Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5467 Report Date: 18-Jul-95:17:27 Version: ********** Check-in Date: ********** 1.Proposal Title: UV PROPERTIES OF THE HOT POST-NOVA GQ MUSCAE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO Sub Category ERUPTIVE BINARIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John S. Gallagher 3884 USA 608 263-2456 ------------------------------------------------------------------------------------ 7. Abstract Ten years after its 1983 eruption as a classical nova, GQ Muscae is still a luminous "supersoft" x-ray source, and is also a high amplitude optical variable. This combination of features can be understood if the white dwarf is continuing to burn hydrogen on tis surface and is heating the secondary component of the nova giving rise to optical light variations. Although this model is attractive, GQ Mus then stands out as being only recent classical nova to achieve a decade-long active lifetime. Thus the behavior of GQ Mus has important consequences for our understanding of the life cycles of classical novae. We propose to use the unique HST UV capabilities to measure key physical spectroscopic properties of this remarkable star. With the FOS we will obtain vacuum ultraviolet (VUV) spectrum to measure the continuum shape of the photosphere and thereby test the hot star model. The VUV spectrum will also allow us to measure the properties and possible varia- bility of emission lines. For example, a stellar wind is expected if this star is still undergoing nuclear burning in its envelope. We will examine our data for short term time dependent effects to study the relationship between the UV line and continuum variations and the optical. The results from the HST observations will be combined with ROSAT x-ray, VUV photometry, and optical data to build an understanding of an important cataclysmic variable system. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.45 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5467 PI: John S. Gallagher Proposal Title: UV PROPERTIES OF THE HOT POST-NOVA GQ MUSCAE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Hakki Ogelman 3884 USA Lea A. Shanley 3884 USA Marina Orio 6438 ITALY X ------------------------------------------------------------------------------------ 3. Description of proposed observations. The objective is to obtain time-resolved UV spectra of GQ Muscae. This object is located in the CVZ and it is therefore feasible to obtain unparalled observations by working during 4 orbits which corresponds to 4 optical variability cycles of this star. (The photometric period of GQ Mus is 85.5 minutes). We are segmenting our observations into 4 exposures, but in fact will be looking at the individual 4 minute spectra. Thus, if problems with scheduling CVZ time occurred, this would then allow observations to be made with these or longer exposure segments. This project requires a series of contiguous observations, that is to say we prefer to observe over about 4 orbits continuously. Grating 160L will be used to provide the necessary sensitivity and wavelength coverage. In this mode we predict a S/N of about 10/4 min. We are requesting observations over 3-4 photometric cycles of GQ Mus as it is critical in eruptive binary studies to be able to separate short term variability from effects which are truely synchronized with orbital phase. Also note that the nova is currently brighter than it will appear in the GSS catalog. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Phase resolved UV spectroscopy is necessary to make an unambiguous interpre- tation of our ongoing ROSAT observations and will give important clues to why this nova has remained bright in soft x-rays for much longer than other novae. The VUV is also an important compliment to optical observations which are known to show high amplitude variability. Optical spectra do NOT give equivalent information to VUV observations. First, the optical is more strongly influenced by re-processed radiation than the VUV. Second, optical lines in hot systems arise in high levels of high ionization potential species, such as He II or N III, and do not have the same sensitivity to winds as is found in the VUV spectral region. Detection of and character- ization of the wind from the stellar remnant will be an important step in understanding remnant evolution. HST observations are necessary because GQ Mus is too faint for IUE. As the object is in a post-nova evolutionary phase, we cannot expect the system to continue in tis present state for an indefinite time, and it is therefore important to obtain HST UV spectroscopy within the next year. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. THIS IS A CVZ TARGET We prefer that the observations be uninterupted so that we can cover sequential orbits. If this is not feasible, we can accept interupted data. If scheduling constraints require that the object cannot be scheduled in CVZ, we will accept data with equivalent spacecraft orbits, roughly 3, during maximum unocculted time with reaquistions at each orbit. Obviously, CVZ is our first priority. Note that the rest of the form is filled out under the assumption of CVZ observations. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Page 3 ------------------------------------------------------------------------------------ 8. Additional comments or special requests. NOTE THAT THIS IS A CVZ TARGET To advance scheduling, the observations have been reworked with Director`s Office approval for non-CVZ. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Gallagher is a co-I on the G02389 Cycle 1 study of young super star clusters in nearby violently star-forming galaxies. He is also a Co-I on the G03532 Cycle 2 program to observe the distri- bution and colors of star clusters in the near edge-on southern spiral galaxy NGC 5170. None of these programs is scientifically related to this project. G02389: Data analysis for NGC 1569 and NGC 1705 is nearly complete. This is VERY complex due to the small sizes of the super-star clusters and the effects of aberrations on the PSF. We are finding that young (t<30 Myr) super-clusters are indeed globular cluster-like in their compactness. The existence of such objects implies the existence of high efficiency mode of star formation in violently star-forming low mass galaxies. Later this year we will work on the more complex cases presented by the observations of NGC 1140 and M82. G03532: Observations have been obtained. Data reduction and analysis will begin this fall. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). MADRAF and its associated cluster of DECStation 5000 and Alpha machines will be available to support data reduction and analysis tasks. UW Astronomy graudate student Lea Shanley will be involved in this project, which we plan to become part of her PhD thesis project. We also have ROSAT observations of GQ Muscae and will be communicating with the HSP group about their photometric results for GQ Muscae. ------------------------------------------------------------------------------------ 11. Address Information Name: John S. Gallagher Category: PI Institution: 3884 Address: Dept. of Astronomy, 5534 Sterling Hall University of Wisconsin 475 North Charter St City: Madison State: WI Zip Code: 53706 Country: USA Telephone: (608) 263-2456 Telex (or e-mail): jsg@jayg.astro.wisc.edu ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5467 [ 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 GQ-MUS NOVA- A,150,162,161 RA = 11H 52M 2.543S +/- 2000 1 F-CONT(1500) = 3 +/- 1.5 E-15 MUSCAE1983 0.17S, GQ-MUSCAE DEC = -67D 12' 19.97" +/- 1.0", PLATE-ID=06AG Comments: THIS IS A CVZ TARGET THIS TARGET IS VARIABLE. OBSERVING PROGRAM AND EXPOSURE TIME ARE DESIGNED TO STUDY VARIABILITY. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5467 [ 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 GQ-MUS FOS/BL ACQ/ 4.3 MIRROR SCAN-STEP- 1 2.0S 1 1 CYCLE 4 / 1.0 - PEAK Y=1.204 1.2 SEARCH-SIZE-X=1 ONBOARD ACQ FOR SEARCH-SIZE-Y=3 1.1 Comments: VARIABLE TARGET ------------------------------------------------------------------------------------------------------------------------------------ 1.1 GQ-MUS FOS/BL ACQ/ 1.0 MIRROR SCAN-STEP- 1 6.0S 1 1 ONBOARD ACQ FOR PEAK X=.172 1.15 SCAN-STEP- Y=.172 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 Comments: VARIABLE TARGET ------------------------------------------------------------------------------------------------------------------------------------ 1.15 GQ-MUS FOS/BL ACQ/ 0.5 MIRROR SCAN-STEP- 1 12S 1 1 ONBOARD ACQ FOR PEAK X=.172 1.2 SCAN-STEP- Y=.172 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 Comments: VARIABLE TARGET ------------------------------------------------------------------------------------------------------------------------------------ 1.2 GQ-MUS FOS/BL ACCUM 1.0 G160L 4 54M 1 1 NON-INT Comments: VARIABLE TARGET LONGER EXP TIME OKAY CONTIGUOUS ORBITS PREFERRED ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5467 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.204 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-X=.172 SCAN-STEP-Y=.172 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.45 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ERUPTIVE BINARIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 1.0 - 1.2; ONBOARD ACQ FOR 1.1; ONBOARD ACQ FOR 1.15 ONBOARD ACQ FOR 1.2 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names GQ-MUS NOVA-MUSCAE1983 GQ-MUSCAE ------------------------------------------------------------------------------------------------------------------------------------