Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5387 Report Date: 18-Jul-95:17:16 Version: ********** Check-in Date: ********** 1.Proposal Title: CONSTRAINTS ON THE BOW SHOCK FROM A HIGH-VELOCITY NEUTRON STAR ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO Sub Category NEUTRON STARS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone James M. Cordes CORNELL UNIVERSITY USA (607) 255-0608 ------------------------------------------------------------------------------------ 7. Abstract Observations with the Wide Field Planetary Camera 2 in the H-ALPHA line aim at probing the spatial structure near the apex of a spectacular bow shock produced by a fast neutron star. The nebula was discovered with the Palomar 5-meter telescope and shows evidence for structure that is unresolved. Theoretically, there should be structure as fine as the resolution limit of the WFPC2 camera. Our goal is to image details of the bow shock close to the contact discontinuity so that we may solve for the three dimensional orientation of the nebula and, hence, the actual direction of motion of the pulsar. Through modeling of the geometry and flux measurements, and including the outcome of further ground based spectroscopy, and radio imaging, we can also put strong constraints on the distance. The net outcome should be a better understanding of the structure of pulsar driven bow shocks, constraints on density irregularities in the interstellar medium on length scales less than 0.001 par sec, and constraints on the content of relativistic pulsar winds. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.24 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5387 PI: James M. Cordes Proposal Title: CONSTRAINTS ON THE BOW SHOCK FROM A HIGH-VELOCITY NEUTRON STAR ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ James M Cordes 1810 USA Scott C Lundgren 1810 USA Roger W Romani 3490 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We will obtain high-resolution images of the head of the bow shock using the PC1 CCD of the WFPC2. A narrow H-ALPHA filter will be sensitive to the limb- brightened emission. A wider R-band filter will be used in a separate exposure and with the same orientation of the camera for the purpose of background subtraction. Placing the head of the bow shock in PC1 requires that the spacecraft be positioned so that the U3 axis is oriented at sky position angle +45 degrees (i.e. toward the north east) in order that the dimmer portions of the nebula (the guitar `body') fall on CCDs WF2, WF3, and WF4. We have calculated that a total of two hours be spent with the narrow H-ALPHA filter (F656N) and 12 minutes with the R-band filter (F675W). It is mandatory that the narrow and R- band images be obtained with the same camera orientation on the sky. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. In July 1992, we made H$\alpha$ observations at the Palomar 5 meter telescope of pulsar 2225+65 as part of a search for pulsar bow shocks. This pulsar displayed a spectacular guitar shaped bow shock. In addition to the image, we obtained a low resolution spectrum of the apex of the shock. The spectrum demonstrated that the shock is nonradiative, but could not resolve the details of the kinematics. We plan to obtain higher resolution spectra this year (1993) to solve for the kinematics. Our Very Large Array (VLA) images of the pulsar from 1985 and 1990 showed that it has a large proper motion, giving it a velocity of 1000 km/s or more depending on the distance, making it the fastest known star in the galaxy. To look for synchrotron emission from particles accelerated by the shock, we have obtained VLA data to form images at several frequencies (analysis in progress). We have requested ROSAT time to look for X-ray emission from the hot shocked gas. Only with the 0.1 arcsecond resolution available with WFPC2 on HST can we hope to constrain structure of near the apex of the PSR2225+65 bow shock. Such an observation will provide important information not available in any of the other observations done or planned. The size of the shock region is a crucial parameter in models of pulsar bow shock systems. Extrapolating models of the PSR1957+20 shock, the PSR2225+65 shock is expected to have a radius on the order of 100 AU at the tip. At its 1 kpc distance, that size makes the apex just resolvable with the upgraded HST. Finding or limiting its size will be an important test of current pulsar bow shock models. Even if we do not fully resolve the most compact component of the apex, we expect to measure sufficient detail in and near the apex that we will be able to tightly constrain the orientation of the nebula's axis and solve for the nebula and pulsar distance. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Page 3 ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Our second exposure uses the `R' filter F675W to obtain a continuum image that may be subtracted from the longer narrow H-ALPHA image. It is important that this subtraction remove the two stars that appear in or adjacent to the brighter portion of the bow-shock nebula. We have designated this as a CALIB exposure because the pointing is identical to that for the H-ALPHA imaging. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. none ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Cornell has a network of Sun workstations with IRAF and AIPS installed. Images will be analyzed on the PI's Sparc-10 worktation connected to the network. Stanford has comparable facilities for data reduction. At both institutions we have colleagues who are experts in astrophysical processes with whom we can confer. We have ample work space and access to Internet for facilitating the analysis of HST data, interpreting the results, and disseminating the results through preprints and journal articles. ------------------------------------------------------------------------------------ 11. Address Information Name: James M Cordes Category: PI Institution: 1810 Address: 520 Space Sciences Bldg. Cornell University City: Ithaca State: NY Zip Code: 14853 Country: USA Telephone: (607) 255-0608 Telex (or e-mail): cordes@astrosun.tn.cornell.edu ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5387 [ 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 NEB- A,160,905,922,929 RA = 22H 25M 52.24S +/- 2000 1 V=13.16 +/- 0.1 222552+65353 0.3S, 2 SURF-LINE(6563) = 1.1 +/- 0.3 E-17 1 GUITAR- DEC = +65D 35' 31.9" +/- 2" 2 W-LINE(6563) = 20 +/- 1 NEBULA 2 SIZE = 3.5 +/- 0.3 Comments: V IN FLUXVAL_1 IS FOR BRIGHTEST HST GUIDE STAR IN FIELD. FLUXNUM_2 VALUES ARE FOR DIFFUSE NEBULAR EMISSION THAT WE ARE TRYING TO MEASURE. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5387 [ 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 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 ORIENT 45D +/- 15D 222552+6535 CYCLE 4 / 1.0-2.51 31 ------------------------------------------------------------------------------------------------------------------------------------ 1.01 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 SAME ORIENT FOR 222552+6535 1.01-2.51 AS 1.00 31 ------------------------------------------------------------------------------------------------------------------------------------ 1.02 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 222552+6535 31 ------------------------------------------------------------------------------------------------------------------------------------ 1.5 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 POS TARG -1.592,- 222552+6535 1.592 31 ------------------------------------------------------------------------------------------------------------------------------------ 1.51 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 SAME POS FOR 1.51- 222552+6535 1.52 AS 1.50 31 ------------------------------------------------------------------------------------------------------------------------------------ 1.52 NEB- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 10 2 1 222552+6535 31 ------------------------------------------------------------------------------------------------------------------------------------ 2 NEB- WFPC2 IMAGE PC1 F675W CR-SPLIT=NO 1 180S 20 2 1 222552+6535 31 ------------------------------------------------------------------------------------------------------------------------------------ 2.01 NEB- WFPC2 IMAGE PC1 F675W CR-SPLIT=NO 1 180S 20 2 1 222552+6535 31 ------------------------------------------------------------------------------------------------------------------------------------ 2.5 NEB- WFPC2 IMAGE PC1 F675W CR-SPLIT=NO 1 180S 20 2 1 POS TARG -1.592,- 222552+6535 1.592 31 ------------------------------------------------------------------------------------------------------------------------------------ 2.51 NEB- WFPC2 IMAGE PC1 F675W CR-SPLIT=NO 1 180S 20 2 1 SAME POS FOR 2.51 222552+6535 AS 2.50 31 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5387 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.24 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category NEUTRON STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 45D +/- 15D; CYCLE 4 / 1.0-2.51 SAME ORIENT FOR 1.01-2.51 AS 1.00 POS TARG -1.592,-1.592 SAME POS FOR 1.51-1.52 AS 1.50 SAME POS FOR 2.51 AS 2.50 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F656N F675W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NEB-222552+653531 GUITAR-NEBULA ------------------------------------------------------------------------------------------------------------------------------------