Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5602 Report Date: 18-Jul-95:17:43 Version: ********** Check-in Date: ********** 1.Proposal Title: STUDY OF ULTRAVIOLET ECHOES AROUND SN 1993J ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO/DD Sub Category SN & SNR ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Prof Nino Panagia SPACE TELESCOPE SCIENCE INST USA 301-338-4916 ESA SNR ASTRONOMER ------------------------------------------------------------------------------------ 7. Abstract We propose to observe the field centered on SN 1993J in M81 with the WFC-2 in several UV bands to reveal UV echoes, produced by scattering on grains in interstellar clouds which belong to the disk of M81 and lie along the line of sight to SN 1993J. The UV light scattered in such echoes provides a measurement of the UV radiation that the supernova emitted at the very early phases after explosion, immediately after shock breakout. This, in turn, will constrain the various models for the supernova explosion. In addition, we will be able to determine the properties of the populations of early type stars in the vicinities of SN 1993J and, therefore, to derive an independent estimate of its original mass that radio observations suggest to be close to 10-15 solar masses. ------------------------------------------------------------------------------------ 8. Scientific Key Words: SUPERNOVA ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.75 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5602 PI: Prof Nino Panagia Proposal Title: STUDY OF ULTRAVIOLET ECHOES AROUND SN 1993J ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Nino Panagia SPACE TELESCOPE SCIENCE USA X INSTITUTE Nino Panagia 3470 USA X Roberto Gilmozzi 3470 USA X Knox Long 3470 USA Salvatore Scuderi 3470 USA X Schuyler Van Dyk 3640 USA Kurt Weiler 3640 USA Robert Kirshner 2160 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan to take images with the Wide Field Camera at the beginning of Cycle 4 in 2 UV broad bands, namely F170W and F218W, with 2100s exposures each (split into about 1000s sub-exposures). According to our flux predictions we should achieve a S/N of 13 per pixel in both bands. After analysis and confirmed detection of the echo, new observations will be made 12 +/- 3 months after the first epoch, when we expect the ring size to have increased 30%, i.e., from 0.58" to 0.76", and the flux per pixel to be reduced by a factor of 1.7. These second-epoch observations will include images (t_exp = 2100s) in six bands, the previous two ones (F170W and F218W) and four more (F122M, F185W, F255W, and F300W), so as to have a full coverage of the spectrum between 1200 A and 3200 A. For the second epoch observations the expected S/N per pixel is about 8 in all bands except, perhaps, in the F122M, in which the S/N may be closer to 6. Since variation of the ring radius between the two epochs (Dtheta~0.18") is greater than twice the resolution, it will be possible to measure the brightness and the spacial distribution of the diffuse UV background and subtract it from the images quite accurately so that the intrinsic brightness of the ring will be determined reliably. As detailed in the Scientific Justification, the expected UV flux per WFC-2 pixel (0.1" x 0.1") from an echo around SN 1993J about one year after explosion is ~2 x 10^-17 erg cm-2 s-1 A-1 in the 1250-1850~ A interval. Using the data provided in the WFPC-2 Handbook and assuming a background of about 1 x 10^-6 counts cm-2 s-1 A-1, we estimate that 2100s exposures in the F170W and F218W filters give a S/N ratio of ~13 per pixel. Since the echo flux decreases as t-1 the observations made on the second epoch (12 +/- 3 months after the first one) will achieve a lower S/N, which is about 8 in the F170W, F185W, F218W, F255W and F300W filters and about 6 for the F160W filter. The required observing time is 4200s for the first epoch and 12600s for the second epoch. The requirements in terms of spacecraft time become ~1.75 and ~4.69 hours, respectively, for the two epochs and the total ~ 6.44 hours of spacecraft time. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The HST angular resolution is essential for the present study, because we want to measure faint UV fluxes emitted by echoes around SN 1993J. In addition, the high angular resolution of HST is also crucial, because we are dealing with structures with total size barely above 1 arcsec in size and which need to be resolved in order to be discerned against the expected background. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The first observations (two images) should be made as early at the beginning of Cycle 4 as possible, whereas the second series (six images) should be made at a later epoch, upon confirmation of a positive detection, approximately 12 +/- 3 months after the first epoch (conditional upon additional DD time being granted to the present project). ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). N. Panagia, R. Gilmozzi, K. Long and S. Scuderi will have access to computing and data processing facilities at STScI. In addition NP, RG and SS will have access to ESA travel funds. K.W. Weiler and S.D. Van Dyk will have access to computing facilities at NRL. R.P Kirshner will have access to computing facilities at CfA. ------------------------------------------------------------------------------------ 11. Address Information Name: NINO PANAGIA Category: PI Institution: SPACE TELESCOPE SCIENCE INSTITUTE Address: 3700 SAN MARTIN DRIVE City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 301-338-4916 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5602 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 SN1993J- B, 182, RA = 09H 51M 19S +/- 0.5", 1950.0 1 V=14.5 +/- 0.3, E(B-V)=0.2 FIELD G, 504 DEC= +69D 15' 26" +/- 0.5" 2 B=15.0 +/- 0.3 3 F-CONT(1500)=2.0+/-0.5 E-17 4 F-CONT(2500)=4.0+/-1.0 E-17 5 F-CONT(3500)=8.0+/-2.0 E-17 Comments: FLUXES SCALED FROM IUE MEASUREMENTS OF AN ECHO DETECTED AROUND SN 1987A COORDINATES ARE THOSE PROVIDED IN IAUC NO. 5730. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5602 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 SN1993J- WFPC2 IMAGE WF3 F170W CR-SPLIT=0.5 1 2100S 10 3 1 CYCLE 4 / 1-8 FIELD CR- 2100S SEQ 1-2 WITHIN 1D TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1993J- WFPC2 IMAGE WF3 F218W CR-SPLIT=0.5 1 2100S 13 3 1 SAME ORIENT FOR 2 FIELD CR- 2100S 4 AS 1 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1993J- WFPC2 IMAGE WF3 F122M CR-SPLIT=0.5 1 2100S 6 3 2 CONDITIONAL ON 1-2 FIELD CR- 2100S IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D SAME ORIENT FOR 3- 8 AS 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 SN1993J- WFPC2 IMAGE WF3 F170W CR-SPLIT=0.5 1 2100S 8 3 2 CONDITIONAL ON 1-2 FIELD CR- 2100S IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ 5 SN1993J- WFPC2 IMAGE WF3 F185W CR-SPLIT=0.5 1 2100S 8 3 2 CONDITIONAL ON 1-2 FIELD CR- 2100S 4 IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ 6 SN1993J- WFPC2 IMAGE WF3 F218W CR-SPLIT=0.5 1 2100S 9 3 2 CONDITIONAL ON 1-2 FIELD CR- 2100S 4 IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5602 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 SN1993J- WFPC2 IMAGE WF3 F255W CR-SPLIT=0.5 1 2100S 9 4 2 CONDITIONAL ON 1-2 FIELD CR- 2100S IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ 8 SN1993J- WFPC2 IMAGE WF3 F300W CR-SPLIT=0.5 1 2100S 10 5 2 CONDITIONAL ON 1-2 FIELD CR- 2100S IF BEING TOLERANCE=0.0 SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED AFTER 1 BY 365D +/ - 90D SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5602 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 CR-TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/DD ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.75 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category SN & SNR ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 1-8; SEQ 1-2 WITHIN 1D SAME ORIENT FOR 2 AS 1 CONDITIONAL ON 1-2 IF BEING SUCCESSFUL AND ADDITIONAL DD TIME BEING GRANTED; AFTER 1 BY 365D +/- 90D; SEQ 3-8 WITHIN 1D; SAME ORIENT FOR 3-8 AS 1 SEQ 3-8 WITHIN 1D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F170W F218W F122M F185W F255W F300W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN1993J-FIELD ------------------------------------------------------------------------------------------------------------------------------------