J/A+A/620/A30 12 embedded protostellar systems APEX spectra (Murillo+, 2018)
Role of environment and gas temperature in the formation of multiple
protostellar systems: molecular tracers.
Murillo N.M., van Dishoeck E.F., Tobin J.J., Mottram J.C., Karska A.
<Astron. Astrophys. 620, A30 (2018)>
=2018A&A...620A..30M 2018A&A...620A..30M (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium; Protostars; YSOs; Spectroscopy
Keywords: astrochemistry - stars: formation - stars: low-mass -
ISM: molecules - methods: observational
Abstract:
Simulations suggest that gas heating due to radiative feedback is a
key factor in whether or not multiple protostellar systems will form.
Chemistry is a good tracer of the physical structure of a protostellar
system, since it depends on the temperature structure.
We aim to study the relationship between envelope gas temperature and
protostellar multiplicity.
Single dish observations of various molecules that trace the cold,
warm and UV-irradiated gas are used to probe the temperature structure
of multiple and single protostellar systems on 7000 AU scales.
Single, close binary, and wide multiples present similar current
envelope gas temperatures, as estimated from H2CO and DCO+ line
ratios. The temperature of the outflow cavity, traced by c-C3H2,
on the other hand, shows a relation with bolometric luminosity and an
anticorrelation with envelope mass. Although the envelope gas
temperatures are similar for all objects surveyed, wide multiples tend
to exhibit a more massive reservoir of cold gas compared to close
binary and single protostars.
Although the sample of protostellar systems is small, the results
suggest that gas temperature may not have a strong impact on
fragmentation. We propose that mass, and density, may instead be key
factors in fragmentation.
Description:
APEX observations toward 12 embedded protostellar systems in the
Perseus molecular cloud (d∼235pc), including multiple (binary and
higher order) and single protostellar systems. The following systems
were observed: B1-B, L1448N, NGC1333 SVS13, NGC1333 IRAS7,
NGC1333 IRAS5 (Per63 and Per52), IC348 Per8+Per55, IRAS03282+3035,
IRAS03292+3039, NGC1333 IRAS1, IRAS03271+3013, L1455 Per25,
NGC1333 SK1. Source positions are listed in Table 1 of the paper.
Single pointing spectra are from SHeFI APEX-1 (one setting:
217112.58MHz) and APEX-2 (two settings: 350337.46 and 361169.78MHz),
and only targeted 10 out of the 12 sources (excluding IC348 Per8+Per55
and IRAS03292+3039). One pointing per source was done. These
observations include at least two transitions of each DCO+, DCN,
H2CO, c-C3H2, C2H. Additional detections include HNC, SO and
CH3OH. On-the-fly maps of 13CO (45"x45") toward all 12 systems
were performed with FLASH (4-3 transition), CHAMP+ and SEPIA B9
(transition 6-5). Spectra are provided in FITS files written out using
GILDAS-CLASS. One file per pointing is provided in the case of the
APEX-1 and APEX-2 observations. One file per map is provided from the
13CO maps, which includes several sources in the case of the wide
multiple protostellar systems. The spectra has been baseline
subtracted. The natural velocity resolution of the data is 0.1km/s.
For the paper, the data were smoothed to 0.4km/s bins using resample
in GILDAS-Class. Beam efficiencies, which are not applied to the fits
files in this catalog, are: 0.75 at 230GHz; 0.73 at 345GHz; 0.60 at
440GHz; 0.56 at 660GHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 163 22 Sample of protostellar systems
list.dat 112 73 List of fits files
fits/* . 73 Individual fits files
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See also:
J/ApJ/774/22 : CO observations of YSOs in NGC 1333 (Plunkett+, 2013)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Type System type
16- 31 A16 --- System System
32 A1 --- n_System [a] Note on System (1)
34- 38 A5 --- Source Source
40- 41 I2 h RAh Right ascension (J2000)
43- 44 I2 min RAm Right ascension (J2000)
46- 50 F5.2 s RAs Right ascension (J2000)
52 A1 --- DE- Declination sign (J2000)
53- 54 I2 deg DEd Declination (J2000)
56- 57 I2 arcmin DEm Declination (J2000)
59- 63 F5.2 arcsec DEs Declination (J2000)
65- 70 F6.3 arcsec Sep ?=- Separation
72 A1 --- Class [0I] Class
74- 86 A13 --- Region Region (2)
87- 92 F6.2 Lsun Lbol Bolometric luminosity
94- 98 F5.2 Lsun e_Lbol rms uncertainty on Lbol
100-111 A12 ---- FileName1 Name of the fits file with APEX-1 spectra
113-124 A12 ---- FileName2 Name of the fits file with APEX-2 spectra
126-137 A12 ---- FileName3 Name of the fits file with APEX-3 spectra
139-150 A12 ---- FileName4 Name of the fits file with
OTF 13CO (5-6) spectra
152-163 A12 ---- FileName5 Name of the fits file with
OTF 13CO (4-3) spectra
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Note (1): Only observed in 13CO with APEX.
Note (2): Clustered regions are defined to have 34 YSO/pc, while non-clustered
regions present 6 YSO/pc (Plunkett et al., 2013, Cat. J/ApJ/774/22).
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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- 5 I5 --- Nsp Number of spectra
7- 16 A10 "date" Obs.date Observation date
18- 25 F8.5 GHz bFreq Lower relative frequency interval value
27- 34 F8.6 GHz BFreq Upper relative frequency interval value
36- 43 F8.1 Hz dFreq Frequency resolution
45- 50 I6 Kibyte size Size of FITS file
52- 63 A12 --- FileName Name of FITS file, in subdirectory fits
65-112 A48 --- Title Title of the FITS file
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Acknowledgements:
Nadia Murillo, nmurillo(at)strw.leidenuniv.nl
(End) Patricia Vannier [CDS] 18-Sep-2018