A dedicated polarimeter for the MuSiCoS échelle spectrograph

Donati, J. F.; Catala, C.; Wade, G. A.; Gallou, G.; Delaigue, G.; Rabou, Patrick

doi:10.1051/aas:1999130

Cited by 111 publications

(110 citation statements)

References 7 publications

(9 reference statements)

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“…The instrument consists of a fiberfed cross dispersed echelle spectrograph with a dedicated polarimeter (Donati et al 1999) mounted at the Cassegrain focus. Stellar light is collected in a 2 arcsec entrance over a spectral range from 4500 to 6600 Å and with a resolution R = 35 000.…”

Section: Spectropolarimetric Observationsmentioning

confidence: 99%

See 1 more Smart Citation

Variability and pulsations in the Be star 66 Ophiuchi

Floquet

Neiner

Janot-Pacheco

et al. 2002

A&A

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Section: Spectropolarimetric Observationsmentioning

confidence: 99%

“…Because the instrumental accuracy in continuum polarization is about 1% and the expected stellar continuum polarization is of the same order, the results obtained in the continuum cannot be trusted (see Donati et al 1999). However, polarization across emission lines can be studied with respect to the surrounding continuum.…”

Section: Linear Polarizationmentioning

confidence: 99%

Variability and pulsations in the Be star 66 Ophiuchi

Floquet

Neiner

Janot-Pacheco

et al. 2002

A&A

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“…To check the consistency of methods between this paper and that of Uytterhoeven et al (2008), a selection of the data taken as part of the 2007 multi-site spectroscopic campaign was analysed in famias. These data were provided as line profiles (as discussed in Uytterhoeven et al, 2008) which were computed using a Least-Squares Deconvolution (lsd) method (Donati et al 1997(Donati et al , 1999. This method differs slightly to the δ-function cross-correlation method used for the more recent hercules data, but produces very similar line profiles.…”

Section: Observations and Data Treatmentmentioning

confidence: 99%

The classification of frequencies in the γ Doradus/δ Scuti hybrid star HD 49434★

Brunsden

Pollard

Cottrell

et al. 2015

Monthly Notices of the Royal Astronomical Society

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Hybrid stars of the γ Doradus and δ Scuti pulsation types have great potential for asteroseismic analysis to explore their interior structure. To achieve this, mode identifications of pulsational frequencies observed in the stars must be made, a task which is far from simple. In this work we begin the analysis by scrutinizing the frequencies found in the CoRoT photometric satellite measurements and ground-based high-resolution spectroscopy of the hybrid star HD 49434. The results show almost no consistency between the frequencies found using the two techniques and no characteristic period spacings or couplings were identified in either dataset. The spectroscopic data additionally show no evidence for any long term (5 year) variation in the dominant frequency. The 31 spectroscopic frequencies identified have standard deviation profiles suggesting multiple modes sharing (l, m) in the δ Scuti frequency region and several skewed modes sharing the same (l, m) in the γ Doradus frequency region. In addition, there is a clear frequency in the γ Doradus frequency region that appears to be unrelated to the others. We conclude HD 49434 remains a δ Scuti/ γ Doradus candidate hybrid star but more sophisticated models dealing with rotation are sought to obtain a clear picture of the pulsational behaviour of this star.

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“…With such instruments, the spectral resolution can be increased sufficiently to undertake polarimetric studies across stellar line profiles. It has become apparent, however, that "fringes" tend to appear in the data -see, for example, Tinbergen (1994), Harries & Howarth (1996) and Donati et al (1999). From their analysis, Harries and Howarth concluded that the observed fringes were consistent with being of the Fabry-Pérot-type producing a fringe-structured instrumental polarization which could be subtracted out by reference observations of unpolarized standard stars.…”

Section: Introductionmentioning

confidence: 99%

Effects in polarimetry of interference within wave plates

Clarke¹

2005

A&A

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Abstract. Multiple-beam interference within wave plates is investigated in terms of the detrimental effects it produces in the data of stellar spectropolarimetry. It is noted that spectral fringe structures occur in the phase delay, the polarizance and, for Pancharatnam designs, the reference axis of the wave plate. The natures of the problems are exposed by considering typical wave plates and experimental procedures used in linear and circular spectropolarimetry. It is demonstrated that the chief bane of accurate measurements is the presence of polarizance fringes, but which can be alleviated by the choice of experimental procedure. For spectral circular polarization studies, problems of cross-talk from any linear polarization present in the source are especially severe. In principle the effects of fringing can be removed in data reductions by calibration measurements of a set of linear polarization standard stars displaying different vibration azimuths and, for circular polarization measurements, knowledge of the linear polarization characteristics of the investigated star must also be known.

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A dedicated polarimeter for the MuSiCoS échelle spectrograph

Cited by 111 publications

References 7 publications

Variability and pulsations in the Be star 66 Ophiuchi

Variability and pulsations in the Be star 66 Ophiuchi

The classification of frequencies in the γ Doradus/δ Scuti hybrid star HD 49434★

Effects in polarimetry of interference within wave plates

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