The SAMI Galaxy Survey: Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model

Mathew R. Varidel, Scott M. Croom, Geraint F. Lewis, Brendon J. Brewer, Enrico M. Di Teodoro, Joss Bland-Hawthorn, Julia J. Bryant, Christoph Federrath, Caroline Foster, Karl Glazebrook, Michael Goodwin, Brent Groves, Andrew M. Hopkins, Jon S. Lawrence, Ángel R. López-Sánchez, Anne M. Medling, Matt S. Owers, Samuel N. Richards, Richard Scalzo, Nicholas Scott & 3 others Sarah M. Sweet, Dan S. Taranu, Jesse van de Sande

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We present a novel Bayesian method, referred to as BLOBBY3D, to infer gas kinematics that mitigates the effects of beam smearing for observations using integral field spectroscopy. The method is robust for regularly rotating galaxies despite substructure in the gas distribution. Modelling the gas substructure within the disc is achieved by using a hierarchical Gaussian mixture model. To account for beam smearing effects, we construct a modelled cube that is then convolved per wavelength slice by the seeing, before calculating the likelihood function. We show that our method can model complex gas substructure including clumps and spiral arms. We also show that kinematic asymmetries can be observed after beam smearing for regularly rotating galaxies with asymmetries only introduced in the spatial distribution of the gas. We present findings for our method applied to a sample of 20 star-forming galaxies from the SAMI Galaxy Survey. We estimate the global H α gas velocity dispersion for our sample to be in the range σ¯v ∼[7, 30] km s−1. The relative difference between our approach and estimates using the single Gaussian component fits per spaxel is σ¯v/σ¯v = −0.29 ± 0.18 for the Hα flux-weighted mean velocity dispersion.

LanguageEnglish
Pages4024-4044
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume485
Issue number3
DOIs
Publication statusPublished - 1 May 2019

Fingerprint

inference
kinematics
galaxies
substructures
gases
gas
asymmetry
clumps
estimates
spatial distribution
spectroscopy
wavelength
stars
method
wavelengths
modeling

Bibliographical note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, Volume 485, Issue 3, May 2019, Pages 4024–4044, https://doi.org/10.1093/mnras/stz670. Copyright 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved

Keywords

  • methods: data analysis
  • methods: statistical
  • techniques: imaging spectroscopy
  • galaxies: kinematics and dynamics

Cite this

Varidel, M. R., Croom, S. M., Lewis, G. F., Brewer, B. J., Di Teodoro, E. M., Bland-Hawthorn, J., ... van de Sande, J. (2019). The SAMI Galaxy Survey: Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model. Monthly Notices of the Royal Astronomical Society, 485(3), 4024-4044. https://doi.org/10.1093/mnras/stz670
Varidel, Mathew R. ; Croom, Scott M. ; Lewis, Geraint F. ; Brewer, Brendon J. ; Di Teodoro, Enrico M. ; Bland-Hawthorn, Joss ; Bryant, Julia J. ; Federrath, Christoph ; Foster, Caroline ; Glazebrook, Karl ; Goodwin, Michael ; Groves, Brent ; Hopkins, Andrew M. ; Lawrence, Jon S. ; López-Sánchez, Ángel R. ; Medling, Anne M. ; Owers, Matt S. ; Richards, Samuel N. ; Scalzo, Richard ; Scott, Nicholas ; Sweet, Sarah M. ; Taranu, Dan S. ; van de Sande, Jesse. / The SAMI Galaxy Survey : Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model. In: Monthly Notices of the Royal Astronomical Society. 2019 ; Vol. 485, No. 3. pp. 4024-4044.
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abstract = "We present a novel Bayesian method, referred to as BLOBBY3D, to infer gas kinematics that mitigates the effects of beam smearing for observations using integral field spectroscopy. The method is robust for regularly rotating galaxies despite substructure in the gas distribution. Modelling the gas substructure within the disc is achieved by using a hierarchical Gaussian mixture model. To account for beam smearing effects, we construct a modelled cube that is then convolved per wavelength slice by the seeing, before calculating the likelihood function. We show that our method can model complex gas substructure including clumps and spiral arms. We also show that kinematic asymmetries can be observed after beam smearing for regularly rotating galaxies with asymmetries only introduced in the spatial distribution of the gas. We present findings for our method applied to a sample of 20 star-forming galaxies from the SAMI Galaxy Survey. We estimate the global H α gas velocity dispersion for our sample to be in the range σ¯v ∼[7, 30] km s−1. The relative difference between our approach and estimates using the single Gaussian component fits per spaxel is σ¯v/σ¯v = −0.29 ± 0.18 for the Hα flux-weighted mean velocity dispersion.",
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Varidel, MR, Croom, SM, Lewis, GF, Brewer, BJ, Di Teodoro, EM, Bland-Hawthorn, J, Bryant, JJ, Federrath, C, Foster, C, Glazebrook, K, Goodwin, M, Groves, B, Hopkins, AM, Lawrence, JS, López-Sánchez, ÁR, Medling, AM, Owers, MS, Richards, SN, Scalzo, R, Scott, N, Sweet, SM, Taranu, DS & van de Sande, J 2019, 'The SAMI Galaxy Survey: Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model', Monthly Notices of the Royal Astronomical Society, vol. 485, no. 3, pp. 4024-4044. https://doi.org/10.1093/mnras/stz670

The SAMI Galaxy Survey : Bayesian inference for gas disc kinematics using a hierarchical Gaussian mixture model. / Varidel, Mathew R.; Croom, Scott M.; Lewis, Geraint F.; Brewer, Brendon J.; Di Teodoro, Enrico M.; Bland-Hawthorn, Joss; Bryant, Julia J.; Federrath, Christoph; Foster, Caroline; Glazebrook, Karl; Goodwin, Michael; Groves, Brent; Hopkins, Andrew M.; Lawrence, Jon S.; López-Sánchez, Ángel R.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel N.; Scalzo, Richard; Scott, Nicholas; Sweet, Sarah M.; Taranu, Dan S.; van de Sande, Jesse.

In: Monthly Notices of the Royal Astronomical Society, Vol. 485, No. 3, 01.05.2019, p. 4024-4044.

Research output: Contribution to journalArticleResearchpeer-review

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T2 - Monthly Notices of the Royal Astronomical Society

AU - Varidel, Mathew R.

AU - Croom, Scott M.

AU - Lewis, Geraint F.

AU - Brewer, Brendon J.

AU - Di Teodoro, Enrico M.

AU - Bland-Hawthorn, Joss

AU - Bryant, Julia J.

AU - Federrath, Christoph

AU - Foster, Caroline

AU - Glazebrook, Karl

AU - Goodwin, Michael

AU - Groves, Brent

AU - Hopkins, Andrew M.

AU - Lawrence, Jon S.

AU - López-Sánchez, Ángel R.

AU - Medling, Anne M.

AU - Owers, Matt S.

AU - Richards, Samuel N.

AU - Scalzo, Richard

AU - Scott, Nicholas

AU - Sweet, Sarah M.

AU - Taranu, Dan S.

AU - van de Sande, Jesse

N1 - This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, Volume 485, Issue 3, May 2019, Pages 4024–4044, https://doi.org/10.1093/mnras/stz670. Copyright 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved

PY - 2019/5/1

Y1 - 2019/5/1

N2 - We present a novel Bayesian method, referred to as BLOBBY3D, to infer gas kinematics that mitigates the effects of beam smearing for observations using integral field spectroscopy. The method is robust for regularly rotating galaxies despite substructure in the gas distribution. Modelling the gas substructure within the disc is achieved by using a hierarchical Gaussian mixture model. To account for beam smearing effects, we construct a modelled cube that is then convolved per wavelength slice by the seeing, before calculating the likelihood function. We show that our method can model complex gas substructure including clumps and spiral arms. We also show that kinematic asymmetries can be observed after beam smearing for regularly rotating galaxies with asymmetries only introduced in the spatial distribution of the gas. We present findings for our method applied to a sample of 20 star-forming galaxies from the SAMI Galaxy Survey. We estimate the global H α gas velocity dispersion for our sample to be in the range σ¯v ∼[7, 30] km s−1. The relative difference between our approach and estimates using the single Gaussian component fits per spaxel is σ¯v/σ¯v = −0.29 ± 0.18 for the Hα flux-weighted mean velocity dispersion.

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KW - methods: data analysis

KW - methods: statistical

KW - techniques: imaging spectroscopy

KW - galaxies: kinematics and dynamics

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