Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4315c Report Date: 09-May-96:19:31 Version: ********** Check-in Date: ********** 1.Proposal Title: CIRCUMSTELLAR MATERIAL AROUND SUPERNOVAE: CYCLE3MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO Sub Category SN & SNR ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Prof. Alexei V. Filippenko UC-BERKELEY USA ------------------------------------------------------------------------------------ 7. Abstract The interaction of a supernova (SN) shock wave with the remnants of the stellar wind of the progenitor can sometimes provide enough energy to sustain the SN luminosity for several years. Optical data, supplemented with radio and X-ray observations, of certain Type II SNe a few years past explosion strongly favor such an interpretation over other possible energy sources, such as a pulsar or long-lived radioactive isotopes. The UV spectrum is a powerful diagnostic for probing the conditions in the shock and the shocked material. We propose to observe SN 1988Z, the brightest and most recent member of this group. Due to its extensive radio and optical data records, it is particularly suited for an investigation of the interaction between ejecta and circumstellar gas. FOS spectra will be obtained. The UV fluxes will be used to test theoretical models of the interaction; the C IV line is predicted to be 3 times the strength of H-alpha, which will be measured from the ground. Optical and near-UV (UBVRI) images will be obtained with the PC to determine background contamination corrections for previous ground-based photometry, to measure accurate current magnitudes, and to investigate the local stellar population near the SN. HST observations of this object will shed light on the physical characteristics of its shock, as well as on the mass-loss history of its progenitor star. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 2.85 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4315c PI: Prof. Alexei V. Filippenko Proposal Title: CIRCUMSTELLAR MATERIAL AROUND SUPERNOVAE: CYCLE3MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Alexei V. Filippenko UC-BERKELEY USA Roger A. Chevalier UNIVERSITY OF VIRGINIA USA Robert A. Fesen DARTMOUTH COLLEGE USA Claes Fransson STOCKHOLM OBSERVATORY SWEDEN X Robert P. Kirshner CENTER FOR ASTROPHYSICS USA Bruno Leibundgut UC-BERKELEY USA X Thomas Matheson UC-BERKELEY USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Since the allocated time is considerably less than requested, we will obtain data only for SN 1988Z (z = 0.022); the TAC said SN 1988Z is mandatory. We will obtain broad-band optical and near-UV images, and UV spectra. The broad-band images will be used to measure precise magnitudes and colors of the SN, to characterize the local environment of the SN (e.g., HII regions, old stellar populations, etc.), and to quantify the extent to which sources close to the SN contaminate our ground-based measurements at late times. FOS spectra will allow us to measure many emission lines and determine the shape of the continuum, for comparison with the results of theoretical models. The broad-band optical images will be obtained with the PC. The use of five standard bands will permit direct comparisons with normal stars and other SNe observed with HST: F336W (U), F439W (B), F555W (V), F702W (R), and F785LP (I). The U-band PC image replaces the originally requested FOC F152M image, since the latter would be very time consuming and the TAC allocated only 5 total hours. The FOS spectra of SN 1988Z will be obtained with the following settings: (1) FOS, G130H grating, 1150-1608 A, 1.0 A/diode, blue digicon. (2) FOS, G190H grating, 1573-2323 A, 1.5 A/diode, red digicon. (3) FOS, G270H grating, 2227-3306 A, 2.1 A/diode, red digicon. The high-resolution gratings are needed to readily distinguish the moderately narrow lines from the SN (FWHM 1500-2000 km/s) from the narrower (unresolved; FWHM less than 100 km/s) emission lines contributed by underlying HII regions. A circular aperture 1" in diameter will be used to exclude the brightest HII region, whose centroid is 1.5"-2" away from SN 1988Z. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The optical ground-based images obtained of SN 1988Z are contaminated, to some extent, by adjacent HII regions and star clusters in the parent galaxy. Given the far higher spatial resolution achievable with HST (even in its currently aberrated state), we will be able to quantify the contamination. This will allow us to correct our ground-based magnitudes of SN 1988Z obtained at late times. Moreover, the HST images will provide optical magnitudes and colors at the present epoch for this faint object. UV spectra of SN 1988Z cannot be obtained with IUE; it is too faint, and the IUE aperture would include bright adjacent contaminating sources. The FOS spectra are of crucial importance for testing theoretical models of the interaction of supernova ejecta with dense circumstellar gas (Fransson & Chevalier 1992). No other SN in recent years provides such a good opportunity for exploring an important new area in SN research, and it is unlikely that an equally promising candidate will be found in the next few years. SN 1988Z has been observed extensively from the ground by the PI and several Co-Is. We anticipate combining the HST data with these results. We are in an excellent position to make substantial progress in understanding this interesting and important object; all we lack are the HST data. The estimated broad-band V mag of SN 1988Z at the time of observation is m = 22. Consider the F785LP filter (I). From the WFPC handbook, we find that the integral of QT dl/l is 0.021 for PC6, and we calculate 8.46 counts/s. However, only about 1/5 of these (i.e., 1.69 counts/s) will fall in the compact core of the HST PSF. For S/N = 26, we require 400 s. Similarly, t = 300 s is required for S/N = 40 with the F702W filter (R), t = 350 s for S/N = 38 with the F555W filter (V), t = 500 s for S/N = 19 with the F439W filter (B), and t = 1300 s for S/N = 18 with the F336W filter (U). The H-alpha flux of SN 1988Z was 2 X 10**-14 erg/s/cm**2 in January 1992, and dropping relatively slowly. The predicted C IV flux is 6 X 10**-14. SN 1988Z has a very low UV extinction; perhaps the C IV line is down by a factor of 1.5. If the flux drops and additional factor of 1.5 by the time the data are taken, the expected flux will be 2.6 X 10**-14 erg/s/cm**2. We wish to study lines a factor of 10 fainter than this, or 2.5 X 10**-15 cgs. Consider first the G130H filter, with the blue digicon, at 1400 A. The efficiency is 0.007 and the throughput of the 1" circular aperture is 0.27. Using eq. 2 of Table 1.2.1, we find that the line count rate is 0.016/s. The dark current is comparable to this. For S/N = 6 in the line, we need 75 min. G190H grating + red dig, at 1900 A: efficiency 0.035, throughput 0.33. Thus, we detect 0.13 counts/s. To get S/N = 16, we need 33 minutes. G270H grating + red dig, at 2800 A: efficiency 0.08, throughput 0.38. Thus, we detect 0.50 counts/s. To get S/N = 20 in an emission line, we require about 15 minutes. The total time for the FOS spectroscopy is therefore 123 minutes. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. None. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. None. Page 4 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Reduction and analysis of images will consist of standard calibrations of the PC data, followed by stellar photometry and surface photometry. Cosmic ray events will be identified and removed. Photometry will be performed on an absolute scale as much as possible. We will measure the colors of SN 1988Z, and comparisons will be made with the colors of normal stars and other SNe observed with HST. Colors and color gradients will be studied near SN 1988Z, to determine stellar populations. We will search for dust features, and contaminating background sources will be identified. This should allow us to perform some corrections to the existing light curves. Deconvolution techniques will be used to improve the effective spatial resolution. Measurement and analysis of the calibrated one- dimensional spectra will be done with an extensive program written by the PI for his studies of optical spectra. All emission lines will be measured (wavelengths, fluxes, equivalent widths, velocity widths), and the continuum shape will be determined. The final UV spectrum will be combined with an optical spectrum, to be obtained at nearly the same epoch (see below). The continuum flux will be extrapolated beyond the Lyman limit to see whether it can account for the emission lines. Photoionization codes (G. Ferland's CLOUDY, as well as C. Fransson's own calculations) will be used to analyze the overall emission-line spectrum. Extensive comparisons with the theoretical predictions of Fransson & Chevalier (1992) will be made. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Target acquisition of SN 1988Z in the FOS aperture will be done by centering on a neighboring star and subsequently offsetting by the precisely measured displacement of the supernova. When our HST observing dates become known, we will request roughly contemporaneous time at Lick Observatory to obtain broad-band optical images of SN 1988Z, for comparison with the corresponding HST images. This will be particularly useful for determining correction factors applicable to previous photometric observations of the object. Also, optical spectra of SN 1988Z will be obtained, and they will be combined with the HST spectra. The ground-based observations will be done at no cost to this proposal. Page 5 ------------------------------------------------------------------------------------ 9. Description of previous HST work. R. P. Kirshner, Co-I: GO 2356, "The Identification of Supernova Remnants in M83 and Other Spiral Galaxies." (PI: K. S. Long). Not related. R. P. Kirshner, PI: GO 2417, "Cas A: The Remnant of a Massive Supernova." Not related to this project; the Cas A remnant is much older. R. A. Fesen, Co-I: GO 2434, "A Study of the Chemical Composition and Velocity Structure of the Young Supernova Remnant AD 1006." (PI: C.-C. Wu). Not related. R. P. Kirshner, PI (Chevalier and Fransson, Co-Is): GO 2563 and GO 3853, "SINS: Supernova Intensive Study." Not directly related to this project, but the HST observations of SNe will be useful for comparison with our results. A. V. Filippenko, PI: GO 2590, "Deep Imaging of the Site of SN 1961V, a Possible Extragalactic Eta Carinae Analogue." Not related to this project. R. A. Fesen, PI: GO 2955, "UV Imaging and Spectroscopy of S Andromedae in M31." Not related to this project; S And was probably a Type I SN. A. V. Filippenko, Co-I: GO 3484, "Probing the Nuclear Regions of the Seyfert Galaxy NGC 5548." (PI: B. M. Peterson). Not related to this project. A. V. Filippenko, PI: GO 3507, "UV Spectroscopy and High-Resolution Imaging of NGC 4395." Not related to this project. A. V. Filippenko, Co-I: GO 3519, "UV Imaging of Nearby Galaxies." (PI: D. Maoz.) Not related to this project. A. V. Filippenko, Co-I: GO 3810, "The Stellar Content of Wolf-Rayet Galaxies." (PI: P. Conti.) Not related to this project. In addition, Filippenko was involved in one of the discoveries made by the QSO Snapshot Survey (PI: J. N. Bahcall.) GO 2434 (Fesen): Data obtained and analysed. FOS spectra show strong Fe II UV features due to multiplets 1-3 (2343, 2382, and 2599 A). These absorptions have equivalent widths of about 20 A each and indicate an Fe II expansion velocity of up to 8000 km/s. GO 2563 and GO 3853 (Kirshner): The earliest observations of SN 1987A resulted in the detection of a circumstellar ring. Subsequent use of the ring geometry and fluorescent line time delay enabled a measurement of the distance to the LMC. Measurements were made of changes in the circumstellar shell. For SN 1992A, we have combined the data from HST, IUE, and CTIO; comparisons were made with the results of stellar evolution and supernova explosion models. GO 2590 (Filippenko): Data were received a few months ago, and are currently being analyzed. An object has been detected at the position of SN 1961V; color information is being used to determine whether this is the supernova remnant, the surviving "progenitor," or an unrelated object. GO 2955 (Fesen): UV FOC image of S And site reduced. It shows a weak detection of the SNR as an absorption spot (0.5" diameter) on the M31 budge. FOS spectra taken of S And are weak and poorly exposed but may show asymmetric UV Fe II resonance line absorptions. GO 3507 (Filippenko): We recently received the data. Preliminary analysis reveals strong emission lines similar to those of luminous Seyfert 1 nuclei (e.g., C IV 1549, C III] 1909, Mg II 2800) superposed on a weak continuum. The nucleus seems unresolved on a scale of 1 pc (0.1"). Other proposals: Data not obtained yet. "First Results from the FOC: Supernova 1987A." P. Jakobsen et al. (including R. P. Kirshner); Astrophysical Journal (Letters), 369, L63, 1991. "Properties of the SN 1987A Circumstellar Ring and the Distance to the Large Magellanic Cloud." N. Panagia et al. (including R. P. Kirshner); Astrophysical Journal (Letters), 380, L23, 1991. "A Gravitational Lens Candidate Discovered with the Hubble Space Telescope." D. Maoz, J. N. Bahcall, D. P. Schneider, R. Doxsey, N. A. Bahcall, A. V. Filippenko, W. M. Goss, O. Lahav, and B. Yanny; Astrophysical Journal (Letters), 386, L1, 1992. "High-Velocity Fe II Absorption Lines in SNR 1006." C.- C. Wu, D. M. Crenshaw, R. A. Fesen, A. J. S. Hamilton, & M. Leventhal, in Proceedings of HST Conference in Elba, Italy; 1992. "HST Spectra of the Type Ia Supernova 1992A." R. P. Kirshner and the SINS team, in preparation. Page 6 ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). U. C. Berkeley, Harvard University, Dartmouth College, and the University of Virginia all have extensive computing facilities (VMS and UNIX) in their Astronomy Departments, as does Stockholm Observatory. Image-processing workstations, graphics terminals, laser printers, large disks, and tape drives are all available. Many computer programs exist for analysis of data. All the universities also have many highly capable graduate students and postdoctoral fellows, some of whom may participate in various aspects of this project. Ground- based complementary observations can readily be obtained (with short notice) at Lick and McGraw-Hill Observatories. The usual secretarial and technical support is available at all of the institutions. ------------------------------------------------------------------------------------ 11. Address Information Name: ALEXEI V. FILIPPENKO Category: PI Institution: UC-Berkeley Address: DEPARTMENT OF ASTRONOMY 601 CAMPBELL HALL UNIVERSITY OF CALIFORNIA City: BERKELEY State: CA Zip Code: 94720 Country: USA Telephone: 510-642-1813 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4315c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 SN1988Z- A,137 RA = 10H 51M 51.12S +/- 2000.0 Z = 1 V = 15.9 +/- 0.2 OFFSET 0.03S, 0.000 2 B-V = 0.8 +/- 0.15 DEC = 15D 59' 28.18" +/- 3 V-R = 0.62 +/- 0.1 0.4" 4 V-I = 1.24 +/- 0.1 5 U-B = 0.2 +/- 0.15 Comments: G5 OFFSET STAR FOR SN1988Z. ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1988Z B,182,H,506 RA-OFF = -0.943S +/- 0.015S, 2000.0 Z = 1 V = 22.0 +/- 1.0 DEC-OFF = +31.55" +/- 0.2", 0.022 2 B-V = 0.0 +/- 0.3 FROM 1 3 V-R = 0.3 +/- 0.3 4 V-I = 0.0 +/- 0.3 5 F-LINE(1549) = 1.0 +/- 0.8 E-14 6 W-LINE(1549) = 6.0 +/- 3.0 Comments: MAGNITUDES AND FLUXES VERY APPROXIMATE; OBJECT FADING WITH TIME, VERY SLOWLY. ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1988Z- B,182,H,506 RA = 10H 51M 50.11S +/- 10", 2000.0 Z = 1 V = 22.0 +/- 1.0 REGION DEC = 15D 59' 59.9" +/- 10", 0.022 2 B-V = 0.0 +/- 0.3 REGION 3 V-R = 0.3 +/- 0.3 4 V-I = 0.0 +/- 0.3 Comments: MAGNITUDE, COLOR, AND REDSHIFT ARE OF SN1988Z ITSELF. MAGNITUDE AND COLOR VERY APPROXIMATE; OBJECT FADING SLOWLY WITH TIME. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4315c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 SN1988Z- PC IMAGE PC6 F791W 8922 CR-SPLIT=NO 1 400S 26 1 1 CYCLE 3 / 1-9 REGION PRE-FLASH=YES 4 GROUP 1-5 NO GAP Comments: WANT DATA FROM ALL 4 CCDS. IF THERE IS EXTRA TIME BEFORE EARTH OCCULATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1988Z- PC IMAGE PC6 F675W 6898 CR-SPLIT=NO 1 300S 40 1 1 REGION PRE-FLASH=YES 4 Comments: WANT DATA FROM ALL 4 CCDS. IF THERE IS EXTRA TIME BEFORE EARTH OCCULATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1988Z- PC IMAGE PC6 F569W 5416 CR-SPLIT=NO 1 350S 38 1 1 REGION PRE-FLASH=YES Comments: WANT DATA FROM ALL 4 CCDS. IF THERE IS EXTRA TIME BEFORE EARTH OCCULATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 4 SN1988Z- PC IMAGE PC6 F439W 4352 CR-SPLIT=NO 1 500S 19 1 1 REGION PRE-FLASH=YES 2 Comments: WANT DATA FROM ALL 4 CCDS. IF THERE IS EXTRA TIME BEFORE EARTH OCCULATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 5 SN1988Z- PC IMAGE PC6 F336W 3360 CR-SPLIT=NO 1 1300S 18 1 2 REGION PRE-FLASH=YES 2 Comments: WANT DATA FROM ALL 4 CCDS. IF THERE IS EXTRA TIME BEFORE EARTH OCCULATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 6 SN1988Z- FOS/RD ACQ/ 4.3 MIRROR 1 17S 1 3 ONBOARD ACQ FOR 7- OFFSET BINARY 2 9 GROUP 6-9 NO GAP Comments: BLUE SIDE ACQ/BINARY: SP- ELEMENT=MIRROR, EXP = 79S. NOTE THAT THIS OBSERVATION MUST PRECEDE LINES 7-9, BUT THAT LINES 7-9 CAN BE EXECUTED IN ANY ORDER (PREFERABLY IN THE LISTED ORDER). ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4315c [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 SN1988Z FOS/RD ACCUM 1.0 G270H 2760 1 15M 20 1 3 2 5 6 Comments: IF THERE IS EXTRA TIME BEFORE EARTH OCCULTATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 8 SN1988Z FOS/RD ACCUM 1.0 G190H 1950 1 33M 16 5 4 6 Comments: IF THERE IS EXTRA TIME BEFORE EARTH OCCULTATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ 9 SN1988Z FOS/BL ACCUM 1.0 G130H 1380 1 86M 6 5 5 6 Comments: IF THERE IS EXTRA TIME BEFORE EARTH OCCULTATION NEAR END OF EXPOSURE, CAN INCREASE EXPOSURE TIME TO INCREASE S/N RATIO. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4315c [ 10] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations PC FOS/RD FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ/BINARY ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 2.85 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category SN & SNR ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 3 / 1-9; GROUP 1-5 NO GAP ONBOARD ACQ FOR 7-9; GROUP 6-9 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F791W F675W F569W F439W F336W MIRROR G270H G190H G130H ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN1988Z-OFFSET SN1988Z SN1988Z-REGION ------------------------------------------------------------------------------------------------------------------------------------