17200( 2) - 12-Jul-2022 19:25:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17200 Version: 2 Check-in Time: 12-Jul-2022 19:25:25 STScI Edit Number: 0 Title A census of massive binaries and luminous blue variables in the Whirlpool Galaxy ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Kareem El-Badry California Institute of Technology Y CoI: Prof. Charlie Conroy Harvard University N CoI: Dr. Daniel R. Weisz University of California - Berkeley N ------------------------------------------------------------------------------------ Abstract We propose UV and optical UVIS/WFC3 photometry of M51, a face-on Milky Way-like galaxy at d = 8.5 Mpc, in which individual luminous stars can be spatially resolved. Previous HST programs obtained 70 epochs of photometry in the red optical F606W and F814 filters, producing high-precision light curves of the 20, 000 most luminous stars in the galaxy. Among these are hundreds of massive eclipsing binaries (EBs) and luminous blue variables (LBVs). These light curves are a treasure trove for studies of massive star evolution and population demographics, enabling a homogenous census of luminous star variability that would be impossible in the Milky Way. However, the existing photometry is in the Rayleigh-Jeans tail for hot stars and thus cannot constrain their temperatures and luminosities reliably. We propose 1 epoch in each of the F275W, F336W, F475W, F606W, and F814W filters (5 orbits total), enabling measurement of temperatures, radii, and luminosities for all hot stars, and masses for EBs. This program will significantly increase the utility of the existing 70 epochs of photometry, enabling a wealth of science related to massive star evolution and binary population modeling. ------------------------------------------------------------------------------------ Observations Description ------------------------ We adopt the well-tested strategy of observing in the UV-optical filters F275W, F336W, F475W, F606W, and F814W. Several authors have demonstrated that this combination of filters enables strong separation of temperature and dust effects, and a similar strategy was adopted by the Multi-Cycle Treasury program PHAT. We request one orbit depth in each of the F275W, F336W, F475W, F606W, and F814 filters. We will split each orbit into 4 sub-exposures using a standard dither pattern. The UVIS ETC predicts SNR=20 at F275W=23.0, F336W=24.0, F475W=25.0, F606W=24.5, F814=24.0. These depths are necessary to: a) measure photometry at the few percent level; b) derive stellar parameters at the 10% level, and (c) enable longer-baseline analysis of optical CMD variability, when combined with archival data. Given that the sources of greatest interest will be time-variable, it is essential that the five filters be observed in consecutive orbits so that reliable stellar parameters can be derived. They are thus grouped into a single visit. The proposed field overlaps with existing WFPC2 data from 1995, existing ACS 17200( 2) - 12-Jul-2022 19:25:25 - [ 2] data from 2005, and the high cadence observations from the Cycle 24 ACS program ID 14704. The orientation constaints are chosen to maximize overlap with the archival data. We add a small amount of FLASH to all filters. This may slightly reduce SNR (and it produces a warning in F606W), but experience suggests that it will make the data more generally usable due to CTE degradation. ------------------------------------------------------------------------------------ 17200( 2) - 12-Jul-2022 19:25:25 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 M-51 GALAXY, DISK, RA=13H30M2.3135S +/- 0.1", J2000 V = 8.36 INTERACTING GALAXY, DEC=+47D09'57.83" +/- 0.1" SPIRAL Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 17200( 2) - 12-Jul-2022 19:25:25 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 17200( 2) - 12-Jul-2022 19:25:25 - [ 5] Visit: 01 Visit Requirements: ORIENT 310D TO 320 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 M-51 WFC3/UVI ACCUM UVIS1 F606W FLASH=5 1 500 S POS TARG S see below 22.05503486973148, (2492 S) 36.03279688265262; PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 M-51 WFC3/UVI ACCUM UVIS1 F275W FLASH=20 1 500 S POS TARG S see below 22.05503486973148, (2468 S) 36.03279688265262; PATTERN 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 M-51 WFC3/UVI ACCUM UVIS1 F336W FLASH=20 1 500 S POS TARG S see below 22.05503486973148, (2466 S) 36.03279688265262; PATTERN 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 M-51 WFC3/UVI ACCUM UVIS1 F814W FLASH=5 1 500 S POS TARG S see below 22.05503486973148, (2486 S) 36.03279688265262; PATTERN 1 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 M-51 WFC3/UVI ACCUM UVIS1 F475W FLASH=8 1 500 S POS TARG S see below 22.05503486973148, (2481 S) 36.03279688265262; PATTERN 1 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 | ------------------------------------------------------------------------------------------------------------------------------------ M-51 1 WFC3/UVI ACCUM UVIS1 F606W 1 none none none 1 647.0 S S M-51 1 WFC3/UVI ACCUM UVIS1 F606W 2 none none none 1 615.0 S S M-51 1 WFC3/UVI ACCUM UVIS1 F606W 3 none none none 1 615.0 S S M-51 1 WFC3/UVI ACCUM UVIS1 F606W 4 none none none 1 615.0 S S M-51 2 WFC3/UVI ACCUM UVIS1 F275W 1 none none none 2 635.0 S S 17200( 2) - 12-Jul-2022 19:25:25 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ M-51 2 WFC3/UVI ACCUM UVIS1 F275W 2 none none none 2 611.0 S S M-51 2 WFC3/UVI ACCUM UVIS1 F275W 3 none none none 2 611.0 S S M-51 2 WFC3/UVI ACCUM UVIS1 F275W 4 none none none 2 611.0 S S M-51 3 WFC3/UVI ACCUM UVIS1 F336W 1 none none none 3 633.0 S S M-51 3 WFC3/UVI ACCUM UVIS1 F336W 2 none none none 3 611.0 S S M-51 3 WFC3/UVI ACCUM UVIS1 F336W 3 none none none 3 611.0 S S M-51 3 WFC3/UVI ACCUM UVIS1 F336W 4 none none none 3 611.0 S S M-51 4 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 4 641.0 S S M-51 4 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 4 615.0 S S M-51 4 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 4 615.0 S S M-51 4 WFC3/UVI ACCUM UVIS1 F814W 4 none none none 4 615.0 S S M-51 5 WFC3/UVI ACCUM UVIS1 F475W 1 none none none 5 639.0 S S M-51 5 WFC3/UVI ACCUM UVIS1 F475W 2 none none none 5 614.0 S S M-51 5 WFC3/UVI ACCUM UVIS1 F475W 3 none none none 5 614.0 S S M-51 5 WFC3/UVI ACCUM UVIS1 F475W 4 none none none 5 614.0 S S 17200( 2) - 12-Jul-2022 19:25:25 - [ 7] Summary Form for Proposal 17200 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=20, FLASH=5, FLASH=8 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 310D TO 320 D, PATTERN 1 1, PATTERN 1 2, PATTERN 1 3, PATTERN 1 4, PATTERN 1 5, POS TARG 22.05503486973148, 36.03279688265262 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F275W, F336W, F475W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names M-51 ------------------------------------------------------------------------------------------------------------------------------------