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Mission Overview

Formation History of Ultra-Faint Dwarf Galaxies (FHUFD)

Primary Investigator: Tom Brown

HLSP Authors: Tom Brown

Released: 2018-01-24

Updated: 2018-01-24

Primary Reference(s): Brown et al. 2014

DOI: 10.17909/T99H5G

Citations: See ADS Statistics

Read Me

FHUFD image of Leo IV
Color image of Leo IV. Image source:


The following proposals are relevant to this HSLP: HST Program 12549

FHUFD is a deep, high-precision, photometric survey of six ultra-faint dwarf galaxy satellites of the Milky Way, in order to discern any cosmologically-driven synchronization of their formation histories. For six ultra-faint dwarf satellites of the Milky Way (Bootes I, Coma Berenices, Canes Venatici II, Hercules, Leo IV, and Ursa Major I), the team provides ACS photometry, astrometry, and co-added (drizzled) images. The photometry and images are in two bands: F606W (broad V) and F814W (I), using the STMAG photometric system. The astrometry is given in equatorial coordinates (degrees, J2000). The drizzled images have a scale of 0.03 arcsec/pix. The images from each pointing are contained in their own FITS files. Each galaxy also has a single catalog file containing the point sources detected in the images.

Data Products

The drizzled images are stored as FITS files with the following naming convention:



  • <galaxy> = name of the galaxy, e.g., "ursamajori"
  • <##> = the pointing number, as a two-digit zero-padded integer
  • <filter> = the filter used, either "f606w" or "f814w"

The source catalogs follow a similar naming convention, except there is no pointing number component, and the string "multi" is used instead of the filter. The extension for the source catalogs is "*cat.fits".

Data Access

Field R.A. (J2000) Dec. (J2000) Exptime F606W (sec) F814W (sec) Images Catalogs
Bootes I 14:00:04 +14:30:47 2340 2200 FITS Files  Source Catalog
Canes Venatici II 12:57:10 +34:19:23 20850 20850 FITS Files Source Catalog
Coma Berenices 12:27:21 +23:53:13 2340 2200 FITS Files Source Catalog
Hercules 16:31:05 +12:47:07 12880 12745 FITS Files Source Catalog
Leo IV 11:32:57 -00:31:00 20530 20530 FITS Files Source Catalog
Ursa Major I 10:35:04 +51:56:51 4215 3725 FITS Files Source Catalog



Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.