Strong absorption by interstellar hydrogen fluoride:<i>Herschel</i>/HIFI observations of the sight-line to G10.6–0.4 (W31C)

Neufeld, David A.; Sonnentrucker, Paule; Phillips, T. G.; Lis, D. C.; Luca, Massimo De; Goicoechea, J. R.; Black, J. H.; Gérin, M.; Bell, T. A.; Boulanger, F.; Cernicharo, J.; Coutens, A.; Dartois, E.; Kaźmierczak, Marzena; Encrenaz, P.; Falgarone, É.; Geballe, T. R.; Giesen, Thomas; Godard, B.; Goldsmith, Paul F.; Gry, C.; Gupta, H. M. Sen; Hennebelle, P.; Herbst, Eric; Hily-Blant, Pierre; Joblin, C.; Kołos, Robert; Krełowski, J.; Martı́n-Pintado, J.; Menten, K. M.; Monje, Raquel; Mookerjea, B.; Pearson, J. C.; Pérault, M.; Persson, C. M.; Plume, R.; Salez, M.; Schlemmer, S.; Schmidt, M.; Stutzki, J.; Teyssier, D.; Vastel, C.; Yu, Shanshan; Caïs, Ph.; Caux, E.; Liseau, R.; Morris, P.; Planesas, P.

doi:10.1051/0004-6361/201014523

Cited by 95 publications

(68 citation statements)

References 16 publications

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“…The OH + ground state lines are known with a good accuracy of ∼1.5 MHz. Velocities obtained by the empirical model agree well with the velocities where deep HCO + (1-0) (Keene et al 1999;Godard et al 2010), p-H 2 O and HF (Neufeld et al 2010) and HI Fish et al (2003) absorptions are detected. It is remarkable that one of the strongest OH + absorption features at V LSR ∼ 7 km s −1 coincides with a strong dip in the HI profile that has no counterpart in CO emission Falgarone et al (2005).…”

Section: Resultssupporting

confidence: 75%

“…The molecular cloud surrounding the star-forming complex shows evidence of continuing accretion onto the embedded stars (Keto & Wood 2006;Sollins & Ho 2005). As discussed by Neufeld et al (2010), line absorption by foreground gas has been detected from [OI] (Keene et al 1999), 13 CH + (Falgarone et al 2005), HCO + , HCN, HNC, CN (Godard et al 2010), and atomic hydrogen (Fish et al 2003). While the gas associated directly with G10.6−0.4 is detected in the velocity range −5 to +5 km s −1 , the A&A 518, L110 (2010) foreground gas along the line of sight is confined to the velocity interval from ∼5 to 45 km s −1 .…”

Section: Introductionmentioning

confidence: 92%

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Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4

Gérin¹,

Luca²,

Black

et al. 2010

A&A

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161

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We report the detection of absorption lines by the reactive ions OH + , H 2 O + and H 3 O + along the line of sight to the submillimeter continuum source G10.6−0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH + at 971 GHz, H 2 O + at 1115 and 607 GHz, and H 3 O + at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6−0.4 as well as in the molecular gas directly associated with that source. The OH + spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H 2 O + lines remains lower than 1 in the same velocity range, and the H 3 O + line shows only weak absorption. For LSR velocities between 7 and 50 km s −1 we estimate total column densities of N(OH + ) ≥ 2.5 × 10 14 cm −2 , N(H 2 O + ) ∼6 × 10 13 cm −2 and N(H 3 O + ) ∼4.0 × 10 13 cm −2 . These detections confirm the role of O + and OH + in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH + by the H 2 O + column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form.

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Section: Resultssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 92%

Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4

Gérin¹,

Luca²,

Black

et al. 2010

A&A

Self Cite

161

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“…Monje et al (2014) reported observations of HF in two luminous galaxies, NGC 253 and NGC 4945, using the Heterodyne Instrument for the Far-Infrared (HIFI) on the Herschel Space Observatory. With Herschel/HIFI, Neufeld et al (2010) detected HF in absorption from the ground rovibrational state. Phillips et al (2010) presented a detection of the fundamental rotational transition of hydrogen fluoride in absorption toward Orion KL using Herschel/HIFI.…”

Section: Introductionmentioning

confidence: 99%

Collisional quenching of highly rotationally excited HF

Yang

Walker

Forrey

et al. 2015

A&A

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Context. Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Aims. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. Methods. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H 2 colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach.Results. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to j = 20 were performed for kinetic energies from 10 −5 to 15 000 cm −1 . State-to-state rate coefficients for temperatures between 0.1 and 3000 K are also presented. The comparison of the present results with previous work for lowly-excited rotational levels reveals significant differences. In estimating HF-H 2 rate coefficients, the reduced-potential method is found to be more reliable than the standard reduced-mass approach. Conclusions. The current state-to-state rate coefficient calculations are the most comprehensive to date for HF-He collisions. We attribute the differences between previously reported data and our results to differences in the adopted interaction potential energy surfaces. The new He rate coefficients can be used in a variety of applications. The estimated H 2 and H collision rates can also augment the smaller datasets previously developed for H 2 and electrons.

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“…Relative abundances measured in diffuse clouds show that, indeed, fluorine is essentially locked in HF (e.g., Neufeld et al 2010;Monje et al 2011), whereas HCl accounts for less than 1% of the elemental chlorine due to a rich chemistry initiated by ionizing radiation (e.g., Monje et al 2013). In dense molecular clouds, HF and HCl are found to be strongly depleted, which is thought to be the result of nearly all HF and HCl molecules freezing out onto grains in such cold environments (Peng et al 2010;Emprechtinger et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with theHerschelSpace Observatory

Bockelée‐Morvan

Biver

Crovisier

et al. 2014

A&A

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Context. Hydrogen chloride (HCl) and hydrogen fluoride (HF) are expected to be the main reservoirs of fluorine and chlorine over a wide range of conditions, wherever hydrogen is predominantly molecular. They are found to be strongly depleted in dense molecular clouds, suggesting freeze-out onto grains in such cold environments. We can then expect that HCl and HF were also the major carriers of Cl and F in the gas and icy phases of the outer solar nebula, and were incorporated into comets. Aims. We aimed to measure the HCl and HF abundances in cometary ices as they can provide insights on the halogen chemistry in the early solar nebula. Methods. We searched for the J(1−0) lines of HCl and HF at 626 and 1232 GHz, respectively, using the Heterodyne Instrument for the Far-Infrared (HIFI) onboard the Herschel Space Observatory. HCl was searched for in comets 103P/Hartley 2 and C/2009 P1 (Garradd), whereas observations of HF were conducted in comet C/2009 P1 (Garradd). In addition, observations of H 2 O and H 2 18 O lines were performed in C/2009 P1 (Garradd) to measure the H 2 O production rate at the time of the HCl and HF observations. Three lines of CH 3 OH were serendipitously observed in the HCl receiver setting. Results. HCl is not detected, whereas a marginal (3.6-σ) detection of HF is obtained. The upper limits for the HCl abundance relative to water are 0.011% and 0.022%, for comet 103P/Hartley 2 and C/2009 P1 (Garradd), respectively, showing that HCl is depleted with respect to the solar Cl/O abundance by a factor more than 6 +6 −3 in 103P/Hartley 2, where the error is related to the uncertainty in the chlorine solar abundance. The marginal HF detection obtained in C/2009 P1 (Garradd) corresponds to an HF abundance relative to water of (1.8 ± 0.5) × 10 −4 , which is approximately consistent with a solar photospheric F/O abundance. The inferred water production rate in comet C/2009 P1 (Garradd) is (1.1±0.3)×10 29 s −1 and (0.75±0.05)×10 29 s −1 on 17 and 23 February 2012, respectively. CH 3 OH abundances relative to water are 2.7 ± 0.3% and 3.4 ± 0.6%, for comets 103P/Hartley 2 and C/2009 P1 (Garradd), respectively. Conclusions. The observed depletion of HCl suggests that HCl was not the main reservoir of chlorine in the regions of the solar nebula where these comets formed. HF was possibly the main fluorine compound in the gas phase of the outer solar nebula. However, this needs to be confirmed by future measurements.

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Strong absorption by interstellar hydrogen fluoride:Herschel/HIFI observations of the sight-line to G10.6–0.4 (W31C)

Cited by 95 publications

References 16 publications

Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4

Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4

Collisional quenching of highly rotationally excited HF

Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with theHerschelSpace Observatory

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Strong absorption by interstellar hydrogen fluoride:Herschel/HIFI observations of the sight-line to G10.6–0.4 (W31C)

Cited by 95 publications

References 16 publications

Interstellar OH+, H2O+and H3O+along the sight-line to G10.6–0.4

Interstellar OH+, H2O+and H3O+along the sight-line to G10.6–0.4

Collisional quenching of highly rotationally excited HF

Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with theHerschelSpace Observatory

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Product

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Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4

Interstellar OH⁺, H₂O⁺and H₃O⁺along the sight-line to G10.6–0.4