J/ApJ/939/44 CHAOS. VII. Large-scale abundance study in M33 (Rogers+, 2022)
CHAOS.
VII. A large-scale direct abundance study in M33.
Rogers N.S.J., Skillman E.D., Pogge R.W., Berg D.A., Croxall K.V.,
Bartlett J., Arellano-Cordova K.Z., Moustakas J.
<Astrophys. J., 939, 44 (2022)>
=2022ApJ...939...44R 2022ApJ...939...44R
ADC_Keywords: Abundances; Galaxies, nearby; H II regions; Spectra, optical;
Spectra, infrared
Keywords: Chemical abundances ; Spiral galaxies ; Triangulum Galaxy ;
Galaxy evolution ; Interstellar medium ; H II regions
Abstract:
The dispersion in chemical abundances provides a very strong
constraint on the processes that drive the chemical enrichment of
galaxies. Due to its proximity, the spiral galaxy M33 has been the
focus of numerous chemical abundance surveys to study the chemical
enrichment and dispersion in abundances over large spatial scales. The
CHemical Abundances Of Spirals project has observed ∼100 HII regions
in M33 with the Large Binocular Telescope (LBT), producing the largest
homogeneous sample of electron temperatures (Te) and direct abundances
in this galaxy. Our LBT observations produce a robust oxygen abundance
gradient of -0.037±0.007dex/kpc and indicate a relatively small
(0.043±0.015dex) intrinsic dispersion in oxygen abundance relative
to this gradient. The dispersions in N/H and N/O are similarly small,
and the abundances of Ne, S, Cl, and Ar relative to O are consistent
with the solar ratio as expected for α-process or
α-process-dependent elements. Taken together, the ISM in M33 is
chemically well-mixed and homogeneously enriched from inside out, with
no evidence of significant abundance variations at a given radius in
the galaxy. Our results are compared to those of the numerous studies
in the literature, and we discuss possible contaminating sources that
can inflate abundance dispersion measurements. Importantly, if
abundances are derived from a single Te measurement and Te-Te
relationships are relied on for inferring the temperature in the
unmeasured ionization zone, this can lead to systematic biases that
increase the measured dispersion up to 0.11 dex.
Description:
The the CHemical Abundances Of Spirals (CHAOS) project
(Berg+ 2015, J/ApJ/806/16) utilizes the Multi-Object Double
Spectrographs (MODS) on the Large Binocular Telescope (LBT) to obtain
the optical spectra of HII regions in nearby spiral galaxies.
The MODS blue channel has a wavelength coverage of 3200-5700Å and
R∼1850 for the G400L (400lines/mm) grating; the red channel has a
wavelength range of 5500-10000Å and R∼2300 for the G670L
(250lines/mm) grating.
Given its proximity and wealth of HII regions, CHAOS observed five
Multi-object slit (MOS) fields in M33 with an additional six longslit
pointings. All MOS observations and the majority of the longslit
observations took place between 2015 October 11 and 15; the remaining
longslit pointings were taken in 2015 December. Each MOS field was
observed in six 1200 second exposures, while longslit pointings were
observed for three 1200 second exposures.
For M33's parameters, we adopt the disk parameters of center, position
angle, and inclination that Koch+ (2018MNRAS.479.2505K 2018MNRAS.479.2505K) derive from a
fit to the velocity field derived from combined VLA and GBT HI 21cm
observations (see Table 1).
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
01 33 50.6 +30 39 29.9 M33 = NAME Triangulum Galaxy
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 63 99 M33 LBT/MODS observations
tablea2.dat 52 6076 M33 emission line intensities
tablea3.dat 59 2275 M33 temperatures, densities, and abundances
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See also:
VI/64 : Recombination line intensities for hydrogenic ions (Storey+ 1995)
VI/141 : Nebular [OIII] collision strengths - SSB (Storey+, 2014)
J/A+A/448/955 : Abundances of emission galaxies in SDSS-DR3 (Izotov+, 2006)
J/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006)
J/AJ/134/2474 : Ha emission-line stars in 7 dwarfs galaxies (Massey+, 2007)
J/ApJ/675/1213 : Abundances in M33 HII regions (Rosolowsky+, 2008)
J/ApJ/700/654 : Keck sp. of extragalactic HII regions (Esteban+ 2009)
J/A+A/500/1253 : Electron-impact excitation of ArIII (Munoz Burgos+, 2009)
J/A+A/512/A63 : Abundances of M33 HII regions (Magrini+, 2010)
J/ApJS/190/233 : Sp. and abundances of SINGS galaxies (Moustakas+, 2010)
J/ApJS/188/32 : Breit-Pauli transition probabilities for SII (Tayal+, 2010)
J/ApJ/790/48 : Variable stars in M31 & M33. II. LBVs (Humphreys+, 2014)
J/ApJ/808/174 : FeII radiative transition rates (Bautista+, 2015)
J/ApJ/806/16 : CHemical Abund. of Spirals (CHAOS). I. NGC628 (Berg+, 2015)
J/ApJ/808/42 : CHemical Abund. of Spirals (CHAOS) 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/ApJ/842/97 : Spectroscopic obs. of 413 HII regions in M33 (Lin+, 2017)
J/ApJS/244/24 : A z=0 Multiwavelength Galaxy Synthesis. I. (Leroy+, 2019)
J/A+A/623/A155 : SII, ClII, ArIV energy levels & transitions (Rynkun+, 2019)
J/MNRAS/497/672 : Abundances in HII regions (Arellano-Cordova+, 2020)
J/ApJ/893/96 : CHAOS IV: NGC3184 LBT obs. & 3 other gal. (Berg+, 2020)
J/ApJS/257/43 : PHANGS-ALMA: CO(2-1) imaging of galaxies (Leroy+, 2021)
J/ApJ/915/21 : CHAOS. VI. Direct abundances in NGC 2403 (Rogers+, 2021)
J/ApJ/925/76 : M33 with LAMOST sp. I. PNe & HII regions (Alexeeva+, 2022)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Region HII region identifier (1)
14- 14 I1 h RAh [1] Hour of Right Ascension (J2000)
16- 17 I2 min RAm [33/34] Minute of Right Ascension (J2000)
19- 22 F4.1 s RAs Second of Right Ascension (J2000)
24 A1 --- DE- [+] Sign of Declination (J2000)
25- 26 I2 deg DEd [30] Degree of Declination (J2000)
28- 29 I2 arcmin DEm [11/52] Arcminute of Declination (J2000)
31- 35 F5.2 arcsec DEs Arcsecond of Declination (J2000)
37- 40 F4.2 kpc Rgc [0.13/7.5] Distance from galactic center
42- 45 F4.2 --- Rgc/Re [0.05/3.3] Distance from galactic center
over effective radius
47- 61 A15 --- Ref Literature reference code(s) (2)
63 A1 --- P Measurements available in Table A3 for this
region; column added by CDS
--------------------------------------------------------------------------------
Note (1): Consistent with previous works, we report the name of the HII region
as the offset in R.A. and Decl. of the center of the extraction
profile relative to the center of the galaxy:
RAJ2000=01:33:50.6,DEJ2000=+30:39:29.9.
We exclude the object M33-224-346 from the tables in the Appendix and
from the following analysis, because it is coincident with the
Luminous Blue Variable (LBV) M33C-7256. See Section 2.2.
Note (2): Reference code as follows:
A22 = Alexeeva & Zhao (2022MNRAS.505.2361A 2022MNRAS.505.2361A);
B11 = Bresolin (2011ApJ...730..129B 2011ApJ...730..129B);
C06 = Crocket et al. (2006ApJ...637..741C 2006ApJ...637..741C);
L17 = Lin et al. (2017, J/ApJ/842/97);
R08 = Rosolowsky & Simon (2008, J/ApJ/675/1213);
T16 = Toribio San Cipriano et al. (2016MNRAS.458.1866T 2016MNRAS.458.1866T).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Region HII region identifier
14- 26 A13 --- Param Parameter description (1)
28- 36 E9.3 --- Value [0/2031]? Parameter value (2)
38- 44 E7.1 --- e_Value [0/42]? Uncertainty in Value
46- 52 E7.1 --- lowValue [0/4.3]? Lower uncertainty in Value (3)
--------------------------------------------------------------------------------
Note (1): The majority of parameters are the emission line identifiers and
associated wavelengths in Angstroms. The last three parameters for
each region are the best-fit reddening correction at Hβ,
c(Hbeta), the stellar absorption equivalent width, aH, and the
Hbeta flux, FHbeta.
Note (2): The line fluxes are relative to Hβ. The c(Hbeta) values are
unitless, aH is in Angstroms, and FHbeta is in
units of 1e-16 ergs/s/cm^2.
Note (3): Only the aH values have asymmetric uncertainties. This column
gives the lower uncertainty while "e_Value" is the upper uncertainty.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Region HII region identifier
14- 33 A20 --- Param Parameter description (1)
35- 42 F8.2 --- Value [-7.36/28100]? Parameter value
43 A1 --- u_Value [:] Uncertainty flag on Value (2)
45- 51 F7.2 --- E_Value [0.01/4900]? Upper uncertainty in Value
53- 59 F7.2 --- e_Value [0.02/4900]? Lower uncertainty in Value
--------------------------------------------------------------------------------
Note (1): The electron temperatures, electron densities, ionic abundances,
and total abundances. Units are given inside parentheses.
Note (2): The MCMC technique described in Section 3.1 can result in large
errors on ne,[ClIII]; [ClIII] densities with uncertainty larger
than three times the calculated density are reported with ":".
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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 Cat. J/ApJ/915/21
Rogers et al. VII. M33. 2022ApJ...939...44R 2022ApJ...939...44R This catalog
Berg et al. VIII. M101. 2024ApJ...971...87B 2024ApJ...971...87B
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Sep-2024