J/A+A/658/A39 31.0-50.3 GHz observations of IRC+10216 (Pardo+, 2022)
Ultra-deep 31.0-50.3 GHz spectral survey of IRC+10216.
Pardo J.R., Cernicharo J., Tercero B., Cabezas C., Bermudez C., Agundez M.,
Gallego J.D., Tercero F., Gomez-Garrido M., de Vicente P., Lopez-Perez J.A.
<Astron. Astrophys. 658, A39 (2022)>
=2022A&A...658A..39P 2022A&A...658A..39P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Spectroscopy
Keywords: line: identification - stars: AGB and post-AGB - stars: carbon -
stars: individual: IRC+10216 - radio lines: stars - surveys
Abstract:
The carbon-rich envelope of the asymptotic giant branch star CW Leo,
IRC+10216, is one of the richest molecular sources in the sky.
Available spectral surveys below 51GHz are more than 25 years old,
and new work is needed.
Characterizing the rich molecular content of this source, specially
for heavy species, requires carrying out very sensitive spectral
surveys at low frequencies. In particular, we have achieved an rms in
the range 0.2-0.6mK per MHz.
Long Q band (31.0-50.3GHz) single-dish integrations were carried
out with the Yebes-40m telescope using specifically built receivers.
The most recent line catalogs were used to identify the lines.
The data contain 652 spectral features, corresponding to 713
transitions from 81 species (we count the isomers, isotopologs, and
ortho/para species separately). Only 57 unidentified lines remain with
signal-to-noise ratios ≥3. Some new species and/or vibrational
modes have been discovered for the first time with this survey.
This IRC+10216 spectral survey is by far the most sensitive survey
carried out to date in the Q band. It therefore provides the most
complete view of IRC+10216 from 31.0 to 50.3GHz, giving unique
information about its molecular content, especially for heavy species.
Rotational diagrams built from the data provide valuable information
about the physical conditions and chemical content of this
circumstellar envelope.
Description:
This IRC+10216 31.0-50.3GHz spectral survey was carried out in
several runs from May 2019 to February 2020, and in April 2021, with
the 40-meter antenna of Yebes Observa- tory (IGN, Spain), hereafter
Yebes-40m, after several improvements in its equipment funded by the
Nanocosmos project. This large antenna now provides a main-beam
efficiency from 0.6 at 31GHz to 0.43 at 50GHz and a beam size in the
range 36-5600 for these frequencies.
This appendix is devoted to provide the exhaustive information of our
IRC+10216 Q band survey with the Yebes-40m telescope in two forms.
First, the most significant line parameters (theoretical + observed)
of all spectral lines that can be assigned to an identified molecular
species are given in Table A1. The accumulated number of
distinguishable lines for each species is provided in the last column
of Table A1. This table is the basis for building Figures fg:freqdiag
and fg:rotdiag. The observed values in this table, including errors in
parentheses and the expansion velocity, come from the line fits
performed over the data with the Gildas SHELL method, as shown in
Figures fig01 to fig39, which can be found in appendix of the paper.
The frequency scale in all tables and figures assumes a velocity of
the source with respect to the local standard of rest of -26.5km/s.
The changing telescope beam across the Q band is taken into account in
the calculation of W=TMBdv.
Objects:
-------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------
09 47 57.41 +13 16 43.6 IRC+10216 = V* CW Leo
-------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 143 713 Line identification and associated parameters
from our 31.0-50.3 GHz observations of IRC+10216
tablea1.pdf 512 243 pdf version of table A1
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See also:
J/A+A/330/676 : IRC+10216 Silicon and sulfur chemistry (Willacy+ 1998)
J/ApJ/688/L83 : Detection of C5N- in IRC +10216 (Cernicharo+, 2008)
J/ApJS/177/275 : 1.3 and 2mm survey of IRC+10216 (He+, 2008)
J/ApJS/190/348 : 1mm spectral survey of IRC+10216 + VY CMa (Tenenbaum+, 2010)
J/ApJS/193/17 : Spectral-line survey of IRC+10216 at 293-355GHz
(Patel+, 2011)
J/A+A/545/A12 : Chemistry of IRC+10216 inner wind modelled
(Cherchneff, 2012)
J/A+A/574/A56 : IRC +10216 17.8GHz-26.3GHz spectrum (Gong+, 2015)
J/ApJ/806/L3 : Disilicon carbide (SiCSi) discovery in CW Leo
(Cernicharo+, 2015)
J/A+A/601/A4 : IRC+10216 carbon chains mapped with ALMA (Agundez+, 2017)
J/A+A/606/A74 : IRC +10216 13.3GHz-18.5GHz spectrum (Zhang+, 2017)
J/A+A/618/A4 : IRC+10216 as a spectroscopic laboratory (Cernicharo+, 2018)
J/A+A/629/A146 : ALMA data cubes for IRC+10216 (Velilla-Prieto+, 2019)
J/MNRAS/489/3492 : IRC+10216 + omi Cet SCUBA-2 light curves
(Dharmawardena+, 2019)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Mol Molecular species
21- 70 A50 --- QN Quantum numbers of the transition
72- 79 F8.2 MHz nurest Rest frequency, νrest
81- 88 F8.2 MHz nuobs ? Observed frequency, νobs
89 A1 --- --- [(]
90- 93 F4.2 MHz e_nuobs ? rms uncertainty on nuobs (1)
94 A1 --- --- [)]
96-101 F6.1 K Eup Upper energy level
103-108 F6.2 --- Sul Line strength
110-116 I7 mK.km/s W Integrated intensity, W=∫TMBdv
118-123 F6.3 --- RotDiag Rotation diagram
ln[(3*kB*W)/(8π3*nurest*Sul*µ2)]
125-128 F4.1 km/s Vexp ? Expansion velocity
129 A1 --- --- [(]
130-132 F3.1 km/s e_Vexp ? rms uncertainty on Vexp (1)
133 A1 --- --- [)]
135-140 A6 --- Fig Figure number
142-143 I2 --- Line Accumulated number of distinguishable lines
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Note (1): An error of 0 or 0.0 means the given observed frequency (νobs)
and/or expansion velocity (Vexp) has been forced in the fit.
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Acknowledgements:
Juan R. Pardo, jr.pardo(at)csic.es
(End) Patricia Vannier [CDS] 27-Dec-2021