J/A+A/432/921 Massive protostellar candidates (Fontani+, 2005)
Search for massive protostellar candidates in the southern hemisphere.
I. Association with dense gas.
Fontani F., Beltran M.T., Brand J., Cesaroni R., Testi L., Molinari S.,
Walmsley C.M.
<Astron. Astrophys., 432, 921-935 (2005)>
=2005A&A...432..921F 2005A&A...432..921F
ADC_Keywords: YSOs ; Radio lines ; Interstellar medium
Keywords: Stars: formation - radio lines: ISM - ISM: molecules
Abstract:
We have observed two rotational transitions of both CS and C17O,
and the 1.2mm continuum emission towards a sample of 130 high-mass
protostellar candidates with DE←30°. This work represents the
first step of the extension to the southern hemisphere of a project
started more than a decade ago aimed at the identification of massive
protostellar candidates. Following the same approach adopted for
sources with DE≥-30°, we have selected from the IRAS Point Source
Catalogue 429 sources which potentially are compact molecular clouds
on the basis of their IR colours. The sample has then been divided
into two groups according to the colour indices [25-12] and [60-12]:
the 298 sources with [25-12]≥0.57 and [60-12]≥1.30 have been called
High sources, the remaining 131 have been called Low sources. In this
paper, we check the association with dense gas and dust in 130 Low
sources. We have obtained a detection rate of ∼85% in CS,
demonstrating a tight association of the sources with dense molecular
clumps.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 58 131 Observed sources and detection summary
tablea2.dat 89 141 *CS line parameters obtained from Gaussian fits
tablea3.dat 89 131 *C17O line parameters
tablea4.dat 49 89 Distance-independent parameters of the clumps
tablea5.dat 56 111 Distance, linear size, luminosity, and dust
temperature of all sources detected in CS
tablea6.dat 51 71 Clumps masses
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Note on tablea2.dat: see transition frequencies in "Table 1" section below.
The typical errors from the fits are ∼0.01-0.07K.km/s in TMBdv,
∼0.01-0.1km/s in vLSR and ∼0.01-0.1km/s in FWHM. Typical rms noise
in the spectra is ∼0.05K and 0.06K for the (2-1) and (3-2) lines,
respectively.
Note on tablea3.dat: see transition frequencies in "Table 1" section below.
Typical rms noise in the spectra is ∼0.05 and ∼0.06K for the (1-0) and
(2-1) lines, respectively. The errors from the fits are
∼0.02-0.06K.km/s in TMBdv, ∼0.01-0.1km/s in VLSR, and
∼0.01-0.1km/s in FWHM.
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See also:
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Table 1: Observed transitions.
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Molecular Freq HPBW Deltav(1) Bandwidth(1)
transition (GHz) (") (km/s) (km/s)
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CS (2-1) 97.980 51 0.13 /2.12 130/3053
CS (3-2) 146.969 34 0.087/1.43 87/2059
CS (5-4) 244.935 21 0.052/0.86 52/1238
C17O (1-0) 112.359 45 0.11 /1.85 110/2664
C17O (2-1) 224.714 22 0.057/0.93 57/1342
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Note (1): The two values refer to the two spectrometers used.
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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- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 21 F4.1 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 31 I2 arcsec DEs Declination (J2000)
33- 37 F5.1 km/s VLSRI ?=- Run I LSR velocity (1)
39- 43 F5.1 km/s VLSRII ?=- Run II LSR velocity (1)
45- 46 A2 --- CS [Y NO] CS detection flag (2)
48- 49 A2 --- C17O [Y NO] C17O detection flag (2)
52- 53 A2 ---- 1.2mm [Y NO c] Detection flag at 1.2mm continuum (2)
55- 57 I3 arcsec Delta ?=- Angular separation between the IRAS
position and the nearest millimeter
peak detected in the SIMBA maps
58 A1 --- u_Delta [?] Uncertainty flag on Delta
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Note (1): VLSR is the velocity at which we centered the CS spectra
during the two observing runs (see text).
Note (2): Detection flags as follows:
Y = Yes
N = No
NO = source not observed in that tracer
c = The continuum maps will be available in a forthcoming paper
(Beltran et al., in prep.).
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
11 A1 --- n_IRAS [*] Note on Source (1)
13- 14 A2 --- l_ITMB1 [≤ ] Limit flag on ITMB1
15- 19 F5.2 K.km/s ITMB1 CS(2-1) brightness temperature integrated over
velocity
20 A1 ---- n_ITMB1 [*] Note on the origin of line parameters (2)
21- 25 F5.2 K.km/s ITMB1l ? Lower value of ITMB1 interval
26 A1 --- --- [,]
27- 31 F5.2 K.km/s ITMB1u ? Upper value of ITMB1 interval
32- 38 F7.2 km/s VLSR1 ?=- CS(2-1) LSR velocity
40- 43 I4 km/s VLSR1l ? Lower value of VLSR1 interval
44 A1 --- --- [,]
46- 49 I4 km/s VLSR1u ? Upper value of VLSR1 interval
52- 56 F5.2 km/s FWHM1 ?=- CS(2-1) FWHM
58- 59 A2 --- l_ITMB2 [≤ ] Limit flag on ITMB2
60- 64 F5.2 K.km/s ITMB2 CS(3-2) brightness temperature integrated over
velocity
65 A1 --- n_ITMB2 [*] Note on ITMB2 (3)
67- 73 F7.2 km/s VLSR2 ?=- CS(3-2) LSR velocity
75- 78 I4 km/s VLSR2l ? Lower value of VLSR2 interval
79 A1 --- --- [,]
81- 83 I3 km/s VLSR2u ? Upper value of VLSR2 interval
85- 89 F5.2 km/s FWHM2 ?=- CS(3-2) FWHM
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Note (1): The asterisk indicates line parameters derived from
moment integrals over the velocity range indicated
Note (2): *: Component observed also in the C17O(1-0) and/or (2-1) spectrum.
Note (3): *: Not observed in the (3-2) line.
The upper limits refer to the (5-4) transition.
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
12- 15 I4 km/s V1l ? C17O(1-0) lower limit of velocity range
16 A1 --- --- [,]
17- 20 I4 km/s V1u ? C17O(1-0) upper limit of velocity range
21 A1 --- Note1 [N] if not observed in the C17O (1-0) and (2-1)
lines
22- 23 A2 --- l_ITMB1 [≤] Limit flag on ITMB1
24- 27 F4.2 K.km/s ITMB1 ? C17O(1-0) brightness temperature integrated
over velocity
29- 35 F7.2 km/s VLSR1 ? C17O(1-0) LSR velocity
37- 41 F5.2 km/s FWHM1 ? C17O(1-0) FWHM
43- 44 A2 --- l_t10 Limit flag on t10
45- 47 F3.1 --- t10 ?=- C17O(1-0) optical depth
49- 52 I4 km/s V2l ? C17O(2-1) lower limit of velocity range
53 A1 --- --- [,]
54- 57 I4 km/s V2u ? C17O(2-1) upper limit of velocity range
58 A1 --- Note2 [N] N: Not observed in the C17O(2-1) line
60- 61 A2 --- l_ITMB2 [≤] Limit flag on ITMB2
62- 66 F5.2 K.km/s ITMB2 ? C17O(2-1) brightness temperature integrated
over velocity
69- 75 F7.2 km/s VLSR2 ?=- C17O(2-1) LSR velocity
79- 82 F4.2 km/s FWHM2 ?=- C17O(2-1) FWHM
84- 85 A2 --- l_t21 Limit flag on t21
86- 89 F4.2 --- t21 ?=- C17O(2-1) optical depth
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
12- 13 A2 --- l_theta Limit flag on theta
14- 17 F4.1 arcsec theta ? Angular diameter
18 A1 --- n_theta [#] Note on theta (#: unresolved sources)
20- 24 F5.2 Jy Fnu ? Integrated flux density, derived from
the 1.2mm continuum maps
26- 27 I2 K Trot ? Rotation temperature
29- 32 F4.1 10+15cm-2 NC17O ? C17O column density
34- 42 E9.4 cm-2 NH2 ? H2 total column density, derived from
C17O line ratios (1)
44- 49 E6.2 cm-3 nH2 ? H2 volume density, obtained from
CS line ratios
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Note (1): Assuming a mean abundance of 3.9x10-8
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Byte-by-byte Description of file: tablea5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
11 A1 --- n_IRAS [*] *: Resolved distance ambiguity
13- 18 F6.2 kpc dnear ? Near distance
20- 24 F5.2 kpc dfar ?=- Far distance (1)
26 A1 --- n_dfar [+] +: No distance estimate
29- 32 F4.2 pc Dnear ?=- Near linear size (1)
34- 37 F4.2 pc Dfar ?=- Far linear size (1)
39- 44 F6.2 10+3solLum Lnear ? Near luminosity
46- 53 F8.3 10+3solLum Lfar ? Far luminosity
55- 56 I2 K Td ?=- Dust temperature
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Note (1): A "---" indicates that we could not derive any source angular
diameter.
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Byte-by-byte Description of file: tablea6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm-DDMM)
12- 14 I3 solMass Mcnear ?=- Near clump mass estimated from
1.2mm continuum
16- 20 I5 solMass Mcfar ?=- Far clump mass estimated from
1.2mm continuum
22- 25 I4 solMass Mvirnear ?=- Near clump mass assuming
virial equilibrium
27- 30 I4 solMass Mvirfar ?=- Far clump mass assuming virial equilibrium
32- 35 I4 solMass MC17Onear ?=- Near clump mass from C17O mass
37- 40 I4 solMass MC17Ofar ?=- Far clump mass from C17O mass
42- 45 I4 solMass MCSnear ?=- Near clump mass from CS mass
47- 51 I5 solMass MCSfar ?=- Far clump mass from CS mass
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 12-Jul-2006