15697( 3) - 18-Apr-2019 15:20:51 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15697 Version: 3 Check-in Time: 18-Apr-2019 15:20:51 STScI Edit Number: 1 Title Photometric Confirmation of the Brightest Known Galaxy Candidate at z > 9 ------------------------------------------------------------------------------------ Type Cycle GO 26 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Steven L. Finkelstein University of Texas at Austin Y CoI: Dr. Keely Finkelstein University of Texas at Austin N CoI: Dr. Mimi Song NASA Goddard Space Flight Center N CoI: Dr. Rebecca A A Bowler University of Oxford N CoI: Dr. Casey Papovich Texas A & M University N CoI: Dr. Micaela Bagley University of Texas at Austin N CoI: Dr. Russell E. Ryan Jr. Space Telescope Science Institute N CoI: Dr. Norbert Pirzkal Space Telescope Science Institute N CoI: Ms. Sofia Rojas University of Texas at Austin N CoI: Ms. Rebecca L. Larson University of Texas at Austin N CoI: Mr. Intae Jung University of Texas at Austin N CoI: Mr. Matthew L Stevans Jr. University of Texas at Austin N CoI: Dr. Harry C. Ferguson Space Telescope Science Institute N CoI: Mr. L. Y. Aaron Yung Rutgers the State University of New Jersey N CoI: Prof. Rachel S. Somerville Rutgers the State University of New Jersey N CoI: Dr. Greg Snyder Space Telescope Science Institute N CoI: Dr. Jennifer Lotz Space Telescope Science Institute N CoI: Dr. Nimish P. Hathi Space Telescope Science Institute N CoI: Prof. Mauro Giavalisco University of Massachusetts - Amherst N CoI: Dr. Anton M. Koekemoer Space Telescope Science Institute Y CoI: Dr. Norman Grogin Space Telescope Science Institute N CoI: Prof. Karl Gebhardt University of Texas at Austin N CoI: Ms. Taylor Alexandra Hutchison Texas A & M University N ------------------------------------------------------------------------------------ Abstract We request two orbits of WFC3 imaging with the F098M filter to confirm the Lyman break and constrain the redshift of a remarkably bright H=24.5 galaxy in the CANDELS COSMOS field. Photometric redshift analyses including previous HST (V, I, J and H-band) and ground-based imaging overwhelmingly prefer a redshift of z ~ 9.5. A galaxy this luminous (in the searched volume) so early in the universe sets tight constraints on the onset of star formation and AGN growth, thus even this single source would be a game changer (regardless of its ionizing source). However, the inclusion of Spitzer/IRAC photometry complicates the picture. Two different deblending methods both successfully subtract bright neighboring galaxies, measuring significant flux at the position of this exceptional source at both 3.6 and 4.5 um. However, the [3.6]-[4.5] color is slightly different between these two methods, with one method measuring a slightly red color, consistent with z~9.5, and the other measuring a slightly blue color, preferring z~2. This systematic uncertainty in the deblending process prevents a concrete determination of the nature of this source. 15697( 3) - 18-Apr-2019 15:20:51 - [ 2] An efficient two orbits of F098M imaging will break this redshift degeneracy. At this depth, if the galaxy is truly at z~2 we will detect it at 5-sigma significance, while a non-detection will rule out all low-redshift solutions, regardless of the IRAC photometry used, at >99.5% confidence. These observations are urgent, as once the nature of this source is known, deep spectroscopy can be pursued to measure the precise redshift, allowing detailed investigations with JWST Cycle 1 spectroscopy. ------------------------------------------------------------------------------------ Observations Description ------------------------ We are observing one source of interest in the F098M filter. We have selected a center position ~40" away from the source, and allowable PAs, to try to exclude a nearby bright star from the image. This submitted APT has one observing window in May-June. We have worked with the contact scientist to create a separate APT for an ORIENT (300) which is observable at the end of the year, should this proposal not be scheduled earlier. We have designed a set of four exposures per orbit, using the "DITHER-BLOB" dither pattern, with a larger dither of two points (one per orbit), with four sub-dithers per orbit. We selected exposures with SPARS25 and NSAMP=13, based on recommendations of previous users, and to allow exposure times to fill our orbits. We have verified a wide schedulability window for our program. I note that we have centered our pointing on the target called "COSMOS-Z910-14822". Our actual target is known by "COSMOS-SOURCE", which we used to ensure it would fall on the detector across the allowable ORIENT range in Aladin. ------------------------------------------------------------------------------------ 15697( 3) - 18-Apr-2019 15:20:51 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 COSMOS-Z910- GALAXY, HIGH REDSHIFT RA=10H00M36.2069S, J2000 V = 24.5 +/- 0.05 14822 GALAXY DEC=+02D13'32.61" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 2 COSMOS-SOURC GALAXY, HIGH REDSHIFT RA=10H00M34.9850S, J2000 V = 24 E GALAXY DEC=+02D14'1.05" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 15697( 3) - 18-Apr-2019 15:20:51 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BLOB WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER DITHER Number_Of_Points 2 4 Point_Spacing 5.183 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 41.859 18.528 Angle_Between_Sides 74.653 Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ 15697( 3) - 18-Apr-2019 15:20:51 - [ 5] Visit: 01 (1) Visit Requirements: ORIENT 102D TO 146 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 COSMOS-Z910 WFC3/IR MULTIAC IR F098M SAMP-SEQ=SPARS25, NSAMP=13 1 DEF PATTERN 1 1-2 -14822 CUM (2423.508 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 COSMOS-Z910 WFC3/IR MULTIAC IR F098M SAMP-SEQ=SPARS25, NSAMP=13 1 DEF -14822 CUM (2423.508 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 | ------------------------------------------------------------------------------------------------------------------------------------ COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 1 1 none none 1 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 1 2 none none 1 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 1 3 none none 1 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 1 4 none none 1 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 2 1 none none 2 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 2 2 none none 2 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 2 3 none none 2 N/A CUM COSMOS-Z910-14822 1 WFC3/IR MULTIAC IR F098M 2 4 none none 2 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 1 1 none none 1 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 1 2 none none 1 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 1 3 none none 1 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 1 4 none none 1 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 2 1 none none 2 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 2 2 none none 2 N/A CUM 15697( 3) - 18-Apr-2019 15:20:51 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 2 3 none none 2 N/A CUM COSMOS-Z910-14822 2 WFC3/IR MULTIAC IR F098M 2 4 none none 2 N/A CUM 15697( 3) - 18-Apr-2019 15:20:51 - [ 7] Summary Form for Proposal 15697 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=13, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 102D TO 146 D, PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F098M ------------------------------------------------------------------------------------------------------------------------------------ Target Names COSMOS-Z910-14822 ------------------------------------------------------------------------------------------------------------------------------------