Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5458 Report Date: 18-Jul-95:17:26 Version: ********** Check-in Date: ********** 1.Proposal Title: EVOLUTION OF GALAXIES IN INTERMEDIATE REDSHIFT CLUSTERS : IMAGING OF ABELL 665 : CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category EVOLUTION/COSMOLOGY ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Marijn Franx 6830 NETHERLAND (011) 31 50 63 ------------------------------------------------------------------------------------ 7. Abstract One of the more fundamental problems in current astronomy is that of galaxy evolution. We still do not have good constraints on how galaxy densities, types, and luminosities evolve with redshift. Most studies until now have used only photometric and spectrophotometric information to derive 'spectral' classifications and luminosities. Whereas these methods will remain essential to understanding evolution, they are insufficient for a unique interpretation of the data. I have started a ground-based program to measure dynamical parameters of galaxies in intermediate redshift clusters. I have successfully measured velocity dispersions, and in some cases, rotational velocities. These dynamical data are a fundamental step forward towards quantifying the effects of 'passive evolution', mergers, starburst, etc. The first results on galaxies in Abell 665 at z=0.18 have demonstrated the value of these data amply: one of the galaxies is an E+A galaxy, rotates rapidly, and lies far off the Faber-Jackson relation measured for other cluster galaxies. This is the first time that such detailed information has become available on such a galaxy, and it provides insight into the mechanisms which cause the rapid evolution of galaxies in rich clusters (the Butcher--Oemler effect). Here it is proposed to obtain 2 color WFPC images of this galaxy, and the other cluster galaxies. This galaxy is ideally suited because of it brightness, rather low redshift, and the detailed groundbased data. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.69 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5458 PI: Marijn Franx Proposal Title: EVOLUTION OF GALAXIES IN INTERMEDIATE REDSHIFT CLUSTERS : IMAGING OF ABELL 665 : CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Marijn Franx 6830 NETHERLANDS X ------------------------------------------------------------------------------------ 3. Description of proposed observations. I propose to take WFPC2 images of Abell 665, a well studied cluster at a redshift of 0.18. This cluster is one of the clusters for which the Sunyaev- Zel'dovitch effect has been established(1), and a good dataset of spectra and radial velocities are available(2,3). I have already measured internal velocity dispersions for a sample of galaxies (4). Images will be taken in two passbands (F606W and F814W). This will provide the detailed morphological information on the galaxies, and detailed color information. The E+A galaxy is one of the best studied Butcher Oemler galaxies, and the color information is going to be particularly interesting. As an example, we can determine whether the starbust formed only a disk component, or whether it contributed to both bulge and disk. We can also hope to determine disk and bulge parameters separately, which will enable us to make an easy comparison with galaxies in nearby clusters. The hope is to find the class of galaxies into which these Butcher Oemler galaxies evolved. Two fields will be studied, both in two colors. These two fields will include all the galaxies for which kinematic data is available. The integration time in each passband will be two orbits. Experience with current deep cluster imaging, and folding in the improved PSF, but lower quantum efficiency, indicates that such integration times will produce images with the fine detail necessary for morphological and color studies. 1 Birkinshaw, Hughes and Arnaud, 1991, Ap. J. in press. 2 Oegerle, Fitchett, Hill, Hintzen, 1991, preprint. 3 Birkinshaw, private communication. 4 Franx, 1993, ApJ L 407, 5. Postscript: Note that the "blue" filter has been changed from F555W to F606W. This is done because of the higher throughput of F606W, which amounts to a factor of 2 more signal. NOTE: THE PI HAS ALTERNATE SUGGESTIONS FOR TARGET POSITIONS, ORIENT ANGLES, AND FOR POSSIBLE RELAXATION OF SOME CONSTRAINTS IN THE SPECIAL REQUIREMENTS IF NEEDED FOR SCHEDULING. PLEASE CONTACT THE PI IF THERE ARE PROBLEMS OF THIS SORT FOR WHICH HE MAY HAVE USEFUL SUGGESTIONS. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The need for HST images is obvious since there is no spherical aberration after the repair mission. It will provide us with 2D photometry comparable to the ground-based data that can be achieved on Coma. Thus detailed structural studies are possible. It is obvious that no such detailed information is available from the ground (see also Figure 5 ground based images can be improved by deconvolution, it is impossible to retrieve the small scale color information that we plan to obtain through the HST images. Especially for the E+A galaxy, such color information is essential for a proper understanding of the underlying mechanisms. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. THERE IS A BRIGHT STAR QUITE NEAR TO THE OBJECT. PLEASE READ SECTION 8 WHERE I EXPLAIN MY STRATEGY TO AVOID BLEEDING AND SCATTERED LIGHT. NOTE: THE PI HAS ALTERNATE SUGGESTIONS FOR TARGET POSITIONS, ORIENT ANGLES, AND FOR POSSIBLE RELAXATION OF SOME CONSTRAINTS IN THE SPECIAL REQUIREMENTS IF NEEDED FOR SCHEDULING. PLEASE CONTACT THE PI IF THERE ARE PROBLEMS OF THIS SORT FOR WHICH HE MAY HAVE USEFUL SUGGESTIONS. Page 3 ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. There is a bright star quite near to the most interesting object in the field. To avoid bleeding and/or ghosts, it is important that the star does NOT get onto the same Chip as the object. The star lies south of the object. The position that I define in ABELL0665-POS1 is in between the galaxy and the star. I define as the field of view PC1-FIX, and then give a POS-TARG = -18.4, -18.4, so that the apex of the pyramid falls exactly on the position ABELL0665-POS1. There is a distance of about 16 arcsec in between the galaxy and the star. I then require that the position angle of the telescope is such that the object falls on one of the chips - this gives four positions angles to choose from, plus some leeway. Note that observations could also be done at other position angles, but I would have to select a different field center, to avoid the bright star. PLEASE CONTACT ME DIRECTLY DURING THE PLANNING OF THE OBSERVATIONS. I CAN AT ANY TIME DEFINE A NEW FIELD CENTER AT ANY GIVEN POSITION ANGLE OF THE TELESCOPE . FEEL WELCOME TO CALL ME OUT OF BED (BUT TRY AN EMAIL FIRST: FRANX@ASTRO.RUG.NL). For field 2 (ABELL0665-POS2) a similar constraint applies. There are some stars near the edge of the field, which I want to avoid. The current field center allows 4 position angles. AGAIN, I CAN ADAPT THE FIELD CENTER TO ACCOMODATE ANY POSITION ANGLE. There is considerable freedom in changing the exposure times. The main purpose is to get as high signal to noise as possible (so, the longest integration time. It helps if each field/passband combination has two exposures with identical exposure time, and this exposure time should be above 1600 sec. Feel free to change things to these criteria, and please contact me to make sure everything is OK. My email is franx@astro.rug.nl. I am asking for 2 images with identical exposure time to facilitate removal of cosmic ray events. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Approved Proposals on which I am PI: Evolution of Galaxies in Intermediate Redshift Clusters: Imaging of CL0024+16 Cycle 2 Archival proposal # 3503. This archival proposal is related to the current proposal. The data has just been released. Co-I on the following proposals: Ellipticals with Kinematically Distinct Nuclei # 3441 Cycle 2. First paper is being written. No direct relation to the current proposal. Nearby Nuclei Snapshot survey # 4664 Cycle 3. The data is just coming in. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). I am a full professor at the University of Groningen, and have full access to all research facilities, which includes computing, library, preprint services, etc. Students, travel money, etc. are available. ------------------------------------------------------------------------------------ 11. Address Information Name: MARIJN FRANX Category: PI Institution: 6830 Address: KAPTEYN ASTRONOMICAL LABORATORY P. O. BOX 800 City: GRONINGEN State: Zip Code: 9700 AV Country: NETHERLANDS Telephone: (011) 31 50 634067 Telex (or e-mail): FRANX@ASTRO.RUG.NL ------------------------------------------------------------------------------------ Page 4 Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5458 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 ABELL0665- F,404 RA= 08H26M09.77S +/-0.1S, B1950 1 SURF-BKG(R) = 19 +/- 1.0 POS1 DEC= +66D00'31.2" +/- 0.1" Comments: PLEASE READ SECTION 8 ABOUT THE POSITIONING. WHEN CENTERED ON THIS POSI- TION, BRIGHT STAR IN SOUTHERN FIELD, WHICH WILL SATURATE CCD ------------------------------------------------------------------------------------------------------------------------------------ 2 ABELL0665- F,404 RA= 08H26M29.85S +/-0.1S, B1950 1 SURF-BKG(R) = 19 +/- 1.0 POS2 DEC= +66D00'11.1" +/- 0.1" Comments: PLEASE READ SECTION 8 ABOUT THE POSITIONING. THIS FIELD DOES NOT CONTAIN THE BRIGHT STAR. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5458 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ABELL0665- WFPC2 IMAGE PC1-FIX F606W CR-SPLIT=NO 2 2200S 1 1 CYCLE 4 / 1-4 POS2 ORIENT 276D +/- 6D POS TARG -18.4, - 18.4 Comments: ORIENTATIONS 96 +-6, 186 +- 6 AND 276 +- 6 ALSO ALLOWED. PLEASE READ GF QUESTION 8 ABOUT THE ORIENTA- TIONS. POS2 OBS TO BE DONE BEFORE POS1 OBS. ------------------------------------------------------------------------------------------------------------------------------------ 2 ABELL0665- WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO 2 2200S 1 1 SAME POS FOR 2 AS POS2 1 GROUP 1-2 NO GAP Comments: ALL OBS OF POS2 SHOULD BE REASONABLY CLOSE TO EACH OTHER IN TIME, BUT WE MAY RELAX THIS CONSTRAINT. CONTACT PI IF NEEDED. ------------------------------------------------------------------------------------------------------------------------------------ 3 ABELL0665- WFPC2 IMAGE PC1-FIX F606W CR-SPLIT=NO 3 1700S 1 1 AFTER 2 POS1 SAME ORIENT FOR 3- 4 AS 1 POS TARG -18.4, - 18.4 Comments: DO NOT USE WFC WITHIN A HALF HOUR AFTER LAST EXPOSURE. DO AFTER LOG LINE 2. ALL OBS OF POS1 SHOULD BE CLOSE TOGETHER IN TIME, BUT CONSTRAINT MAY BE RELAXED. CALL PI. ------------------------------------------------------------------------------------------------------------------------------------ 4 ABELL0665- WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO 3 1600S 1 1 SAME POS FOR 4 AS POS1 3 GROUP 3-4 NO GAP Comments: SAME POSITION AND ORIENT AS EXP LOG LINE 3. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5458 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.69 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category EVOLUTION/COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 1-4; ORIENT 276D +/- 6D; POS TARG -18.4, -18.4 SAME POS FOR 2 AS 1; GROUP 1-2 NO GAP AFTER 2; SAME ORIENT FOR 3-4 AS 1; SAME POS FOR 4 AS 3; GROUP 3-4 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ABELL0665-POS1 ABELL0665-POS2 ------------------------------------------------------------------------------------------------------------------------------------