14846( 3) - 22-Jun-2017 19:05:22 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14846 Version: 3 Check-in Time: 22-Jun-2017 19:05:22 STScI Edit Number: 1 Title Ultra-diffuse Galaxies in Clusters and the Field: Masses and Stellar Populations ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Aaron Romanowsky San Jose State University Y CoI: Dr. Seppo J. Laine California Institute of Technology N CoI: Dr. Jessica Krick Caltech/IPAC N CoI: Prof. Pieter van Dokkum Yale University N CoI: Ms. Alexa Villaume University of California - Santa Cruz N CoI: Prof. Jean P. Brodie University of California - Santa Cruz N ------------------------------------------------------------------------------------ Abstract Ultra-diffuse galaxies (UDGs) were recognized only last year as a novel class of galaxies, with luminosities like dwarfs but sizes like giants. Although some UDGs appear to be just unusually extended dwarfs, others show evidence of being very different and unexpected: their dark matter halos are overmassive by factors of ~10, with one UDG even being arguably a "failed Milky Way." These exotic galaxies might be a byproduct of environmental processes within galaxy clusters, but UDGs have also now been found in the field. It is crucial for understanding their origins to test if UDGs have the same properties in cluster and field environments. Here we propose studying the stellar populations (ages and metallicities) of seven UDGs using Spitzer/IRAC 3.6- and 4.5-micron imaging combined with optical photometry, along with mass estimation of three of the UDGs using HST/ACS imaging to provide globular cluster number counts and colors (proxies for halo mass). This ultra low surface brightness photometry in the near infrared, on an important new class of galaxies, could become a legacy result from the Spitzer mission. ------------------------------------------------------------------------------------ Observations Description ------------------------ The technical goal of the observations is to detect globular cluster candidates around ultra-diffuse galaxies (UDGs), with 5-sigma point-source detection limits of F606W = 27.7, F814W = 27.2. We will observe each of 3 UDGs in 2 filters, with 1 orbit per filter. The same orientation is used for both filters. We will use a large+small 4-point dither pattern to remove chip gap, hot pixels, and cosmic rays. ------------------------------------------------------------------------------------ 14846( 3) - 22-Jun-2017 19:05:22 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 DGSAT-I GALAXY, LSB, RA=01H17M35.5900S +/- 0.5", J2000 V = 5450 V = 18.18 +/- 0.04 UNDESIGNATED DEC=+33D31'42.37" +/- 0.5" Reference Frame: ICRS Comments: Low surface brightness galaxy, diameter ~ 20 arcsec. ------------------------------------------------------------------------------------------------------------------------------------ 2 R-127-1 GALAXY, LSB, RA=11H36M17.5847S +/- 1", J2000 V = 5250 V = 18.4 UNDESIGNATED DEC=+47D38'48.71" +/- 0.5" Reference Frame: ICRS Comments: Low surface brightness galaxy, diameter ~ 40 arcsec. ------------------------------------------------------------------------------------------------------------------------------------ 3 M-161-1 GALAXY, LSB, RA=13H29M53.6198S +/- 0.5", J2000 V = 5600 V = 18.7 UNDESIGNATED DEC=+46D22'19.95" +/- 0.5" Reference Frame: ICRS Comments: Low surface brightness galaxy, diameter ~ 40 arcsec. ------------------------------------------------------------------------------------------------------------------------------------ 14846( 3) - 22-Jun-2017 19:05:22 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 3.034 0.145 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 85.29 47.23 Angle_Between_Sides Center_Pattern NO NO Pattern_Comments: Large dither over gap combined with 2-point hot-pixel dither subpattern. ------------------------------------------------------------------------------------------------------------------------------------ 14846( 3) - 22-Jun-2017 19:05:22 - [ 4] Visit: 01 (DGSAT I) 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 DGSAT-I ACS/WFC ACCUM WFC1 F814W 1 553 S PATTERN 2 1 (2212 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 DGSAT-I ACS/WFC ACCUM WFC1 F606W 1 588 S PATTERN 2 2 (2352 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 | ------------------------------------------------------------------------------------------------------------------------------------ DGSAT-I 1 ACS/WFC ACCUM WFC1 F814W 1 1 none none 1 N/A DGSAT-I 1 ACS/WFC ACCUM WFC1 F814W 1 2 none none 1 N/A DGSAT-I 1 ACS/WFC ACCUM WFC1 F814W 2 1 none none 1 N/A DGSAT-I 1 ACS/WFC ACCUM WFC1 F814W 2 2 none none 1 N/A DGSAT-I 2 ACS/WFC ACCUM WFC1 F606W 1 1 none none 2 N/A DGSAT-I 2 ACS/WFC ACCUM WFC1 F606W 1 2 none none 2 N/A DGSAT-I 2 ACS/WFC ACCUM WFC1 F606W 2 1 none none 2 N/A DGSAT-I 2 ACS/WFC ACCUM WFC1 F606W 2 2 none none 2 N/A 14846( 3) - 22-Jun-2017 19:05:22 - [ 5] Visit: 02 (R-127-1) 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 R-127-1 ACS/WFC ACCUM WFC1 F814W 1 580 S PATTERN 2 1 (2320 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 R-127-1 ACS/WFC ACCUM WFC1 F606W 1 614 S PATTERN 2 2 (2456 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 | ------------------------------------------------------------------------------------------------------------------------------------ R-127-1 1 ACS/WFC ACCUM WFC1 F814W 1 1 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 1 2 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 2 1 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 2 2 none none 1 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 1 1 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 1 2 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 2 1 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 2 2 none none 2 N/A 14846( 3) - 22-Jun-2017 19:05:22 - [ 6] Visit: 03 (M-161-1) 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 M-161-1 ACS/WFC ACCUM WFC1 F814W 1 580 S PATTERN 2 1 (2320 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 M-161-1 ACS/WFC ACCUM WFC1 F606W 1 614 S PATTERN 2 2 (2456 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 | ------------------------------------------------------------------------------------------------------------------------------------ M-161-1 1 ACS/WFC ACCUM WFC1 F814W 1 1 none none 1 N/A M-161-1 1 ACS/WFC ACCUM WFC1 F814W 1 2 none none 1 N/A M-161-1 1 ACS/WFC ACCUM WFC1 F814W 2 1 none none 1 N/A M-161-1 1 ACS/WFC ACCUM WFC1 F814W 2 2 none none 1 N/A M-161-1 2 ACS/WFC ACCUM WFC1 F606W 1 1 none none 2 N/A M-161-1 2 ACS/WFC ACCUM WFC1 F606W 1 2 none none 2 N/A M-161-1 2 ACS/WFC ACCUM WFC1 F606W 2 1 none none 2 N/A M-161-1 2 ACS/WFC ACCUM WFC1 F606W 2 2 none none 2 N/A 14846( 3) - 22-Jun-2017 19:05:22 - [ 7] Visit: 52 (R-127-1) 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 R-127-1 ACS/WFC ACCUM WFC1 F814W 1 580 S PATTERN 2 1 (2320 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 R-127-1 ACS/WFC ACCUM WFC1 F606W 1 614 S PATTERN 2 2 (2456 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 | ------------------------------------------------------------------------------------------------------------------------------------ R-127-1 1 ACS/WFC ACCUM WFC1 F814W 1 1 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 1 2 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 2 1 none none 1 N/A R-127-1 1 ACS/WFC ACCUM WFC1 F814W 2 2 none none 1 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 1 1 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 1 2 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 2 1 none none 2 N/A R-127-1 2 ACS/WFC ACCUM WFC1 F606W 2 2 none none 2 N/A 14846( 3) - 22-Jun-2017 19:05:22 - [ 8] Summary Form for Proposal 14846 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 2 1, PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names DGSAT-I, M-161-1, R-127-1 ------------------------------------------------------------------------------------------------------------------------------------