! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5985,v 16.1 1995/04/19 20:26:57 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Doug Van Orsow ! Phone: 410 338-4568 , E-mail: vanorsow@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sun Dec 18 10:11:31 EST 1994 ! Proposal_Information ! Section 4 Title: WFPC2 B-band + Ly-alpha imaging of a cluster of young galaxies at z=2.40 Proposal_Category: GO Scientific_Category: Galaxies & Clusters, Distant Galaxies Cycle: 5 Investigators PI_name: Rogier Windhorst PI_Institution: Arizona State University CoI_Name: Simon Driver CoI_Institution: ASU, Dept. of Phys. & Astr., Tempe Contact: ! Y or N (designate at most one contact) CoI_Name: Paul Schmidtke CoI_Institution: ASU, Dept. of Phys. & Astr., Tempe Contact: ! Y or N (designate at most one contact) CoI_Name: Sam Pascarelle CoI_Institution: ASU, Dept. of Phys. & Astr., Tempe Contact: ! Y or N (designate at most one contact) CoI_Name: William Keel CoI_Institution: U. Alabama, Dept. of Phys. & Astr., Box 870324, Tuscaloosa, AL\ 35487 Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We request 39 orbits (28 hr) with WFPC2 to obtain B- (F450W) and narrow-band redshifted Ly-Alpha imaging of a cluster of galaxies at z=2.40 recently discovered in deep WFPC2 V & I images. These contain two compact HST galaxies with spectroscopic z's=2.40, several candidates with excess light at 4120Angstrom in ground-based Ly-alpha-images, and several compact HST galaxies with blue continua and the UBVRIgriJHK colors of galaxies with z\cge 2. The WFPC2 F410M-filter has exactly the right and DeltaLambda to image their Ly- alpha at z=2.40. The 10hr B-image will nearly match the existing V+I images in depth for blue galaxies, and be used to: (a) subtract the restframe UV-continuum to obtain a Ly- alpha-image at 0"pt 1 resolution; (b) study restframe UV- morphology and BVI color gradients to constrain stellar populations and dust at z=2.40; (c) do (b) for all foreground galaxies with z 1. The 18-hr Ly-alpha-image will be combined with deep ground-based Ly-alpha images to provide good S/N at 0.1---1.0" resolution, so that we can: (1) locate all Ly- Alpha emitting objects at z=2.40 within 3', determine their Ly -alpha fluxes and SFR; (2) study the sub-kpc starburst morphology of young star-forming galaxies at z=2.40, and locate their star-formation regions; (3) combined with CO- detections, determine the gas-to-stellar mass conversion rate and the efficiency of galaxy formation at z=2.40; ! and (4) ! disentangle reflected AGN-light in a cone from jet-induced ! star-formation in a young elliptical radio galaxy at z=2.39. Questions ! Free format text (please update) Observing_Description: We need to detect field galaxies with B~eq22.9--25.9, V~eq22.8--25.8 mag (Fig. 1& 2), which are much bluer than the sky (NEP HST-sky~eq23.3 \magarc in V, 23.9 in B, 24.2 in Ly- alpha; W92, W94c). This requires a B-image that is ~0.5 mag shallower than our 5.7-hr Cycle 4 V-band image (3Sigma limit: V~26.4 mag for a \rs~0"pt 4 galaxy), and a Ly-alpha image ~1.0 mag shallower than V (to image their core structure). The cosmological SB-dimming is less severe than \propto (1+z)^-4 for semi-unresolved objects, so that the central Ly-alpha emission is expected to be relatively easily visible in F410M. 53W002 has m^AB_F606W=22.80, m^AB_F450W=23.04, m^AB_F410M= 21.80 mag (W91), the other candidates ~20--50\ count rate for 53W002 of 8.51, 2.37 and 0.83 in/sec in V, B, & Ly-alpha, respectively. About 20\ (WK94), the remainder is r^1/4-distributed over ~80 pixels. The average S/N per (0"pt 1) pixel is ~13, 6.3, and 3.1 for 53W002, using 2400 sec in F606W & F450W, and 2700 sec in F410M (lower sky and RN -limited, so we can push longer per orbit after subtracting 9 min for overhead and 15 min for the first aquisition). Assuming that the (majority) non-AGN light of the other galaxies follows an exponential disk with \rs~0"pt 4, their S/N will be ~ 2-3* lower. We need to detect galaxies with \rs~eq0"pt 4 (G94) at least 2 scale-lengths out into the wings with a minimum S/N~eq1 per wing pixel (W94a). From this, we computed total exposure times of 10-hr (15 orbits) in B and 18-hr (24-orbits) in Ly-alpha. We will achieve S/N~eq1 at r~eq1"pt 2 in F450W and 1"pt 0 in F410M (compared to r~eq1"pt 4 achieved in F606W) for 53W002, and at r~eq8 & 6 (and 10) pixels for objects ~1.0 mag fainter. We confirmed these calculations with WFPC2 simulations, similar as in 1993, which the actual Cycle 4 images of WK94 showed were accurate to within ~10\ We need to subtract the continuum B- from the Ly-alpha-image, so that we require somewhat higher signal-to-noise in F450W, to avoid corrupting the S/N of the F410M-image. The deep ground-based redshifted Ly-alpha images will provide better S/N at lower spatial frequencies. We will combine the WFPC2 Ly-alpha image (at 0.07--0.1" resolution) with the ground-based image (~1"pt 0 resolution) to provide good S/N at 0.07---1.0" through the Lucy-Hook method. The Cycle 5 images will be reduced like our Cycle 4 images, as described in Windhorst & Keel (1994), Windhorst, Franklin, & Neuschaefer (1994b, W94b), Franklin & Windhorst (1994), Griffiths Etal (1994b), and Holtzman Etal (1994), which are similar to the optimized Cycle 1--3 WF/PC reduction techniques of Griffiths Etal (1994a), Ratnatunga Etal (1994), Windhorst Etal (1992, 1994a, 1994c, 1994d). We need an HST space-craft orientation angle similar to our Cycle 4 images to have the Cycle 5 images overlap with Cycle 4 as much as possible. The best scheduling times are therefore mid May -- mid June. This should not impose an undue constraint to the scheduling, as the 17\hh+50degrees field is only 3degrees away from the CVZ, and so can be observed almost year-round. If it does cause scheduling conflicts in May-June 1995, we will observe the field with a Cycle 5 orientation angle that differs from Cycle 4 by a multiple of 90(+/- 7)^o, and substep the WFPC2 exposures to simulate the ~0"pt 05 PC-pixels of Cycle 4. Real_Time_Justification: Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: \n bullet Ground-based spectroscopy: We have carried out an extensive program of ground-based follow-up on our WFPC2 field around 53W002. For this, we used the MMT Red Spectrograph with multi-aperture plates for low-resolution spectroscopy; the Palomar 200 inch Four-shooter CCD-array and the Steward 90 inch with a 2048^2 Lesser CCD for deep UBVRI imaging; and the Steward NICMOS 256*256 arrays for JHK imaging (W91, W94c, M94b). The goal is to measure redshifts for faint field galaxies surrounding the radio source 53W002, constrain their nature in terms of starburst and/or weak AGN, and to use UBVRIgriJHK photometry to constrain the effects of dust in z=2.40 candidates and provide photometric redshift- estimates for galaxies with V\cge 23.5 mag. With the MMT, we have made five masks with 10--14 slits each for our WFPC2 field in less than 10 days lead-time. In July 1994, we obtained 45 spectra down to V~24 mag (in 2 nights) in this WFPC2 field (D94b), or ~10 objects per square arcmin. We take advantage of the a priori knowledge of accurate coordinates for the HST galaxy cores (and/or H-II regions) from WFPC2 astrometry using the measured on-orbit astrometric transformation coefficients of H94. Since the median scale- length of HST galaxies is 0.3--0.4" (G94a), we can use 0.5-- 0.75" slits in good seeing to optimize the multi-slit spectrograph through-put. We thus regard it as a more efficient use of HST time to measure the redshifts a posteriori, because the accurate relative WFPC2 positions allow us to construct the most accurate masks. Pre-existing ground-based redshift surveys have the problem of less accurate a-priori positions and lower galaxy surface density (~1--2 redshifts per square arcmin), and are therefore more expensive in HST follow-up. \n bullet Ground- based narrow-band imaging: We purchased a nearly identical filter to F410M from Custom Scientific Inc. (who also made the WFPC2 filters) to image a much wider field in redshifted narrow-band Ly-alpha (<=ff 4120Angstrom, DeltaLambda~eq 150Angstrom FWHM) with the Steward 90 inch. The WFPC2 Ly- alpha image will provide the best resolution and sensitivity at 0.07--0.2" resolution --- inaccessible to our best ground- based Ly-alpha images --- and will be combined with the deep Steward Ly-alpha-image (~1"pt 0 FWHM) to provide good S/N at all spatial frequencies 0.07---1.0", using the Lucy-Hook algorithm. \n bullet Keck, sub-mm follow-up: Drs. Koo, Illingworth (UCSC) and Spinrad (UCB) have offered to spend Keck Low-Res time on our HST galaxies in the 53W002 field. They will concentrate on galaxies ~1 mag fainter (V 24.9 mag) than we can do with the MMT, and we will prepare a joint publication on these fainter objects. We plan on imaging the entire 3' field with the OVRO interferometer in redshifted CO (at 102 GHz) to get gas-mass estimates for all z=2.40 cluster candidates, in collaboration with Drs. Scoville and deGeus (Caltech), and with the new Steward SMT to get a few very-high sensitivity CO beams. Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: 53W002 Alternate_Names: HERC202 Description: GALAXY, RADIO GALAXY, CLUSTER OF GALAXIES Position: RA = 17H 12M 59.860S +/- 0.3", ! Most common specification format is DEC = +50D 18' 51.30" +/- 0.3" ! PLATE-ID=0000 Equinox: B1950.0 RV_or_Z: Z = 2.390 ! RA_PM: 0.000 ! Units are seconds of time per year ! Dec_PM: 0.000 ! Units are seconds of arc per year ! Epoch: B1975.0 !Annual_Parallax: 0.000 Flux: U = 23.1 +/- 0.15, ! Include at least V and B-V ! Lya = 22.1 +/- 0.15, B = 23.3 +/- 0.15, V = 22.8 +/- 0.10, R = 22.45 +/- 0.10, I = 22.0 +/- 0.10, ! SURF(U) = 25.0 +/- 0.15, ! SURF(Lya) = 24.3 +/- 0.3, ! SURF(B) = 24.7 +/- 0.3, ! SURF(V) = 24.3 +/- 0.15, ! SURF(R) = 24.7 +/- 0.15, ! SURF(I) = 23.9 +/- 0.15, Comments: We need 4x6 exp in the B (F450W) filter with 53W002 on four positions: A,B,C,D, EACH on the corners of a square 0.5478" in size to do n+0.5 pix WFC substepping. We need 53W002 in the most sensitiv PC1 area. We also need 3x4 + 1x3 orbits in the Lya ! (F410M) filter with 53W002 on the corners ! of the SAME square 0.5478" on a side. ! The TAC comments stated this was the ! highest ranked z>2 cluster proposal, as we ! already had 28 orbits in V+I in Cycle 4. ! A critical part of the proposal is to get ! the SAME FIELD COVERED WITH THE SAME ORIENT ! AS IN CYCLE 4. Please make sure it can be ! scheduled that way, or contact me if not. Thx. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN