J/PASP/133/L4501 HII regions found with LAMOST spectra (Yang+, 2021)
Searching for Galactic H II regions from the LAMOST Spectroscopic database.
Yang Y., Jiang B.
<Publ. Astron. Soc. Pac. 133, l4501 (2021)>
=2021PASP..133l4501Y 2021PASP..133l4501Y (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Spectroscopy
Keywords: Surveys - Astronomy data analysis - H II regions
Abstract:
In this paper, we pioneer a new machine-learning method to search for
HII regions in spectra from The Large Sky Area Multi-Object Fiber
Spectroscopic Telescope (LAMOST). HII regions are emission nebulae
created when young and massive stars ionize nearby gas clouds with
high-energy ultraviolet radiation. Having more HII region samples
will help us understand the formation and evolution of stars.
Machine-learning methods are often applied to search for special
celestial bodies such as H II regions. LAMOST has conducted spectral
surveys and provided a wealth of valuable spectra for the research of
special and rare celestial bodies. To overcome the problem of sparse
positive samples and diversification of negative samples, a novel
method called the self-calibrated convolution network is introduced
and implemented for spectral processing. A deep network classifier
with a structure called a self-calibrated block provides a high
precision rate, and the recall rate is improved by adding the strategy
of positive-unlabeled bagging. Experimental results show that this
method can achieve better performance than other current methods.
Eighty-nine spectra are identified as Galactic HII regions after
cross-matching with the WISE Catalog of Galactic HII Regions,
confirming the effectiveness of the method proposed in this paper.
Description:
In this study, an automatic method based on deep learning is first
implemented to select HII region candidates in the massive spectra of
LAMOST. The results from the WISE Catalog are cross-matched to confirm
the final results.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 79 89 Matched Galactic HII region candidates
of the experiment
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See also:
J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [1/89] ID number for our results
4- 12 I9 --- OBSID Unique LAMOST ID of this spectrum
14- 21 F8.4 deg RAdeg Right ascension (J2000)
23- 29 F7.4 deg DEdeg Declination (J2000)
31- 45 A15 --- WISE WISE name (1)
47- 53 F7.3 deg GLON Galactic longitude
55- 61 F7.3 deg GLAT Galactic latitude
63- 64 I2 arcmin Rad Radius of cross-matching within
this search range
66 A1 --- Class Classification (2)
68- 72 F5.3 [-] log(Ha/[NII]) Abundance Hα/[NII]
74- 79 F6.3 [-] log(Ha/[SII]) Abundance Hα/[SII]
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Note (1): in the Anderson Galactic HII regions catalog
(Anderson et al., 2014ApJS..212....1A 2014ApJS..212....1A, Cat. J/ApJS/212/1).
Note (2): Classification (from Anderson et al., 2014ApJS..212....1A 2014ApJS..212....1A,
Cat. J/ApJS/212/1) as follows:
K = Known
G = Group
C = Candidate
Q = radio Quiet
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 11-Apr-2022