J/MNRAS/517/140 M33 massive young stellar objects (Kinson+, 2022)
Massive young stellar objects in the Local Group spiral galaxy M 33 identified
using machine learning.
Kinson D.A., Oliveira J.M., van Loon J.T
<Mon. Not. R. Astron. Soc. 517, 140 (2022)>
=2022MNRAS.517..140K 2022MNRAS.517..140K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; YSOs ; Photometry, millimetric/submm ;
Photometry, infrared
Keywords: methods: statistical - stars: formation - stars: protostars -
galaxies: individual (M 33) - Local Group -
galaxies: stellar content
Abstract:
We present a supervised machine learning classification of stellar
populations in the Local Group spiral galaxy M 33. The Probabilistic
Random Forest (PRF) methodology, previously applied to populations in
NGC 6822, utilizes both near and far-IR classification features. It
classifies sources into nine target classes: young stellar objects
(YSOs), oxygen, and carbon-rich asymptotic giant branch stars, red
giant branch, and red super-giant stars, active galactic nuclei, blue
stars (e.g. O-, B-, and A-type main sequence stars), Wolf-Rayet stars,
and Galactic foreground stars. Across 100 classification runs the PRF
classified 162746 sources with an average estimated accuracy of ∼86
per cent, based on confusion matrices. We identified 4985 YSOs across
the disc of M 33, applying a density-based clustering analysis to
identify 68 star forming regions (SFRs) primarily in the galaxy's
spiral arms. SFR counterparts to known HII regions were recovered with
∼91 per cent of SFRs spatially coincident with giant molecular clouds
identified in the literature. Using photometric measurements, as well
as SFRs in NGC 6822 with an established evolutionary sequence as a
benchmark, we employed a novel approach combining ratios of
[Halpha]/[24um] and [250um]/[500um] to estimate the relative
evolutionary status of all M 33 SFRs. Masses were estimated for each
YSO ranging from 6-27M☉. Using these masses, we estimate star
formation rates based on direct YSO counts of 0.63M☉/yr in M
33's SFRs, 0.79±0.16M☉/yr in its centre and
1.42=/-0.16M☉/yr globally.
Description:
Near infrared properties, cluster associations and estimated masses of
YSOs identified in the galaxy M33.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 119 4985 Catalogue of YSOs in M33 classified using
the PRF analysis
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right Ascension (J2000)
4- 5 I2 min RAm Right Ascension (J2000)
7- 12 F6.3 s RAs Right Ascension (J2000)
14 A1 --- DE- Declination sign (J2000)
15- 16 I2 deg DEd Declination (J2000)
18- 19 I2 arcmin DEm Declination (J2000)
21- 26 F6.3 arcsec DEs Declination (J2000)
28- 33 F6.3 mag Jmag ?=99.999 J magnitude
35- 40 F6.4 mag e_Jmag ?=9.999 J magnitude error
42- 47 F6.3 mag Hmag ?=99.999 H magnitude
49- 54 F6.4 mag e_Hmag ?=9.999 H magnitude error
56- 73 F18.15 mag Kmag K magnitude
75- 94 F20.18 mag e_Kmag K magnitude error
96- 97 I2 --- SFR-ID SFR identification number
99-117 F19.16 Msun Mass Estimated YSO mass
119 A1 --- Flag [*] Flag (1)
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Note (1): * for estimated by nearest 3 models only.
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Acknowledgements:
David Kinson, d.a.kinson(at)keele.ac.uk
(End) Patricia Vannier [CDS] 12-Nov-2022