J/other/RMxAA/45.261 Diffuse ionized gas database DIGEDA (Flores-Fajardo+ 2009)
Analysis of the diffuse ionized gas database: DIGEDA.
Flores-Fajardo N., Morisset C., Binette L.
<Rev. Mex. Astron. Astrofis., 45, 261-272 (2009)>
=2009RMxAA..45..261F 2009RMxAA..45..261F
ADC_Keywords: Galaxies, spectra ; H II regions ; Interstellar medium ;
Spectroscopy
Keywords: astronomical data bases: miscellaneous - galaxies: general -
ISM: HII regions - ISM: lines and bands - line: formation
Abstract:
Studies of the Diffuse Ionized Gas (DIG) have progressed without
providing so far any strict criterion to distinguish DIGs from HII
regions. In this work, we compile the emission line measurements of 29
galaxies that are available in the scientific literature, thereby
setting up the first DIG database DIGEDA. Making use of this database,
we proceeded to analyze global properties of the DIG using the
[NII]6583/Halpha, [OI]6300/Halpha, [OIII]5007/Hbeta and
[SII]6716/Halpha lines ratios, including the Halpha emission measure.
This analysis leads us to conclude that the [NII]/Halpha ratio
provides an objective criterion for distinguishing whether an emission
region is DIG or an HII region, while the EM(Halpha) is a useful
quantity only when the galaxies are considered individually. Finally,
we find that the emission regions of Irr galaxies classified as DIG in
the literature appear in fact to be much more similar to HII regions
than to the DIGs of spiral galaxies.
Description:
DIGEDA is a comprehensive database comprising 1061 DIG and HII region
spectroscopic observations of 29 different galaxies (25 spiral
galaxies and 4 irregulars) from 18 bibliographic references. This
survey contains galaxies with significant spread in star formation
rates, Halpha luminosities, distances, disk inclinations, slit
positions and slit orientations. The 1061 observations obtained from
these references were extracted by digitalization of published figures
or tables. The data were subsequently normalized and incorporated in
DIGEDA. This resulted in a table of 26 columns containing 1061 data
lines or records (DIGEDA.dat file). We have not performed any
reddening by dust correction or for the presence of underlying
absorption lines, although we did use the reddening corrected ratios
when made available by the authors. Missing entries are represented by
(-1) in the corresponding data field. In DIGEDA the observed areas are
classificated in three possible emission region types: HII region,
transition zones or DIG. When this classification was not reported (no
matter the criterion) for the authors, we introduce our own
classification taking into account the value of |z| as described in
the paper.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
digeda.dat 142 1061 DIG and HII regions spectroscopic observations
database
refsid.dat 68 44 Bibliographical references used for the
compilation of DIGEDA
galaxies.dat 58 29 List of galaxies in DIGEDA
refs.dat 82 17 References
--------------------------------------------------------------------------------
See also:
J/ApJS/165/307 : Ionization in neutral gas galaxies survey. I. (Meurer+, 2006)
J/ApJ/661/801 : Ionization in neutral gas galaxies survey. III. (Oey+ 2007)
Byte-by-byte Description of file: digeda.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ObsID Positive, consecutive and unique number
for row identification
6- 13 F8.2 pc Pos Value of the observation position in
each galaxy (1)
15- 19 F5.2 --- I3727 ?=-1.00 OII 3727 line intensity (2)
21- 25 F5.2 --- I4363 ?=-1.00 OIII 4363 line intensity (2)
27- 31 F5.2 --- IHb ?=-1.00 Hbeta 4861 line intensity (2)
33- 37 F5.2 --- I4959 ?=-1.00 OIII 4959 line intensity (2)
39- 43 F5.2 --- I5007 ?=-1.00 OIII 5007 line intensity (2)
45- 49 F5.2 --- I5876 ?=-1.00 HeI 5876 line intensity (2)
51- 55 F5.2 --- I6300 ?=-1.00 OI 6300 line intensity (2)
57- 61 F5.2 --- I6548 ?=-1.00 NII 6548 line intensity (2)
63- 67 F5.2 --- IHa ?=-1.00 Halpha 6563 line intensity (2)
69- 73 F5.2 --- I6583 ?=-1.00 NII 6583 line intensity (2)
75- 79 F5.2 --- I6716 ?=-1.00 SII 6716 line intensity (2)
81- 85 F5.2 --- I6731 ?=-1.00 SII 6731 line intensity (2)
87- 91 F5.2 --- I16+31 ?=-1.00 SII 6716+6731 line intensity (2)
93- 97 F5.2 10+4K Te ?=-1.00 Electronic temperature
99-103 F5.2 --- R16/31 ?=-1.00 SII 6716/6731 ratio
105-109 F5.2 --- R07/59 ?=-1.00 OIII 5007/4959 ratio
111-115 F5.2 --- RHa/Hb ?=-1.00 Observational or theoretical
Halpha/Hbeta ratio (3)
117-124 F8.2 pc/cm6 EM(Ha) ?=-1.00 The Halpha Emission Measure
126-127 I2 --- RefID [1/18] Bibliographical reference, in refs.dat
file
129-130 I2 --- MType Galaxy morphology and orientation (5)
133 I1 --- Slit [1/3] Slit orientation with respect to the
galactic plane (6)
135-136 I2 --- Region Refers to the three possible emission
region types (7)
138-139 I2 --- GalID Galaxy sequential number as in galaxy.dat file
141-142 I2 --- RefN Integer number pointing to the
corresponding entry in the refsid.dat file
--------------------------------------------------------------------------------
Note (1): In case that the observations was carried out perpendicular to
the galaxy plane, this is the distance from the plane, for parallel
slits this is the position from galaxy center and in face-on galaxies
the position is determined with respect to some reference point that
the authors had specified.
Note (2): Line intensities are given in arbitrary units, depending on the
authors. Divide it by IHa or IHb before using.
Note (3): The ratio is what the authors reported, were no the theoretical
2.86 was assumed to normalize the forbidden lines.
Note (5): Galaxy morphology and orientation flag for spiral galaxies as follows:
11 = spiral galaxy, edge-on object
12 = spiral galaxy, face-on object
2 = irregular galaxy
Note (6): Slit orientation flag as follows:
1 = parallel slit
2 = perpendicular slit
3 = observation of face-on object
Note (7): Emission region types flag as follows:
1 = HII regions (authors original classification)
11 = HII regions (our own classification)
2 = transition zone (authors original classification)
21 = transition zone (our own classification)
3 = DIG region (authors original classification)
31 = DIG region (our own classification)
4 = data that does not fit any classification
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refsid.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- RefID Unique identification number for each
reference, as in refs.dat file
5- 23 A19 --- BibCode Associated bibliographical reference used to
performed DIGEDA
25- 26 I2 --- RefN Integer number that relates uniquely each entry
of this table
28- 37 A10 --- Galaxy Name of the galaxies studied in each reference
39- 46 A8 --- Region Slit orientation respect to the galactic plane
in the case of edge-on galaxies, or the region
type in face-on galaxies case (1)
48 I1 --- I3727 [0/1] OII 3727 line observed (2)
50 I1 --- I4959 [0/1] OIII 4959 line observed (2)
52 I1 --- I5007 [0/1] OIII 5007 line observed (2)
54 I1 --- I5876 [0/1] HeI 5876 line observed (2)
56 I1 --- I6300 [0/1] OI 6300 line observed (2)
58 I1 --- I6583 [0/1] NII 6583 line observed (2)
60 I1 --- I6716 [0/1] SII 6716 line observed (2)
62 I1 --- I16+31 [0/1] SII 6716+6731 line observed (2)
64 I1 --- EM(Ha) [0/1] The Halpha Emission Measure flag (2)
67- 68 I2 --- NoReg Total number of areas or positions observed
within each galaxy
--------------------------------------------------------------------------------
Note (1): Slit orientation uses the conventions:
* For edge-on galaxies:
perp = used for slits that were perpendicular to the galactic plane,
parallel = used for parallel slits.
* For face-on galaxies:
Interarm = Interarm
DIG = Diffuse Ionized Gas
HII = HII region
SBR = Super Bubble Remnant
Note (2): The value is:
1 = line were observed;
0 = line were not observed
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Byte-by-byte Description of file: galaxies.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- GalID Integer number that relates uniquely the
galaxy's name to its source catalog (1)
4- 13 A10 --- Galaxy The NED catalog name of each galaxy in DIGEDA
15- 16 I2 h RAh Right ascension (J2000.0)
18- 19 I2 min RAm Right ascension (J2000.0)
21- 24 F4.1 s RAs Right ascension (J2000.0)
26 A1 --- DE- Declination sign (J2000.0)
27- 28 I2 deg DEd Declination (J2000.0)
30- 31 I2 arcmin DEm Declination (J2000.0)
33- 36 F4.1 arcsec DEs Declination (J2000.0)
38- 52 A15 --- MType Galaxy morphology in NED catalog
54- 58 F5.2 deg i ?=-1.00 The inclination angle for each galaxy
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Note (1): Messier: 1-19, New General Catalog: 20-69,
Uppsala General Catalog: 70- 89 and others 90-99
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 42 A19 --- Aut Author's name
44- 82 A39 --- Com Comments
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Acknowledgements:
Christophe Morisset, <chris.morisset(at)gmail.com>
(End) Patricia Vannier [CDS] 10-Sep-2009