Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5377 Report Date: 18-Jul-95:17:15 Version: ********** Check-in Date: ********** 1.Proposal Title: UV OBSERVATIONS OF PULSARS: CYCLE4MEDIUM ------------------------------------------------------------------------------------ 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 France A. Cordova 3150 USA 814-865-0418 ------------------------------------------------------------------------------------ 7. Abstract We propose to make UV observations of three nearby pulsars - PSR 0656+14, PSR 0950+08 and PSR 1929+10. The former one is a relatively young soft X-ray pulsar which shows the highest intensity of the soft X-ray flux and has a thermal-like spectrum. The latter two are the nearest old radio and soft X-ray pulsars. None of these objects have been imaged in the UV. Preliminary estimates of their surface temperatures, made with the aid of X-ray observations and theoretical cooling scenarios, indicate they should be sufficiently hot objects, and their thermal-like UV radiation should be observable with the HST Faint Object Camera. The UV spectra, together with the soft X-ray spectra, will be fitted with a new generation of neutron star atmosphere models that we are developing. This will allow us to determine parameters of the atmospheres (effective temperature, magnetic field, chemical composition), to study the thermal evolution of neutron stars and to investigate properties of the super-high-density matter in their interiors. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.25 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5377 PI: France A. Cordova Proposal Title: UV OBSERVATIONS OF PULSARS: CYCLE4MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ France A. Cordova 3150 USA George G. Pavlov 3150 USA Guy S. Stringfellow 3150 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to use FOC/96 for detection of the nearby pulsars 0656+14, 0950+08 and 1929+10. These objects have not yet been detected in the optical/UV range so that actual values of their fluxes are unknown. To detect them firmly and to evaluate the total UV flux, we propose to use the long pass F130LP filter (the filter is used to cut off the airglow background). To estimate the exposure times, we used ROSAT data and neutron star atmosphere models. The models yield optical/UV fluxes close to Rayleigh-Jeans fluxes corresponding to surface temperatures of the neutron stars. Extending the soft X-ray spectrum of PSR 0656+14 down to the UV range yields an estimate U=26.5-27.5 (Anderson et al., 1993, Ap.J., 414, 867). The 85 min exposure with F130LP would then provide a signal-to-noise ratio S/N=7-14 (at n=21 pixels). This estimate is obtained assuming a background rate R_B/n=0.002 counts/s/pix. The main contribution to the background comes from the zodiacal light; its intensity was assumed to be 200 S10 units, which is close to the maximum value over a half-year period when the difference between the target ecliptic longitude (105D) and the longitude of the Sun exceeds 90D. ROSAT data available on the old cooler pulsars 0950+08 and 1929+10 give only upper limits on their surface temperatures. We chose the same exposures for these, which would allow significant detections if the temperatures are 100000 and 200000 K, respectively. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. All the proposed objects are expected to be so hot that they are brighter in the UV range unobservable from the ground. The old pulsars, 0950+08 and 1929+10, are too faint, V > 27 - 28, for ground-based or other space observations. At least, all attempts to detect the radio pulsars with ground-based telescopes (Perriman et al., 1989, Astron. Astrophys, 215, 195; Van Kerkwijk, 1992, private communication) have been so far unsuccessful. For PSR 0656+14 only limiting magnitudes, R > 23 and V > 25, are known. Thus the presently proposed FOC observations are justified on the basis of the need to obtain ULTRAVIOLET imaging at wavelengths as short as 1300 A, and to ensure that the source is detected with a S/N ratio high enough to measure the broadband spectrum of the object and to constrain the surface temperature of the neutron star. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. To reach the faint source limit with the F130LP filter which is sensitive to 1304 A airglow, we request nighttime observations for all three exposures. Since the targets lie at low ecliptic latitudes (-8.5D, -4.6D and 32.3D for 0656+14, 0950+08 and 1929+10, respectively) where the zodiacal light is rather intense, it is very desirable to observe in seasons when the ecliptic longitudes of the targets (105D, 145D and 297D, respectively) are sufficiently far from the longitude of the Sun. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. F. Cordova is a Co-I on the HST proposals: ID 3578, "Line Eclipse Mapping of an Accretion Disk Wind", ID 3579, "The UV Orbital Light Curve of the X-ray Binary X 1822-371". G. Stringfellow is a Co-I on the HST proposal: ID 2590, "Deep Imaging of the Site of SN 1961V". These observations are not related to the present project. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Penn State's Astronomy and Astrophysics department will provide computing capabilities including a network of Sun workstations connected by Ethernet, as well as access to mainframes and supercomputers outside the department. ------------------------------------------------------------------------------------ 11. Address Information Name: FRANCE A. CORDOVA Category: PI Institution: 3150 Address: DEPARTMENT OF ASTRONOMY AND ASTROPHYSICS 525 DAVEY LABORATORY City: UNIVERSITY PARK State: PA Zip Code: 16802 Country: USA Telephone: 814-865-0418 Telex (or e-mail): cordova@astro.psu.edu ------------------------------------------------------------------------------------ Name: DAVID H. LUMB Category: CON Institution: 3150 Address: DEPARTMENT OF ASTRONOMY AND ASTROPHYSICS 525 DAVEY LABORATORY City: UNIVERSITY PARK State: PA Zip Code: 16802 Country: USA Telephone: 814-863-6041 Telex (or e-mail): dlumb@astro.psu.edu ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5377 [ 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 PSR0656+14 A,160 RA = 6H 59M 48.148S +/- J2000 1 V=28.3 +/- 1, E(B-V)= 0.02 +/- 0.004S, 2 0.02 DEC = +14D 14' 21.31" +/- 2 B-V= -0.3 +/- 0.1, U-B= -1.1 +/- 0.04" 3 0.2 A(U)= 0.15 +/- 0.1 F(3450)= 7 +/- 6 E-20 ------------------------------------------------------------------------------------------------------------------------------------ 2 PSR0950+08 A,160 RA = 9H 53M 09.326S +/- J2000 1 V=28.4 +/- 2, E(B-V)=0.01 +/- 0.01 0.008S, 2 B-V= -0.3 +/- 0.1, U-B= -1.1 +/- DEC = +7D 55' 35.91" +/- 2 0.2 0.09" 3 A(U)= 0.05 +/- 0.05 F(3450)= 7 +/- 6 E-20 ------------------------------------------------------------------------------------------------------------------------------------ 3 PSR1929+10 A,160 RA = 19H 32M 13.924S +/- J2000 1 V=28.2 +/- 2, E(B-V)= 0.1 +/- 0.05 0.009S, 2 B-V=0.2 +/- 0.1, U-B=1.0 +/- 0.2 DEC = +10D 59' 32.07" +/- 2 A(U)= 0.5 +/- 0.3 0.19" 3 F(3450)= 7 +/-6 E-20 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5377 [ 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 PSR0656+14 FOC/96 IMAGE 512X512 F130LP 1 85M 10 3 1 CYCLE 4 DARK TIME AT 5-JAN-95 +/- 90D Comments: THE EXPOSURE MAY BE TAKEN ALSO BEFORE 5-APR-1994, I.E., REQ_3 CAN BE REPLACED BY "AT 18-MAR- 94 +/- 18D". THE LATTER PERIOD IS CHOSEN ASSUMING CYCLE 4 STARTS AT 1-MAR-94. ------------------------------------------------------------------------------------------------------------------------------------ 2 PSR0950+08 FOC/96 IMAGE 512X512 F130LP 1 85M 10 3 2 CYCLE 4 DARK TIME AT 1-MAR-94 +/- 75D Comments: REQ_3 CAN BE REPLACED BY "AT 15 -FEB-95 +/- 90D". ------------------------------------------------------------------------------------------------------------------------------------ 3 PSR1929+10 FOC/96 IMAGE 512X512 F130LP 1 85M 10 3 2 CYCLE 4 DARK TIME AT 19-JUL-94 +/- 140D Comments: THE EXPOSURE MAY BE TAKEN ALSO AFTER 1-MAR-95, I.E., REQ_3 CAN BE REPLACED BY "AT APR-10-95 +/ - 41D". THE LATTER PERIOD IS CHOSEN ASSUMING CYCLE 4 IS COMPLETED AT 1-JUL-95. ------------------------------------------------------------------------------------------------------------------------------------ 4 PSR1929+10 FOC/96 IMAGE 512X512 F130LP 1 1449S 10 3 2 CYCLE 4 AT 19-JUL-94 +/- 20D Comments: SCIENCE SHOULD BE DONE IN DARK TIME; ------------------------------------------------------------------------------------------------------------------------------------ 4.1 PSR1929+10 FOC/96 IMAGE 512X102 F430W PIXEL=50X25 1 10M 10 3 2 CYCLE 4 4 AT 19-JUL-94 +/- 140D ------------------------------------------------------------------------------------------------------------------------------------ 4.2 INTFLAT FOC/96 RESEAU 512X102 F430W PIXEL=50X25 1 5M 10 3 2 CYCLE 4 4 LED=GREEN-2 AT 19-JUL-94 +/- LED-STEP=32 140D ------------------------------------------------------------------------------------------------------------------------------------ 4.3 INTFLAT FOC/96 RESEAU 512X512 F430W PIXEL=25X25 1 5M 10 3 2 CYCLE 4 LED=GREEN-2 AT 19-JUL-94 +/- LED-STEP=96 140D ------------------------------------------------------------------------------------------------------------------------------------ 5 PSR1929+10 FOC/96 IMAGE 512X512 F342W 1 61M 10 3 2 CYCLE 4 DARK TIME AT 19-JUL-94 +/- 20D ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5377 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE RESEAU ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=50X25 LED=GREEN-2 LED-STEP=32 PIXEL=25X25 LED-STEP=96 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.25 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category NEUTRON STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; DARK TIME; AT 5-JAN-95 +/- 90D AT 1-MAR-94 +/- 75D AT 19-JUL-94 +/- 140D AT 19-JUL-94 +/- 20D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F130LP F430W F342W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PSR0656+14 PSR0950+08 PSR1929+10 ------------------------------------------------------------------------------------------------------------------------------------