J/ApJ/806/16 CHemical Abundances of Spirals (CHAOS). I. NGC628 (Berg+, 2015)
CHAOS
I. Direct chemical abundances for H II regions in NGC 628.
Berg D.A., Skillman E.D., Croxall K.V., Pogge R.W., Moustakas J.,
Johnson-Groh M.
<Astrophys. J., 806, 16 (2015)>
=2015ApJ...806...16B 2015ApJ...806...16B (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Galaxies, nearby ; Spectroscopy ; Equivalent widths
Keywords: galaxies: abundances; galaxies: evolution;
galaxies: individual: NGC 628;
galaxies: ISM; galaxies: spiral; ISM: lines and bands
Abstract:
The CHemical Abundances of Spirals (CHAOS) project leverages the
combined power of the Large Binocular Telescope (LBT) with the broad
spectral range and sensitivity of the Multi Object Double Spectrograph
(MODS) to measure "direct" abundances (based on observations of the
temperature-sensitive auroral lines) in large samples of HII regions
in spiral galaxies. We present LBT MODS observations of 62 HII regions
in the nearby spiral galaxy NGC 628, with an unprecedentedly large
number of auroral lines measurements (18 [OIII]λ4363, 29
[NII]λ5755, 40 [SIII]λ6312, and 40
[OII]λλ7320,7330 detections) in 45 HII regions. We
conduct a uniform abundance analysis prioritizing the temperatures
derived from [SIII]λ6312 and [NII]λ5755, and report the
gas-phase abundance gradients for NGC 628. Relative abundances of S/O,
Ne/O, and Ar/O are constant across the galaxy, consistent with no
systematic change in the upper IMF over the sampled range in
metallicity. These alpha-element ratios, along with N/O, all show
small dispersions (σ∼0.1dex) over 70% of the azimuthally
averaged radius. We interpret these results as an indication that, at
a given radius, the interstellar medium in NGC 628 is chemically
well-mixed. Unlike the gradients in the nearly temperature-independent
relative abundances, O/H abundances have a larger intrinsic dispersion
of ∼0.165dex. We posit that this dispersion represents an upper limit
to the true dispersion in O/H at a given radius and that some of that
dispersion is due to systematic uncertainties arising from temperature
measurements.
Description:
Optical spectra of NGC 628 were acquired with MODS1 on the Large
Binocular Telescope (LBT) as part of the CHemical Abundances Of
Spirals (CHAOS) project on the UT dates of 2012 October 14 and 16.
Objects:
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RA (ICRS) DE Designation(s)
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01 36 41.77 +15 47 00.5 NGC 628 = M 74
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 86 64 *Logs for NGC628 Large Binocular Telescope (LBT)
observations
table3a.dat 40 3149 Emission-line intensities for LBT observations
of HII regions in NGC 628
table3b.dat 50 48 Equivalent withs for LBT observations
of HII regions in NGC 628
table5.dat 328 45 *Ionic and total abundances for MODS/LBT
observations of NGC 628
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Note on table2.dat: Observing logs for HII regions observed in NGC 628 using
MODS of the LBT on the UT dates of 2012 October 14 and 16. Each field was
observed over an integrated exposure time of 1200s on clear nights, with on
average ∼1" seeing, and airmasses less than 1.5.
Note on table5.dat: Electron temperatures and ionic and total abundances for
objects with an [OIII]4363, [NII]5755, or [SIII]6312 line signal to noise
ratio of 3σ or greater.
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See also:
VI/141 : Nebular [OIII] collision strengths - SSB (Storey+, 2014)
J/ApJ/808/42 : CHAOS II. NGC 5194 (Croxall+, 2015)
J/ApJ/752/148 : κ-distributed electrons & OIII (Nicholls+, 2012)
J/A+A/546/A2 : Spectroscopy of HII regions in nearby gal. (Sanchez+, 2012)
J/A+A/545/A43 : HII regions in NGC 628 and NGC 6946 (Cedres+, 2012)
J/ApJS/192/6 : A GALEX UV imaging survey of nearby galaxies (Lee+, 2011)
J/ApJS/190/233 : Spectroscopy & abundances of SINGS galaxies (Moustakas+, 2010)
J/ApJS/188/32 : Breit-Pauli transition probabilities for SII (Tayal+, 2010)
J/ApJ/703/1569 : Radial distribution in SINGS gal. I. (Munoz-Mateos+, 2009)
J/ApJ/700/654 : Keck spectroscopy of extragalactic HII regions (Esteban+ 2009)
J/A+A/500/1253 : Electron-impact excitation of ArIII (Munoz Burgos+, 2009)
J/ApJ/675/1213 : Abundances in M33 HII regions (Rosolowsky+, 2008)
J/A+A/466/905 : HII regions in NGC 628 (Fathi+, 2007)
J/A+A/462/535 : Low-metallicity HII regions and galaxies (Yin+, 2007)
J/ApJ/636/214 : HII regions in dwarf irregular galaxies (van Zee+, 2006)
J/A+A/441/981 : HII regions in 5 spiral galaxies (Bresolin+, 2005)
J/A+A/385/716 : N-like and O-like Breit-Pauli energy levels (Tachiev+, 2002)
J/AJ/120/1306 : NGC 628 H II regions (Lelievre+, 2000)
J/ApJ/526/544 : Collision strengths in S III (Tayal+, 1999)
J/ApJ/510/104 : Ionizing Stars of Extragalactic H II Regions (Bresolin+ 1999)
J/AJ/116/2805 : H II regions in spiral galaxies (Van Zee+, 1998)
J/A+AS/119/499 : NGC 628 and companions photometric distances (Sharina+ 1996)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Gal Galaxy name (NGC628)
7- 18 A12 --- Reg HII Region (±offsets in RA/DE)
20 I1 h RAh Hour of right ascension (J2000)
22- 23 I2 min RAm Minute of right ascension (J2000)
25- 29 F5.2 s RAs Second of right ascension (J2000)
31 A1 --- DE- Sign of declination (J2000)
32- 33 I2 deg DEd Degree of declination (J2000)
35- 36 I2 arcmin DEm Arcminute of declination (J2000)
38- 42 F5.2 arcsec DEs Arcsecond of declination (J2000)
44- 50 F7.3 arcsec Rgarc [12/300.5] Deprojected HII distance
from galaxy center in arcsec
52- 56 F5.3 --- R/R25 [0.03/1] Deprojected HII distance from galaxy
center in fraction of R25
58- 62 F5.2 kpc Rgkpc [0.4/10.5] Deprojected HII distance from
galaxy center in kpc
64- 69 F6.1 arcsec oRA [-206.5/298.4] RA offset
71- 76 F6.1 arcsec oDE [-191.1/190.2] DE offset
78 A1 --- dOIII [Y/ ] [OIII]4363 detection at 4σ?
80 A1 --- dNII [Y/ ] [NII]5755 detection at 4σ?
82 A1 --- dSIII [Y/ ] [SIII]6312 detection at 4σ?
84 A1 --- dOII [Y/ ] [OII]7320,7330 detection at 4σ?
86 A1 --- dSII [ ] [SII]4068,4076 detection at 4σ?
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Byte-by-byte Description of file: table3a.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Reg Region identifier (offsets in RA/DE) (G1)
14- 21 A8 --- Line Line identifier
23- 26 I4 0.1nm lambda [3721/9546] Wavelength in Angstroms
28 A1 --- l_Flux Limit flag on Flux
30- 34 F5.3 --- Flux [0.001/5.2]? Emission line flux
relative to Hβ
36- 40 F5.3 --- e_Flux [0.001/0.3]? Uncertainty in Flux
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Byte-by-byte Description of file: table3b.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Reg Region identifier (offsets in RA/DE) (G1)
14 A1 --- l_CHb Limit flag on CHb
15- 19 F5.3 --- CHb [0.03/0.6] Reddening value at Hβ:
CHβ=1.43*E(B-V)
21- 25 F5.3 --- e_CHb [0.01/0.03]? CHb uncertainty
27- 32 F6.1 10-19W/m2 FHb [22.6/1618] Reddening corrected Hβ flux
in units of 1e-16erg/s/cm2
34- 37 F4.1 10-19W/m2 e_FHb [0.2/12] FHb uncertainty
39- 43 F5.1 0.1nm EWHa [26.8/912.1] Hα equivalent width
in Angstroms
45- 50 F6.1 0.1nm EWHb [87.6/3474.3] Hβ equivalent width
in Angstroms
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Reg Region identifier (offsets in RA/DE) (G1)
14- 18 I5 K TO2m [7300/13800]? Measured electron temperature in
the [OII] region (1)
20- 22 I3 K e_TO2m [100/700]? TO2m uncertainty
24- 28 I5 K T03m [8200/13200]? Measured electron temperature in
the [OIII] region (1)
30- 33 I4 K e_T03m [100/1100]? T03m uncertainty
35- 39 I5 K TN2m [6700/12000]? Measured electron temperature in
the [NII] region (1)
41- 44 I4 K e_TN2m [100/1200]? TN2m uncertainty
46- 49 I4 K TS3m [5300/9900]? Measured electron temperature in
the [SIII] region (1)
51- 53 I3 K e_TS3m [0/800]? TS3m uncertainty
55- 57 I3 cm-3 ne1 [8/404]? Measured electron density ne
59- 63 I5 K TO2 [6000/12200] Used electron temperature in
the [OII] region (1)
65- 67 I3 K e_TO2 [200/900] TO2 uncertainty
69- 73 I5 K TO3 [4300/13200] Used electron temperature in
the [OIII] region (1)
75- 78 I4 K e_TO3 [500/1100] TO3 uncertainty
80- 84 I5 K TN2 [6000/12200] Used electron temperature in
the [NII] region (1)
86- 89 I4 K e_TN2 [200/1200] TN2 uncertainty
91- 95 I5 K TS3 [5300/12600] Used electron temperature in
the [SIII] region (1)
97- 99 I3 K e_TS3 [200/800] TS3 uncertainty
101-103 I3 --- ne [100/404] Used electron density
105-109 F5.2 10-5 O+/H+ [4.5/52.4] O+/H+ abundance ratio
111-115 F5.2 10-5 e_O+/H+ [0.5/13] O+/H+ uncertainty
117-121 F5.2 10-5 O++/H+ [3.8/40.5] O++/H+ abundance ratio
123-127 F5.2 10-5 e_O++/H+ [0.4/14] O++/H+ uncertainty
129-132 F4.2 [-] log(O/H) [8/9] Oxygen abundance 12+log(O/H)
134-137 F4.2 [-] e_log(O/H) [0.03/0.1] log(O/H) uncertainty
139-143 F5.2 10-6 N+/H+ [2/93] N+/H+ abundance ratio
145-149 F5.2 10-6 e_N+/H+ [0.1/15] N+/H+ uncertainty
151-155 F5.3 --- ICF(N) [1/5.6] Nitrogen ionization correction factor
157-161 F5.3 --- e_ICF(N) [0.1/0.8] ICF(N) uncertainty
163-167 F5.2 [-] log(N/O) [-1.4/-0.6] Nitrogen-to-oxygen abundance ratio
169-172 F4.2 [-] e_log(N/O) [0.01/0.2] log(N/O) uncertainty
174-177 F4.2 [-] log(N/H) [6.8/8.2] Nitrogen abundance, 12+log(N/H)
179-182 F4.2 [-] e_log(N/H) [0.03/0.2] log(N/H) uncertainty
184-188 F5.2 10-7 S+/H+ [3.4/69] S+/H+ abundance ratio
190-193 F4.2 10-7 e_S+/H+ [0.2/10] S+/H+ uncertainty
195-199 F5.1 10-7 S++/H+ [24/271] S++/H+ abundance ratio
201-205 F5.2 10-7 e_S++/H+ [0.9/21] S++/H+ uncertainty
207-211 F5.3 --- ICF(S) [1/1.7] Sulfer ionization correction factor
213-217 F5.3 --- e_ICF(S) [0.1/0.2] ICF(S) uncertainty
219-223 F5.2 [-] log(S/O) [-1.7/-1.1] Sulfer-to-oxygen abundance ratio
225-228 F4.2 [-] e_log(S/O) [0.05/0.2] log(S/O) uncertainty
230-233 F4.2 [-] log(S/H) [6.6/7.6] Sulfer abundance, 12+log(S/H)
235-238 F4.2 [-] e_log(S/H) [0.04/0.07] log(S/H) uncertainty
240-245 F6.2 10-6 Ne++/H+ [8/103]? Ne++/H+ abundance ratio
247-251 F5.3 10-6 e_Ne++/H+ [0.05/4]? Ne++/H+ uncertainty
253-257 F5.3 --- ICF(Ne) [1.2/6.3] Neon ionization correction factor
259-263 F5.3 --- e_ICF(Ne) [0.1/2.6] ICF(Ne) uncertainty
265-269 F5.2 [-] log(Ne/O) [-1/-0.4]? Neon-to-oxygen abundance ratio
271-274 F4.2 [-] e_log(Ne/O) [0.04/0.2]? log(Ne/O) uncertainty
276-279 F4.2 [-] log(Ne/H) [7.4/8.3]? Neon abundance, 12+log(Ne/H)
281-284 F4.2 [-] e_log(Ne/H) [0.05/0.2]? log(Ne/H) uncertainty
286-290 F5.2 10-7 Ar++/H+ [4.5/25.4] Ar++/H+ abundance ratio
292-295 F4.2 10-7 e_Ar++/H+ [0.1/2.4] Ar++/H+ uncertainty
297-301 F5.3 --- ICF(Ar) [1.4/3.5] Argon ionization correction factor
303-307 F5.3 --- e_ICF(Ar) [0.1/0.4] ICF(Ar) uncertainty
309-313 F5.2 [-] log(Ar/O) [-2.5/-1.9] Argon-to-oxygen abundance ratio
315-318 F4.2 [-] e_log(Ar/O) [0.05/0.2] log(Ar/O) uncertainty
320-323 F4.2 [-] log(Ar/H) [5.9/6.6] Argon abundance, 12+log(Ar/H)
325-328 F4.2 [-] e_log(Ar/H) [0.04/0.1] log(Ar/H) uncertainty
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Note (1): Electron temperatures were calculated using the
[OIII] (λ4959+λ5007)/λ4363,
[NII] (λ6548+λ6584)/λ5755, or the
[SIII] (λ9069+λ9532)/λ6312 diagnostic line ratio.
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Global notes:
Note (G1): +289.4+12.3 in tables 3 and 5 are very likely a misprint for
+298.4+12.3; corrected at CDS.
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History:
From electronic version of the journal
References:
Berg et al. I. NGC628. 2015ApJ...806...16B 2015ApJ...806...16B This catalog
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 Cat. J/ApJ/915/21
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] 21-Sep-2015