J/A+A/694/A61 Sulphur abundance distribution of HII galaxies (Gavilan+, 2025)
Deriving the abundance distribution of HII galaxies using sulphur as tracer:
Exploring the high metallicity end.
Gavilan M, Diaz A.I., Zamora S.
<Astron. Astrophys. 694, A61 (2025)>
=2025A&A...694A..61G 2025A&A...694A..61G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; H II regions ; Abundances ; Optical
Keywords: H II regions - galaxies: abundances - galaxies: ISM -
galaxies: starburst - galaxies: star clusters: general -
Abstract:
The main objective of this work is to derive the distribution of the
metal content of HII galaxies using sulphur as an abundance tracer.
This increases the metallicity range that can safely be reached.
We selected a sample of emission-line galaxies that we extracted from
the SDSS-DR16. These objects have a redshift of z≤0.04 so that the
[SIII] λ 9069Å emission line and H{beat} equivalent widths
that are higher than 10Å in emission were included, and they are
compact in appearance. We used the so-called direct method for objects
with the electron-temperature-sensitive [SIII] λ 6312Å
emission line, and an empirical method based on the S23 parameter. The
last provided an abundance calibration that monotonically increased up
to at least the solar value, and can be applied based on the spectral
range from 6000 to 9500Å alone.
We show that the bias that is introduced when the [OIII] λ
4363Å line is required restricts the sample to objects with an
[OIII] electron temperature higher than 10000K, and their
temperature distribution is then rather narrow. For objects with
determinations of te[SIII], the distribution is flatter and wider,
which fits a more realistic scenario better. For these objects, we
calculated the ionic abundances of sulphur and their ratios. In all
cases, S2+ was found to be the dominant ion, with a contribution
greatly exceeding that of S+. This fact justifies the adoption
te[SIII] as the dominant temperature throughout the nebula,
although in 20% of the objects, an estimated ionization correction
factor is required. For the objects in the sample that required the
detection of the [OIII] λ 4363Å line (sample 3) and
[SIII] λ 6312Å, the distribution abundances as traced
directly by oxygen and sulphur appear to be very similar to each
other. The median values are 12+log(O/H)=8.1 and 12+log(S/H)=6.4,
which corresponds to an S/O ratio of log(S/O)=-1.7 that is close to
the solar value (-1.5). However, when the restriction for weak
temperature-sensitive lines is relaxed, the abundance distribution is
wider and the median value is 12+log(S/H)=6.6. When the S/O ratio is
assumed to be constant, the median sulphur abundance value found here
would imply a median value of the oxygen abundance of 12+log(O/H)=8.3.
In summary, the abundance distributions traced by sulphur can reach
reliable abundances up to the solar value at least and provide a more
complete picture of the metallicity distribution of HII galaxies. The
method presented here only involves the red part of the spectrum
(between 6000 and 9600Å), and the effect of reddening is weak
there. Although the strong nebular [SIII] lines shift beyond the far
red spectral region for high-redshift objects, present-day infrared
spectrographs can overcome this difficulty. Observations made with
NIRSpec on board the JWST would be able to provide data for objects
with redshifts between 0 and 4.24.
Description:
We have selected a sample of emission line galaxies extracted from the
SDSS-DR16. These objects have redshift z≤0.04 in order to include the
[SIII]9060Å emission line, Hbeta equivalent widths in emission
larger than 10Å, and show a compact appearance. We have used the so
called "direct method" for those objects showing the electron
temperature sensitive [SIII]6312Å emission line, and an empirical
method based on the S_23 parameter that provides an abundance
calibration which is monotonically increasing up to, at least, the
solar value. This last method can be applied using only the spectral
range from 6000 to 9500Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 206 224 Reddening corrected emission line intensity
relative to Hbeta/100
table2.dat 127 141 Electron temperatures, ionic abundances and
total oxygen and sulphur abundance
table3.dat 19 224 Objects SDSS DR15 Plate-MJD-Fiber
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See also:
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Object number
5- 10 F6.3 --- OIII4363 ?=0 The [OIII] 4363Å reddening
corrected emission line intensity relative
to Hbeta/100
12- 16 F5.3 --- e_OIII4363 ?=- Error in OIII4363
18- 22 F5.3 --- ArIV4740 ?=0 The [ArIV] 4740Å reddening
corrected emission line intensity relative
to Hbeta/100
24- 28 F5.3 --- e_ArIV4740 ?=- Error in ArIV4740
30- 32 I3 --- Hbeta [100] The Hbeta value relative to Hbeta/100
34- 38 F5.3 --- e_Hbeta Error in Hbeta
40- 46 F7.3 --- OIII4959 The [OIII] 4959Å reddening
corrected emission line intensity relative
to Hbeta/100
48- 52 F5.3 --- e_OIII4959 Error in OIII4959
54- 60 F7.3 --- OIII5007 The [OIII] 5007Å reddening
corrected emission line intensity relative
to Hbeta/100
62- 66 F5.3 --- e_OIII5007 Error in OIII5007
68- 73 F6.3 --- SIII6312 The [SIII] 6312Å reddening
corrected emission line intensity relative
to Hbeta/100
75- 79 F5.3 --- e_SIII6312 Error in SIII6312
81- 87 F7.3 --- Halpha Halpha reddening corrected emission
line intensity relative
to Hbeta/100
89- 93 F5.3 --- e_Halpha Error in H_alpha
95-100 F6.3 --- SII6717 The [SII] 6717Å reddening
corrected emission line intensity relative
to Hbeta/100
102-106 F5.3 --- e_SII6717 Error in SII6717
108-113 F6.3 --- SII6731 The [SII] 6731Å reddening
corrected emission line intensity relative
to Hbeta/100
115-119 F5.3 --- e_SII6731 Error in SII6731
121-126 F6.3 --- ArIII7135 ?=0 The [ArIII] 7135Å reddening
corrected emission line intensity relative
to Hbeta/100
128-132 F5.3 --- e_ArIII7135 ?=- Error in ArIII7135
134-138 F5.3 --- OII7322 ?=0 The [OII] 7322Å reddening
corrected emission line intensity relative
to Hbeta/100
140-144 F5.3 --- e_OII7322 ?=- Error in OII7322
146-151 F6.3 --- OII7330 ?=0 The [OII] 7330Å reddening
corrected emission line intensity relative
to Hbeta/100
153-157 F5.3 --- e_OII7330 ?=- Error in OII7330
159-164 F6.3 --- SIII9069 The [SIII] 9069Å reddening
corrected emission Line intensity relative
to Hbeta/100
166-170 F5.3 --- e_SIII9069 Error in SIII9069
172-180 F9.3 10-20W/m2 FHbeta Hbeta flux in 10-17erg/s/cm2
182-187 F6.3 10-20W/m2 e_FHbeta Error in FHbeta
189-196 F8.3 0.1nm EWHbeta Hbeta equivalent width
198-201 F4.2 --- chbeta Extintion coefficient
203-206 F4.2 --- e_chbeta Error in chbeta
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Object number
5- 9 F5.3 10+4K teOIII OIII Electron temperature
11- 15 F5.3 10+4K e_teOIII Error in teOIII
17- 21 F5.3 10+4K teSIII SIII Electron temperature
23- 27 F5.3 10+4K e_teSIII Error in teSIII
29- 32 F4.2 --- O+ 12 + log(O+/H+)
34- 37 F4.2 --- e_O+ Error in O+
39- 42 F4.2 --- O2+ 12 + log(O2+/H+)
44- 47 F4.2 --- e_O2+ Error in O2+
49- 52 F4.2 --- S+ 12 + lof(S+/H+)
54- 57 F4.2 --- e_S+ Error in S+
59- 62 F4.2 --- S2+ 12 + log(S2+/H+)
64- 67 F4.2 --- e_S2+ Error in S2+
69- 72 F4.2 --- S3+ ?=- 12 + log(S3+/H+)
74- 77 F4.2 --- e_S3+ ?=- Error in S3+
79- 82 F4.2 --- Ar2+ ?=- 12 + log(Ar2+/H+)
84- 87 F4.2 --- e_Ar2+ ?=- Error in Sr2+
89- 92 F4.2 --- Ar3+ ?=- 12 + log(Ar3+/H+)
94- 97 F4.2 --- e_Ar3+ ?=- Error in Ar3+
99-102 F4.2 --- ICF Ionization correction factor
104-107 F4.2 --- e_ICF Error in ICF
109-112 F4.2 --- O/H 12 + log(O/H)
114-117 F4.2 --- e_O/H Error in O/H
119-122 F4.2 --- S/H 12 + log(S/H)
124-127 F4.2 --- e_S/H Error in S/H
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Object number
5- 8 I4 --- Plate SDSS DR15 plate number
10- 14 I5 --- MJD SDSS DR15 MJD number
16- 19 I4 --- Fiber SDSS DR15 Fiber number
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Acknowledgements:
Marta Gavilan, marta(at)langeber.es
(End) Patricia Vannier [CDS] 17-Dec-2024