F814W parallel. The F606W parallel has a simple shift introduced between two half-orbit exposures. LOW-SKY is selected to provide a low sky background essential for identification of very faint galaxies. An ORIENT range is selected so that the parallel WFPC2 will be placed optimally within our radio field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-221725+ STIS/C ACCUM 50CCD MIRROR 1 1250 S LOW-SKY PATTERN 1 1-2 PAR 001240 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 950 S ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-221725+ STIS/C ACCUM 50CCD MIRROR 1 1250 S LOW-SKY PATTERN 2 3-4 PAR 001240 CD 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFPC2 IMAGE WFALL F606W 1 950 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 7] Visit: 02 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-131231+ STIS/C ACCUM 50CCD MIRROR 1 1250 S LOW-SKY PATTERN 1 1-2 PAR 424430 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 950 S ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-131231+ STIS/C ACCUM 50CCD MIRROR 1 1250 S LOW-SKY PATTERN 2 3-4 PAR 424430 CD 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFPC2 IMAGE WFALL F606W 1 950 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 8] Visit: 03 Visit Priority: Visit Requirements: ORIENT 135D TO 155D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123600+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 620253 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 9] Visit: 04 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123621+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 621709 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-123621+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 2 3-4 PAR 621709 CD 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFPC2 IMAGE WFALL F606W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 10] Visit: 05 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123625+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 621744 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-123625+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 2 3-4 PAR 621744 CD 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFPC2 IMAGE WFALL F606W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 11] Visit: 06 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123610+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 622650 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 12] Visit: 07 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-141809+ STIS/C ACCUM 50CCD MIRROR 1 1170 S LOW-SKY PATTERN 2 1-2 PAR 522201 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 13] Visit: 08 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123714+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 621827 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 14] Visit: 09 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-123553+ STIS/C ACCUM 50CCD MIRROR 1 1200 S LOW-SKY PATTERN 1 1-2 PAR 621338 CD 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFPC2 IMAGE WFALL F814W 1 900 S ------------------------------------------------------------------------------------------------------------------------------------ 9174( 6) - 03/14/01 07:59 - [ 15] Summary Form for Proposal 9174 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 50CCD WFALL ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements LOW-SKY PATTERN 1 1-2 PAR 2 WITH 1 LOW-SKY PATTERN 2 3-4 PAR 4 WITH 3 ORIENT 135D TO 155D LOW-SKY PATTERN 2 1-2 PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR F814W F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-221725+001240 ANY GAL-131231+424430 GAL-123600+620253 GAL-123621+621709 GAL-123625+621744 GAL-123610+622650 GAL-141809+522201 GAL-123714+621827 GAL-123553+621338 ------------------------------------------------------------------------------------------------------------------------------------