Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI

M. Harwit; M. Houde; P. Sonnentrucker; A. C. A. Boogert; J. Cernicharo; E. De Beck; L. Decin; C. Henkel; R. D. Higgins; W. Jellema; A. Kraus; C. McCoey; G. J. Melnick; K. M. Menten; C. Risacher; D. Teyssier; J. E. Vaillancourt; J. Alcolea; V. Bujarrabal; C. Dominik; K. Justtanont; A. de Koter; A.P. Marston; H. Olofsson; P. Planesas; M. Schmidt; F. L. Schöier; R. Szczerba; L.B.F.M. Waters

doi:10.1051/0004-6361/201015042

Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI

M. Harwit, M. Houde, P. Sonnentrucker, A. C. A. Boogert, J. Cernicharo, E. De Beck, L. Decin, C. Henkel, R. D. Higgins, W. Jellema, A. Kraus, C. McCoey, G. J. Melnick, K. M. Menten, C. Risacher, D. Teyssier, J. E. Vaillancourt, J. Alcolea, V. Bujarrabal, C. DominikK. Justtanont, A. de Koter, A.P. Marston, H. Olofsson, P. Planesas, M. Schmidt, F. L. Schöier, R. Szczerba, L.B.F.M. Waters

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Abstract

Water vapour maser emission from evolved oxygen-rich stars remains poorly understood. Additional observations, including polarisation studies and simultaneous observation of different maser transitions may ultimately lead to greater insight. Aims. We have aimed to elucidate the nature and structure of the VY CMa water vapour masers in part by observationally testing a theoretical prediction of the relative strengths of the 620.701 GHz and the 22.235 GHz maser components of ortho H2O. Methods. In its high-resolution mode (HRS) the Herschel Heterodyne Instrument for the Far Infrared (HIFI) offers a frequency resolution of 0.125 MHz, corresponding to a line-of-sight velocity of 0.06 km s−1, which we employed to obtain the strength and linear polarisation of maser spikes in the spectrum of VY CMa at 620.701 GHz. Simultaneous ground based observations of the 22.235 GHz maser with the Max-Planck- Institut für Radioastronomie 100-m telescope at Effelsberg, provided a ratio of 620.701 GHz to 22.235 GHz emission. Results. We report the first astronomical detection to date of H2O maser emission at 620.701 GHz. In VY CMa both the 620.701 and the 22.235 GHz polarisation are weak. At 620.701 GHz the maser peaks are superposed on what appears to be a broad emission component, jointly ejected from the star. We observed the 620.701 GHz emission at two epochs 21 days apart, both to measure the potential direction of linearly polarised maser components and to obtain a measure of the longevity of these components. Although we do not detect significant polarisation levels in the core of the line, they rise up to approximately 6% in its wings.

Original language	English
Pages (from-to)	L51/1-L51/5
Number of pages	5
Journal	Astronomy and Astrophysics
Volume	521
Issue number	1
DOIs	https://doi.org/10.1051/0004-6361/201015042
Publication status	Published - 2010

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Harwit, M., Houde, M., Sonnentrucker, P., Boogert, A. C. A., Cernicharo, J., De Beck, E., Decin, L., Henkel, C., Higgins, R. D., Jellema, W., Kraus, A., McCoey, C., Melnick, G. J., Menten, K. M., Risacher, C., Teyssier, D., Vaillancourt, J. E., Alcolea, J., Bujarrabal, V., ... Waters, L. B. F. M. (2010). Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI. Astronomy and Astrophysics, 521(1), L51/1-L51/5. https://doi.org/10.1051/0004-6361/201015042

@article{d9b0dabb1fa14e968c5801c571df3e6b,

title = "Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI",

abstract = "Water vapour maser emission from evolved oxygen-rich stars remains poorly understood. Additional observations, including polarisation studies and simultaneous observation of different maser transitions may ultimately lead to greater insight. Aims. We have aimed to elucidate the nature and structure of the VY CMa water vapour masers in part by observationally testing a theoretical prediction of the relative strengths of the 620.701 GHz and the 22.235 GHz maser components of ortho H2O. Methods. In its high-resolution mode (HRS) the Herschel Heterodyne Instrument for the Far Infrared (HIFI) offers a frequency resolution of 0.125 MHz, corresponding to a line-of-sight velocity of 0.06 km s−1, which we employed to obtain the strength and linear polarisation of maser spikes in the spectrum of VY CMa at 620.701 GHz. Simultaneous ground based observations of the 22.235 GHz maser with the Max-Planck- Institut f{\"u}r Radioastronomie 100-m telescope at Effelsberg, provided a ratio of 620.701 GHz to 22.235 GHz emission. Results. We report the first astronomical detection to date of H2O maser emission at 620.701 GHz. In VY CMa both the 620.701 and the 22.235 GHz polarisation are weak. At 620.701 GHz the maser peaks are superposed on what appears to be a broad emission component, jointly ejected from the star. We observed the 620.701 GHz emission at two epochs 21 days apart, both to measure the potential direction of linearly polarised maser components and to obtain a measure of the longevity of these components. Although we do not detect significant polarisation levels in the core of the line, they rise up to approximately 6% in its wings.",

author = "M. Harwit and M. Houde and P. Sonnentrucker and Boogert, {A. C. A.} and J. Cernicharo and {De Beck}, E. and L. Decin and C. Henkel and Higgins, {R. D.} and W. Jellema and A. Kraus and C. McCoey and Melnick, {G. J.} and Menten, {K. M.} and C. Risacher and D. Teyssier and Vaillancourt, {J. E.} and J. Alcolea and V. Bujarrabal and C. Dominik and K. Justtanont and {de Koter}, A. and A.P. Marston and H. Olofsson and P. Planesas and M. Schmidt and Sch{\"o}ier, {F. L.} and R. Szczerba and L.B.F.M. Waters",

year = "2010",

doi = "10.1051/0004-6361/201015042",

language = "English",

volume = "521",

pages = "L51/1--L51/5",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

number = "1",

}

Harwit, M, Houde, M, Sonnentrucker, P, Boogert, ACA, Cernicharo, J, De Beck, E, Decin, L, Henkel, C, Higgins, RD, Jellema, W, Kraus, A, McCoey, C, Melnick, GJ, Menten, KM, Risacher, C, Teyssier, D, Vaillancourt, JE, Alcolea, J, Bujarrabal, V, Dominik, C, Justtanont, K, de Koter, A, Marston, AP, Olofsson, H, Planesas, P, Schmidt, M, Schöier, FL, Szczerba, R & Waters, LBFM 2010, 'Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI', Astronomy and Astrophysics, vol. 521, no. 1, pp. L51/1-L51/5. https://doi.org/10.1051/0004-6361/201015042

TY - JOUR

T1 - Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI

AU - Harwit, M.

AU - Houde, M.

AU - Sonnentrucker, P.

AU - Boogert, A. C. A.

AU - Cernicharo, J.

AU - De Beck, E.

AU - Decin, L.

AU - Henkel, C.

AU - Higgins, R. D.

AU - Jellema, W.

AU - Kraus, A.

AU - McCoey, C.

AU - Melnick, G. J.

AU - Menten, K. M.

AU - Risacher, C.

AU - Teyssier, D.

AU - Vaillancourt, J. E.

AU - Alcolea, J.

AU - Bujarrabal, V.

AU - Dominik, C.

AU - Justtanont, K.

AU - de Koter, A.

AU - Marston, A.P.

AU - Olofsson, H.

AU - Planesas, P.

AU - Schmidt, M.

AU - Schöier, F. L.

AU - Szczerba, R.

AU - Waters, L.B.F.M.

PY - 2010

Y1 - 2010

N2 - Water vapour maser emission from evolved oxygen-rich stars remains poorly understood. Additional observations, including polarisation studies and simultaneous observation of different maser transitions may ultimately lead to greater insight. Aims. We have aimed to elucidate the nature and structure of the VY CMa water vapour masers in part by observationally testing a theoretical prediction of the relative strengths of the 620.701 GHz and the 22.235 GHz maser components of ortho H2O. Methods. In its high-resolution mode (HRS) the Herschel Heterodyne Instrument for the Far Infrared (HIFI) offers a frequency resolution of 0.125 MHz, corresponding to a line-of-sight velocity of 0.06 km s−1, which we employed to obtain the strength and linear polarisation of maser spikes in the spectrum of VY CMa at 620.701 GHz. Simultaneous ground based observations of the 22.235 GHz maser with the Max-Planck- Institut für Radioastronomie 100-m telescope at Effelsberg, provided a ratio of 620.701 GHz to 22.235 GHz emission. Results. We report the first astronomical detection to date of H2O maser emission at 620.701 GHz. In VY CMa both the 620.701 and the 22.235 GHz polarisation are weak. At 620.701 GHz the maser peaks are superposed on what appears to be a broad emission component, jointly ejected from the star. We observed the 620.701 GHz emission at two epochs 21 days apart, both to measure the potential direction of linearly polarised maser components and to obtain a measure of the longevity of these components. Although we do not detect significant polarisation levels in the core of the line, they rise up to approximately 6% in its wings.

AB - Water vapour maser emission from evolved oxygen-rich stars remains poorly understood. Additional observations, including polarisation studies and simultaneous observation of different maser transitions may ultimately lead to greater insight. Aims. We have aimed to elucidate the nature and structure of the VY CMa water vapour masers in part by observationally testing a theoretical prediction of the relative strengths of the 620.701 GHz and the 22.235 GHz maser components of ortho H2O. Methods. In its high-resolution mode (HRS) the Herschel Heterodyne Instrument for the Far Infrared (HIFI) offers a frequency resolution of 0.125 MHz, corresponding to a line-of-sight velocity of 0.06 km s−1, which we employed to obtain the strength and linear polarisation of maser spikes in the spectrum of VY CMa at 620.701 GHz. Simultaneous ground based observations of the 22.235 GHz maser with the Max-Planck- Institut für Radioastronomie 100-m telescope at Effelsberg, provided a ratio of 620.701 GHz to 22.235 GHz emission. Results. We report the first astronomical detection to date of H2O maser emission at 620.701 GHz. In VY CMa both the 620.701 and the 22.235 GHz polarisation are weak. At 620.701 GHz the maser peaks are superposed on what appears to be a broad emission component, jointly ejected from the star. We observed the 620.701 GHz emission at two epochs 21 days apart, both to measure the potential direction of linearly polarised maser components and to obtain a measure of the longevity of these components. Although we do not detect significant polarisation levels in the core of the line, they rise up to approximately 6% in its wings.

U2 - 10.1051/0004-6361/201015042

DO - 10.1051/0004-6361/201015042

M3 - Article

SN - 0004-6361

VL - 521

SP - L51/1-L51/5

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

IS - 1

ER -

Polarisation observations of VY Canis Majoris H2O 5 32-441 620.701 GHz maser emission with HIFI

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