Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5410 Report Date: 18-Jul-95:17:19 Version: ********** Check-in Date: ********** 1.Proposal Title: SHOCK MORPHOLOGY IN STAR-FORMING RING GALAXIES - CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category PECULIAR/INTERACTING ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Kirk D. Borne STSCI USA 410-338-4945 ------------------------------------------------------------------------------------ 7. Abstract We propose to obtain multi-band WFPC2 images of two smoke-ring galaxies chosen on the basis of showing evidence (in ground-based images) for strong star formation in the ring. We wish to map the sharp features in those rings (e.g., density waves, shock fronts, HII regions, star-forming complexes). We will use the images to study various phenomena: (1) the thresholds for star formation in the ring; (2) the size distribution of the HII regions (compared to that in normal galaxies); (3) evidence for a two-phase starburst (as in Eta Carinae); (4) evidence for color gradients across the ring; (5) comparisons between the age of the tidally induced starburst and the dynamical age of the collision event; (6) the gas dynamical response to strong galactic scale perturbations (density waves); and (7) the character of small- scale structure observed in the rings in terms of starburst strength, density wave strength, magnitude of gas compression, scale length of shocks, location of star- forming regions, and collision age. We will test the results against sophisticated stars+gas simulations of collision-induced ring morphologies. This will be a significant test since the smoke-ring galaxies represent a class of colliding galaxies with very simple and easily interpreted histories: a one-time passage of a companion nearly through the center of a gas-rich disk galaxy. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.94 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5410 PI: Kirk D. Borne Proposal Title: SHOCK MORPHOLOGY IN STAR-FORMING RING GALAXIES - CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Kirk D. Borne STSCI USA Philip Appleton IOWA STATE UNIVERSITY USA Ray A. Lucas STSCI USA Alfred Schultz STSCI USA Lon Spight UNIVERSITY OF NEVADA USA Curtis Struck-Marcell IOWA STATE UNIVERSITY USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan to image two ring galaxies, AM0035-335 ("The Cartwheel") and IIZw28, using the WFPC2. Number of exposures and time_per_exposure, etc. are as follows: AM0035-335 F450W 2x800s CR-SPLIT=NO WFALL-FIX POS TARG +10,- 22 F450W 2x800s CR-SPLIT=NO WFALL-FIX POS TARG +12,-21 F814W 1x400s + 1x500s CR-SPLIT=NO WFALL-FIX POS TARG +10,-22 F814W 1x500s + 1x400s CR-SPLIT=NO WFALL-FIX POS TARG +12,-21 IIZw28 F450W 2x800s CR-SPLIT=NO WF3 DEFAULT POSITION F450W 2x800s CR- SPLIT=NO WF3 POS TARG +1,+2 F814W 1x400s + 1x500s CR-SPLIT=NO WF3 DEFAULT POSITION F814W 1x500s + 1x400s CR-SPLIT=NO WF3 POS TARG +1,+2 F673N 4x1000s CR-SPLIT=NO WF3 DEFAULT POSITION F673N 2x1000s + 2x900s CR-SPLIT=NO WF3 POS TARG +1,+2 The F814W exposures of both galaxies have been split into two parts of unequal length to help in fitting them into an orbit. We do not believe that this difference of 100s between the F814W 400s frames and the F814W 500s frames will be very significant in terms of S/N when comparing them for cosmic ray removal. The final F673N exposures were split into 2x1000 and 2x900 parts so as to meet TAC time allocation -- 1000s vs 900s should be insignificant in final analysis. Other details are as follows: AM0035-335 A specific ORIENT angle is requested in order to properly place the target and two nearby galaxies in the three Wide Field chips' L-shaped field of view. Because the natural orientation on the sky of this galaxy and its two other companions is also somewhat L-shaped, there is one preferred ORIENT angle of 338D +/-15D when used in combination with the WFALL -FIX aperture and a POS TARG position of +10,-22. The target position chosen is an area between the central condensation and the outer ring of AM0035-335, and we place this point on the WF3-WF4 chip boundary about 32 arcsec away from the apex of the pyramid in the Y-direction. ( The default WFALL-FIX position is on WF3 at 10" in X and 10" in Y from the apex of the pyramid, hence our use of POS TARG +10,-22. ) A small offset from this position ( 2" in X and 1" in Y, to +12,-21 ) is used to assist in detecting effects of bad pixels, etc. The off-center central knot in AM0035-335 will be placed on WF3, and the elongated outer ring of the galaxy will be stretched across both WF3 and WF4, while the two nearby small galaxies will be on WF2. The +/-15D range allows the two small galaxies to be displaced across WF2, from one side of the chip to the other, but still keeps them in its field of view. All exposures of this galaxy should be done GROUP NO GAP and should be taken at the SAME ORIENT. IIZw28 The optimal WF3 aperture location is our choice for this galaxy which is much smaller in angular size than AM0035-335. We have again requested GROUP NO GAP for all exposures of this target, and all images should again also be taken at the SAME ORIENT. Also, as with AM0035-335, we have specified small POS TARG offsets to assist us in detecting the effects of bad pixels, etc. There is no special preferred ORIENT for this target due to its geometry and small size. Any ORIENT angle will do, as long as the data are all taken at the SAME ORIENT Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. HST provides the unique opportunity to perform high-resolution imaging of the point-like and sharp-edged features produced in these galaxies as a result of their clean head-on collision with a companion (eg, shock fronts, HII regions, sharp color gradients). These galaxies provide an ideal laboratory for studying the gas dynamical response in strongly penetrating galaxy collisions and for studying in particular: the properties (eg, amplitudes, locations, phase lags) of the propagating wavefronts of star formation and shocked compressed gas, the size and spatial distribution of star-forming regions and HII complexes, and the potential production of globular clusters in the wake of the expanding ring. Since most of these features in the galaxies are not resolvable from the ground, HST imaging is required. In particular, all of the most-structured ring galaxies are at redshifts that place them just beyond the resolution limit of ground-based facilities, with the thickness of the rings being only a few arcseconds across. Ground-based BVRI photometry and IUE UV spectra of ring galaxies (eg, Arp 147; Schultz et al 1991) reveal evidence of a young stellar population in the ring. From the colors, different knots in the rings actually appear to have different stellar population ages. There also appears to be a sudden transition at the ring boundary from older to younger stars. Parameterizing the onset of this transition, its radial steepness, and its azimuthal variations, and mapping the fine-scale spatial variations in stellar population mixes are among the goals and unique by-products of our proposed HST observations. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. As described in Question #3, we request a special orientation for one of our targets: AM0035-335. This is requested because of the natual L-shaped distribution of the various components in this small group of galaxies. This L- shape arrangement matches the L-arrangement of the 3 WF chips in only one orientation: ORIENT = 338D +/- 15D. The specified range in the orientation still permits all of the different target objects to appear fully on the 3 WF chips. Going beyond this range would cause one or the other of the two small companion galaxies to fall off the WF2 boundary and it would cause significant portions of the ring in the primary target (a ring galaxy) to fall off the WF3 and WF4 boundaries. This galaxy has an elliptical-ring morphology, with dimensions 74 arcsec by 60 arcsec. The long axis of the ellipse will straddle chips WF3 and WF4, thus splitting the object across two chips. Any deviation from the stated range of orientations will cause parts of the ring to enter the PC1 chip and other parts of the ring to be totally unobserved. This would not be acceptable. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. (none) ------------------------------------------------------------------------------------ 8. Additional comments or special requests. (none) ------------------------------------------------------------------------------------ 9. Description of previous HST work. (none) ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). STScI Investigators: Some research assistance will be provided to the PI as a regular "visiting" GO for a brief period after the data are obtained. Workstations and numerous data analysis packages are available on site, with expert assistance also available. Iowa State Investigators: Workstations and numerous data analysis packages are also available on site. ------------------------------------------------------------------------------------ 11. Address Information Page 4 Name: KIRK D. BORNE Category: PI Institution: STSCI Address: 3700 SAN MARTIN DRIVE HOMEWOOD CAMPUS City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 410-338-4945 Telex (or e-mail): BORNE@STSCI.EDU ------------------------------------------------------------------------------------ Name: KIRK D. BORNE Category: CON Institution: STSCI Address: 3700 SAN MARTIN DRIVE HOMEWOOD CAMPUS City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 410-338-4945 Telex (or e-mail): BORNE@STSCI.EDU ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5410 [ 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 AM0035-335 E,301,320 RA = 00H 37M 39.55S +/- 2000.0 V=+8930 1 V = 14.0 +/- 0.5 0.1S, DEC = -33D 42' 48.3" +/- 0.1", PLATE-ID = 024K Comments: COORDS ARE ~HALFWAY BETWEEN CENTRAL KNOT AND OUTER RING, TO NORTHWEST OF CENTRAL COMPONENT (KNOT) INSIDE THE OUTER RING. TWO SMALL GALAXIES LIE ~40" TO THE NE, OUTSIDE THE RING. ONE MAY HAVE MADE THE RING. ------------------------------------------------------------------------------------------------------------------------------------ 2 IIZW28 E,301,320 RA = 05H 01M 42.037S +/- 2000.0 V=+8650 1 V = 15.3 +/- 0.5 0.1S, DEC = +03D 34' 25.20" +/- 0.1", PLATE-ID = 04YO Comments: COORDS ARE NOT CENTERED ON THE BRIGHTEST KNOT, BUT RATHER IN CENTER OF RING ON SIDE OF KNOT. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5410 [ 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 AM0035-335 WFPC2 IMAGE WFALL- F450W CR-SPLIT=NO 2 800S 1 CYCLE 4 / 1-4.5 FIX POS TARG +10,-22 GROUP 1-4.5 NO GAP SAME ORIENT FOR 2- 4.5 AS 1 ORIENT 338D +/- Comments: THIS PREFERRED POSITION AND 15D ORIENT PLACES THE CENTRAL COMPONENT ON WF3, THE OUTER RING ON WF3 & WF4, AND THE TWO NEARBY GALAXIES ON WF2. THE FIXED TARGET LIST COORDS ARE PLACED AT A POSN ON WF3-WF4 BORDER 32" FROM APEX. ------------------------------------------------------------------------------------------------------------------------------------ 2 AM0035-335 WFPC2 IMAGE WFALL- F450W CR-SPLIT=NO 2 800S 1 POS TARG +12,-21 FIX Comments: OFFSET 2 ARCSEC IN X AND 1 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. FIXED TARG LIST COORDS ARE NOW 2" FROM WF3-WF4 BORDER IN X, ON WF4, AND ~31" IN Y FROM THE APEX OF THE PYRAMID. ------------------------------------------------------------------------------------------------------------------------------------ 3 AM0035-335 WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 400S 1 POS TARG +10,-22 FIX Comments: THE FIXED TARGET LIST COORDS ARE PLACED ON THE WF3-WF4 BORDER 32" IN Y FROM APEX OF PYRAMID, EXACTLY AS IN EXP LOG LINE 1. SLIGHTLY SHORTER EXP TIME ALLOWS TO FIT IN ORBIT WITHOUT BIG DROP IN S/N. ------------------------------------------------------------------------------------------------------------------------------------ 3.5 AM0035-335 WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 500S 1 POS TARG +10,-22 FIX Comments: THE FIXED TARGET LIST COORDS ARE PLACED ON THE WF3-WF4 BORDER 32" IN Y FROM APEX OF PYRAMID, EXACTLY AS IN EXP LOG LINE 1. EXP TIME OF 500S SHOULD NOT MAKE TOO BIG A DIFFERENCE WHEN DOING CR REMOVAL. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5410 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4 AM0035-335 WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 500S 1 POS TARG +12,-21 FIX Comments: OFFSET 2 ARCSEC IN X AND 1 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. FIXED TARG LIST COORDS ARE NOW 2" FROM THE WF3- WF4 BORDER IN X, ON WF4, AND ~31" FROM THE APEX OF THE PYRAMID IN Y. ------------------------------------------------------------------------------------------------------------------------------------ 4.5 AM0035-335 WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 400S 1 POS TARG +12,-21 FIX Comments: SAME POSITION AND ORIENT AS FOR EXP LOG LINE 4, BUT THIS EXP TIME WAS SHORTENED SLIGHTLY TO ALLOW BETTER FIT INTO ORBIT. S/ N SHOULD NOT BE AFFECTED MUCH BY BEING 400S INSTEAD OF 500S WHEN DOING CR REMOVAL. ------------------------------------------------------------------------------------------------------------------------------------ 5 IIZW28 WFPC2 IMAGE WF3 F450W CR-SPLIT=NO 2 800S 1 CYCLE 4 / 5-10 GROUP 5-10 NO GAP SAME ORIENT FOR 6- 10 AS 5 Comments: FIXED TARGET LIST COORDS ARE TO BE PLACED AT OPTIMAL CENTER OF WF3 CHIP. THERE IS NO PREFERRED ORIENT FOR THIS TARGET, BUT ALL DATA IN ALL FILTERS SHOULD BE TAKEN AT THE SAME ORIENT. ------------------------------------------------------------------------------------------------------------------------------------ 6 IIZW28 WFPC2 IMAGE WF3 F450W CR-SPLIT=NO 2 800S 1 POS TARG +1,+2 Comments: OFFSET 1 ARCSEC IN X AND 2 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. ------------------------------------------------------------------------------------------------------------------------------------ 7 IIZW28 WFPC2 IMAGE WF3 F814W CR-SPLIT=NO 1 400S 1 Comments: FIXED TARGET LIST COORDS ARE AT THE OPTIMAL CENTER OF WF3. USE SAME ORIENT AS THAT FOR F450W AND F673N EXPOSURES. ------------------------------------------------------------------------------------------------------------------------------------ 7.5 IIZW28 WFPC2 IMAGE WF3 F814W CR-SPLIT=NO 1 500S 1 Comments: FIXED TARGET LIST COORDS ARE AT THE OPTIMAL CENTER OF WF3. USE SAME ORIENT AS THAT FOR F450W AND F673N EXPOSURES. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5410 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 8 IIZW28 WFPC2 IMAGE WF3 F814W CR-SPLIT=NO 1 500S 1 POS TARG +1,+2 Comments: OFFSET 1 ARCSEC IN X AND 2 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. ------------------------------------------------------------------------------------------------------------------------------------ 8.5 IIZW28 WFPC2 IMAGE WF3 F814W CR-SPLIT=NO 1 400S 1 POS TARG +1,+2 Comments: OFFSET 1 ARCSEC IN X AND 2 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. ------------------------------------------------------------------------------------------------------------------------------------ 9 IIZW28 WFPC2 IMAGE WF3 F673N CR-SPLIT=NO 4 1000S 1 Comments: FIXED TARGET LIST COORDS ARE AT THE OPTIMAL CENTER OF WF3. USE SAME ORIENT AS THAT USED FOR ALL F450W AND F814W EXPOSURES. ------------------------------------------------------------------------------------------------------------------------------------ 9.5 IIZW28 WFPC2 IMAGE WF3 F673N CR-SPLIT=NO 2 1000S 1 POS TARG +1,+2 Comments: OFFSET 1 ARCSEC IN X AND 2 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. ------------------------------------------------------------------------------------------------------------------------------------ 10 IIZW28 WFPC2 IMAGE WF3 F673N CR-SPLIT=NO 2 900S 1 POS TARG +1,+2 Comments: OFFSET 1 ARCSEC IN X AND 2 ARCSEC IN Y TO REMOVE POSSIBLE EFFECTS ASSOC WITH INDIVIDUAL PIXELS ETC. EXPOSURE TIME SHORTENED SLIGHTLY TO FIT TAC ALLOCATION. SHOULD NOT MAKE MUCH DIFFERENCE FOR CR DETECTION & REMOVAL. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5410 [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.94 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category PECULIAR/INTERACTING ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 1-4.5; POS TARG +10,-22; GROUP 1-4.5 NO GAP; SAME ORIENT FOR 2-4.5 AS 1; ORIENT 338D +/- 15D; POS TARG +12,-21; CYCLE 4 / 5-10; GROUP 5-10 NO GAP; SAME ORIENT FOR 6-10 AS 5; POS TARG +1,+2; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F450W F814W F673N ------------------------------------------------------------------------------------------------------------------------------------ Target Names AM0035-335 IIZW28 ------------------------------------------------------------------------------------------------------------------------------------