NASA's James Webb Space Telescope

ERS Program 1334

The Resolved Stellar Populations Early Release Science Program

PI: Daniel Weisz (University of California - Berkeley)
Co-PIs: N/A)

Science Category Stellar Populations icon
Keywords Astrometry, Color-Magnitude Diagrams, Dwarf Galaxies, Local Group Galaxies, Star-Formation Histories
Investigators Jay Anderson (Space Telescope Science Institute)
Martha L. Boyer (Space Telescope Science Institute)
Andrew A. Cole (University of Tasmania)
Andrew Eugene Dolphin (Raytheon Company)
Marla C. Geha (Yale University)
Jason S. Kalirai (Space Telescope Science Institute)
Nitya Kallivayalil (The University of Virginia)
Kristen B. W. McQuinn (University of Texas at Austin)
Karin Marie Sandstrom (University of California - San Diego)
Benjamin F. Williams (University of Washington)

We propose to obtain deep multi-band NIRCam and NIRISS imaging of three resolved stellar systems within 1 Mpc (NOI 104).  We will use this broad science program to optimize observational setups and to develop data reduction techniques that will be common to JWST studies of resolved stellar populations.  We will combine our expertise in HST resolved star studies with these observations to design, test, and release point spread function (PSF) fitting software specific to JWST.  PSF photometry is at the heart of resolved stellar populations studies, but is not part of the standard JWST reduction pipeline.

Our program will establish JWST-optimized methodologies in six scientific areas: star formation histories, measurement of the sub-Solar mass stellar IMF, extinction maps, evolved stars, proper motions, and globular clusters, all of which will be common pursuits for JWST in the local Universe. Our observations of globular cluster M92, ultra-faint dwarf Draco II, and star-forming dwarf WLM, will be of high archival value for other science such as calibrating stellar evolution models, measuring properties of variable stars, and searching for metal-poor stars.

We will release the results of our program, including PSF fitting software, matched HST and JWST catalogs, clear documentation, and step-by-step tutorials (e.g., Jupyter notebooks) for data reduction and science application, to the community prior to the Cycle 2 Call for Proposals.  We will host a workshop to help community members plan their Cycle 2 observations of resolved stars. Our program will provide blueprints for the community to efficiently reduce and analyze JWST observations of resolved stellar populations.

Instrument and Mode NIRCam: Imaging
NIRISS: Imaging
What does the program enable for the user community?
  • Develop NIRCam and NIRISS PSF photometry modules for DOLPHOT
  • Provide guidance and tutorials on how to perform optimal NIRCam and NIRISS photometry
  • Construct NIRCam and NIRISS catalogs
  • Empirically calibrate the ETC for NIRCam and NIRISS imaging
  • Demonstrate how exposure time and filter combinations affect analysis of resolved stellar populations (e.g., measuring star formation histories and proper motions)
How will you engage the user community?
  • Webinars
  • Proposal Planning workshop prior to Cycle 2
  • Interactive online tutorials and Jupyter notebooks
Team website URL