6043( 9) - 11/21/95 12:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6043 Version: 9 Check-in Date: ********** 1.Proposal Title: The Interaction of Supernovae with their Circumstellar Medium ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Alexei Filippenko University of California, Berkeley CoI: Roger Chevalier University of Virginia N CoI: Robert Fesen Dartmouth College N CoI: Claes Fransson Stockholm Observatory N CoI: Robert Kirshner Harvard University N CoI: Bruno Leibundgut European Southern Observatory N CoI: Thomas Matheson University of California, Berkeley N CoI: Schuyler Van Dyk University of California, Berkeley N ------------------------------------------------------------------------------------ 6. Abstract The interaction of supernova (SN) ejecta with circumstellar material supplied by the wind of the evolved progenitor star can sometimes provide enough energy to sustain the SN luminosity for several decades. Existing observations of certain Type II SNe strongly favor such an interpretation over other possible late-time energy sources. Some peculiar SNe II have such dense circumstellar winds that interaction with the ejecta substantially alters their observed properties even at early times. The UV spectrum is a powerful diagnostic for probing the conditions in the shocked outer ejecta and circumstellar gas. We propose to observe two old SNe (t = 7- 15 years) which, due to their extensive radio and optical data records, are particularly well suited for an investigation of the interaction between ejecta and circumstellar gas. We will also observe one of the most recent SNe II (SN 1994Y), which shows strong evidence for very early interaction with its circumstellar medium. The fluxes and intensity ratios of UV emission lines measured in FOS spectra will be used to test theoretical models of the interaction. HST observations of these objects will shed light on differences among them and their shocks, as well as on the mass-loss histories of their progenitor stars. ------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 2] Observations Description ------------------------ We wish to obtain UV FOS spectra of two old SNe, as well as the new one, SN 1994Y. The expected fluxes of UV emission lines were calculated according to the predictions of CF94 (power-law and RSG models), in each case using the known HAlpha or HBeta flux and extinction (see below). The flux of SN 1980K is from Fesen & Matonick (1994); the HBeta flux of SN 1988Z was 6 * 10^-16 erg/s/cm^2 in a June 1994 Keck spectrum (Fig. 5). Extrapolations into Cycle 5 were generally simple: in recent years the observed fluxes have been staying nearly constant or declining very slowly. An exception is SN 1994Y, which was discovered only in August 1994; thus, we adopted a distance of 34 Mpc and the HBeta luminosity predicted by CF94 at t = 1.5 years (corresponding to the middle of Cycle 5). Ideally, we would obtain spectra of each SN with all three high-resolution UV gratings (G130H, G190H, G270H), in order to get accurate emission-line profiles. However, calculations show that in some cases the signal will be substantially less than the dark current. Thus, we must compromise. (a) SN 1980K, in the outskirts of NGC 6946, suffers from a Galactic reddening of E(B-V) = 0.40 mag (Burstein & Heiles 1984; BH84). This makes it too time consuming to obtain any UV spectra except with the G270H grating. (b) From BH84, we find that Galactic E(B-V) < 0.01 mag for SN 1988Z. Internal reddening, estimated from the Balmer decrements of H II regions adjacent to the SN, is negligible. High-resolution G190H and G270H FOS spectra are feasible. (c) From BH84, we find that E(B-V) < 0.01 mag for SN 1994Y. Extinction due to dust in the parent galaxy is also probably low, based on the object's location. Interstellar Na I D absorption is weak in the spectrum. We assume E(B-V) = 0.1 mag, and find that observations with the high-resolution gratings can easily be obtained. To maximize throughput while excluding most contaminants (H II regions, adjacent stars, etc.), we will use the 0.86 arcsec circular aperture. Target acquisition will generally be done by centering on a neighboring star and subsequently offsetting to the SN; the offsets are determined from ground- based images. Scattered red light should not be a significant problem in the spectra because we will be looking primarily at emission lines. We estimate that SN 1988Z requires 5 orbits for 2 spectra. The G190H setting will be observed with the blue digicon, rather than red, since the red digicon is not sensitive near 1600 Ang, where the CIV 1549 line of SN 1988Z falls. Since SN 1980K is in a CVZ, the G270H spectrum will require only 1 orbit. The three spectra of SN 1994Y will be obtained in the remaining 6 orbits, for a grand total of 12 orbits (as allocated). Note that we had listed SN 1994W rather than SN 1994Y in the original proposal, but SN 1994W subsequently faded unexpectedly fast. A better object of the same type is SN 1994Y. Several weeks ago we sought and obtained approval from STScI to swap SN 1994Y for SN 1994W. See the e-mail message below: Real Time Justification ----------------------- Since we have access to many observatories, we will continue to maintain our ground-based work on these SNe between now and the time of the HST observations. Complementary optical spectra of the two old SNe will be obtained at the Keck telescope, while SN 1994Y will be observed with the Lick 3-m reflector. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS __Diagnosti Email: , ------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1980K- STAR, K V-IV RA = 20H 35M 30.10S +/- 0.05S, J2000 V = 16.33 +/- 0.1 B-V = 1.13 +/- 0.1 U-B OFFSET DEC = 60D 06' 02.2" +/- 0.5", = 0.61 +/- 0.15 PLATE-ID=02RK Comments: K3 OFFSET STAR FOR SN1980K. 2 SN1980K EXT-STAR, SUPERNOVA RA-OFF = -0.027S +/- 0.02S, DEC- 2000 V = +50 V = 24 +/- 1 B-V = 0.5 +/- 0.3 F- TYPE II OFF = +21.58" +/- 0.15", FROM 1 LINE(2800) = 2 +/- 1 E-15 W-LINE(2800) = 4 +/- 1 Comments: MAGNITUDES AND FLUXES VERY APPROXIMATE; OBJECT SLOWLY FADING WITH TIME. 3 SN1988Z- STAR, G V-IV RA = 10H 51M 51.12S +/- 0.03S, J2000 V = 15.9 +/- 0.2 B-V = 0.8 +/- 0.15 V-R OFFSET DEC = 15D 59' 28.18" +/- 0.4", = 0.62 +/- 0.1 V-I = 1.24 +/- 0.1 U-B = PLATE-ID=01AJ 0.2 +/- 0.15 Comments: G5 OFFSET STAR FOR SN1988Z. 4 SN1988Z EXT-STAR, SUPERNOVA RA-OFF = -0.944S +/- 0.01S, DEC- 2000 V = 6600 V = 23.5 +/- 1.0 B-V = 0.0 +/- 0.5 F- TYPE II OFF = +31.58" +/- 0.15", FROM 3 LINE(1549) = 3 +/- 2 E-15 W-LINE(1549) = 4 +/- 1 Comments: MAGNITUDES AND FLUXES VERY APPROXIMATE; OBJECT SLOWLY FADING WITH TIME. 5 SN1994Y EXT-STAR, SUPERNOVA RA = 13H 53M 30.58S +/- 0.07S, 1950 V = V = 19 +/- 1 B-V = 0.5 +/- 0.3 F- TYPE II DEC = 40D 42' 33.0" +/- 0.4" +2560 LINE(1549) = 2 +/- 1 E-13 W-LINE(1549) = 10 +/- 5 Comments: MAGNITUDES AND FLUXES VERY APPROXIMATE; OBJECT SLOWLY FADING WITH TIME. 6043( 9) - 11/21/95 12:44 - [ 5] Visit: 01 Visit Requirements: CVZ On Hold Comments: Additional Comments: OBJECT FALLS IN CVZ, AS DISCUSSED IN ORIGINAL PROPOSAL. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1980K- FOS/RD ACQ/BIN 4.3 MIRROR 1 22S ONBOARD ACQ FOR 2 OFFSET ARY Comments: NEED TO OFFSET FROM THIS STAR TO THE TARGET. ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1980K FOS/RD ACCUM 1.0 G270H 1 3588S ------------------------------------------------------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1988Z- FOS/RD ACQ/BIN 4.3 MIRROR 1 12S ONBOARD ACQ FOR 2-3 OFFSET ARY Comments: NEED TO OFFSET FROM THIS STAR TO THE TARGET. ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1988Z FOS/RD ACCUM 1.0 G270H 1 2400S MAX DUR 200% END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1988Z FOS/BL ACCUM 1.0 G190H 1 7200S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 7] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1994Y FOS/RD ACQ/PEA 4.3 MIRROR TYPE=UP SCAN- 1 40S ONBOARD ACQ FOR 2 K STEP-Y=1.23 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1994Y FOS/RD ACQ/PEA 1.0 MIRROR TYPE=UP SCAN- 1 40S ONBOARD ACQ FOR 3 K STEP-X=0.61 SCAN-STEP- Y=0.61 SEARCH- SIZE-X=6 SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1994Y FOS/RD ACQ/PEA 0.5 MIRROR TYPE=UP SCAN- 1 46S ONBOARD ACQ FOR 4-6 K STEP-X=0.29 SCAN-STEP- Y=0.29 SEARCH- SIZE-X=3 SEARCH Comments: -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 4 SN1994Y FOS/RD ACCUM 1.0 G270H 1 1560S ------------------------------------------------------------------------------------------------------------------------------------ 5 SN1994Y FOS/RD ACCUM 1.0 G190H 1 3480S END ORBIT MAX DUR 200% EXPAND ------------------------------------------------------------------------------------------------------------------------------------ 6 SN1994Y FOS/BL ACCUM 1.0 G130H 1 7380S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6043( 9) - 11/21/95 12:44 - [ 8] Summary Form for Proposal 6043 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters TYPE=UP SCAN-STEP-Y=1.23 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 TYPE=UP SCAN-STEP-X=0.61 SCAN-STEP-Y=0.61 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 TYPE=UP SCAN-STEP-X=0.29 SCAN-STEP-Y=0.29 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 2-3 MAX DUR 200% END ORBIT ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4-6 END ORBIT MAX DUR 200% EXPAND ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G270H G190H G130H ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN1980K-OFFSET SN1980K SN1988Z-OFFSET SN1988Z SN1994Y ------------------------------------------------------------------------------------------------------------------------------------