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Galaxy and Mass Assembly (GAMA): Stellar-to-dynamical Mass Relation. I. Constraining the Precision of Stellar Mass Estimates

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Peer-reviewed

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Abstract

jats:titleAbstract</jats:title> jats:pIn this empirical work, we aim to quantify the systematic uncertainties in stellar-mass (jats:italicM</jats:italic> jats:sub⋆</jats:sub>) estimates made from spectral energy distribution (SED) fitting through stellar population synthesis (SPS) for galaxies in the local Universe by using the dynamical mass (jats:italicM</jats:italic> jats:subdyn</jats:sub>) estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high-dimensional space of galaxy properties; including size (jats:italicR</jats:italic> jats:sub jats:italice</jats:italic> </jats:sub>), velocity dispersion (jats:italicσ</jats:italic> jats:sub jats:italice</jats:italic> </jats:sub>), surface brightness (jats:italicI</jats:italic> jats:sub jats:italice</jats:italic> </jats:sub>), mass-to-light ratio (jats:italicM</jats:italic> jats:sub⋆</jats:sub>/jats:italicL</jats:italic>), rest-frame color, Sérsic index (jats:italicn</jats:italic>), and dynamical mass (jats:italicM</jats:italic> jats:subdyn</jats:sub>), and accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in jats:italicM</jats:italic> jats:sub⋆</jats:sub>/jats:italicM</jats:italic> jats:subdyn</jats:sub> is driven by jats:italicσ</jats:italic> jats:sub jats:italice</jats:italic> </jats:sub>, Sérsic index and color. We use these parameters to calibrate an SED-independent jats:italicM</jats:italic> jats:sub⋆</jats:sub> estimator, jats:inline-formula jats:tex-math

</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> mml:msub mml:mrow <mml:mover accent="true"> mml:mrow mml:miM</mml:mi> </mml:mrow> mml:mrow mml:moˆ</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> mml:mrow mml:mo⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjacde56ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. We find the random scatter of the relation jats:inline-formula jats:tex-math

</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> mml:msub mml:mrow mml:miM</mml:mi> </mml:mrow> mml:mrow mml:mo⋆</mml:mo> </mml:mrow> </mml:msub> mml:mo−</mml:mo> mml:msub mml:mrow <mml:mover accent="true"> mml:mrow mml:miM</mml:mi> </mml:mrow> mml:mrow mml:moˆ</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> mml:mrow mml:mo⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjacde56ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> to be 0.108 dex and 0.147 dex for quiescent and star-forming galaxies, respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, and star formation rate) and spectral indices (Hjats:italicα</jats:italic>, Hjats:italicδ</jats:italic>, and jats:italicD</jats:italic> jats:sub jats:italicn</jats:italic> </jats:sub>4000). For quiescent galaxies, ∼65% of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only ∼13% of the scatter. These results leave us with remaining unmodelled scatters of 0.055 dex and 0.122 dex for quiescent and star-forming galaxies, respectively. This can be interpreted as a conservative limit on the precision in jats:italicM</jats:italic> jats:sub⋆</jats:sub> that can be achieved via simple SPS modeling.</jats:p>

Description

Keywords

5101 Astronomical Sciences, 51 Physical Sciences

Journal Title

Astrophysical Journal

Conference Name

Journal ISSN

0004-637X
1538-4357

Volume Title

953

Publisher

American Astronomical Society