J/ApJ/835/3 218GHz obs. of embedded protostars in Ophiuchus (Lindberg+, 2017)
Externally heated protostellar cores in the Ophiuchus star-forming region.
Lindberg J.E., Charnley S.B., Jorgensen J.K., Cordiner M.A., Bjerkeli P.
<Astrophys. J., 835, 3-3 (2017)>
=2017ApJ...835....3L 2017ApJ...835....3L (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Millimetric/submm sources ; Interstellar medium ;
Molecular clouds
Keywords: astrochemistry; ISM: individual objects: Ophiuchus;
ISM: molecules; radiative transfer; stars: formation
Abstract:
We present APEX 218GHz observations of molecular emission in a
complete sample of embedded protostars in the Ophiuchus star-forming
region. To study the physical properties of the cores, we calculate
H2CO and c-C3H2 rotational temperatures, both of which are good
tracers of the kinetic temperature of the molecular gas. We find that
the H2CO temperatures range between 16K and 124K, with the highest
H2CO temperatures toward the hot corino source IRAS 16293-2422
(69-124K) and the sources in the ρ Oph A cloud (23-49K) located
close to the luminous Herbig Be star S1, which externally irradiates
the ρ Oph A cores. On the other hand, the c-C3H2 rotational
temperature is consistently low (7-17K) in all sources. Our results
indicate that the c-C3H2 emission is primarily tracing more
shielded parts of the envelope whereas the H2CO emission (at the
angular scale of the APEX beam; 3600 au in Ophiuchus) mainly traces
the outer irradiated envelopes, apart from in IRAS 16293-2422, where
the hot corino emission dominates. In some sources, a secondary
velocity component is also seen, possibly tracing the molecular
outflow.
Description:
Our observations were executed with the APEX (Atacama Pathfinder
Experiment) 12m telescope in August and October 2014 and May 2015.
The SHeFI APEX-1 receiver was used to cover the
frequency range 216-220GHz toward a complete sample of the 38 deeply
embedded protostellar sources in the Ophiuchus star-forming region.
The sample consists of all embedded protostellar sources in the region
detected by Jorgensen+ (2008, J/ApJ/683/822) and
Enoch+ (2009, J/ApJ/692/973); see Table 1 and Figures 1-2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 38 Coordinates and other properties of the
observed sources
table3.dat 92 47 Measured rotational temperatures, column densities,
median line widths, and LSR velocities
table4.dat 89 363 Measured line parameters
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See also:
J/A+A/216/44 : Walraven photometry in Sco-Cen association (De Geus+, 1989)
J/A+A/372/173 : ISOCAM obs. of the rho Ophiuchi cloud (Bontemps+, 2001)
J/A+A/432/369 : Leiden Atomic and Molecular Database (LAMDA) (Schoeier+, 2005)
J/AJ/130/1733 : Optical spectroscopy of ρ Oph stars (Wilking+, 2005)
J/A+A/447/609 : 1.2mm continuum observations in rho Oph cloud (Stanke+, 2006)
J/ApJ/683/822 : Star formation in Ophiuchus and Perseus II. (Jorgensen+, 2008)
J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/A+A/532/A23 : TIMASSS. I. (Caux+, 2011)
J/A+A/548/A24 : 1.3mm observations of CrA cluster (Lindberg+, 2012)
J/A+A/560/A73 : Horsehead H2CO and CH3OH 30m and PdBI maps (Guzman+, 2013)
J/A+A/578/A131 : Gas & dust in the star-forming region rho OphA (Liseau+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Cloud Cloud
11- 25 A15 --- Name Source name
27- 28 I2 h RAh [16] Hour of Right Ascension (J2000)
30- 31 I2 min RAm [26/33] Minute of Right Ascension (J2000)
33- 37 F5.2 s RAs Second of Right Ascension (J2000)
39 A1 --- DE- [-] Sign of the Declination (J2000)
40- 41 I2 deg DEd [24] Degree of Declination (J2000)
43- 44 I2 arcmin DEm [1/57] Arcminute of Declination (J2000)
46- 49 F4.1 arcsec DEs Arcsecond of Declination (J2000)
51- 54 F4.1 mK RMS [10.9/30.5] Measured spectral RMS noise when
averaging to 1km/s channels
56 A1 --- l_Tbol Limit Flag on Tbol
57- 60 I4 K Tbol [41/1500]? Bolometric Temperature
62 A1 --- l_Lbol Limit flag on Lbol
63- 69 F7.4 Lsun Lbol [0.009/18]? Luminosity
71- 75 F5.2 --- alpha [-1.3/5.1]? IR SED Slope
77-103 A27 --- OName Other common identifier(s)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Cloud Cloud
13- 27 A15 --- Name Source name
34- 34 A1 --- m_Name [ms ] main or secondary emission
line component
36- 36 A1 --- l_TrH2CO Limit flag for Trot-H2CO
38- 42 F5.1 K TrH2CO [15/292]? H2CO Rotational Temperature (1)
44- 46 F3.1 K e_TrH2CO ? Uncertainty in Trot-H2CO (1)
48- 51 F4.1 10+12cm-2 NH2CO [4/79]? H2CO number density (1)
53- 56 F4.1 10+12cm-2 e_NH2CO ? Uncertainty in N-H2CO (1)
58- 60 F3.1 km/s dvH2CO [0.2/3]? H2CO linewidth, median value (1)
62- 64 F3.1 km/s vlsrH2CO [2/5]? H2CO LSR velocity,
median value (1)
66- 66 A1 --- l_TrcC3H2 Limit flag for Trot-cC3H2
67- 70 F4.1 K TrcC3H2 [6.7/17]? c-C3H2 Rotational Temperature
72- 74 F3.1 K e_TrcC3H2 ? Uncertainty in Trot-cC3H2
76- 79 F4.2 10+12cm-2 NcC3H2 [0.4/6.5]? c-C3H2 number density
81- 84 F4.2 10+12cm-2 e_NcC3H2 ? Uncertainty in N-cC3H2
86- 88 F3.1 km/s dvcC3H2 [0.2/2]? c-C3H2 linewidth, median value
90- 92 F3.1 km/s vlsrcC3H2 [2.9/5]? c-C3H2 LSR velocity,
median value
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Note (1): H2CO column densities were calculated by non-LTE methods assuming
nH2=8.9±1.0x105cm-3^; see Section 4.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Source name
17- 17 A1 --- m_Name [ms ] main or secondary emission
line component (1)
19- 27 F9.2 MHz Freq0 [216112/219950]? Rest Frequency (2)
29- 39 A11 --- Mol Molecule
41- 66 A26 --- Trans Transition
68- 68 A1 --- f_Trans Flag on Transition (3)
71- 73 F3.1 km/s vlsr [0/6.5]? LSR velocity from Gaussian fit
75- 78 F4.1 km/s dv [0.1/10.1]? linewidth from Gaussian fit
80- 84 F5.2 K.km/s Tmbdv [-9.99/19.5]? Integrated intensity (4)
86- 89 F4.2 K.km/s e_Tmbdv [0.01/0.07]? Uncertainty in Tmbdv
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Note (1): In sources with two components, these are listed as separate sources.
Note (2): Rest frequencies from the CDMS (Muller+ 2001A&A...370L..49M 2001A&A...370L..49M)
and JPL (Pickett+ 1998JQSRT..60..883P 1998JQSRT..60..883P) molecular spectroscopy
databases.
Note (3): Transition Blend flags as follows:
a = Blend of F=9/2-7/2, F=7/2-5/2, and F=5/2-3/2;
b = Blend of F=7/2-5/2, F=5/2-3/2, and F=3/2-1/2;
c = Blend of F=13/2-11/2 and F=15/2-13/2;
d = F_1=2-2, F=2-1;
e = F_1=2-1, F=2-1;
f = F_1=2-1, F=3-2;
g = F_1=3-2, F=2-1;
Note (4): For the sources with two components (m_Name not blank), the integrated
intensities are from Gaussian fits.
Considerable C18O emission in the off-position made the C18O line
data unreliable for some sources. Those are indicated by Tmbdv=-9.99.
Tmbdv with blank values indicates no emission lines were detected.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Aug-2017