PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31
The Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Hubble Space Telescope program imaging ∼0.45 deg ^2 of the southern half of M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. The PHAST survey area extends the northern coverage of the Panc...
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2025-01-01
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| author | Zhuo Chen Benjamin Williams Dustin Lang Andrew Dolphin Meredith Durbin Julianne J. Dalcanton Adam Smercina Léo Girardi Claire E. Murray Eric F. Bell Martha L. Boyer Richard D’Souza Karoline Gilbert Karl Gordon Puragra Guhathakurta Francois Hammer L. Clifton Johnson Tod R. Lauer Margaret Lazzarini Jeremiah W. Murphy Ekta Patel Amanda Quirk Mariangelly Díaz Rodríguez Julia Christine Roman-Duval Robyn E. Sanderson Anil Seth Tobin M. Wainer Daniel R. Weisz |
| author_facet | Zhuo Chen Benjamin Williams Dustin Lang Andrew Dolphin Meredith Durbin Julianne J. Dalcanton Adam Smercina Léo Girardi Claire E. Murray Eric F. Bell Martha L. Boyer Richard D’Souza Karoline Gilbert Karl Gordon Puragra Guhathakurta Francois Hammer L. Clifton Johnson Tod R. Lauer Margaret Lazzarini Jeremiah W. Murphy Ekta Patel Amanda Quirk Mariangelly Díaz Rodríguez Julia Christine Roman-Duval Robyn E. Sanderson Anil Seth Tobin M. Wainer Daniel R. Weisz |
| author_sort | Zhuo Chen |
| collection | DOAJ |
| description | The Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Hubble Space Telescope program imaging ∼0.45 deg ^2 of the southern half of M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. The PHAST survey area extends the northern coverage of the Panchromatic Hubble Andromeda Treasury (PHAT) down to the southern half of M31, covering out to a radius of ∼13 kpc along the southern major axis and in total ∼two-thirds of M31's star-forming disk. This new legacy imaging yields stellar photometry of over 90 million resolved stars using the Advanced Camera for Surveys in the optical (F475W and F814W), and the Wide Field Camera 3 (WFC3) in the NUV (F275W and F336W). The photometry is derived using all overlapping exposures across all bands, and achieves a 50% completeness-limited depth of F475W ∼ 27.7 in the lowest surface density regions of the outer disk and F475W ∼ 26.0 in the most crowded, high surface brightness regions near M31's bulge. We provide extensive analysis of the data quality, including artificial star tests to quantify completeness, photometric uncertainties, and flux biases, all of which vary due to the background source density and the number of overlapping exposures. We also present seamless population maps of the entire M31 disk, which show relatively well-mixed distributions for stellar populations older than 1–2 Gyr, and highly structured distributions for younger populations. The combined PHAST + PHAT photometry catalog of ∼0.2 billion stars is the largest ever produced for equidistant sources and is available for public download by the community. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| spelling | doaj-art-12f8cb7afe134cb0b0accb39e9c2e8122025-01-16T19:11:53ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0197913510.3847/1538-4357/ad7e2bPHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31Zhuo Chen0https://orcid.org/0000-0002-3038-3896Benjamin Williams1https://orcid.org/0000-0002-7502-0597Dustin Lang2https://orcid.org/0000-0002-1172-0754Andrew Dolphin3https://orcid.org/0000-0001-8416-4093Meredith Durbin4https://orcid.org/0000-0001-7531-9815Julianne J. Dalcanton5https://orcid.org/0000-0002-1264-2006Adam Smercina6https://orcid.org/0000-0003-2599-7524Léo Girardi7https://orcid.org/0000-0002-6301-3269Claire E. Murray8https://orcid.org/0000-0002-7743-8129Eric F. Bell9https://orcid.org/0000-0002-5564-9873Martha L. Boyer10https://orcid.org/0000-0003-4850-9589Richard D’Souza11https://orcid.org/0000-0001-9269-8167Karoline Gilbert12https://orcid.org/0000-0003-0394-8377Karl Gordon13https://orcid.org/0000-0001-5340-6774Puragra Guhathakurta14https://orcid.org/0000-0001-8867-4234Francois Hammer15https://orcid.org/0000-0002-2165-5044L. Clifton Johnson16https://orcid.org/0000-0001-6421-0953Tod R. Lauer17https://orcid.org/0000-0003-3234-7247Margaret Lazzarini18https://orcid.org/0000-0003-3252-352XJeremiah W. Murphy19https://orcid.org/0000-0003-1599-5656Ekta Patel20https://orcid.org/0000-0002-9820-1219Amanda Quirk21https://orcid.org/0000-0001-8481-2660Mariangelly Díaz Rodríguez22https://orcid.org/0000-0002-4652-5983Julia Christine Roman-Duval23https://orcid.org/0000-0001-6326-7069Robyn E. Sanderson24https://orcid.org/0000-0003-3939-3297Anil Seth25https://orcid.org/0000-0003-0248-5470Tobin M. Wainer26https://orcid.org/0000-0001-6320-2230Daniel R. Weisz27https://orcid.org/0000-0002-6442-6030Department of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.eduDepartment of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.eduMcWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University , 5000 Forbes Ave., Pittsburgh, PA, USARaytheon , Tucson, AZ 85756, USA; Steward Observatory, University of Arizona , Tucson, AZ 85726, USADepartment of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.edu; Department of Astronomy, University of California Berkeley , Berkeley, CA 94720, USADepartment of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.edu; Center for Computational Astrophysics, Flatiron Institute , 162 Fifth Ave., New York, NY 10010, USADepartment of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.edu; Space Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USAOsservatorio Astronomico di Padova—INAF , Vicolo dell’Osservatorio 5, I-35122 Padova, ItalySpace Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USA; The William H. Miller III Department of Physics & Astronomy, Bloomberg Center for Physics and Astronomy, Johns Hopkins University , 3400 N. Charles St., Baltimore, MD 21218, USADepartment of Astronomy, University of Michigan , 1085 S. University Ave., Ann Arbor, MI 48109-1107, USASpace Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USAVatican Observatory , Specola Vaticana V-00120, Vatican City StateSpace Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USA; The William H. Miller III Department of Physics & Astronomy, Bloomberg Center for Physics and Astronomy, Johns Hopkins University , 3400 N. Charles St., Baltimore, MD 21218, USASpace Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USADepartment of Astronomy and Astrophysics, University of California Santa Cruz , University of California Observatories, 1156 High St., Santa Cruz, CA 95064, USAGEPI, Observatoire de Paris , Paris Sciences et Lettres, CNRS, Place Jules Janssen, F-92195 Meudon, FranceCenter for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University , 1800 Sherman Ave., Evanston, IL 60201, USANOAO , 950 North Cherry Ave., Tucson, AZ 85721, USADepartment of Physics and Astronomy, California State University , Los Angeles, CA 90032, USADepartment of Physics, Florida State University , 77 Chieftan Wy., Tallahassee, FL 32306, USADepartment of Physics and Astronomy, University of Utah , 115 South 1400 East, Salt Lake City, UT 84112, USADepartment of Astronomy, Columbia University , 538 West 120th St., New York, NY 10027, USADepartment of Physics, Florida State University , 77 Chieftan Wy., Tallahassee, FL 32306, USASpace Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USADepartment of Physics & Astronomy, University of Pennsylvania , Philadelphia, PA 19104, USADepartment of Physics and Astronomy, University of Utah , 115 South 1400 East, Salt Lake City, UT 84112, USADepartment of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA ; zczhuo@uw.eduDepartment of Astronomy, University of California Berkeley , Berkeley, CA 94720, USAThe Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Hubble Space Telescope program imaging ∼0.45 deg ^2 of the southern half of M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. The PHAST survey area extends the northern coverage of the Panchromatic Hubble Andromeda Treasury (PHAT) down to the southern half of M31, covering out to a radius of ∼13 kpc along the southern major axis and in total ∼two-thirds of M31's star-forming disk. This new legacy imaging yields stellar photometry of over 90 million resolved stars using the Advanced Camera for Surveys in the optical (F475W and F814W), and the Wide Field Camera 3 (WFC3) in the NUV (F275W and F336W). The photometry is derived using all overlapping exposures across all bands, and achieves a 50% completeness-limited depth of F475W ∼ 27.7 in the lowest surface density regions of the outer disk and F475W ∼ 26.0 in the most crowded, high surface brightness regions near M31's bulge. We provide extensive analysis of the data quality, including artificial star tests to quantify completeness, photometric uncertainties, and flux biases, all of which vary due to the background source density and the number of overlapping exposures. We also present seamless population maps of the entire M31 disk, which show relatively well-mixed distributions for stellar populations older than 1–2 Gyr, and highly structured distributions for younger populations. The combined PHAST + PHAT photometry catalog of ∼0.2 billion stars is the largest ever produced for equidistant sources and is available for public download by the community.https://doi.org/10.3847/1538-4357/ad7e2bGalaxiesAndromeda GalaxyStellar populationsLocal GroupHST photometry |
| spellingShingle | Zhuo Chen Benjamin Williams Dustin Lang Andrew Dolphin Meredith Durbin Julianne J. Dalcanton Adam Smercina Léo Girardi Claire E. Murray Eric F. Bell Martha L. Boyer Richard D’Souza Karoline Gilbert Karl Gordon Puragra Guhathakurta Francois Hammer L. Clifton Johnson Tod R. Lauer Margaret Lazzarini Jeremiah W. Murphy Ekta Patel Amanda Quirk Mariangelly Díaz Rodríguez Julia Christine Roman-Duval Robyn E. Sanderson Anil Seth Tobin M. Wainer Daniel R. Weisz PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 The Astrophysical Journal Galaxies Andromeda Galaxy Stellar populations Local Group HST photometry |
| title | PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 |
| title_full | PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 |
| title_fullStr | PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 |
| title_full_unstemmed | PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 |
| title_short | PHAST. The Panchromatic Hubble Andromeda Southern Treasury. I. Ultraviolet and Optical Photometry of over 90 Million Stars in M31 |
| title_sort | phast the panchromatic hubble andromeda southern treasury i ultraviolet and optical photometry of over 90 million stars in m31 |
| topic | Galaxies Andromeda Galaxy Stellar populations Local Group HST photometry |
| url | https://doi.org/10.3847/1538-4357/ad7e2b |
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