J/A+A/640/A72 Distance results for the Galactic Ring Survey (Riener+, 2020)
Autonomous Gaussian decomposition of the Galactic Ring Survey.
II. The Galactic distribution of 13CO.
Riener M., Kainulainen J., Henshaw J.D., Beuther H.
<Astron. Astrophys. 640, A72 (2020)>
=2020A&A...640A..72R 2020A&A...640A..72R (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio lines ; Galactic plane ; Stars, distances ;
Velocity dispersion ; Interstellar medium
Keywords: methods: data analysis - radio lines: ISM -
ISM: kinematics and dynamics - ISM: lines and bands -
Galaxy: structure - Galaxy: kinematics and dynamics
Abstract:
Knowledge about the distribution of CO emission in the Milky Way is
essential to understand the impact of Galactic environment on the
formation and evolution of structures in the interstellar medium.
However, currently our insight about the fraction of CO in spiral arm
and interarm regions is still limited by large uncertainties in
assumed rotation curve models or distance determination techniques. In
this work we use the Bayesian approach from Reid et al.
(2016ApJ...823...77R 2016ApJ...823...77R) and Reid et al. (2019ApJ...885..131R 2019ApJ...885..131R) that is
based on our presently most precise knowledge about the structure and
kinematics of the Milky Way to obtain the current best assessment of
the Galactic distribution of 13CO from the Galactic Ring Survey
(GRS). We performed two different distance estimates that either
included (Run A) or excluded (Run B) a model for Galactic features,
such as spiral arms or spurs. We also include a prior for the solution
of kinematic distance ambiguity that was determined from a compilation
of literature distances and an assumed size-linewidth relationship.
Even though the two distance runs show strong differences due to the
prior for Galactic features for Run A and larger uncertainties due to
kinematic distances in Run B, the majority of their distance results
are consistent with each other within the uncertainties. We find that
the fraction of 13CO emission associated with spiral arm features
varies between 76% to 84% between the two distance runs. The vertical
distribution of the gas is concentrated around the Galactic midplane
showing full-width at half-maximum values of ∼75pc. We do not find any
significant difference between gas emission properties associated with
spiral arm and interarm features. In particular the distribution of
velocity dispersion values of gas emission in spurs and spiral arms is
very similar. We detect a trend of higher velocity dispersion values
with increasing heliocentric distance, which we however attribute to
beam averaging effects caused by differences in spatial resolution. We
argue that the true distribution of the gas emission is likely more
similar to a combination of the two discussed distance results, and
highlight the importance of using complementary distance estimations
to safeguard against the pitfalls of any single approach. We conclude
that the methodology presented in this work is a good approach for
distance determinations of gas emission features in Galactic plane
surveys.
Description:
In this work we present distance estimates for the Gaussian
decomposition results of the Galactic Ring Survey presented in Riener
et al. (2020, Cat. J/A+A/633/A14). Using the most recent version of
the Bayesian Distance Calculator tool Reid et al.
(2016ApJ...823...77R 2016ApJ...823...77R, 2019ApJ...885..131R 2019ApJ...885..131R), we perform two separate
distance calculations for the ∼4.6 million individual Gaussian fit
components, for which we vary the settings so as to either incorporate
or neglect a prior for an association with spiral arm structure
(labelled Run A and Run B, respectively). In addition, we include
literature distance information of objects overlapping with the GRS
coverage as prior information for solving the kinematic distance
ambiguity.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 99 4648990 Distance results
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See also:
J/A+A/633/A14 : GaussPy+ decomposition of Galactic Ring Survey (Riener+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 F6.3 deg GLON [14/56] Galactic longitude position
8- 13 F6.3 deg GLAT [-1.1/1.1] Galactic latitude position
15- 20 F6.2 km/s VLSR Fitted centroid velocity value
22- 26 F5.2 kpc DistA Heliocentric distance value for BDC Run A
28- 31 F4.2 kpc e_DistA Uncertainty in distA
33- 37 F5.2 kpc RgalA Galactocentric distance value for BDC Run A
39- 42 F4.2 --- probA [0/1] Estimated probability value for BDC Run A
44- 46 A3 --- ArmA Associated Galactic feature
48- 51 F4.2 --- pfarA [0/1] Probability value for the Pfar prior
53- 57 A5 --- r_DistA Reference for associated literature distance (1)
59 I1 --- FlagA [0/4] Flag for the distance choice (2)
61- 65 F5.2 kpc DistB Heliocentric distance value for BDC Run B
67- 71 F5.2 kpc e_DistB Uncertainty in distB
73- 77 F5.2 kpc RgalB Galactocentric distance value for BDC Run B
79- 82 F4.2 --- probB Estimated probability value for BDC Run B
84- 86 A3 --- ArmB Associated Galactic feature
88- 91 F4.2 --- pfarB [0/1] Probability value for the Pfar prior
93- 97 A5 --- r_DistB Reference for associated literature distance (1)
99 I1 --- FlagB [0/4] Flag for the distance choice (2)
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Note (1): References as follows:
A+09 = Anderson et al. (2009, Cat. J/ApJS/181/255);
Anderson & Bania (2009, Cat. J/ApJ/690/706)
A+14 = Anderson et al. (2014, Cat. J/ApJS/212/1)
BH14 = Battisti & Heyer (2014, Cat. J/ApJ/780/173)
C+19 = Colombo et al. (2019MNRAS.483.4291C 2019MNRAS.483.4291C)
E+12 = Rosolowsky et al. (2010,Cat. J/ApJS/188/123);
Eden et al. (2012, Cat. J/MNRAS/422/3178);
Eden et al. (2013, Cat. J/MNRAS/431/1587)
E+17 = Elia et al. (2017, Cat. J/MNRAS/471/100)
EB+15 = Ginsburg et al. (2013, Cat. J/ApJS/208/14);
Ellsworth-Bowers et al. (2015. Cat. J/ApJ/799/29);
Svoboda et al. (2016, Cat. J/ApJ/822/59)
R+18 = Leahy & Ranasinghe (2018ApJ...866....9L 2018ApJ...866....9L);
Ranasinghe & Leahy (2018AJ....155..204R 2018AJ....155..204R);
Ranasinghe & Leahy (2018MNRAS.477.2243R 2018MNRAS.477.2243R);
Ranasinghe et al. (2018AJ....155..204R 2018AJ....155..204R, 2018MNRAS.477.2243R 2018MNRAS.477.2243R);
Green (2019JApA...40...36G 2019JApA...40...36G)
R+19 = Rigby et al. (2019, Cat. J/A+A/632/A58)
RD+09 = Rathborne et al. (2009, Cat. J/ApJ/699/742);
Roman-Duval et al. (2009, Cat. J/ApJ/699/1153)
S+06 = Simon et al. (2006, Cat. J/ApJ/639/227);
Simon et al. (2006, Cat. J/ApJ/640/270);
Marshall et al. (2009ApJ...694..924M 2009ApJ...694..924M)
U+18 = Wienen et al. (2012, Cat. J/A+A/544/A146);
Urquhart et al. (2014, Cat. J/A+A/658/A41);
Urquhart et al. (2018, Cat. J/MNRAS/473/1059)
Note (2): Flag for the distance choice as follows:
0 = distance assignment yielded only one distance solution
1 = associated Gaussian fit of one distance solution did not satisfy the
criterion for the amplitude threshold
2 = distance solution with the highest probability (i.e. the highest
integrated intensity of the associated Gaussian fit) was chosen
3 = distance solution with the lowest absolute distance error was chosen
4 = near kinematic distance solution was picked randomly
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Acknowledgements:
Manuel Riener, riener(at)mpia.de
References:
Riener et al., Paper I 2020A&A...633A..14R 2020A&A...633A..14R, Cat. J/A+A/633/A14
(End) Manuel Riener [MPIA, Germany], Patricia Vannier [CDS] 02-Jun-2020