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Two-point Separation Functions for Modeling Wide Binary Systems in Nearby Dwarf Galaxies

Published version
Peer-reviewed

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Authors

Kervick, Christopher  ORCID logo  https://orcid.org/0000-0001-5781-0598
Peñarrubia, Jorge 

Abstract

jats:titleAbstract</jats:title> jats:pWe use a geometric method to derive (two-dimensional) separation functions among pairs of objects within populations of specified position function jats:inline-formula jats:tex-math

</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic">dN</mml:mi> mml:mrow <mml:mo stretchy="true">/</mml:mo> </mml:mrow> mml:mid</mml:mi> <mml:mi mathvariant="bold-italic">R</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac5b5fieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. We present analytic solutions for separation functions corresponding to a uniform surface density within a circular field, a Plummer sphere (viewed in projection), and the mixture thereof—including contributions from binary objects within both subpopulations. These results enable inferences about binary object populations via direct modeling of object position and pair separation data, without resorting to standard estimators of the two-point correlation function. Analyzing mock data sets designed to mimic known dwarf spheroidal galaxies, we demonstrate the ability to recover input properties including the number of wide binary star systems and, in cases where the number of resolved binary pairs is assumed to be ≳a few hundred, characteristic features (e.g., steepening and/or truncation) of their separation function. Combined with forthcoming observational capabilities, this methodology opens a window onto the formation and/or survival of wide binary populations in dwarf galaxies, and offers a novel probe of inferred dark matter substructure on the smallest galactic scales.</jats:p>

Description

Keywords

5109 Space Sciences, 5107 Particle and High Energy Physics, 5101 Astronomical Sciences, 51 Physical Sciences

Journal Title

The Astrophysical Journal

Conference Name

Journal ISSN

0004-637X
1538-4357

Volume Title

929

Publisher

American Astronomical Society
Sponsorship
National Science Foundation (NSF) (AST-1813881)
National Science Foundation (NSF) (AST-1909584)
National Aeronautics and Space Administration (NASA) (NNG16PJ28C)