Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5751 Report Date: 18-Jul-95:17:55 Version: ********** Check-in Date: ********** 1.Proposal Title: UNDERSTANDING THE GEMINGA (1E0630+178) OPTICAL COUNTERPART CYCLE 4 - HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO 5484 Sub Category NEUTRON STARS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Giovanni F. Bignami CNR ISTITUTO DI FISICA COSMI ITALY 39-2-2367587 ------------------------------------------------------------------------------------ 7. Abstract The recent discovery of a common X/Gamma periodicity for GEMINGA and of the proper motion of the optical candidate have finally closed the X/Gamma/optical identification chain. The object is a rotating neutron star, the only one invisible in radio, but visible in the optical. Two main problems remain open for the understanding of Geminga: the physical characteristics of its emission and its distance. The first was the aim of our Cycle 1 proposal N.2525, approved with high priority but then deferred. In it we proposed to study this unique object through few color photometry with the FOC. The distance problem could be solved by measuring Geminga's annual parallax: this is the aim of the ongoing DD proposal N.4593, already approved for several PC observations covering both Cycles 3 and 4. The current proposal is a merging of the two, exploiting the post-refurbishment capabilities of the HST instruments. Establishing a reliable flux in near UV is crucial for grasping the overall energy balance and for distinguishing between non- thermal and thermal emission models, especially in comparison with the soft X-ray spectral information now available from ROSAT. Obviously, a measurement of the parallax would give for the first time a quantitative assesment of the multi-band luminosities of a neutron star. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOC WF/PC ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5751 PI: Giovanni F. Bignami Proposal Title: UNDERSTANDING THE GEMINGA (1E0630+178) OPTICAL COUNTERPART CYCLE 4 - HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Giovanni Bignami 6408 ITALY X Patrizia Caraveo 6408 ITALY X Sandro Mereghetti 6408 ITAL X Roberto Mignani 6408 ITALY X Laurence Taff 3470 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. For the proposed scientific objectives, we need the FOC in direct image mode at F/96 (with F320W filter),thus reaching the required sensitivity in about 8000 sec. For the PC images, we need to take three sequences of 2 exposures of about one orbit each. The first pair of one orbit exposure should be around March 21,1994,the second around Sept.21,1994 (when the parallatic displacement is maximum) and the third around March 21,1995. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Near UV measurments are not possible from the ground, so that the post COSTAR FOC appears as a natural choice. To measure the parallatic displacement we need a very accurate position of our object (G"), together with few reference stars, taken 6 months apart. The very accurate position coupled with a large FOV can be obtained with the WFPC2. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. While the FOC image is time independent, the WFPC2 images must be performed when the parallatic displacement is expected to be maximum, i.e. near the spring and fall equinoxes.The FOC exposure has been added to the second pair of WFPC2 images in order to save acquisition time. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. NONE ------------------------------------------------------------------------------------ 8. Additional comments or special requests. NONE ------------------------------------------------------------------------------------ 9. Description of previous HST work. NO RESULTS YET. TWO PROPOSALS DEVOTED TO THE STUDY OF THE GEMINGA OPTICAL COUNTERPART HAVE BEEN APPROVED, NAMELY 2525 FOR CYCLE 1 AND 4593 FOR CYCLE 3. WHILE PROP.2525 WAS DEFERRED, PROP. 4593 WAS PARTIALLY CARRIED OUT BUT THE WFPC1 WAS NOT ABLE TO DETECT THE FAINT GEMINGA OPTICAL COUNTERPART. BECAUSE OF THE FAILURE TO DETECT THE SOURCE, PART OF THE OBSERVING TIME ALLOCATED TO PROPOSAL 4593 WAS GIVEN UP. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The Istituto di Fisica Cosmica has VAX and SUN WS equipped with MIDAS and IRAF (With STSDAS). Ph.D. students from the Istituto di Fisica of the Milan University normally take active part in the data analysis. Funds for the italian partecipants will be provided by the Agenzia Spaziale Italiana and by the CNR. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: GIOVANNI BIGNAMI Category: PI Institution: 6408 Address: City: State: Zip Code: Country: ITALY Telephone: 39-2-2367587 Telex (or e-mail): gfb@ifctr.mi.cnr.it ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5751 [ 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 STAR- A, 160 PLATE-ID = 001S, J2000 1 V = 25.3 +/- 0.2, E(B-V)=0.15 0633+1746 RA = 06H 33M 54.13S +/- 2 B = 26.5 +/- 0.5 GEMINGA 0.5", 1E0630+178 DEC = 17D 46' 12.43" +/- 0.5" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5751 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 3 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1400S 10 1 1 AT 21-SEP-94 +/- 0633+1746 7D CYCLE 4 GROUP 3-4.5 NO GAP SAME ORIENT FOR 3.5,4 AS 3 ------------------------------------------------------------------------------------------------------------------------------------ 3.5 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1500S 10 1 1 AT 21-SEP-94 +/- 0633+1746 7D CYCLE 4 GROUP 3-4.5 NO GAP SAME ORIENT FOR 3.5,4 AS 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1700S 10 1 1 CYCLE 4 0633+1746 ------------------------------------------------------------------------------------------------------------------------------------ 4.5 STAR- FOC/96 IMAGE 512X512 F342W 3360 1 5000S 10 2 1 CYCLE 4 0633+1746 ------------------------------------------------------------------------------------------------------------------------------------ 5 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1400S 10 1 1 AT 21-MAR-95 +/- 0633+1746 7D GROUP 5-6 NO GAP SAME POS FOR 5.5,6 AS 5 ORIENT 92.648D +/- 0D POS TARG .9, .9 CYCLE 4 / 5 - 6 ------------------------------------------------------------------------------------------------------------------------------------ 5.5 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1500S 10 1 1 AT 21-MAR-95 +/- 0633+1746 7D ------------------------------------------------------------------------------------------------------------------------------------ 6 STAR- WFPC2 IMAGE PC1 F555W 5407 1 1700S 10 1 1 0633+1746 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5751 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category NEUTRON STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AT 21-SEP-94 +/- 7D; CYCLE 4; GROUP 3-4.5 NO GAP; SAME ORIENT FOR 3.5,4 AS 3; AT 21-MAR-95 +/- 7D; GROUP 5-6 NO GAP; SAME POS FOR 5.5,6 AS 5; ORIENT 92.648D +/- 0D; POS TARG .9, .9; CYCLE 4 / 5 - 6; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F342W ------------------------------------------------------------------------------------------------------------------------------------ Target Names STAR-0633+1746 GEMINGA 1E0630+178 ------------------------------------------------------------------------------------------------------------------------------------