J/A+A/637/A7 PKS1830-211 HDO, ND and NH2D spectra (Muller+, 2020)
Detection of deuterated molecules, but not of lithium hydride,
in the z=0.89 absorber toward PKS 1830-211.
Muller S., Roueff E., Black J.H., Gerin M., Guelin M., Menten K.M.,
Henkel C., Aalto S., Combes F., Martin S., Marti-Vidal I.
<Astron. Astrophys. 637, A7 (2020)>
=2020A&A...637A...7M 2020A&A...637A...7M (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Radio lines ; Spectra, radio
Keywords: quasars: absorption lines - quasars: individual: PKS 1830-211 -
galaxies: ISM - galaxies: abundances - ISM: molecules -
radio lines: galaxies
Abstract:
Deuterium and lithium are light elements of high cosmological and
astrophysical importance. In this work we report the first detection
of deuterated molecules and a search for lithium hydride, 7LiH, at
redshift z=0.89 in the spiral galaxy intercepting the line of sight to
the quasar PKS 1830-211. We used ALMA to observe several submillimeter
lines of ND, NH2D, and HDO, and their related isotopomers NH2,
NH3, and H182O, in absorption against the southwest image of the
quasar, allowing us to derive XD/XH abundance ratios. The absorption
spectra mainly consist of two distinct narrow velocity components for
which we find remarkable differences. One velocity component shows
XD/XH abundances that is about 10 times larger than the primordial
elemental D/H ratio, and no variability of the absorption profile
during the time span of our observations. In contrast, the other
component shows a stronger deuterium fractionation. Compared to the
first component, this second component has XD/XH abundances that are
100 times larger than the primordial D/H ratio, a deepening of the
absorption by a factor of two within a few months, and a rich chemical
composition, with relative enhancements of N2H+, CH3OH, SO2
and complex organic molecules. We therefore speculate that this
component is associated with the analog of a Galactic dark cloud,
while the first component is likely more diffuse. Our search for the
7LiH (1-0) line was unsuccessful and we derive an upper limit
7LiH/H2=4x10-13 (3σ) in the z=0.89 absorber toward PKS
1830.211. Besides, with ALMA archival data, we could not confirm the
previous tentative detections of this line in the z=0.68 absorber
toward B0218+357; we derive an upper limit 7LiH/H2=5x10-11
(3σ), although this is less constraining than our limit toward
PKS 1830.211. We conclude that, as in the Milky Way, only a tiny
fraction of lithium nuclei are possibly bound in LiH in these
absorbers at intermediate redshift.
Description:
The data used in this study were observed with the Atacama Large
Millimeter/submillimeter Array (ALMA) on 2019 April 11 and 2019 July
28, in the frame of two different science projects (2018.1.00692.S and
2018.1.00051.S).
Spectra of ND (transitions at 522 and 546GHz), NH2D, and HDO, along
the SW line of sight toward PKS1830-211. See Table 2 of the paper for
more details (frequency and date of observations).
Objects:
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RA (2000) DE Designation(s)
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18 33 39.92 -21 03 39.9 PKS1830-211 = PKS 1830-211
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sphdo.dat 35 25 PKS1830-211 spectrum of the 464GHz transition of HDO
spnd522.dat 35 227 PKS1830-211 spectrum of the 522GHz transition of ND
spnd546.dat 35 119 PKS1830-211 spectrum of the 546GHz transition of ND
spnh2d.dat 35 25 PKS1830-211 spectrum of the 470GHz transition of NH2D
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Byte-by-byte Description of file: sphdo.dat spnd522.dat spnd546.dat spnh2d.dat
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Bytes Format Units Label Explanations
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1- 18 F18.14 km/s HV Velocity in heliocentric frame, z=0.88582
20- 35 F16.14 --- Int Intensity normalized to the continuum level
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Acknowledgements:
Sebastien Muller, mullers(at)chalmers.se
(End) Patricia Vannier [CDS] 07-Apr-2020