16047( 4) - 19-Mar-2020 19:09:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16047 Version: 4 Check-in Time: 19-Mar-2020 19:09:14 STScI Edit Number: 1 Title A SN Ia Event in a Globular Cluster of a Nearby Galaxy ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Joel N. Bregman University of Michigan Y CoI: Dr. Oleg Y. Gnedin University of Michigan N CoI: Dr. Patrick O. Seitzer University of Michigan N ------------------------------------------------------------------------------------ Abstract The path to a SN Ia is not observationally known as we have never observed the progenitor or its properties: mass, age, and metallicity. These shortcomings are removed when a SN Ia occurs in a globular cluster, an old population with near-uniform metallicity. Previous efforts to discover a SN Ia in globular cluster have failed, but a recent Ia event, SN 2019ein, lies within 0.5 arcseconds of a globular cluster candidate in the early-type galaxy NGC 5353 (D = 28 Mpc) on a pre-SN WFC3/IR F110W image (SN is 5.5 kpc from the galaxy center). To establish that this SN Ia-GC association is real and not due to chance, we propose observations that will reduce the error circle for the SN by a factor of 50 to 0.01 arcsec (1.4 pc, less than the half-light radii for a typical globular cluster). This is accomplished by obtaining an HST image while the supernova is still visible and registering that image on the pre-SN image; we propose to use the ACS/WFC F475W and F814W. These observations can also show the location of SN 2019ein within the GC, and as the binary is relatively heavy, it should lie toward the center. A confirmation of the SN-GC association would be powerful evidence for the double-degenerate path, and once the SN has faded, further properties of the globular cluster can be obtained. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program constitutes images in two filter on the ACS/WFC, W475W and F814W, of approximate equal observing time, and for a total of 1 orbit. The target is a fading SN Ia, SN2019ein, which lies about 5 kpc from the center of NGC 5353. The image should be dithered to achieve the highest spatial resolution. There are no particularly bright objects in the field, being mostly 20-27 mag plus some diffuse emission from the elliptical galaxy. ------------------------------------------------------------------------------------ 16047( 4) - 19-Mar-2020 19:09:14 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2019EIN GALAXY, ELLIPTICAL RA=13H53M29.1000S +/- 0.5", J2000 V = 2325 V = 21. +/- 1.0 DEC=+40D16'31.40" +/- 0.5" Reference Frame: ICRS Comments: Target should not be placed near the chip gap of the detectors. ------------------------------------------------------------------------------------------------------------------------------------ 16047( 4) - 19-Mar-2020 19:09:14 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.262 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 18.39 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16047( 4) - 19-Mar-2020 19:09:14 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: 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 SN2019EIN ACS/WFC ACCUM WFC1-CTE F475W 1 400 S PATTERN 1 1-2 see below (1064 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2019EIN ACS/WFC ACCUM WFC1-CTE F814W 1 400 S see below (1064 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2019EIN 1 ACS/WFC ACCUM WFC1-CTE F475W 1 none none none 1 532.0 S SN2019EIN 1 ACS/WFC ACCUM WFC1-CTE F475W 2 none none none 1 532.0 S SN2019EIN 2 ACS/WFC ACCUM WFC1-CTE F814W 1 none none none 1 532.0 S SN2019EIN 2 ACS/WFC ACCUM WFC1-CTE F814W 2 none none none 1 532.0 S 16047( 4) - 19-Mar-2020 19:09:14 - [ 5] Visit: 51 Visit Requirements: On Hold Comments: 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 SN2019EIN ACS/WFC ACCUM WFC1-CTE F475W 1 400 S PATTERN 1 1-2 see below (1064 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2019EIN ACS/WFC ACCUM WFC1-CTE F814W 1 400 S see below (1064 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2019EIN 1 ACS/WFC ACCUM WFC1-CTE F475W 1 none none none 1 532.0 S SN2019EIN 1 ACS/WFC ACCUM WFC1-CTE F475W 2 none none none 1 532.0 S SN2019EIN 2 ACS/WFC ACCUM WFC1-CTE F814W 1 none none none 1 532.0 S SN2019EIN 2 ACS/WFC ACCUM WFC1-CTE F814W 2 none none none 1 532.0 S 16047( 4) - 19-Mar-2020 19:09:14 - [ 6] Summary Form for Proposal 16047 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2019EIN ------------------------------------------------------------------------------------------------------------------------------------