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

被引:148
作者
Munoz, Ricardo R. [1 ,2 ]
Cote, Patrick [3 ]
Santana, Felipe A. [1 ]
Geha, Marla [2 ]
Simon, Joshua D. [4 ]
Oyarzun, Grecco A. [1 ]
Stetson, Peter B. [3 ]
Djorgovski, S. G. [5 ]
机构
[1] Univ Chile, Dept Astron, Camino Observ 1515, Santiago, Chile
[2] Yale Univ, Dept Astron, New Haven, CT 06520 USA
[3] Natl Res Council Canada, Herzberg Astron & Astrophys Program, 5071 W Saanich Rd, Victoria, BC V9E 2E7, Canada
[4] Observ Carnegie Inst Washington, 813 Santa Barbara St, Pasadena, CA 91101 USA
[5] CALTECH, Dept Astron, Pasadena, CA 91125 USA
基金
美国国家科学基金会;
关键词
galaxies: dwarf; galaxies: photometry; galaxies: structure; globular clusters: general; Local Group; surveys; DWARF SPHEROIDAL GALAXY; MILKY-WAY SATELLITE; STAR-FORMATION HISTORY; GLOBULAR-CLUSTER SYSTEM; VELOCITY DISPERSION PROFILES; HOT STELLAR-SYSTEMS; DIGITAL SKY SURVEY; URSA-MAJOR-II; GIANT STARS; GALACTIC HALO;
D O I
10.3847/1538-4357/aac16b
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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 similar or equal to 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 Sersic 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, Sersic 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.
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页数:54
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