J/A+A/557/A94 SiO and HCO+ massive molecular outflows (Sanchez-Monge+, 2013)
Evolution and excitation conditions of outflows in high-mass star-forming
regions.
Sanchez-Monge A., Lopez-Sepulcre A., Cesaroni R., Walmsley C.M.,
Codella C., Beltran M.T., Pestalozzi M., Molinari S.
<Astron. Astrophys. 557, A94 (2013)>
=2013A&A...557A..94S 2013A&A...557A..94S
ADC_Keywords: Infrared sources ; H II regions ; Interstellar medium
Keywords: stars: formation - stars: massive - ISM: jets and outflows -
radio lines: ISM
Abstract:
We present the results of a study of 14 molecular outflows associated
with high-mass star formation. We used the IRAM30m telescope to
characterize the outflow emission in the SiO(2-1), SiO(5-4) and
HCO+(1-0) lines. We detect outflows in all the 14 high-mass
star-forming regions in both, the SiO and HCO+ lines. Six of the
fourteen outflows show bipolarity. The physical parameters derived for
these outflows are consistent with outflows powered by massive young
stellar objects with luminosities in the range 103-104L☉. We
found a decrease of the SiO abundance (from 10-8 to 10-9) as the
object evolves in time, while there are hints of a possible increase
of the HCO+ outflow energetics with time. These results suggest a
scenario in which SiO is largely enhanced in the first evolutionary
stages, probably due to strong shocks produced by the protostellar
jet. As the object evolves, the power of the jet would decrease and so
does the SiO abundance. During this process, however, the material
surrounding the protostar would have been swept up by the jet, and the
outflow activity, traced by entrained molecular material (HCO+),
would increase with time.
Description:
Data cubes in FITS format of the SiO(2-1), SiO(5-4) and HCO+(1-0)
lines for the 14 high-mass star-forming regions. The name of the files
is: NN_MOLTT.fit, where NN is the number as listed in Table 1 of the
paper, MOL is the molecule SiO or HCO+, and TT is the transition
(2-1, 5-4 or 1-0). Each file has a total of 438 spectral channels of
0.8km/s each. The rest frequency is 86846.96MHz for SiO(2-1),
217104.98MHz for SiO(5-4), and 89188.5247MHz for HCO+(1-0), and
corresponds to the channel 219. The units of the map are K (main beam
temperature).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 114 14 List of observed sources, and spectral energy
distribution parameters
fits/* . 42 Individual FITS data cube files
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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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1- 2 I2 --- Seq Source sequential number
4- 15 A12 --- Source Source name (1)
16 A1 --- n_Source [f] Simultaneous observations (2)
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 27 F4.1 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 39 F4.1 arcsec DEs Declination (J2000)
41- 46 F6.1 km/s Vlsr Systemic LSR velocity (3)
48- 50 F3.1 kpc Dist Distance
52 A1 --- Cl [LD] IR classification: L=IR-luminous (IRL),
or D=IR-dark (IRD) (4)
54- 56 F3.1 --- beta SED fit β value (5) (6)
58- 59 I2 K Td SED fit dust temperature (5)
61- 64 I4 Msun Mass SED fit mass (5)
66- 70 I5 Lsun Lbol Bolometric luminosity (7)
72- 75 F4.1 Sun L/M Luminosity to mass ratio
77- 88 A12 --- F-HCO Data cube file name in subdirectory fits
with HCO+(1-0) line (89.1885GHz)
(resolution 4.5arcsec/pix, 2.7m/s)
90-101 A12 --- F-SiO21 Data cube file name in subdirectory fits
with SiO(2-1) line (86.8470GHz)
(resolution 4.6arcsec/pix, 2.7m/s)
103-114 A12 --- F-SiO54 Data cube file name in subdirectory fits
with SiO(5-4) line (217.1050GHz)
(resolution 1.8arcsec/pix, 1.1m/s)
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Note (1): Name of sources starting with numbers (e. g., 18151-1208) refer
to the IRAS name (Neugebauer et al. 1984ApJ...278L...1N 1984ApJ...278L...1N, Cat. II/125).
Note (2): f: Observed simultaneously with (in the same map as) source
number 11, i.e. 18507+0121.
Note (3): Systemic velocity derived from the hyperfine fit to the N2H+
(1-0) and C2H(1-0) lines (see Sect. 3.1).
Note (4): Sources classified as IR-luminous (IRL) or IR-dark (IRD)
according to its emission or not at mid-IR wavelengths according to
Lopez-Sepulcre et al. (2010A&A...517A..66L 2010A&A...517A..66L).
Note (5): Parameters obtained from the single-temperature, modified black
body fit to the spectral energy distribution (see Sect. 3.3).
Note (6): where β represents the frequency-dependent optical depth:
τν=τ0(ν/ν0)β (ν0=230.6GHz)
Note (7): Bolometric luminosity derived by integrating over the full
observed spectral distribution (see Sect. 3.3).
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Acknowledgements:
Alvaro Sanchez-Monge, Osservatorio di Arcetri, Italy,
asanchez(at)arcetri.astro.it
(End) A. Sanchez-Monge [Oss. di Arcetri, Italy], P. Vannier [CDS] 27-May-2013