16453( 4) - 07-May-2021 14:38:00 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16453 Version: 4 Check-in Time: 07-May-2021 14:38:00 STScI Edit Number: 1 Title Measuring the Distance to SN Ia Host NGC 4457 ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Kristen B W McQuinn Rutgers the State University of New Jersey Y CoI: Max Joseph Brenner Newman Rutgers the State University of New Jersey N CoI: Dr. Evan D. Skillman University of Minnesota - Twin Cities N CoI: Dr. Andrew Eugene Dolphin Raytheon Company N CoI: Dr. Saurabh W. Jha Rutgers the State University of New Jersey N ------------------------------------------------------------------------------------ Abstract The local measurement of the Hubble constant, H0, is now in tension with measurements from the distant universe by 4.4 sigma. The local H0 value is based on using Type Ia Supernovae (SNe Ia) as standard candles, calibrated from a small sample (<20) of nearby galaxies and limited by the (in)frequency of SN Ia events. One of the biggest improvements we can make in measuring H0 locally is to increase the number of calibrating systems. A new SN Ia event has just occurred in the nearby galaxy NGC 4457, estimated to be at ~17 Mpc based on the light-curve. The host galaxy is close enough that a precision distance can be made using the tip of the red giant branch (TRGB) method. We propose ACS+WFC3 imaging of the resolved stars in the galaxy to precisely measure the distance and calibrate the SN Ia luminosity. A statistical sample of galaxies with SNe Ia and independent distance measurements is the ultimate goal for improving the local H0 measurement and such a sample is only built galaxy-by-galaxy when a nearby SN Ia occurs. In this context, NGC 4457 is a high priority target for a precision TRGB distance measurement. In addition, the host-galaxy NGC 4457 is a more massive galaxy with little recent star formation. These properties are unique among SNe Ia calibrating systems but common in galaxies in the Hubble flow. SNe Ia in massive hosts standardize to a luminosity up to 10% brighter than those in lower mass hosts, a potential source of systematic uncertainty in the SN Ia distance scale. The new TRGB distance will provide an independent distance to a SN Ia in a galaxy with such properties and enable a comparison with SN Ia luminosity offsets estimated from galaxy redshifts. ------------------------------------------------------------------------------------ Observations Description ------------------------ The primary goal of this proposal is to measure the tip of the red giant branch (TRGB) distance to the galaxy NGC 4457 using optical imaging from the ACS camera of the halo stars and an additional halo field from WFC3 UVIS imaging. Orbit allocation = 6 (3 per filter) orbits which includes 6 primary ACS orbits and 6 coordinated parallel WFC3 orbits. All visits are broken into 2 orbits. ACS/WFC exposure times are split between 16453( 4) - 07-May-2021 14:38:00 - [ 2] the F606W filter and the F814W. The coordinated parallel observations are to be obtained with the WFC UVIS camera with exposure times split between the F606W and F814W filters. Small ditherings are performed between orbits in order to remove hot pixels, smooth the detector response, and provide some sub-pixel sampling of the PSF. We don't intend to cover the interchip gap. Ditherings are performed using POS-TARG and follow the 3-point pattern no. 13 with shifts of 2-5 pix in the x and y direction. After the first 3 orbits have completed a full dither patter, we shift the field by ~10 pixels in the x direction and repeat the 3-point pattern no. 13. The first visit is requested with specific orient ranges. The orientation ranges have been chosen such that the primary observations are of a field in the halo of NGC 4457 while the coordinated parallels images cover an additional halo field of the target galaxy. Subsequent visits are requested to be obtained with the same ORIENT as the first visit in order to maximize the sky area covered at full depth and ensure precise alignments of the observations. ------------------------------------------------------------------------------------ 16453( 4) - 07-May-2021 14:38:00 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-4457 EXT-STAR, K III-I RA=12H28M57.5947S, J2000 V = 28.15 DEC=+03D36'56.24" Reference Frame: Other: NED Extended: NO Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 16453( 4) - 07-May-2021 14:38:00 - [ 4] Visit: 01 (NGC4457-1) Visit Requirements: ORIENT 114D TO 135 D 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 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1173 S POS TARG 0.0, 0.0; SEQ (1173 S) 1-4 NON-INT; PAR 3-4 WITH 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1173 S POS TARG 0.0, 0.0 (1173 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1173.5 S POS TARG 0.115, 0.125; see below SEQ 5-8 NON-INT; PAR 7-8 (1181.5 S) WITH 5-6 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1173.5 S POS TARG 0.115, 0.125 see below (1181.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4457 1 ACS/WFC ACCUM WFCENTER F606W none none none none 1 N/A NGC-4457 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 N/A ANY 3 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 1 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 1 1282.0 S S TER NGC-4457 5 ACS/WFC ACCUM WFCENTER F606W none none none none 2 1181.5 S NGC-4457 6 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1181.5 S ANY 7 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 2 1282.0 S S TER ANY 8 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 2 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 6] Visit: 02 (NGC4457-2) Visit Requirements: SAME ORIENT AS 01 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 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1173 S POS TARG 0.231, 0.249; (1173 S) SEQ 1-4 NON-INT; PAR 3-4 WITH 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1173 S POS TARG 0.231, 0.249 (1173 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1182 S POS TARG 0.5, 0.0; SEQ (1182 S) 5-8 NON-INT; PAR 7-8 WITH 5-6 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1182 S POS TARG 0.5, 0.0 (1182 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4457 1 ACS/WFC ACCUM WFCENTER F606W none none none none 1 N/A NGC-4457 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 N/A ANY 3 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 1 1282.0 S S TER ANY 4 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 1 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4457 5 ACS/WFC ACCUM WFCENTER F606W none none none none 2 N/A NGC-4457 6 ACS/WFC ACCUM WFCENTER F814W none none none none 2 N/A ANY 7 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 2 1282.0 S S TER ANY 8 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 2 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 8] Visit: 03 (NGC4457-3) Visit Requirements: SAME ORIENT AS 01 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 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1209 S POS TARG 0.615, 0.125; see below SEQ 1-4 NON-INT; PAR 3-4 (1172 S) WITH 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1210 S POS TARG 0.615, 0.125 see below (1173 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1173 S POS TARG 0.731, 0.249; see below SEQ 5-8 NON-INT; PAR 7-8 (1182 S) WITH 5-6 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1173 S POS TARG 0.731, 0.249 see below (1182 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4457 1 ACS/WFC ACCUM WFCENTER F606W none none none none 1 1172.0 S NGC-4457 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1173.0 S ANY 3 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 1 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 1 1282.0 S S TER NGC-4457 5 ACS/WFC ACCUM WFCENTER F606W none none none none 2 1182.0 S NGC-4457 6 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1182.0 S ANY 7 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 2 1282.0 S S TER ANY 8 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 2 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 10] Visit: 53 (NGC4457-3) Visit Requirements: SAME ORIENT AS 01 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 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1209 S POS TARG 0.615, 0.125; see below SEQ 1-4 NON-INT; PAR 3-4 (1172 S) WITH 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1210 S POS TARG 0.615, 0.125 see below (1173 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC-4457 ACS/WFC ACCUM WFCENTER F606W CR-SPLIT=NO 1 1173 S POS TARG 0.731, 0.249; see below SEQ 5-8 NON-INT; PAR 7-8 (1182 S) WITH 5-6 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC-4457 ACS/WFC ACCUM WFCENTER F814W CR-SPLIT=NO 1 1173 S POS TARG 0.731, 0.249 see below (1182 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 ANY WFC3/UVI ACCUM UVIS-CENT F606W CR-SPLIT=NO 1 1250 S S ER see below (1282 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY WFC3/UVI ACCUM UVIS-CENT F814W CR-SPLIT=NO 1 1250 S S ER see below (1282 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-4457 1 ACS/WFC ACCUM WFCENTER F606W none none none none 1 1172.0 S NGC-4457 2 ACS/WFC ACCUM WFCENTER F814W none none none none 1 1173.0 S ANY 3 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 1 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 11] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 1 1282.0 S S TER NGC-4457 5 ACS/WFC ACCUM WFCENTER F606W none none none none 2 1182.0 S NGC-4457 6 ACS/WFC ACCUM WFCENTER F814W none none none none 2 1182.0 S ANY 7 WFC3/UVI ACCUM UVIS-CEN F606W none none none none 2 1282.0 S S TER ANY 8 WFC3/UVI ACCUM UVIS-CEN F814W none none none none 2 1282.0 S S TER 16453( 4) - 07-May-2021 14:38:00 - [ 12] Summary Form for Proposal 16453 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-CENTER, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 114D TO 135 D, PAR 3-4 WITH 1-2, PAR 7-8 WITH 5-6, POS TARG 0.0, 0.0, POS TARG 0.115, 0.125, POS TARG 0.231, 0.249, POS TARG 0.5, 0.0, POS TARG 0.615, 0.125, POS TARG 0.731, 0.249, SAME ORIENT AS 01, SEQ 1-4 NON-INT, SEQ 5-8 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, NGC-4457 ------------------------------------------------------------------------------------------------------------------------------------