J/A+A/600/A16 Six LMC star forming region spectra (Tang+, 2017)
Kinetic temperature of massive star forming molecular clumps measured with
formaldehyde. II. The Large Magellanic Cloud.
Tang X.D., Henkel C., Chen C.-H.R., Menten K.M., Indebetouw R., Zheng X.W.,
Esimbek J., Zhou J.J., Yuan Y., Li D.L., He Y.X.
<Astron. Astrophys. 600, A16 (2017)>
=2017A&A...600A..16T 2017A&A...600A..16T (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; H II regions ; Spectroscopy
Keywords: star formation - Magellanic Clouds - ISM: clouds - ISM: molecules -
radio lines: ISM
Abstract:
The kinetic temperature of molecular clouds is a fundamental physical
parameter affecting star formation and the initial mass function. The
Large Magellanic Cloud (LMC), the closest star forming galaxy with low
metallicity, provides an ideal laboratory to study star formation in
such an environment.
The classical dense molecular gas thermometer NH3 is rarely
available in a low metallicity environment because of photoionization
and a lack of nitrogen atoms. Our goal is to directly measure the gas
kinetic temperature with formaldehyde toward six star-forming regions
in the LMC.
Three rotational transitions (JKAKC = 303-202, 322-221, and
321-220) of para-H2CO near 218GHz were observed with the
Atacama Pathfinder EXperiment (APEX) 12m telescope toward six star
forming regions in the LMC. Those data are complemented by C18O 2-1
spectra.
Description:
Our observations were carried out in 2008 and 2014 (summarized in
Table 1) with the Atacama Pathfinder EXperiment (APEX) 12m telescope
located on Chajnantor (Chile) using the APEX-1 (SHeFI) receiver. The
beam size is ∼30" (∼7pc at 50kpc distance) at 218GHz. The main beam
efficiency and the forward efficiency were 0.75 and 0.97,
respectively. N113 and N159W were observed in 2008 with an old Fast
Fourier Transform Spectrometer (FFTS), which consists of two units
with a bandwidth of 1 GHz each and a velocity resolution of
0.1675km/s. The frequency is centered at 218.480GHz. Our data includes
all three of the 218GHz para-H2CO lines. 30 Dor, N159E, N159S, and
N44BC were observed in 2014. Here we used the new eXtended bandwidth
Fast Fourier Transform Spectrometer (XFFTS) backend with two spectral
windows of 2.5GHz bandwidth and a velocity resolution of 0.1047km/s.
The central frequency is set at 218.550GHz. These data do not only
include the three para-H2CO lines but also the 219.560GHz C18O
(2-1) transition.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 6 Source parameters
table2.dat 73 23 Para-H2CO and C18O spectral parameters
table3.dat 90 6 Integrated intensity ratios, column densities,
spacial densities and temperatures
list.dat 142 22 List of fits spectra
fits/* . 22 Individual fits spectra
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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- 6 A6 --- Source Source name
9- 10 I2 h RAh Right ascension (J2000)
12- 13 I2 min RAm Right ascension (J2000)
15- 18 F4.1 s RAs Right ascension (J2000)
20 A1 --- DE- declination sign (J2000)
21- 22 I2 deg DEd declination (J2000)
24- 25 I2 arcmin DEm declination (J2000)
27- 30 F4.1 arcsec DEs declination (J2000)
32- 34 I3 min Tint Integrated time
36- 49 A14 --- Date Observation date
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Source Source name
9- 14 A6 --- Mol Molecule
16- 28 A13 --- Trans Transition
30 A1 --- l_intTmbdv Limit flag on intTmbdv
31- 35 F5.3 K.km/s intTmbdv Velocity-integrated intensity
37- 41 F5.3 K.km/s e_intTmbdv ? rms uncertainty on intTmbdv (1)
43- 48 F6.2 km/s Vlsr ?=- LSR velocity
50- 53 F4.2 km/s e_Vlsr ? rms uncertainty on Vlsr (1)
55- 58 F4.2 km/s FWHM ?=- Full width to half maximum line width
60- 63 F4.2 km/s e_FWHM ? rms uncertainty on FWHM (1)
65- 69 F5.3 K Tmb ?=- Peak mean brightness temperature
71- 73 F3.1 mK rms rms noise
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Note (1): standard deviations from Gaussian fits using CLASS as part of the
GILDAS software.
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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- 6 A6 --- Source Source name
8 A1 --- n_Source [ab] Note on Source (1)
10 A1 --- l_R1 Limit flag on R1
11- 15 F5.3 --- R1 321-220/303-202 ratio
17- 20 F4.2 --- e_R1 ? rms uncertainty on
321-220/303-202 ratio
22- 25 F4.2 --- R2 H2CO 303-202/C18O 2-1 ratio
27- 30 F4.2 --- e_R2 rms uncertainty on
H2CO 303-202/C18O 2-1 ratio
32- 34 F3.1 10+14cm-2 NC18O C18O column density
36- 38 F3.1 10+12cm-2 NpH2CO Para-H2CO column density
40- 42 F3.1 10+22cm-2 NH2a H2 column density from C18O
44- 46 F3.1 10+22cm-2 NH2b H2 column density from 12CO(1-0)
48 A1 --- l_nH2 Limit flag on nH2
49- 52 F4.2 10+5cm-3 nH2 H2 density number
54- 57 F4.2 10+5cm-3 E_nH2 ? Error on nH2 (upper value)
59- 62 F4.2 10+5cm-3 e_nH2 ? Error on nH2 (lower value)
64 A1 --- l_Tkin Limit flag on Tkin
65- 68 F4.1 K Tkin Kinematic temperature derived with the
density n(H2)
70- 73 F4.1 K E_Tkin ? Error on Tkin (upper value)
75- 78 F4.1 K e_Tkin ? Error on Tkin (lower value)
80 A1 --- l_TLTE Limit flag on TLTE
81- 84 F4.1 K TLTE LTE temperature
86- 90 A5 K Tdust Interval of dust temperature (2)
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Note (1): Notes as follows:
a = N113: Para-H2CO 303-202/C18O 2-1 ratio data taken from
Heikkila et al. (1998A&A...332..493H 1998A&A...332..493H) and
Wang et al. (2009ApJ...690..580W 2009ApJ...690..580W)
N(C18O) derived from C18O 2-1 taken from
Heikkila et al. (1998A&A...332..493H 1998A&A...332..493H).
b = N159W: Para-H2CO 303-202/C18O 2-1 ratio data taken from
Heikkila et al. (1998A&A...332..493H 1998A&A...332..493H, 1999A&A...344..817H 1999A&A...344..817H).
N(C18O) derived from C18O 2-1 taken from
Heikkila et al. (1998A&A...332..493H 1998A&A...332..493H).
N(H2) data taken from Ott et al. (2010ApJ...710..105O 2010ApJ...710..105O).
Note (2): Dust temperature references:
30 Dor = Werner et al. (1978MNRAS.184..365W 1978MNRAS.184..365W);
Heikkila et al. (1999A&A...344..817H 1999A&A...344..817H);
Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G)
N113 = Wang et al. (2009ApJ...690..580W 2009ApJ...690..580W);
Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G);
Seale et al. (2014, Cat. J/AJ/148/124)
N44BC = Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G)
N159W = Heikkila et al. (1999A&A...344..817H 1999A&A...344..817H);
Bolatto et al. (2000ApJ...545..234B 2000ApJ...545..234B);
Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G)
N159E = Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G)
N159S = Gordon et al. (2014ApJ...797...85G 2014ApJ...797...85G)
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of points
25- 47 A23 --- Obs.Date Observation date (YYYY-MM-DDThh:mm:ss.sss)
49- 60 E12.6 Hz b_Freq Lower value of relative frequency interval
62- 72 E11.6 Hz B_Freq Upper value of relative frequency interval
74- 79 I6 Hz dFreq Frequency resolution
81- 82 I2 Kibyte size Size of FITS file
84-105 A22 --- FileName Name of FITS file, in subdirectory fits
107-142 A36 --- Title Title of the FITS file
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Acknowledgements:
Xindi Tang, xdtang(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 06-Jan-2017