16922( 5) - 03-May-2022 12:16:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16922 Version: 5 Check-in Time: 03-May-2022 12:16:14 STScI Edit Number: 1 Title Late-time Observations of Calcium-Rich Transient SN 2021gno ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. Wynn Vicente Jacobson-Galan University of California - Berkeley Y CoI: Dr. Raffaella Margutti University of California - Berkeley N CoI: Prof. Ryan Foley University of California - Santa Cruz N CoI: Dr. Charles Kilpatrick Northwestern University N CoI: Dr. Armin Rest Space Telescope Science Institute N CoI: Dr. Yossef Zenati The Johns Hopkins University N CoI: Huei Sears Northwestern University N ------------------------------------------------------------------------------------ Abstract Supernova (SN) 2021gno in NGC 4165 (D=30.5 Mpc) is the second closest known Calcium-rich (Ca-rich) transient and only the second object in this class with an X-ray detection. Prompt, high-cadence follow-up of this transient across the EM spectrum has indicated that the progenitor star was likely low mass (e.g., white dwarf or <10 Msun) and surrounded by dense circumstellar material (CSM) whose geometry/density was capable of producing luminous X-ray emission as well as a double-peaked light curve. The close proximity of SN 2021gno provides only the second opportunity to track the photometric evolution of a Ca-rich transient at late phases (>300 days) when the SN luminosity is governed by radioactive decay and/or additional power sources e.g., CSM, and is too faint for ground-based observatories. These objects typically decrease in magnitude rapidly and thus their late-time decline rate and power source remains ambiguous. Here we propose multi-color imaging of SN 2021gno in order to understand its late-time bolometric behavior and to constrain the total masses of radioactive decay isotopes Ni-56 and Ni-57 synthesized in the explosion. This will allow us to test whether SN 2021gno is powered solely by radioactive decay or by additional CSM at large distances from the progenitor system. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to observe nearby supernova 2021gno with WFC3/IR in F110W and F160W filters in the first of our two allocated orbits. In the second orbit, we will observe SN 2021gno with WFC3/UVIS in filters F555W and F814W. Our optimal observing window is between 28-April-2022 and 01-June-2022. We have requested that IR imaging be taken within 3 days of the UVIS imaging orbit. Below is our observing plan for each filter in each orbit: Orbit 1: F110W/F160W: Four ~300s individual exposures for each filter using the WFC3-IR-DILTER-BOX-MIN pattern. 16922( 5) - 03-May-2022 12:16:14 - [ 2] Orbit 2: F555W: Total Exposure time = 1500s; Split into two 750s exposures using WFC3-UVIS-DITHER-LINE pattern F814W: Total Exposure time = 900s; Split into two 450s exposures using WFC3-UVIS-DITHER-LINE pattern ------------------------------------------------------------------------------------ 16922( 5) - 03-May-2022 12:16:14 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2021GNO STAR, SUPERNOVA RA=12H12M10.2900S, J2000 V = 25 g ~ 26-27, r ~ 25, i/z ~ 24 DEC=+13D14'57.04" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 16922( 5) - 03-May-2022 12:16:14 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16922( 5) - 03-May-2022 12:16:14 - [ 5] Visit: 02 (UVIS/IR Orbits) Visit Requirements: BETWEEN 28-APR-2022:00:00:00 AND 01-JUN-2022:00:00:00 On Hold Comments: Additional Comments: Orbit 1: Filters: F110W, F160W Orbit 2: Filters: F555W, F814W 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 SN2021GNO WFC3/IR MULTIAC IR F110W NSAMP=12, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 1-2 CUM (1111.752 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2021GNO WFC3/IR MULTIAC IR F160W SAMP-SEQ=SPARS25, NSAMP=13 1 DEF CUM (1211.754 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2021GNO WFC3/UVI ACCUM UVIS F814W FLASH=7 1 420 S (840 PATTERN 1 3-4 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2021GNO WFC3/UVI ACCUM UVIS F555W 1 740 S S (1480 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2021GNO 1 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 4 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM SN2021GNO 3 WFC3/UVI ACCUM UVIS F814W 1 none none none 2 N/A S 16922( 5) - 03-May-2022 12:16:14 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2021GNO 3 WFC3/UVI ACCUM UVIS F814W 2 none none none 2 N/A S SN2021GNO 4 WFC3/UVI ACCUM UVIS F555W 1 none none none 2 N/A S SN2021GNO 4 WFC3/UVI ACCUM UVIS F555W 2 none none none 2 N/A S 16922( 5) - 03-May-2022 12:16:14 - [ 7] Visit: 03 (UVIS/IR Orbits) Visit Requirements: BETWEEN 28-APR-2022:00:00:00 AND 01-JUN-2022:00:00:00 On Hold Comments: Additional Comments: Orbit 1: Filters: F110W, F160W Orbit 2: Filters: F555W, F814W HOPR repeat of visit 2 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 SN2021GNO WFC3/IR MULTIAC IR F110W NSAMP=12, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 1-2 CUM (1111.752 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2021GNO WFC3/IR MULTIAC IR F160W SAMP-SEQ=SPARS25, NSAMP=13 1 DEF CUM (1211.754 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2021GNO WFC3/UVI ACCUM UVIS F814W FLASH=7 1 420 S (840 PATTERN 1 3-4 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2021GNO WFC3/UVI ACCUM UVIS F555W 1 740 S S (1480 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2021GNO 1 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A CUM SN2021GNO 1 WFC3/IR MULTIAC IR F110W 4 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SN2021GNO 2 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM 16922( 5) - 03-May-2022 12:16:14 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2021GNO 3 WFC3/UVI ACCUM UVIS F814W 1 none none none 2 N/A S SN2021GNO 3 WFC3/UVI ACCUM UVIS F814W 2 none none none 2 N/A S SN2021GNO 4 WFC3/UVI ACCUM UVIS F555W 1 none none none 2 N/A S SN2021GNO 4 WFC3/UVI ACCUM UVIS F555W 2 none none none 2 N/A S 16922( 5) - 03-May-2022 12:16:14 - [ 9] Summary Form for Proposal 16922 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=7, NSAMP=12, NSAMP=13, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 28-APR-2022:00:00:00 AND 01-JUN-2022:00:00:00, PATTERN 1 3-4, PATTERN 2 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F555W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2021GNO ------------------------------------------------------------------------------------------------------------------------------------