J/ApJ/915/21 CHAOS. VI. Direct abundances in NGC 2403 (Rogers+, 2021)
CHAOS. VI. Direct abundances in NGC 2403.
Rogers N.S.J., Skillman E.D., Pogge R.W., Berg D.A., Moustakas J.,
Croxall K.V., Sun J.
<Astrophys. J., 915, 21 (2021)>
=2021ApJ...915...21R 2021ApJ...915...21R
ADC_Keywords: Abundances; H II regions; Galaxies, nearby; Spectra, optical
Keywords: Chemical abundances ; Spiral galaxies ; Galaxy evolution ;
Interstellar medium ; H II regions
Abstract:
We report the direct abundances for the galaxy NGC 2403 as observed by
the CHemical Abundances Of Spirals (CHAOS) project. Using the
Multi-Object Double Spectrograph on the Large Binocular Telescope, we
observe two fields with HII regions that cover an Rg/Re range of
0.18-2.31. Thirty-two HII regions contain at least one auroral line
detection, and we detect a total of 122 temperature-sensitive auroral
lines. Here, for the first time, we use the intrinsic scatter in the
Te-Te diagrams, added in quadrature to the uncertainty on the measured
temperature, to determine the uncertainty on an electron temperature
inferred for one ionization zone from a measurement in a different
ionization zone. We then use all available temperature data within a
HII region to obtain a weighted-average temperature within each
ionization zone. We rederive the oxygen abundances of all CHAOS
galaxies using this new temperature prioritization method, and we find
that the gradients are consistent with the results of a recent study
of Berg+ (2020, J/ApJ/893/96). For NGC 2403, we measure a direct
oxygen abundance gradient of -0.09(±0.03)dex/Re, with an intrinsic
dispersion of 0.037(±0.017)dex and a N/O abundance gradient of
-0.17(±0.03)dex/Re with an intrinsic dispersion of
0.060(±0.018)dex. For direct comparison, we use the line intensities
from an earlier study of NGC 2403 by Berg et al. and find their
recomputed values for the O/H and N/O gradients are consistent with
ours.
Description:
The Multi-Object Double Spectrograph (MODS) on the Large Binocular
Telescope (LBT) is used to observe two fields of NGC 2403. MODS uses
the G400L grating (400lines/mm; R∼1850) for the blue and the G670L
grating (250lines/mm; R∼2300) for the red to cover a wavelength range
of 3200-10000Å.
The first and second fields were observed on 2017 November 16 and
2018 February 8, respectively.
Slits are cut to target bright HII regions spanning the disk of the
galaxy. The slit locations are shown in Figure 1.
Objects:
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RA (ICRS) DE Designation(s)
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07 36 51.33 +65 36 09.6 NGC 2403 = UGC 3918
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 145 33 *NGC 2403 MODS/LBT observations
tablea1.dat 48 1881 *Emission line intensities in NGC 2403
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Note on table2.dat: Table 2 provides the radial locations of, and the auroral
lines detected in, each of the 33 HII regions targeted.
Note on tablea1.dat: Table A1 reports the line intensities relative to Hβ
measured from the HII regions in NGC 2403.
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See also:
VI/64 : Recombination line intensities for hydrogenic ions (Storey+ 1995)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/448/955 : Abundances of emission galaxies in SDSS-DR3 (Izotov+, 2006)
J/ApJ/675/1213 : Abundances in M33 HII regions (Rosolowsky+, 2008)
J/ApJ/700/654 : Keck sp. of extragalactic HII regions (Esteban+ 2009)
J/ApJS/190/233 : Spectrosc. & abundances of SINGS galaxies (Moustakas+, 2010)
J/ApJ/765/140 : Stacked sp. of SDSS star forming galaxies (Andrews+, 2013)
J/A+A/559/A114 : Updated O3N2 and N2 abundance indicators (Marino+, 2013)
J/AJ/146/86 : Cosmicflows-2 catalog (Tully+, 2013)
J/ApJ/806/16 : CHemical Abundances of Spirals. I. NGC628 (Berg+, 2015)
J/ApJ/808/42 : CHemical Abundances of Spirals. II. M51 (Croxall+, 2015)
J/MNRAS/455/2627 : Oxygen abundance gradient in M81 (Arellano-Cordova+, 2016)
J/ApJ/830/4 : HII region abundances in NGC 5457 (M101) (Croxall+, 2016)
J/A+A/587/A70 : CALIFA face-on spiral gal. oxygen (Sanchez-Menguiano+, 2016)
J/ApJ/853/151 : Oxygen abund. for giant HII regions in NGC 2403 (Mao+, 2018)
J/ApJ/887/80 : Gas phase oxygen abundances for HII regions (Kreckel+, 2019)
J/ApJS/244/24 : A z=0 Multiwavelength Galaxy Synthesis. I. (Leroy+, 2019)
J/ApJ/893/96 : CHAOS IV: NGC3184 LBT obs. (Berg+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Gal Galaxy name
9- 16 A8 --- ID HII region ID within galaxy (G1)
18 I1 h RAh Hour of right ascension (J2000)
20- 21 I2 min RAm Minute of right ascension (J2000)
23- 26 F4.1 s RAs Second of right ascension (J2000)
28 A1 --- DE- Sign of declination (J2000)
29- 30 I2 deg DEd Degree of declination (J2000)
32- 33 I2 arcmin DEm Arcminute of declination (J2000)
35- 39 F5.2 arcsec DEs Arcsecond of declination (J2000)
41- 46 F6.2 arcsec Rg [32.58/411.4] Radial distance of the region
in arcsec
48- 51 F4.2 --- Rg/Re [0.18/2.31] Radial distance of the region
normalized to the effective radius, Re
53- 56 F4.2 kpc Rg-kpc [0.5/6.34] Radial distance of the region
in kpc
58- 62 A5 --- OIII Detection of [OIII]λ4363 auroral
line within S/N>3
64- 68 A5 --- NII Detection of [NII]λ5755 auroral line
within S/N>3
70- 74 A5 --- SIII Detection of [SIII]λ6312 auroral
line within S/N>3
76- 80 A5 --- OII Detection of [OII]λλ7320,7330
auroral line within S/N>3 (1)
82- 86 A5 --- SII Detection of [SII]λλ4068,4076
auroral line within S/N>3 (1)
88- 92 A5 --- RL-CII CIIλ4267Å recombination line
detection
94- 98 A5 --- WR Presence of Wolf-Rayet features in the HII
region optical spectrum
100- 103 F4.2 --- CHb Reddening at Hβ, (Hβ) (2)
105- 108 F4.2 --- e_CHb Lower uncertainty on CHb
110- 113 F4.2 --- E_CHb Upper uncertainty on CHb
115- 117 F3.1 --- aH The underlying stellar absorption, aH (2)
119- 121 F3.1 --- e_aH Lower uncertainty on aH
123- 125 F3.1 --- E_aH Upper uncertainty on aH
127- 133 F7.2 10-19W/m2 FHb The integrated Hβ flux density,
F(Hβ), in units of
10-16erg/cm2/s (2)
135- 139 F5.2 10-19W/m2 e_FHb Lower uncertainty on FHb
141- 145 F5.2 10-19W/m2 E_FHb Upper uncertainty on FHb
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Note (1): If only one of the [OII] or [SII] lines is detected at S/N>3 then
the region is still marked with a check.
Note (2): Values taken from Table A1 by CDS.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- ID HII region identifier (G1)
11- 20 A10 --- Ion Ion identifier
22- 25 I4 0.1nm lambda [3721/9546]? Wavelength in Angstroms
27- 34 F8.3 --- Int [0/1433]? Line intensity relative to Hβ
36- 41 F6.3 --- E_Int [0.001/42]? Upper uncertainty in Int
43- 48 F6.3 --- e_Int [0/42]? Lower uncertainty in Int
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Global notes:
Note (G1): The IDs of the targets are provided in terms of the R.A. and decl.
offsets, in arcsec, of their surface brightness peaks relative to the
center of NGC 2403: RAJ2000=07:36:51.4,DEJ2000=65:36:09.2 (taken from
2MASX, see VII/233).
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History:
From electronic version of the journal
References:
Berg et al. I. NGC628. 2015ApJ...806...16B 2015ApJ...806...16B Cat. J/ApJ/806/16
Croxall et al. II. NGC5194. 2015ApJ...808...42C 2015ApJ...808...42C Cat. J/ApJ/808/42
Croxall et al. III. NGC5457. 2016ApJ...830....4C 2016ApJ...830....4C Cat. J/ApJ/830/4
Berg et al. IV. NGC3184. 2020ApJ...893...96B 2020ApJ...893...96B Cat. J/ApJ/893/96
Skillman et al. V. M101. 2020ApJ...894..138S 2020ApJ...894..138S
Rogers et al. VI. NGC2403. 2021ApJ...915...21R 2021ApJ...915...21R This catalog
Rogers et al. VII. M33. 2022ApJ...939...44R 2022ApJ...939...44R Cat. J/ApJ/939/44
Berg et al. VIII. M101. 2024ApJ...971...87B 2024ApJ...971...87B
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Dec-2022