13797( 13) - 02-Apr-2015 19:15:21 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13797 Version: 13 Check-in Time: 02-Apr-2015 19:15:21 STScI Edit Number: 9 Title Early-Time UV Spectroscopy of Stripped-Envelope Supernovae: A New Window ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Alex V. Filippenko University of California - Berkeley Y CoI: Prof. Paolo A. Mazzali Liverpool John Moores University N CoI: Prof. Maryam Modjaz New York University N CoI: Dr. Nathan Smith University of Arizona N CoI: Dr. Thomas Matheson National Optical Astronomy Observatory, N AURA CoI: Dr. Jeffrey M. Silverman University of Texas at Austin N CoI: Dr. WeiKang Zheng University of California - Berkeley N CoI: Dr. Jon Mauerhan University of California - Berkeley N CoI: Dr. Ori Dosovitz Fox University of California - Berkeley N CoI: Mr. Isaac Shivvers University of California - Berkeley Y ------------------------------------------------------------------------------------ Abstract We propose to continue our Cycle 19 and 20 Target-of-Opportunity (ToO) programs to obtain three early-time UV spectra of a stripped-envelope core-collapse supernova (SN Ib or SN Ic), starting well before maximum brightness. The underlying nature of these objects, from the mass-loss process stripping the envelope to the details of the explosion mechanism, remain mysterious. Connections to gamma-ray bursts and X-ray flashes further motivate this study. Many high-redshift SNe are being found in deep transient surveys, but the ability to distinguish between thermonuclear Type Ia SNe and stripped-envelope core-collapse SNe requires thorough knowledge of the latter at UV wavelengths. By comparing the evolution of the spectra as the photosphere recedes to deeper layers of the ejecta with our time series of spectral models, we will gain a better understanding of the explosion, and possibly of the progenitor star. Specifically, we may be able to determine the metal content of the progenitor through comparisons with our spectral models, and we should be able to probe the degree of mixing during the explosion. The heterogeneity seen in stripped-envelope SNe will allow us to choose objects with different characteristics than the ones observed in Cycles 19-20, gaining further insights into this unique class of cosmic explosion. We need to seize this opportunity now, while we still have access to the space UV, and indeed the UV is the Cycle 22 priority of HST. ------------------------------------------------------------------------------------ Observations Description ------------------------ Obtain STIS UV spectra of one bright (Vmax < 15.5 mag), nearby, stripped-envelope SN as soon as possible after discovery (preferably at t < -6 d, relative to maximum brightness), with subsequent spectra just before and just after maximum, for a total of 3 epochs (16 orbits). The cadence of the spectral observations has been determined from the timescale over which significant changes are observed in ground-based optical/near-UV spectra. 13797( 13) - 02-Apr-2015 19:15:21 - [ 2] -------- Realtime Justification -------- This is a disruptive ToO observation of a single bright SN. However, it is not an ultra-rapid (< 2 day turnaround) ToO. We will work with STScI staff to expedite the observations, and we will try to choose an object that minimizes the time between ToO activation and observations. If our object is found 14 days before maximum brightness, and we have a turnaround time of 8 days (i.e., significantly longer than the 2-5 day minimum), the first observation will commence about 6 days before maximum light. We will use both the STIS/CCD and MAMA detectors to provide full wavelength coverage. The CCD observations can be done during the final MAMA orbit of each epoch. The requirement that such observations be split into separate visits presents a substantial problem for our program. The spectra of SNe change rapidly (on a time scale of 1-2 days) at these early phases; temporally separating pieces of the spectrum might seriously compromise our ability to model it. Our program would greatly benefit if the whole spectrum were obtained in a single visit, as was the case in our Cycle 19 and 20 programs. Therefore, we once again request an exception to this rule, a possibility explicitly mentioned in Section 2.6 of the STIS Instrument Handbook. We hope to split our 16 allocated orbits between 3 total visits, which means that we will require a visit of 6 orbits using STIS/MAMA. This is discouraged, due to the interfering effects of the SAA, but in consultation with our Contact Scientist and Program Coordinator (Dr. Hugues Sana, Tony Roman), we were told this is likely to be possible, contingent on the exact position of our chosen target. ------ Calibration Justification ------- Our SN, which is optically bright, will have ground-based astrometry with respect to HST guide stars accurate to better than 0.2''. Using the STIS Acquisition ETC we find acquisition times of less than 1 min for all epochs, for the 0.2'' slit. Previously, we have successfully acquired SNe with STIS in this manner. --------- Additional Comments ---------- This is a ToO proposal. We will update our phase 2 with the supernova coordinates as they become available. In order to make sure there are no bright objects in the target vicinity and to estimate the target UV flux, we will obtain rapid-response Swift/UVOT observations, as we have done in the past for this program. ------------------------------------------------------------------------------------ 13797( 13) - 02-Apr-2015 19:15:21 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 PSN2037+6607 EXT-STAR, SUPERNOVA RA=20H37M25.5600S, J2000 V = 16.7 DEC=+66D07'11.68" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13797( 13) - 02-Apr-2015 19:15:21 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.275 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.275 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 13797( 13) - 02-Apr-2015 19:15:21 - [ 5] Visit: 01 Visit Requirements: BEFORE 08-APR-2015; ON HOLD ; TOO RESPONSE TIME 8.0D; VISIBILITY INTERVAL 53.5 M On Hold Comments: Initial ToO visit Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PSN2037+660 STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) 7 Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 2 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S PATTERN 1 2 7 -MAMA see below (8320 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PSN2037+660 STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 8 S (8 S) 7 K Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 4 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S POS TARG 0, 0.825; 7 -MAMA see below PATTERN 1 4 (7269 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 200 S (200 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G750L 7751 1 100 S (100 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 52X0.1 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 1 2400.0 S -MAMA 13797( 13) - 02-Apr-2015 19:15:21 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 2 2960.0 S -MAMA PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 3 none none none 3 2960.0 S -MAMA PSN2037+6607 3 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 4 N/A K PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 4 2345.0 S -MAMA PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 5 2960.0 S -MAMA PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 3 none none none 6 1964.0 S -MAMA PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 6 N/A PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 6 N/A PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 1 6 N/A PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 2 6 N/A CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 1 none 6 N/A CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 2 none 6 N/A 13797( 13) - 02-Apr-2015 19:15:21 - [ 7] Visit: 02 Visit Requirements: AFTER 01 BY 6 D TO 8 D; ON HOLD ; TOO RESPONSE TIME 8.0D; VISIBILITY INTERVAL 53.5 M On Hold Comments: 2nd ToO visit Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PSN2037+660 STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) 7 Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 2 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S PATTERN 1 2 7 -MAMA see below (8320 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PSN2037+660 STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 8 S (8 S) 7 K Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 4 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S POS TARG 0, 0.825; 7 -MAMA see below PATTERN 2 4 (4205 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 200 S (200 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G750L 7751 1 100 S (100 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 52X0.1 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 1 2400.0 S -MAMA 13797( 13) - 02-Apr-2015 19:15:21 - [ 8] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 2 2960.0 S -MAMA PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 3 none none none 3 2960.0 S -MAMA PSN2037+6607 3 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 4 N/A K PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 4 2345.0 S -MAMA PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 5 1860.0 S -MAMA PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 5 N/A PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 5 N/A PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 1 5 N/A PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 2 5 N/A CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 1 none 5 N/A CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 2 none 5 N/A 13797( 13) - 02-Apr-2015 19:15:21 - [ 9] Visit: 03 Visit Requirements: AFTER 02 BY 6 D TO 9 D; ON HOLD ; TOO RESPONSE TIME 8.0D; VISIBILITY INTERVAL 53.5 M On Hold Comments: 3rd ToO visit Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PSN2037+660 STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) 7 Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 2 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S PATTERN 1 2 7 -MAMA see below (8320 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PSN2037+660 STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 8 S (8 S) 7 K Comments: Our SN. though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. ------------------------------------------------------------------------------------------------------------------------------------ 4 PSN2037+660 STIS/NUV ACCUM 52X0.2 G230L 2376 1 3000 S POS TARG 0, 0.825; 7 -MAMA see below PATTERN 2 4 (4005 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 200 S (200 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PSN2037+660 STIS/CCD ACCUM 52X0.2E1 G750L 7751 1 100 S 7 see below (300 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 52X0.1 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 1 2400.0 S -MAMA 13797( 13) - 02-Apr-2015 19:15:21 - [ 10] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 2 2960.0 S -MAMA PSN2037+6607 2 STIS/NUV ACCUM 52X0.2 G230L 2376 3 none none none 3 2960.0 S -MAMA PSN2037+6607 3 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 4 N/A K PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 4 2345 S -MAMA PSN2037+6607 4 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 5 1660.0 S -MAMA PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 5 N/A PSN2037+6607 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 5 N/A PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 1 5 150.0 S PSN2037+6607 6 STIS/CCD ACCUM 52X0.2E1 G750L 7751 none none none 2 5 150.0 S CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 1 none 5 N/A CCDFLAT 7 STIS/CCD ACCUM 52X0.1 G750L 7751 none none 2 none 5 N/A 13797( 13) - 02-Apr-2015 19:15:21 - [ 11] Summary Form for Proposal 13797 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.1, 52X0.2, 52X0.2E1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 6 D TO 8 D, AFTER 02 BY 6 D TO 9 D, BEFORE 08-APR-2015, ON HOLD , PATTERN 1 2, PATTERN 1 4, PATTERN 2 4, POS TARG 0, 0.825, TOO RESPONSE TIME 8.0D, VISIBILITY INTERVAL 53.5 M ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G230L, G430L, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, PSN2037+6607 ------------------------------------------------------------------------------------------------------------------------------------