J/A+A/618/A143 Cool, evolved stars PACS and SPIRE spectroscopy (Nicolaes+, 2018)
PACS and SPIRE range spectroscopy of cool, evolved stars.
Nicolaes D., Groenewegen M.A.T., Royer P., Lombaert R., Danilovich T.,
Decin L.
<Astron. Astrophys. 618, A143 (2018)>
=2018A&A...618A.143N 2018A&A...618A.143N (SIMBAD/NED BibCode)
ADC_Keywords: Mass loss ; Infrared sources ; Spectra, infrared
Keywords: stars: AGB and post-AGB - stars: mass loss - infrared: stars -
Abstract:
At the end of their lives AGB stars are prolific producers of dust and
gas. The details of this mass-loss process are still not understood
very well. Herschel PACS and SPIRE spectra which cover the wavelength
range from ∼55 to 670um almost continuously, offer a unique way of
investigating properties of AGB stars in general and the mass-loss
process in particular as this is the wavelength region where dust
emission is prominent and molecules have many emission lines.
We present the community with a catalogue of AGB stars and red
supergiants (RSGs) with PACS and/or SPIRE spectra reduced according to
the current state of the art.
The Herschel Interactive Processing Environment (HIPE) software with
the latest calibration is used to process the available PACS and SPIRE
spectra of 40 evolved stars. The SPIRE spectra of some objects close
to the Galactic plane require special treatment because of the weaker
fluxes in combination with the strong and complex background emission
at those wavelengths. The spectra are convolved with the response
curves of the PACS and SPIRE bolometers and compared to the fluxes
measured in imaging data of these sources. Custom software is used to
identify lines in the spectra, and to determine the central
wavelengths and line intensities. Standard molecular line databases
are used to associate the observed lines. Because of the limited
spectral resolution of the PACS and SPIRE spectrometers (∼1500),
several known lines are typically potential counterparts to any
observed line. To help identifications in follow-up studies the
relative contributions in line intensity of the potential counterpart
lines are listed for three characteristic temperatures based on local
thermodynamic equilibrium (LTE) calculations and assuming optically
thin emission.
The following data products are released: the reduced spectra, the
lines that are measured in the spectra with wavelength, intensity,
potential identifications, and the continuum spectra, i.e. the full
spectra with all identified lines removed. As simple examples of how
this data can be used in future studies we have fitted the continuum
spectra with three power laws (two wavelength regimes covering PACS,
and one covering SPIRE) and find that the few OH/IR stars seem to have
significantly steeper slopes than the other oxygen- and carbon-rich
objects in the sample, possibly related to a recent increase in
mass-loss rate. As another example we constructed rotational diagrams
for CO (and HCN for the carbon stars) and fitted a two-component model
to derive rotational temperatures.
Description:
In this paper PACS and SPIRE spectra are presented for about 40
evolved stars. The following products are made available:
- The fully reduced flux-calibrated spectra
(for all available spectral bands)
- The lines measured in these spectra,
with possible molecular identifications
- The full spectra with all identified lines subtracted,
that represents the best estimate of the dust continuum.
Note that the PACS spectra are presented using an oversampling factor
of two, i.e. with Nyquist sampling with respect to the instrumental
resolution. For the PACS and SPIRE continuum spectra it is recommended
to re-bin them to an appropriately lower spectral resolution when
comparing them to dust radiative transfer models for example.
The original and line-subtracted spectra are named:
[inst][C][name][obsid]_[band].dat
Where
inst = PACS or SPIRE
C = is absent for the full spectrum, and "C" for the line-subtracted
continuum spectra
name = is the name of the star
obsid = gives the Herschel Observation Identification number(s)
(see Table A1)
band = the spectral band: B2A, B2B, B3A, R1A, R1B (when inst=PACS;
R1 indicates R1A+R1B segments in a single file),
SSW, SLW (when inst=SPIRE).
Not all bands are available for all stars.
The files with the observed lines and possible identifications are
named: [name]_IdentifiedLines.tex, in IdLines subdirectory,
and compiled as a single file, lines.dat
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 94 40 Basic properties of the sample stars
splist.dat 248 132 List of all spectrum files
lines.dat 186 14763 Integrated line strengths and possible
identifications for the selected spectral lines
sp/* . 410 Individual spectra
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Type Type (AGB-stars or Red-SG for Red Super Giants)
12- 21 A10 --- IRAS IRAS name
23- 45 A23 --- OName Identifier(s)
47 A1 --- CType [MSC] Chemical type
49- 52 A4 --- VType Variability type
54- 57 F4.2 kpc Dist Distance
59- 60 I2 --- r_Dist Distance reference (1)
62- 66 F5.1 km/s vLSR LSR velocity
68- 69 I2 --- r_vLSR vLRS reference (1)
71- 76 E6.2 Msun/yr dM/dt Mass loss rate
78- 79 I2 --- r_dM/dt dM/dt reference (1)
81- 94 A14 --- Name Source name, as in lines.dat file
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Note (1): References as follows:
1 = Olivier et al. , 2001MNRAS.326..490O 2001MNRAS.326..490O
2 = van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, Cat. I/311
3 = Lombaert et al., 2013A&A...554A.142L 2013A&A...554A.142L
4 = Richards, 2012, Cat. J/A+A/546/A16
5 = Molster et al., 2001A&A...366..923M 2001A&A...366..923M
6 = Groenewegen et al., 2012A&A...543L...8G 2012A&A...543L...8G
7 = Groenewegen et al., 2002, Cat. J/A+A/390/501
8 = Justtanont et al., 2006A&A...450.1051J 2006A&A...450.1051J
9 = van Langevelde et al., 1990A&A...239..193V 1990A&A...239..193V
10 = Groenewegen & De Jong, 1998A&A...337..797G 1998A&A...337..797G
11 = Loup et al. 1993, J/A+AS/99/291
12 = Reid et al., 2014, Cat. J/ApJ/783/130
13 = De Beck et al., 2010A&A...523A..18D 2010A&A...523A..18D
14 = Danilovich et al., 2015A&A...581A..60D 2015A&A...581A..60D
15 = de Vicente et al., 2016A&A...589A..74D 2016A&A...589A..74D
16 = Danilovich et al., 2016A&A...588A.119D 2016A&A...588A.119D
17 = Sahai et al., 2009ApJ...699.1015S 2009ApJ...699.1015S
18 = Desmurs et al., 2014, Cat. J/A+A/565/A127
19 = Gonzalez-delgado et al., 2003A&A...411..123G 2003A&A...411..123G
20 = Schoeier et al., 2013A&A...550A..78S 2013A&A...550A..78S
21 = Maercker et al., 2016A&A...591A..44M 2016A&A...591A..44M
22 = Khouri et al., 2014A&A...561A...5K 2014A&A...561A...5K
23 = Olofsson et al., 2002A&A...391.1053O 2002A&A...391.1053O
24 = Knapp & Morris, 1985ApJ...292..640K 1985ApJ...292..640K
25 = Smith et al., 2009AJ....137.3558S 2009AJ....137.3558S
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Byte-by-byte Description of file: splist.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Inst Instrument (1)
9- 22 A14 --- Name Source name, as in lines.dat file
24- 68 A45 --- FileName1 Spectrum file name, in subdirectory sp
70-114 A45 --- FileName2 Spectrum file name, in subdirectory sp
116-160 A45 --- FileName3 Spectrum file name, in subdirectory sp
162-206 A45 --- FileName4 Spectrum file name, in subdirectory sp
218-248 A31 --- FileName5 Spectrum file name, in subdirectory sp
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Note (1): Instrument as follows:
PACSC = line-subtracted PACS spectrum
PACS = original PACS spectrum
SPIREC = line-subtracted SPIRE spectrum
SPIRE = original SPIRE spectrum
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Byte-by-byte Description of file: lines.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name
16- 25 A10 --- Band Spectral band (1)
26- 31 F6.2 um lambdaObs Observed wavelength
33- 41 F9.4 GHz nuObs Observed frequency
43- 52 E10.4 W/m2 Fint Integrated line flux
54- 61 E8.3 W/m2 e_Fint rms uncertainty on Fint
63- 68 F6.3 --- RelFWHM Relative FWHM of the line (2)
70-118 A49 --- Species Molecular species
120-145 A26 --- Trans Transition
147-152 F6.2 um lambda0 ? Laboratory wavelength
154-162 F9.4 GHz nu0 ? Laboratory frequency
164 A1 --- l_Con75K Limit flag on Con75K
165-170 F6.2 % Con75K ? Contribution of the laboratory line to the
observed line for temperature of 75K
assuming LTE and optically thin line emission
172 A1 --- l_Con300K Limit flag on Con300K
173-178 F6.2 % Con300K ? Contribution of the laboratory line to the
observed line for temperature of 300K
assuming LTE and optically thin line emission
180 A1 --- l_Con500K Limit flag on Con500K
181-186 F6.2 % Con500K ? Contribution of the laboratory line to the
observed line for temperature of 500K
assuming LTE and optically thin line emission
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Note (1): Bands:
PACS: B2A, B2B, B3A, R1 short (R1A), R1 long (R1B) and
full R1 (R1 long+R1 short)
SPIRE: SLW and SSW
Note (2): the relative FWHM represents the measured width of the line relative
to the theoretical instrumental spectral resolution at the corresponding
wavelength.
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.4 um lambda Wavelength
10- 17 F8.3 Jy Flux Flux
19- 25 F7.3 Jy e_Flux Error in the flux
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Acknowledgements:
Martin Groenewegen, martin.groenewegen(at)oma.be
(End) Patricia Vannier [CDS] 09-Aug-2018