9502( 7) - 04/15/02 08:05 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9502 Version: 7 Check-in Date: 15-Apr-2002 08:05:08 1.Proposal Title: Evolution of the Tully-Fisher Relation of Field Spiral Galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Bodo Ziegler Universitats-Sternwarte Gottingen CoI: Prof. Immo Appenzeller Landessternwarte Heidelberg N CoI: Prof. Ralf Bender University Observatory Munich N CoI: Asmus Boehm University Observatory Goettingen N CoI: Prof. Klaus Fricke University Observatory Goettingen N CoI: Dr. Jochen Heidt Landessternwarte Heidelberg N CoI: Dr. Ulrich Hopp University Observatory Munich N CoI: Dr. Doerte Mehlert Landessternwarte Heidelberg N CoI: Dr. Claus Moellenhoff Landessternwarte Heidelberg N CoI: Dr. Roberto Saglia University Observatory Munich N CoI: Dr. Stella Seitz University Observatory Munich N ------------------------------------------------------------------------------------ 5. Abstract We seek imaging of the FORS deep field (FDF) with the ACS to determine morphological and structural parameters of a complete sample of 80 late-type galaxies brighter than R_ lim=23^m (corresponding to ~ M_B^*+2 at z=0.5) selected there. We already obtained spectra and derived velocity curves of these galaxies using the ESO VLT. Only combined with the ACS HST observations this will allow us to establish the Tully- Fisher relation between luminosity and rotation of spirals at a mean redshift of 0.5 and therefore measure the luminosity and mass evolution of spiral and irregular galaxies within about half of the age of the Universe, strongly constraining current theories of galaxy formation and evolution. Several other important scientific projects based on the FDF, such as a study of the Fundamental Plane of field elliptical galaxies at ~ 0.3, a study of the size and type evolution of high-z galaxies (up to z~5) and a study of galaxy-galaxy lensing will also benefit from these observations. ------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 2] Observations Description ------------------------ The ~ 80 galaxies in the FORS Deep Field of which we have rotation curves are distributed across the entire field. Therefore, to have a statistically significant number of galaxies for the distant Tully-Fisher relation it is essential to observe the entire FDF (6'*6') with ACS/WFC. This can be achieved by a mosaic of 4 pointings with a small overlap area (4") between different pointings. The offset from one pointing to another is ~3', so that 4 different visits are necessary according to the HST primer. We calculate that 1 orbit per visit (pointing) is needed to get sufficient S/N and resolution elements for the determination of morphology, surface brightness, disk scale length and inclination of the target galaxies as described below. Besides a visual classification of morphologies we will quantitatively assess the galaxies' structure using the publicly available GIM2D software (Simard et al. 2001) that analyses the two-dimensional light distribution of a galaxy. Key morphological parameters are the bulge-to-total luminosity ratio (B/T), the concentration index and the asymmetry parameter (e.g. Abraham et al. 1996). The spectral energy distributions of all the distant spiral and elliptical galaxies that we will use for the TF and FP studies peak in the I-band. Therefore, we propose to use the high- throughput broad I-filter F814W. Our measured rotation curves typically cover r=1.5-2" in I (Fig. 1). With that we reach 3-6 disk scale lengths in I corresponding to 2-4 disk scale lengths of the emitting gas (Ryder & Dopita 1994). The average surface brightnesses of our spirals at the maximum disk scale lengths are distributed within 22<=Mu_I<=25, at 1 disk scale length within 20<=Mu_I<=23. According to the simulations of GIM2D (Simard et al. 2001, Fig. 6) our faintest and smallest target galaxies will have a systematic error of ~5% and a random error of ~10% in B/T for an S/N=10 per square arcsec. This is more than adequate for a quantitative morphological classification. Based on the ACS handbook (mainly Fig. 10.33) and the online Exposure Time Calculator we calculate that S/N values of S/N>10 per square arcsec within an isophote of Mu_I=23 can be reached for all our extended targets with an integration time of ~ 2000s. At Mu_I=20 we will have S/N~50. Typically, an exposure time of ~ 2400s can be achieved within a single orbit with an orbit visibility of the FDF of 53 min., guide star acquisition of 6 min., an ACS overhead of 4 min., and one SAM of 1 min.. Therefore, the exposures can be split into 2 with a small integer pixel offset to be able to remove cosmics and bad pixels. We do not want to do sub- pixel dithering because the GIM2D software is sensitive to the regridding pattern, and drizzle techniques do not accurately preserve the noise characteristics of the pixels. Another reason is that nothing would be gained by drizzling with respect to the determination of structural parameters (like disk scale length, half-light radius etc.) since a galaxy extending to r=2" already covers about 125 resolution elements on the ACS/WFC chip. The calculated exposure times and S/N values match those of our FP studies we had with WFPC2 (GOs 6003, 6478, 8325) taking into account a factor of 4 higher throughput for ACS/WFC over WFPC2. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 FIELD-010555 CLUSTER OF GALAXIES, RA=01H 5M 55S +/- 1", DEC=-25D J2000 SURF(I) = 23.0+/-0.3 -254359 BLANK SKY 43' 59" +/- 1" Coordinate Source: OTHER_SOURCE Comments: Targets of interest are field galaxies at z=0.1-1.0 with R<23mag and sizes 1-2arcsec. Brightest star in the field has B=18.6mag and I=17.5mag. 2 FIELD-010555 CLUSTER OF GALAXIES, RA=01H 5M 55S +/- 1", DEC=-25D J2000 SURF(I) = 23.0+/-0.3 -254717 BLANK SKY 47' 17" +/- 1" Coordinate Source: OTHER_SOURCE Comments: Targets of interest are field galaxies at z=0.1-1.0 with R<23mag and sizes 1-2arcsec. Brightest star in the field has B=18.6mag and I=17.5mag. 3 FIELD-010610 CLUSTER OF GALAXIES, RA=01H 6M 10S +/- 1", DEC=-25D J2000 SURF(I) = 23.0+/-0.3 -254359 BLANK SKY 43' 59" +/- 1" Coordinate Source: OTHER_SOURCE Comments: Targets of interest are field galaxies at z=0.1-1.0 with R<23mag and sizes 1-2arcsec. Brightest star in the field has B=18.6mag and I=17.5mag. 4 FIELD-010610 CLUSTER OF GALAXIES, RA=01H 6M 10S +/- 1", DEC=-25D J2000 SURF(I) = 23.0+/-0.3 -254717 BLANK SKY 47' 17" +/- 1" Coordinate Source: OTHER_SOURCE Comments: Targets of interest are field galaxies at z=0.1-1.0 with R<23mag and sizes 1-2arcsec. Brightest star in the field has B=18.6mag and I=17.5mag. 9502( 7) - 04/15/02 08:05 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 86D TO 89D ORIENT 176D TO 179D ORIENT 266D TO 269D ORIENT 356D TO 359D GROUP 01-04 WITHIN 110D On Hold Comments: Additional Comments: The ORIENTation of the field should be PA=0D +/- 1D modulo 90D. All uncommented orients are ok, but picking one is easier to plan Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 FIELD-01055 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S 5-254359 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 12 FIELD-01055 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S POS TARG 0.25, 3.0 5-254359 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: The ORIENTation of the field should be PA=0D +/- 1D modulo 90D. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 FIELD-01055 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S 5-254717 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 22 FIELD-01055 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S POS TARG 0.25, 3.0 5-254717 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 6] Visit: 03 Visit Priority: Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: The ORIENTation of the field should be PA=0D +/- 1D modulo 90D. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 31 FIELD-01061 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S 0-254359 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 32 FIELD-01061 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S POS TARG 0.25, 3.0 0-254359 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 7] Visit: 04 Visit Priority: Visit Requirements: ORIENT -90D TO -90D FROM 01 On Hold Comments: Additional Comments: The ORIENTation of the field should be PA=0D +/- 1D modulo 90D. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 41 FIELD-01061 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S 0-254717 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 42 FIELD-01061 ACS/WF ACCUM WFC F814W CR-SPLIT=NO 1 1180 S POS TARG 0.25, 3.0 0-254717 C Comments: Each target is assigned 1 visit which should fill 1 orbit. Besides guide star acquisition and ACS overhead time, 1 orbit should be split into 2 exposures with equal amounts of time. Telescope position should be shifted by 5 pixel in x and 60 pixel in y between the 2 exposures to fill the intra-chip gap. No further CR-SPLIT is necessary. ------------------------------------------------------------------------------------------------------------------------------------ 9502( 7) - 04/15/02 08:05 - [ 8] Summary Form for Proposal 9502 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 86D TO 89D ORIENT 176D TO 179D ORIENT 266D TO 269D ORIENT 356D TO 359D GROUP 01-04 WITHIN 110D POS TARG 0.25, 3.0 SAME ORIENT AS 01 ORIENT -90D TO -90D FROM 01 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names FIELD-010555-254359 FIELD-010555-254717 FIELD-010610-254359 FIELD-010610-254717 ------------------------------------------------------------------------------------------------------------------------------------