J/PASP/130/K4301 101 Galactic HII regions spectroscopy (Wang+, 2018)
Spectroscopic identification and chemical distribution of HII regions in the
Galactic anti-center area from LAMOST.
Wang L.-L., Luo A.-L., Hou W., Wang M.-X., Du B., Qin L., Han J.-S.
<Publ. Astron. Soc. Pac., 130, k4301 (2018)>
=2018PASP..130k4301W 2018PASP..130k4301W (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Spectroscopy
Keywords: ISM: abundances - (ISM:) HII regions - Galaxy: abundances -
techniques: spectroscopic
Abstract:
We spectroscopically identify 101 Galactic HII regions using spectra
from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope
(LAMOST) survey, cross-matched with an HII region catalog derived from
the all-sky Wide-Field Infrared Survey Explorer (WISE) data. Among all
HII regions in our sample, 47 sources are newly confirmed. Spatially,
most of our identified HII regions are located in the anti-center area
of the Galaxy. For each of the HII regions, we accurately extract and
measure the nebular emission lines of the spectra, and estimate the
oxygen abundances using the strong-line method. We focus on the
abundance distribution of HII regions in the Galactic anti-center
area. Accordingly, we derive the oxygen abundance gradient with a
slope of -0.036±0.004dex/kpc, covering a range of RG from 8.1 to
19.3kpc. In particular, we also fit the outer disk objects with a
slope of -0.039±0.012dex/kpc, which indicates that there is no
flattening of the radial oxygen gradient in the outer Galactic disk.
Description:
We presented the spectroscopic identifications of 101 HII regions
based on the WISE HII region catalog at
http://astro.phys.wvu.edu/wise, among which 47 sources were newly
confirmed. We first selected the spectra with [SII]6718,6732 emission
lines, and thereafter classified the HII regions from other types of
gaseous nebulae using an emission-line diagnostic based on
[SII]6718,6732/Hα versus [NII]6585/Hα. Spatially, most of
our HII regions were located in the anti-center direction of the Milky
Way, which provides opportunities for studying the radial gradient of
chemical abundance in the Galactic anti-center area.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 98 101 Catalog for the spectroscopic properties of
HII regions in our sample
table2.dat 32 11 Comparison of 12+log(O/H) between our abundance
values and Te-based ones from the literature
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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: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Name (GLLL.lll+BB.bbb) (1)
16 A1 --- n_Name [*] * for our newly confirmed HII regions
18- 24 F7.3 deg GLON Galactic longitude (1)
26- 32 F7.3 deg GLAT Galactic latitude (1)
34- 37 F4.2 deg Rad ?=- Radius (1)
39- 42 F4.1 kpc RG ?=- Galactocentric radius (1)
44 A1 --- Cat [KQGC] (2)
46- 52 F7.2 0.1nm EWHa Hα equivalent width
54- 58 F5.2 0.1nm e_EWHa rms uncertainty on EWHa
60- 63 F4.2 --- [OIII]/Hb ?=- Line ratio [OIII]5007/Hβ, not
corrected for interstellar extinction (3)
65- 68 F4.2 --- e_[OIII]/Hb ? rms uncertainty on [OIII]/Hb
70- 73 F4.2 --- [NII]/Ha Line ratio [NII]6585/Hα, not corrected
for interstellar extinction (3)
75- 78 F4.2 --- e_[NII]/Ha rms uncertainty on [NII]/Ha
80- 83 F4.2 --- [SII]/Ha Line ratio [SII]6718,673/Hα, not
corrected for interstellar extinction
85- 88 F4.2 --- e_[SII]/Ha rms uncertainty on [SII]/Ha
90- 93 F4.2 --- 12+log(O/H) Abundance 12+log(O/H), not corrected for
interstellar extinction)
95- 98 F4.2 --- e_12+log(O/H) rms uncertainty on 12+log(O/H)
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Note (1): from WISE catalog V2.0, at http://astro.phys.wvu.edu/wise.
Note (2): Classification of HII regions presented by Anderson et al.
(2014, Cat. J/ApJS/212/1)as follows:
K = known
C = candidate
G = group
Q = radio quiet
Note (3): If Hbeta or [OIII]lambda5007 have not been detected in our spectra,
the line ratios [OIII]/Hbeta are labeled as "---".
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Name (GLLL.lll+BB.bbb)
17- 20 A4 --- OName Other name (SNNN)
22- 25 F4.2 --- 12+log(O/H) Abundance 12+log(O/H), this work
27- 30 F4.2 --- 12+log(O/H)l Abundance 12+log(O/H), literature
32 I1 --- r_12+log(O/H)l Reference for 12+(O/H)l (1)
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Note (1): References as follows:
1 = Esteban et al., 2017MNRAS.471..987E 2017MNRAS.471..987E
2 = Rudolph et al., 2006, Cat. J/ApJS/162/346
3 = Fernandez-Martin et al., 2017A&A...597A..84F 2017A&A...597A..84F
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Apr-2019