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A MegaCam Survey of Outer Halo Satellites. III. Photometric and Structural Parameters

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. III. Photometric and Structural Parameters. Astrophysical Journal, 860 (1). Art. No. 66. ISSN 1538-4357. doi:10.3847/1538-4357/aac16b. https://resolver.caltech.edu/CaltechAUTHORS:20180612-094525500

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Abstract

We present structural parameters from a wide-field homogeneous imaging survey of Milky Way satellites carried out with the MegaCam imagers on the 3.6 m Canada–France–Hawaii Telescope and 6.5 m Magellan-Clay telescope. Our survey targets an unbiased sample of "outer halo" satellites (i.e., substructures having galactocentric distances greater than 25 kpc) and includes classical dSph galaxies, ultra-faint dwarfs, and remote globular clusters. We combine deep, panoramic gr imaging for 44 satellites and archival gr imaging for 14 additional objects (primarily obtained with the DECam instrument as part of the Dark Energy Survey) to measure photometric and structural parameters for 58 outer halo satellites. This is the largest and most uniform analysis of Milky Way satellites undertaken to date and represents roughly three-quarters (58/81 ≃ 72%) of all known outer halo satellites. We use a maximum-likelihood method to fit four density laws to each object in our survey: exponential, Plummer, King, and Sérsic models. We systematically examine the isodensity contour maps and color–magnitude diagrams for each of our program objects, present a comparison with previous results, and tabulate our best-fit photometric and structural parameters, including ellipticities, position angles, effective radii, Sérsic indices, absolute magnitudes, and surface brightness measurements. We investigate the distribution of outer halo satellites in the size–magnitude diagram and show that the current sample of outer halo substructures spans a wide range in effective radius, luminosity, and surface brightness, with little evidence for a clean separation into star cluster and galaxy populations at the faintest luminosities and surface brightnesses.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4357/aac16bDOIArticle
ORCID:
AuthorORCID
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 April 28; accepted 2018 April 30; 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. This paper is based on observations obtained with the MegaPrime/MegaCam, a joint project of the Canada–France–Hawaii Telescope (CFHT) and CEA/DAPNIA, at CFHT, which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work was supported in part by the facilities and staff of the Yale University Faculty of Arts and Sciences High Performance Computing Center. The authors would like to thank an anonymous referee for helping us improve this article and Alan McConnachie for helpful discussions. R.R.M. and F.A.S. acknowledge partial support from project BASAL PFB-06. RRM also acknowledges support from FONDECYT project No. 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 NSF grants AST-1313422, AST-1413600, AST-1518308 and by the Ajax Foundation. Facilities: CFHT - Canada-France-Hawaii Telescope, Magellan.
Funders:
Funding AgencyGrant Number
Yale UniversityUNSPECIFIED
Basal-CATAPFB-06
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1170364
NSFAST-0908752
Alfred P. Sloan FoundationUNSPECIFIED
NSFAST-1313422
NSFAST-1413600
NSFAST-1518308
Ajax FoundationUNSPECIFIED
Subject Keywords:galaxies: dwarf – galaxies: photometry – galaxies: structure – globular clusters: general – Local Group – surveys
Issue or Number:1
DOI:10.3847/1538-4357/aac16b
Record Number:CaltechAUTHORS:20180612-094525500
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180612-094525500
Official Citation:Ricardo R. Muñoz et al 2018 ApJ 860 66
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86996
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Jun 2018 17:03
Last Modified:15 Nov 2021 20:44

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