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A MegaCam Survey of Outer Halo Satellites. I. Description of the Survey

Muñoz, Ricardo R. and Côté, Patrick and Santana, Felipe A. and Geha, Marla and Simon, Joshua D. and Oyarzún, Grecco A. and Stetson, Peter B. and Djorgovski, S. G. (2018) A MegaCam Survey of Outer Halo Satellites. I. Description of the Survey. Astrophysical Journal, 860 (1). Art. No. 65. ISSN 1538-4357. doi:10.3847/1538-4357/aac168.

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We describe a deep, systematic imaging study of satellites in the outer halo of the Milky Way. Our sample consists of 58 stellar overdensities—i.e., substructures classified as either globular clusters, classical dwarf galaxies, or ultra-faint dwarf galaxies—that are located at Galactocentric distances of R_(GC) ≥ 25 kpc (outer halo) and out to ~400 kpc. This includes 44 objects for which we have acquired deep, wide-field, g- and r-band imaging with the MegaCam mosaic cameras on the 3.6 m Canada–France–Hawaii Telescope and the 6.5 m Magellan-Clay telescope. These data are supplemented by archival imaging, or published gr photometry, for an additional 14 objects, most of which were discovered recently in the Dark Energy Survey (DES). We describe the scientific motivation for our survey, including sample selection, observing strategy, data reduction pipeline, calibration procedures, and the depth and precision of the photometry. The typical 5σ point-source limiting magnitudes for our MegaCam imaging—which collectively covers an area of ≈52 deg^2—are g_(lim) ≃ 25.6 and r_(lim) ≃ 25.3 AB mag. These limits are comparable to those from the coadded DES images and are roughly a half-magnitude deeper than will be reached in a single visit with the Large Synoptic Survey Telescope. Our photometric catalog thus provides the deepest and most uniform photometric database of Milky Way satellites available for the foreseeable future. In other papers in this series, we have used these data to explore the blue straggler populations in these objects, their density distributions, star formation histories, scaling relations, and possible foreground structures.

Item Type:Article
Related URLs:
URLURL TypeDescription
Côté, Patrick0000-0003-1184-8114
Santana, Felipe A.0000-0002-4023-7649
Geha, Marla0000-0002-7007-9725
Oyarzún, Grecco A.0000-0003-0028-4130
Stetson, Peter B.0000-0001-6074-6830
Djorgovski, S. G.0000-0002-0603-3087
Additional Information:© 2018 The American Astronomical Society. Received 2017 August 10; revised 2018 March 20; accepted 2018 April 9; published 2018 June 12. Based on observations obtained at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. The authors thank Dongwon Kim, Helmut Jerjen, and Eduardo Balbinot for kindly sharing their photometric catalogs for several of our secondary targets. We also thank David Nidever for providing code used for the SMASH survey to help derive astrometric solutions using GAIA as reference and an anonymous referee for helping us improve this article. This work was supported in part by the facilities and staff of the Yale University Faculty of Arts and Sciences High Performance Computing Center. R.R.M. acknowledges partial support from project BASAL PFB-06, as well as FONDECYT project N°1170364. M.G. acknowledges support from the National Science Foundation under award number AST-0908752 and the Alfred P. Sloan Foundation. S.G.D. was supported in part by the NSF grants AST-1313422, AST-1413600, AST-1518308, and by the Ajax Foundation. This work was supported in part by the facilities and staff of the Yale University Faculty of Arts and Sciences High Performance Computing Center.
Funding AgencyGrant Number
Yale UniversityUNSPECIFIED
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1170364
Alfred P. Sloan FoundationUNSPECIFIED
Ajax FoundationUNSPECIFIED
Subject Keywords:galaxies: dwarf – galaxies: fundamental parameters – galaxies: photometry – Galaxy: halo – globular clusters: general – Local Group
Issue or Number:1
Record Number:CaltechAUTHORS:20180612-092128138
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Official Citation:Ricardo R. Muñoz et al 2018 ApJ 860 65
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86992
Deposited By: Tony Diaz
Deposited On:12 Jun 2018 16:33
Last Modified:15 Nov 2021 20:44

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