Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51

M. Gerin; M. de Luca; J. R. Goicoechea; E. Herbst; E. Falgarone; B. Godard; T. A. Bell; A. Coutens; M. Kaźmierczak; P. Sonnentrucker; J. H. Black; D. A. Neufeld; T. G. Phillips; J. Pearson; P. B. Rimmer; G. Hassel; D. C. Lis; C. Vastel; F. Boulanger; J. Cernicharo; E. Dartois; P. Encrenaz; T. Giesen; P. F. Goldsmith; H. Gupta; C. Gry; P. Hennebelle; P. Hily-Blant; C. Joblin; R. Kołos; J. Krełowski; J. Martín-Pintado; R. Monje; B. Mookerjea; M. Perault; C. Persson; R. Plume; M. Salez; M. Schmidt; J. Stutzki; D. Teyssier; S. Yu; A. Contursi; K. Menten; T. R. Geballe; S. Schlemmer; P. Morris; W. A. Hatch; M. Imram; J. S. Ward; E. Caux; R. Güsten; T. Klein; P. Roelfsema; P. Dieleman; R. Schieder; N. Honingh; J. Zmuidzinas

doi:10.1051/0004-6361/201015115

Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51

M. Gerin, M. de Luca, J. R. Goicoechea, E. Herbst, E. Falgarone, B. Godard, T. A. Bell, A. Coutens, M. Kaźmierczak, P. Sonnentrucker, J. H. Black, D. A. Neufeld, T. G. Phillips, J. Pearson, P. B. Rimmer, G. Hassel, D. C. Lis, C. Vastel, F. Boulanger, J. CernicharoE. Dartois, P. Encrenaz, T. Giesen, P. F. Goldsmith, H. Gupta, C. Gry, P. Hennebelle, P. Hily-Blant, C. Joblin, R. Kołos, J. Krełowski, J. Martín-Pintado, R. Monje, B. Mookerjea, M. Perault, C. Persson, R. Plume, M. Salez, M. Schmidt, J. Stutzki, D. Teyssier, S. Yu, A. Contursi, K. Menten, T. R. Geballe, S. Schlemmer, P. Morris, W. A. Hatch, M. Imram, J. S. Ward, E. Caux, R. Güsten, T. Klein, P. Roelfsema, P. Dieleman, R. Schieder, N. Honingh, J. Zmuidzinas

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We report the detection of the ground state N,J = 1,3/2 → 1,1/2 doublet of the methylidyne radical CH at ~532 GHz and ~536 GHz with the Herschel/HIFI instrument along the sight-line to the massive star-forming regions G10.6-0.4 (W31C), W49N, and W51. While the molecular cores associated with these massive star-forming regions show emission lines, clouds in the diffuse interstellar medium are detected in absorption against the strong submillimeter background. The combination of hyperfine structure with emission and absorption results in complex profiles, with overlap of the different hyperfine components. The opacities of most of the CH absorption features are linearly correlated with those of CCH, CN, and HCO+ in the same velocity intervals. In specific narrow velocity intervals, the opacities of CN and HCO+ deviate from the mean trends, giving rise to more opaque absorption features. We propose that CCH can be used as another tracer of the molecular gas in the absence of better tracers, with [CCH]/[ H2] ~ 3.2±1.1×10-8. The observed [CN]/[CH], [CCH]/[CH] abundance ratios suggest that the bulk of the diffuse matter along the lines of sight has gas densities nH = n(H) + 2n(H2) ranging between 100 and 1000 cm-3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices A and B (pages 6, 7) are only available in electronic form at http://www.aanda.org

Originele taal-2	English
Artikelnummer	L16
Aantal pagina's	9
Tijdschrift	Astronomy and astrophysics
Volume	521
DOI's	https://doi.org/10.1051/0004-6361/201015115
Status	Published - okt.-2010

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10.1051/0004-6361/201015115

http://adsabs.harvard.edu/abs/2010A%26A...521L..16G

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Gerin, M., de Luca, M., Goicoechea, J. R., Herbst, E., Falgarone, E., Godard, B., Bell, T. A., Coutens, A., Kaźmierczak, M., Sonnentrucker, P., Black, J. H., Neufeld, D. A., Phillips, T. G., Pearson, J., Rimmer, P. B., Hassel, G., Lis, D. C., Vastel, C., Boulanger, F., ... Zmuidzinas, J. (2010). Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51. Astronomy and astrophysics, 521, [L16]. https://doi.org/10.1051/0004-6361/201015115

@article{27ab6cb1e6cd41ceadd1e98a5888a4e8,

title = "Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51",

abstract = "We report the detection of the ground state N,J = 1,3/2 → 1,1/2 doublet of the methylidyne radical CH at ~532 GHz and ~536 GHz with the Herschel/HIFI instrument along the sight-line to the massive star-forming regions G10.6-0.4 (W31C), W49N, and W51. While the molecular cores associated with these massive star-forming regions show emission lines, clouds in the diffuse interstellar medium are detected in absorption against the strong submillimeter background. The combination of hyperfine structure with emission and absorption results in complex profiles, with overlap of the different hyperfine components. The opacities of most of the CH absorption features are linearly correlated with those of CCH, CN, and HCO+ in the same velocity intervals. In specific narrow velocity intervals, the opacities of CN and HCO+ deviate from the mean trends, giving rise to more opaque absorption features. We propose that CCH can be used as another tracer of the molecular gas in the absence of better tracers, with [CCH]/[ H2] ~ 3.2±1.1×10-8. The observed [CN]/[CH], [CCH]/[CH] abundance ratios suggest that the bulk of the diffuse matter along the lines of sight has gas densities nH = n(H) + 2n(H2) ranging between 100 and 1000 cm-3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices A and B (pages 6, 7) are only available in electronic form at http://www.aanda.org",

keywords = "ISM: clouds, ISM: molecules, submillimeter: ISM, ISM: individual objects: G10.6-0.4, ISM: individual objects: W49N, ISM: individual objects: W51",

author = "M. Gerin and {de Luca}, M. and Goicoechea, {J. R.} and E. Herbst and E. Falgarone and B. Godard and Bell, {T. A.} and A. Coutens and M. Ka{\'z}mierczak and P. Sonnentrucker and Black, {J. H.} and Neufeld, {D. A.} and Phillips, {T. G.} and J. Pearson and Rimmer, {P. B.} and G. Hassel and Lis, {D. C.} and C. Vastel and F. Boulanger and J. Cernicharo and E. Dartois and P. Encrenaz and T. Giesen and Goldsmith, {P. F.} and H. Gupta and C. Gry and P. Hennebelle and P. Hily-Blant and C. Joblin and R. Ko{\l}os and J. Kre{\l}owski and J. Mart{\'i}n-Pintado and R. Monje and B. Mookerjea and M. Perault and C. Persson and R. Plume and M. Salez and M. Schmidt and J. Stutzki and D. Teyssier and S. Yu and A. Contursi and K. Menten and Geballe, {T. R.} and S. Schlemmer and P. Morris and Hatch, {W. A.} and M. Imram and Ward, {J. S.} and E. Caux and R. G{\"u}sten and T. Klein and P. Roelfsema and P. Dieleman and R. Schieder and N. Honingh and J. Zmuidzinas",

note = "M1 - Journal Article",

year = "2010",

month = oct,

doi = "10.1051/0004-6361/201015115",

language = "English",

volume = "521",

journal = "Astronomy & astrophysics",

issn = "0004-6361",

publisher = " EDP Sciences",

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Gerin, M, de Luca, M, Goicoechea, JR, Herbst, E, Falgarone, E, Godard, B, Bell, TA, Coutens, A, Kaźmierczak, M, Sonnentrucker, P, Black, JH, Neufeld, DA, Phillips, TG, Pearson, J, Rimmer, PB, Hassel, G, Lis, DC, Vastel, C, Boulanger, F, Cernicharo, J, Dartois, E, Encrenaz, P, Giesen, T, Goldsmith, PF, Gupta, H, Gry, C, Hennebelle, P, Hily-Blant, P, Joblin, C, Kołos, R, Krełowski, J, Martín-Pintado, J, Monje, R, Mookerjea, B, Perault, M, Persson, C, Plume, R, Salez, M, Schmidt, M, Stutzki, J, Teyssier, D, Yu, S, Contursi, A, Menten, K, Geballe, TR, Schlemmer, S, Morris, P, Hatch, WA, Imram, M, Ward, JS, Caux, E, Güsten, R, Klein, T, Roelfsema, P, Dieleman, P, Schieder, R, Honingh, N & Zmuidzinas, J 2010, 'Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51', Astronomy and astrophysics, vol. 521, L16. https://doi.org/10.1051/0004-6361/201015115

TY - JOUR

T1 - Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51

AU - Gerin, M.

AU - de Luca, M.

AU - Goicoechea, J. R.

AU - Herbst, E.

AU - Falgarone, E.

AU - Godard, B.

AU - Bell, T. A.

AU - Coutens, A.

AU - Kaźmierczak, M.

AU - Sonnentrucker, P.

AU - Black, J. H.

AU - Neufeld, D. A.

AU - Phillips, T. G.

AU - Pearson, J.

AU - Rimmer, P. B.

AU - Hassel, G.

AU - Lis, D. C.

AU - Vastel, C.

AU - Boulanger, F.

AU - Cernicharo, J.

AU - Dartois, E.

AU - Encrenaz, P.

AU - Giesen, T.

AU - Goldsmith, P. F.

AU - Gupta, H.

AU - Gry, C.

AU - Hennebelle, P.

AU - Hily-Blant, P.

AU - Joblin, C.

AU - Kołos, R.

AU - Krełowski, J.

AU - Martín-Pintado, J.

AU - Monje, R.

AU - Mookerjea, B.

AU - Perault, M.

AU - Persson, C.

AU - Plume, R.

AU - Salez, M.

AU - Schmidt, M.

AU - Stutzki, J.

AU - Teyssier, D.

AU - Yu, S.

AU - Contursi, A.

AU - Menten, K.

AU - Geballe, T. R.

AU - Schlemmer, S.

AU - Morris, P.

AU - Hatch, W. A.

AU - Imram, M.

AU - Ward, J. S.

AU - Caux, E.

AU - Güsten, R.

AU - Klein, T.

AU - Roelfsema, P.

AU - Dieleman, P.

AU - Schieder, R.

AU - Honingh, N.

AU - Zmuidzinas, J.

N1 - M1 - Journal Article

PY - 2010/10

Y1 - 2010/10

N2 - We report the detection of the ground state N,J = 1,3/2 → 1,1/2 doublet of the methylidyne radical CH at ~532 GHz and ~536 GHz with the Herschel/HIFI instrument along the sight-line to the massive star-forming regions G10.6-0.4 (W31C), W49N, and W51. While the molecular cores associated with these massive star-forming regions show emission lines, clouds in the diffuse interstellar medium are detected in absorption against the strong submillimeter background. The combination of hyperfine structure with emission and absorption results in complex profiles, with overlap of the different hyperfine components. The opacities of most of the CH absorption features are linearly correlated with those of CCH, CN, and HCO+ in the same velocity intervals. In specific narrow velocity intervals, the opacities of CN and HCO+ deviate from the mean trends, giving rise to more opaque absorption features. We propose that CCH can be used as another tracer of the molecular gas in the absence of better tracers, with [CCH]/[ H2] ~ 3.2±1.1×10-8. The observed [CN]/[CH], [CCH]/[CH] abundance ratios suggest that the bulk of the diffuse matter along the lines of sight has gas densities nH = n(H) + 2n(H2) ranging between 100 and 1000 cm-3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices A and B (pages 6, 7) are only available in electronic form at http://www.aanda.org

AB - We report the detection of the ground state N,J = 1,3/2 → 1,1/2 doublet of the methylidyne radical CH at ~532 GHz and ~536 GHz with the Herschel/HIFI instrument along the sight-line to the massive star-forming regions G10.6-0.4 (W31C), W49N, and W51. While the molecular cores associated with these massive star-forming regions show emission lines, clouds in the diffuse interstellar medium are detected in absorption against the strong submillimeter background. The combination of hyperfine structure with emission and absorption results in complex profiles, with overlap of the different hyperfine components. The opacities of most of the CH absorption features are linearly correlated with those of CCH, CN, and HCO+ in the same velocity intervals. In specific narrow velocity intervals, the opacities of CN and HCO+ deviate from the mean trends, giving rise to more opaque absorption features. We propose that CCH can be used as another tracer of the molecular gas in the absence of better tracers, with [CCH]/[ H2] ~ 3.2±1.1×10-8. The observed [CN]/[CH], [CCH]/[CH] abundance ratios suggest that the bulk of the diffuse matter along the lines of sight has gas densities nH = n(H) + 2n(H2) ranging between 100 and 1000 cm-3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices A and B (pages 6, 7) are only available in electronic form at http://www.aanda.org

KW - ISM: clouds

KW - ISM: molecules

KW - submillimeter: ISM

KW - ISM: individual objects: G10.6-0.4

KW - ISM: individual objects: W49N

KW - ISM: individual objects: W51

UR - http://adsabs.harvard.edu/abs/2010A%26A...521L..16G

U2 - 10.1051/0004-6361/201015115

DO - 10.1051/0004-6361/201015115

M3 - Article

SN - 0004-6361

VL - 521

JO - Astronomy & astrophysics

JF - Astronomy & astrophysics

M1 - L16

ER -