! File: 3003C.PROP ! Database: PEPDB ! Date: 18-FEB-1994:09:48:31 coverpage: title_1: RECOVERY OF THE HISTORICAL NOVA IN M80 sci_cat: STELLAR ASTROPHYSICS proposal_for: SAT/FOS pi_title: PROF. pi_fname: BRUCE pi_lname: MARGON pi_inst: WASHINGTON, UNIVERSITY OF pi_country: USA pi_phone: 206-543-0089 keywords_1: NOVA, GLOBULAR CLUSTER hours_pri: 5.40 num_pri: 3 wf_pc: X foc: X fos: X pi_position: CHAIR AND PROFESSOR ! end of coverpage abstract: line_1: Imaging and spectroscopy will be used in an attempt to recover the line_2: historical nova in the globular cluster M80. This nova is within line_3: a few arc seconds of the cluster core, and thus recovery is not line_4: currently feasible from the ground. The proposed observations line_5: will also more generally test the feasibility of both HST line_6: spectroscopy and imaging (UV and optical) in crowded fields. ! ! end of abstract general_form_proposers: lname: BEAVER fname: EDWARD inst: UC, SAN DIEGO country: USA ! lname: BURBIDGE fname: E. MARGARET inst: UC, SAN DIEGO country: USA ! lname: MARGON fname: BRUCE inst: WASHINGTON, UNIVERSITY OF country: USA ! lname: ANGEL fname: J. ROGER mi: P. inst: ARIZONA, UNIVERSITY OF country: USA ! lname: BARTKO fname: FRANK inst: MARTIN MARIETTA CORPORATION country: USA ! lname: DAVIDSEN fname: ARTHUR mi: F. inst: JOHNS HOPKINS UNIVERSITY country: USA ! lname: HARMS fname: RICHARD mi: J. inst: APPLIED RESEARCH CORPORATION country: USA ! lname: BOHLIN fname: RALPH inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: FORD fname: HOLLAND mi: C. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The proposed observations will test the feasiblity of both line_2: spectroscopy and imaging (both optical and UV) in crowded fields line_3: through an attempt to recover the historical nova in the globular line_4: cluster M80. A wide variety of observing programs currently line_5: planned for HST rely on taking FOC or WF/PC images as EARLY ACQs line_6: for follow-up spectroscopy in confused or crowded fields. Due to line_7: the present HST image quality, there is considerable uncertainty line_8: about the feasiblity of such programs. A major hope in this regard line_9: is that (in certain situations), much of the original spatial line_10: resolution of such EARLY ACQ images can be recovered via image line_11: deconvolution/reconstruction techniques. It is especially those line_12: cases of high color contrast (e.g, a UV object in a field of red line_13: stars) that hold the most promise for these techniques. line_14: Additionally, spectra taken through small apertures in a line_15: wavelength regime where there is high color contrast between the line_16: object of interest and the confusing background, may also still line_17: allow much of the original science to be accomplished despite the line_18: currently reduced capability for spatially resolved spectra. line_19: Globular clusters (hereafter, GCs) provide an excellent line_20: end-to-end test of such difficult imaging/spectroscopic programs. line_21: The large number of stars available allows an accurate empirical line_22: characterization of the PSF, and deconvolution/reconstruction ! question: 2 section: 2 line_1: techniques seem to work quite well in GCs. The range in magnitudes line_2: of the stars available allow useful tests on how faint one can line_3: push such image deconvolution/reconstruction techniques. Because line_4: much of the light from a typical GC is rather red (e.g., because line_5: of the dominance of K giants), even the SPECTRA of UV objects may line_6: also be obtainable in crowded fields: the "background" from red line_7: stars being substantially suppressed at these UV wavelengths. line_8: Among the UV globular cluster objects of particular interest are line_9: those with bright accretion disks, such as are found in close, line_10: mass-transfer binaries (e.g., see GTO proposal no. 1053, from line_11: which this SAT proposal is largely derived). line_12: Recent theoretical work suggests that a small number of close line_13: binaries (defined here to be binaries with orbital periods of a line_14: few days or less) may dominate the dynamic evolution of GCs (e.g., line_15: Elson et al. 1987). Because of their high BINARY orbital line_16: velocities, just a handful of such close binaries in a GC can line_17: store as much kinetic energy as the combined kinetic energy line_18: associated with the CLUSTER orbital motions of all 100,000 line_19: single stars in the GC. This binary-orbital energy may be line_20: liberated by three-body encounters of single stars with the line_21: binaries, and is likely to be the dominant source of kinetic line_22: energy needed to counterbalance the kinetic energy sinks of stars ! question: 2 section: 3 line_1: escaping from the GC. The GC binaries may be primordial, or may line_2: have formed later through encounter processes, especially during line_3: collapse of the cluster core. Elson et al. have pointed out the line_4: analogy of this energy source to thermonuclear fusion in stars: in line_5: this case, the GC collapses, forms binaries, and then "burns" the line_6: orbital kinetic energy via encounters. Although this provides an line_7: elegant theoretical picture, from an observational point of view, line_8: it should be noted that there are only a handful of confirmed line_9: close binaries known in GCs. Thus it remains highly desirable to line_10: observationally confirm some of the suspected, but less secure, line_11: candidate close binaries in globular clusters. line_12: A particularly interesting candidate GC close binary is the line_13: historical nova in M80, reported to have undergone an outburst in line_14: 1860 (Pogson 1860, Luther 1860). Nova T Sco attained a visual line_15: magnitude of about 7 in M80 in 1860, and this event occurred line_16: (apparently) quite near the core of the GC (within a few arc line_17: seconds). This central field is sufficiently crowded that line_18: ground-based recovery has not proved feasible. line_19: The proposed HST images will be used to identify the old nova line_20: from its expected UV color and H-alpha emission. If a nova shell line_21: is present (which might be seen in the light of H-alpha), an line_22: expansion parallax may also be determinable, yielding an accurate ! question: 2 section: 4 line_1: distance to both the nova, and by its membership, the GC. For line_2: these reasons, we have chosen to take F220W, F342W and F430W line_3: images with the FOC plus an F656N image with the PC. As discussed line_4: below, we also propose to take a PC image with F230W for a direct line_5: comparison of the UV imaging capabilities of the two cameras. The line_6: FOC and PC images will be examined to precisely locate a candidate line_7: of unusual color relative to other GC stars in the field. The old line_8: nova is expected to be UV compared with other GC stars (e.g., the line_9: other historical nova in a GC, located in M14, is known to be line_10: relatively ultraviolet; see discussion by Shara et al. 1986, 1990). line_11: Recovery of the nova in M80 may require use of sophisticated image line_12: deconvolution/reconstruction techniques; as noted above the M80 line_13: nova is displaced from the core by only a few arc sec, and so the line_14: crowding is quite high. Unfortunately, image line_15: deconvolution/reconstruction requires very high S/N, at least of line_16: order S/N=30 (Evans, private communication). We have chosen line_17: integration times of 2500s each in F342W and F430W to achieve such line_18: a S/N for the nova (assuming its B magnitude is about 19-20), line_19: while retaining an expected spatial resolution (after line_20: deconvolution/reconstruction) of at least 0.1-0.2". The F656N, line_21: H-alpha image will provide essential, strong confirmation of the line_22: candidate, and is needed to search for a possible nova shell. The ! question: 2 section: 5 line_1: 2500s exposure time chosen for the H-alpha image will provide line_2: comparable S/N, but at a poorer effective spatial resolution of line_3: about 0.2"-0.3" (i.e., we will have to further bin pixels to line_4: recover high S/N if deconvolution/reconstruction is required for line_5: the H-alpha image). line_6: Because the crowding is large at the cluster core, we also line_7: propose to exploit (and explore) the near-UV imaging capabilities line_8: of HST. This is a reasonable approach in the case of M80 because line_9: the reddening is quite modest. In this case, we propose UV images line_10: with the FOC using filter F220W and with the PC using filter F230W. line_11: The idea is to more fully exploit (and test) the UV capabilities line_12: of HST by looking for a UV bright nova in a field of UV-weak stars line_13: (i.e, red K giants); the expected extreme color contrast in the UV line_14: should further aid in the recovery of the nova. Once again, we line_15: have chosen an exposure time of 2500s for the FOC F220W UV image; line_16: as described above for the H-alpha image, such an exposure time line_17: should provide adequate S/N for deconvolution/reconstruction, but line_18: only at a reduced effective spatial resolution of 0.2-0.3". The PC line_19: image with F230W (taken with the same integration time) will allow line_20: for a direct comparison between FOC and WF/PC imaging capabilities line_21: in the UV. Many of our other GTO programs (e.g., proposal no. line_22: 1052) in addition to GTO no. 1053, rely heavily on such UV images, ! question: 2 section: 6 line_1: and we need to understand the trade-offs between FOC vs. PC early line_2: in the program. line_3: A 2500sec confirming prism spectrum with the FOS will follow line_4: after a candidate has been selected from the FOC and PC images. line_5: Based on results from the FOS Simulator (corrected for the line_6: existing poorer HST PSF), we expect to get a peak S/N in the line_7: continuum of order 10 in such a 2500s exposure for a nova with line_8: B=19-20. However, this estimate is somewhat uncertain, since we line_9: don't (a priori) know how ultraviolet the nova candidate will line_10: actually turn out to be, nor how serious the crowding. We will use line_11: the 0.5" aperture rather than the 1" aperture to limit line_12: "background" contamination from the nearby stars. This prism line_13: spectrum includes the spectral range of about 2200-7000A, and line_14: should provide strong spectral confirmation of the candidate line_15: chosen from the images; e.g., we expect to see strong Balmer as line_16: well as UV emission lines. Especially in the UV portion of the line_17: spectrum, we expect a marked improvement over any currently line_18: possible ground-based spectrum because of significant reduction in line_19: contamination from nearby stars (precise positioning and a small line_20: aperture), and because of expected strong suppression of the line_21: contaminating (red) background light in the UV. ! question: 3 section: 1 line_1: FOC and WF/PC images of globular cluster nova will be line_2: obtained as EARLY ACQ for FOS spectra. ! question: 5 section: 1 line_1: The SV prerequisite programs for all FOS observations in line_2: this program are: line_4: Prop ID 2195..FOS Target Acquisition Tests...first line_5: successful binary search acquisition. ! question: 7 section: 1 line_1: Data reduction will be performed at the ST ScI, and the analysis will be line_2: performed using FOS IDT computer facilities. ! question: 8 section: 1 line_1: Candidate for spectroscopy will all appear in FOC and WF/PC images. If line_2: identical guide stars are available for both observations, FOS acquisition line_3: could be significantly faster and more reliable. If not, we will offset from line_4: arbitrary anonymous bright stars in field. ! question: 10 section: 1 line_1: Data analysis, research assistant support, and funding will be provided under line_2: NASA's FOS GTO contract(s). ! !end of general form text general_form_address: lname: MARGON fname: BRUCE category: PI inst: UNIVERSITY OF WASHINGTON addr_1: ASTRONOMY DEPARTMENT, FM-20 city: SEATTLE state: WA zip: 98195 country: USA phone: 206 543-0089 telex: 4740096 ! lname: DOWNES fname: RONALD category: CON inst: UC, SAN DIEGO addr_1: GODDARD SPACE FLIGHT CENTER addr_2: CODE 936 city: GREENBELT state: MD zip: 20771 country: USA phone: 301 286-4384 ! lname: ANDERSON fname: SCOTT category: CON inst: UNIVERSITY OF WASHINGTON addr_1: ASTRONOMY DEPARTMENT, FM-20 city: SEATTLE state: WA zip: 98195 country: USA phone: 206 685-2392 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: NGC6093 name_2: M80 descr_1: GLOBULAR CLUSTER WITH OLD NOVA, pos_1: RA =16H 41M 03.4S +/- 0.5S, pos_2: DEC= -22D 51' 09.2" +/- 1.0" equinox: 1950 comment_1: COORDINATES FROM A.J. 91,312,1986. fluxnum_1: 1 fluxval_1: SURF(V) = 14.4 +/- 0.5 ! targnum: 2 name_1: NGC6093-OFFSET descr_1: OFFSET STAR FOR TA pos_1: TBD-EARLY, pos_2: RA= 16H 41M 03.4S +/- 0.1M, pos_3: DEC = -22D 51' 09.2" +/- 1.5' equinox: 1950 ! targnum: 3 name_1: NGC6093-NOVA descr_1: OLD NOVA IN GLOBULAR CLUSTER pos_1: TBD-EARLY, pos_2: RA-OFF = 0S +/- 4.01S, pos_3: DEC-OFF = 0" +/- 60", pos_4: FROM 2 equinox: 1950 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: FOC targname: # config: FOC/48 opmode: IMAGE aperture: 512X512 sp_element: F342W wavelength: 3377 num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 req_1: SEQ 1-5 NO GAP; ! linenum: 2.000 sequence_1: ^ targname: ^ config: ^ opmode: ^ aperture: ^ sp_element: F430W wavelength: 3920 num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 ! linenum: 3.000 sequence_1: ^ targname: ^ config: ^ opmode: ^ aperture: ^ sp_element: F220W wavelength: 2239 num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 ! linenum: 4.000 sequence_1: ^ targname: ^ config: PC opmode: IMAGE aperture: ALL sp_element: F656N wavelength: 6559 num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=0.1, param_2: CR-TOLERANCE=0.1 ! linenum: 5.000 sequence_1: ^ targname: ^ config: ^ opmode: ^ aperture: ^ sp_element: F230W wavelength: 2297 num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=0.1, param_2: CR-TOLERANCE=0.1 comment_1: FOC AND PC PICTURES FOR NOVAE. ! linenum: 6.000 sequence_1: DEFINE sequence_2: OFFSET targname: # config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 1.40S fluxnum_1: 1 priority: 1 comment_1: ACQUIRE OFFSET STAR. comment_2: THE EXPOSURE TIME WILL BE comment_3: UPDATED ONCE THE OBJECT IS comment_4: FOUND ON THE FOC/PC IMAGE. ! linenum: 7.000 sequence_1: DEFINE sequence_2: IDGOOD targname: # config: FOS/RD opmode: ACCUM aperture: 0.5 sp_element: PRISM num_exp: 1 time_per_exp: 2500S fluxnum_1: 1 priority: 1 ! linenum: 8.000 sequence_1: USE sequence_2: FOC targname: NGC6093 req_1: EARLY ACQ FOR 9-10; req_2: CYCLE 0 / 8-10; ! linenum: 9.000 sequence_1: USE sequence_2: OFFSET targname: NGC6093-OFFSET req_2: AFTER 8 BY 60D +/- 15D; ONBOARD ACQ FOR req_3: 10; comment_1: BLIND OFFSET TO OBJECT. ! linenum: 10.000 sequence_1: USE sequence_2: IDGOOD targname: NGC6093-NOVA comment_1: NGC 6093 (NOVA T SCO) ! ! end of exposure logsheet ! No scan data records found