The Panchromatic Hubble Andromeda Treasury is a Hubble Space Telescope Multi-cycle program to map roughly a third of M31’s star forming disk, using 6 filters covering from the ultraviolet through the near infrared. With HST’s resolution and sensitivity, the disk of M31 is resolved into more than 100 million stars, enabling a wide range of scientific endeavors.

PHAT at a Glance
Area covered 0.5 deg2
Bands F275W, F336W (WFC3/UVIS), F475W, F814W (ACS/WFC), F110W, F160W (WFC3/IR)
Depth (5σ, F275W,F336W,F475W,F814W,F110W,F160W) 25.1, 24.8, 27.9, 27.1, 25.0, and 24.0 mag
Spatial resolution (F275W,F336W,F475W,F814W,F110W,F160W) ~0.08,0.08,0.1,0.1,0.25,0.25 arcsec
Number of bricks 23
Number of objects ~117,000,000
Number of measurements ~7,500,000,000
Photometric precision ~1%
Astrometric accuracy ~5 mas
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  • Star formation histories derived on 50-100 parsec scales
  • Improved stellar evolution models, calibrated at UV through NIR wavelengths
  • Well-defined catalogs of stellar clusters, at all ages
  • Characterization of variations in the stellar mass function from ~3 to 30 solar masses
  • Measurements of the mass function and age distributions of stellar clusters
  • Maps of extinction from dust, and characterization of the extinction law
  • Calibration of star formation indicators
  • Age dating of supernova remnants
  • Quantitative constraints on the coupling between star formation and the interstellar medium
  • Identification and characterization of variable stars
  • Kinematic decompositions of structural components
  • Cross-identification of multi-wavelength sources and emission line objects
PHAT Brick coverage:

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Data Release

All PHAT data products are available as files from the MAST Archive. The Data Lab service provided here is database access to the photometric catalog, including the combined photometry and the single epoch measurements.

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Data Reduction

The PHAT survey, the data reduction procedure, and photometric pipeline are described in the following papers:

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