J/A+AS/101/153 Galactic H2O masers (Palagi+ 1993)
Classification and statistical properties of galactic H2O masers
Palagi F., Cesaroni R., Comoretto G., Felli M., Natale V.
<Astron. Astrophys. Suppl. Ser. 101, 153 (1993)>
=1993A&AS..101..153P 1993A&AS..101..153P
ADC_Keywords: Masers; Infrared sources
Keywords: masers - interstellar medium: general - circumstellar matter -
infrared: interstellar continuum - infrared: stars
Abstract:
The association between galactic H2O masers and IRAS sources from the
Point Source Catalog (Cat. II/125) is established for 442 sources out
of a list of 505 objects, which includes all the galactic H2O masers
north of 30°, known up to 1988. Using a multivariate statistical
analysis on the four far-IR fluxes of the associated IRAS source,
galactic H2O masers are reclassified into two classes: those
associated to star forming regions (SFR, 52%) and those associated to
late type stars (STAR, 45%). The remaining 3% cannot be included in
either class. The present classification is compared with others in
the literature. Distances for a large subsample of 1120 masers are
derived, using the galactic rotation curve for SFR and literature data
for STAR.The parameters of the H2O maser emission (e.g. integrated
flux, luminosity, variability), collected in a homogeneous way in the
Arcetri H2O atlas (Comoretto et al. 1990A&AS...84..179C 1990A&AS...84..179C), and those of
the associated IRAS sources (e.g. flux density, luminosity, colours)
are used to investigate, in a statistical way, the properties of the
STAR and SFR classes. In particular, we investigate the spatial
distribution of masers both in the galactic plane and perpendicular
to it. We also compare the H2O and IRAS luminosities, finding a good
correlation. Moreover, we find that high luminosity sources show low
colour temperatures and vice versa. The spectral profile and
variability are then investigated by different means. Finally, the
luminosity function for each maser class is derived.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 111 505 H2O Masers and IRAS-PSC sources.
table5.dat 108 505 Parameters of H2O Masers.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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3- 5 I3 --- Seq [1/505]+ Sequential number
<[PCC93] NNN> in Simbad
8- 9 I2 h RAh Right Ascension of H2O observations (B1950)
11- 12 I2 min RAm Right Ascension (minutes)
14- 17 F4.1 s RAs Right Ascension (seconds)
20 A1 --- DE- Declination Sign
21- 22 I2 deg DEd Declination of H2O observations (B1950)
24- 25 I2 arcmin DEm Right Ascension (arcminutes)
27- 30 F4.1 arcsec DEs Right Ascension (arcseconds)
35- 48 A14 --- Name Name of the maser source
53- 56 A4 --- Class Class to which the source is assigned (1)
58- 64 F7.3 deg GLON Galactic longitude
65- 71 F7.3 deg GLAT Galactic latitude
74- 84 A11 --- IRAS IRAS name
90- 95 F6.1 arcsec dRA ? R.A. offset H2O - IRAS
99-104 F6.1 arcsec dDE ? Dec. offset H2O - IRAS
111 A1 --- Rem [123mbs-] IRAS associations (2)
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Note (1): classes as follows:
SFR = star-forming region
STAR = stellar source
STRN = strange
UNKN = unknown
Note (2): This column indicates the number of IRAS sources associated
with the maser if the column contains a digit (1, 2, or 3); otherwise:
m = 2 or more masers are associated with the same IRAS sources;
'm' indicates the selected maser
b = 2 or more masers are associated with the same IRAS sources;
'b' indicates it's not the selected maser
s = not surveyed
- = extended IR source, or lack of association.
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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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3- 5 I3 --- Seq [1/505]+ Sequential number
8 A1 --- l_F.H2O [<*] Flag: < (upper limit) or
* (single component source)
11- 18 F8.1 Jy F.H2O Flux density of the strongest component
in the spectrum
21- 28 F8.1 Jy Fi.H2O ? Integrated H2O flux
30- 35 F6.1 km/s Vpeak ? Velocity of the peak
37- 42 F6.1 km/s Vlow ? Velocity of the lowest component
44- 49 F6.1 km/s Vhigh ? Velocity of the highest component
52- 57 F6.3 km/s FWHM ? FWHM of the strongest component
60- 64 F5.2 --- dV ? Offset of the strongest component from
the mean velocity, normalized to the
emission interval.
69- 76 E8.3 W/m2 FIR ? Far-IR flux integrated over the four IRAS bands
80- 84 F5.2 kpc Dist ? Distance of source
90- 96 E7.2 Lsun Lmaser ? Maser luminosity
102-108 E7.2 Lsun L.FIR ? Far-IR luminosity
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(End) [CDS] 12-Mar-1993