Mission Overview
The HST Survey of M31 Satellites (M31-SATELLITES)
Primary Investigator: Daniel R. Weisz
HLSP Authors: Alessandro Savino
Released: 2025-1-22
Updated: 2025-1-22
Primary Reference(s): Savino et al. 2022, Savino et al. 2025 (link coming soon!)
DOI: 10.17909/2xyp-hh35
Citations: (link coming soon!)
Source Data:
- Source Data DOI
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New Observations: HST Proposal 15902
Archival Observations (click "Expand All" to see):
Overview
The HST Survey of M31 Satellite Galaxies used HST to obtain deep ACS/WFC3 imaging of 23 low-mass galaxies associated with M31. These data consist of primary ACS/WFC and parallel WFC3/UVIS fields observed with deep F606W and F814W exposures. In addition, the program homogeneously reprocessed archival data (consisting of ACS/WFC and WFC3/UVIS exposures in F475W, F606W, and F814W) for: 13 additional low-mass galaxies within 500 kpc from M31, 2 fields in the halo of M31, 8 fields in M33. The full survey is described in Savino et al. (2024). These observations were used to produce: i) deep photometric source catalogs (obtained with DOLPHOT, Dolphin 2000, 2016), ii) a census of the RR Lyrae population in the ACS fields, and iii) lifetime star formation histories from the ACS fields. New imaging for this program was taken to satisfy common first epoch proper motion requirements.
Data Products
M31-SATELLITES provides drizzled images, star formation histories, and photometric, artificial star, and RR Lyrae catalogs for each galaxy.
Data file naming convention:
hlsp_m31-satellites_hst_<instrument>_<target>-<catType>_<filters>_v1.0_<fileType>.fits
where:
- <instrument> is the instrument used for the observation, either "acs" or "wfc3"
- <target> is the target galaxy
- <catType> is the type of catalog contained in the file (omitted for images and star formation histories)
- <filters> are the filters used to derive the product
- <fileType> is the file type suffix, "drz" for images, "sfh" for star formation history, or "cat" for catalogs
Data product types:
| _drz.fits | Drizzled image of the field that was used as the astrometric reference image for the photometric reduction. |
| _sfh.fits | Star formation history. |
| _cat.fits | Source catalog (photometric, artificial star, or RR Lyrae stars). |
Catalog types:
| phot-full | Complete photometric catalog, as obtained from the DOLPHOT photometric pipeline, including epoch-by-epoch photometry. |
| phot-clean | Cleaner photometric catalog, culled through a series of photometric quality cuts and spatial masks. |
| ast-full | Artificial star catalog, processed like the cat-full photometry. |
| ast-clean | Artificial star catalog, processed like the cat-clean photometry. |
| rrl | Catalog of RR Lyrae stars, including pulsation properties from template fitting. |
| rrl-candidates | Catalog of likely RR Lyrae stars, for which no successful template fitting was achieved. |
Data Access
MAST Portal and Astroquery
All observations are available in the MAST Portal and astroquery. Set the 'Provenance Name' filter to M31-SATELLITES in the Portal Advanced Search to match all observations. The files can be downloaded for each field as a bundle or individually retrieved by selecting the download basket. The observations can also be retrieved programmatically using the astroquery.mast module. The full M31-SATELLITES data set is larger than 50 GB, so we recommend using astroquery with 'curl_flag=True' to produce a cURL script to download the full data set, as in the code example below.
from astroquery.mast import Observations
all_obs = Observations.query_criteria(provenance_name="m31-satellites")
data_products = Observations.get_product_list(all_obs)
Observations.download_products(data_products, curl_flag=True)
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A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory.
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Search for and download M31-SATELLITES data products programmatically in Python.
