8303( 3) - 10/26/99 11:52 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8303 Version: 3 Check-in Date: 18-Mar-1999 08:52:22 1.Proposal Title: What is 52W036? ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Steven Majewski The University of Virginia CoI: Dr. Matthew Bershady University of Wisconsin-Madison N ------------------------------------------------------------------------------------ 5. Abstract We have found a most peculiar galaxy, 52W036, in our large, deep redshift survey of faint galaxies. This galaxy, previously identified as a submillijansky radio source at z=0.24, is outstanding in almost every property. Its combination of enormous size and luminosity, high surface- brightness, and very blue color do not compare to that of any other known galaxy. In addition, its morphology changes dramatically from a horse-shoe shape in the ultra-violet to an apparent source pair in the near- infrared. Over the past decade we have given this particular object special attention in attempt to understand its bizarre nature. At present, the reason for its unusual properties still eludes us. Possibilities include that it is a powerfully starbursting ring galaxy, a tidally interacting galaxy pair, or perhaps even a gravitational lens. Discriminating between these possible scenarios, or others, is not presently possible with the resolution of our ground-based imaging; only HST can reveal what must be a complex (and beautiful) morphology for a galaxy at this redshift. Moreover, with STIS near-UV imaging we can determine whether 52W036 provides a local counterpart to the most extreme star forming galaxies at z = 3 as seen, e.g., in the Hubble Deep Field. Whatever the nature of 52W036, HST imaging will be an essential element to understanding a system which may well be the most extreme of all ``normal" galaxies known to date. ------------------------------------------------------------------------------------ 8303( 3) - 10/26/99 11:52 - [ 2] Observations Description ------------------------ We propose to image the bizarre and extreme galaxy 52W036 with the PC chip of the WFPC2 and with the STIS MAMA-NUV chip. This complement of instruments will be used to obtain images at three wavelengths (0.24, 0.55, and 0.81 Mum) to study in detail the nature and cause of the strong color gradients and excessive UV flux of this galaxy at the much needed, higher resolution than possible from the ground. We expect the HST images will reveal complex structure on subarcsecond scales. Bershady has extensive experience with HST image processing from working with prior programs. The image fields of the STIS MAMAs and the PC are sufficient to image 52W036 and the star NNW of the galaxy (see figure 1). This star is an important reference needed to ensure accurate registration with the optical images for producing color maps. This task would be particularly difficult otherwise, given the small fields of view and the strong morphological changes with color in the source 52W036. The STIS NUV-MAMA with long pass filter (F25QTZ) and WFPC filters F555W and F814W were chosen as a compromise between efficiently optimizing signal-to-noise (S/N) and spanning as large a wavelength baseline as possible. Moreover, in the rest frame of 52W036, these bands correspond roughly to 2000Angstrom, B and R bands; the former two bands match exactly the bands used in the ultraviolet-selected redshift survey of Treyer et al. (1998) so that we can compare directly to the star formation rates for their 142 random field sources. Moreover, we can compare the 2000-B color of the intense star forming galaxy 52W036 directly to the I-H colors of z = 3 Hubble Deep Field galaxies with z = 3. Multiple frames (with offsets) per pointing and filter (e.g. CRSPLIT) will be adopted, as we will detail in Phase II. Exposure time estimates of roughly one orbit for each filter will yield on average a S/N of 10 per pixel for the PC. In two orbits with STIS/NUV and long pass filter for geocoronal emission blocking we can get S/N > 9 in two orbits, assuming 2x2 binning of the MAMA pixels which will yield the same pixel scale as the PC. These estimates include the extreme blueness in the UV and redness in the I-band. Parallel data from WFPC-2 are also desired: (1) We have deep multicolor optical and near-infrared images of the surrounding fields, (2) we have excellent photometric calibration in surrounding area. Indeed, the latter point motivates that we use the same filters for 52W036 as for the parallel observations. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- Since we have no experience with STIS, we would especially appreciate someone checking our work there. We note that though we asked for parallel data in our proposal (see Observing Description), this was not mentioned in our notification and therefore we have not included these requests here. ------------------------------------------------------------------------------------ 8303( 3) - 10/26/99 11:52 - [ 3] Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8303( 3) - 10/26/99 11:52 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 52W036 GALAXY RA=13H 06M 50.28S +/- 0.05S, 1950.0 Z=0.24 SURF(V) = 21.86 DEC=+29D 40' 29.1" +/- 0.1" B-V = 0.44 U-B = -0.4 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1950.0 0.0 0.0 0.0 8303( 3) - 10/26/99 11:52 - [ 5] Visit: 01 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 52W036 WFPC2 IMAGE PC1 F555W DITHER-TYPE=LINE, 1 400 S DITHER-LINE-STEPS=2, DITHER-LINE-SPACING=0.707 ------------------------------------------------------------------------------------------------------------------------------------ 2 52W036 WFPC2 IMAGE PC1 F814W DITHER-TYPE=LINE, 1 400 S DITHER-LINE-STEPS=2, DITHER-LINE-SPACING=0.707 ------------------------------------------------------------------------------------------------------------------------------------ 8303( 3) - 10/26/99 11:52 - [ 6] 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 52W036 STIS/N ACCUM F25QTZ MIRROR PATTERN=BOX,NUM-POS=4 1 643 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8303( 3) - 10/26/99 11:52 - [ 7] Summary Form for Proposal 8303 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 F25QTZ ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DITHER-TYPE=LINE DITHER-LINE-STEPS=2 DITHER-LINE-SPACING=0.707 NUM-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names 52W036 ------------------------------------------------------------------------------------------------------------------------------------