Recent Work On SiO Masers at the Centro Astronómico de Yebes

Bujarrabal, V.; Alcolea, J.; Martínez, A.; Barcia, A.; Gallego, J. D.; Gómez-González, J.; Pino, Andrés del; Planesas, P.; Bachiller, R.; Rodriguez, Antonio C.; Romero, A.; Tafalla, M.; Vicente, P. de

doi:10.1007/3-540-56343-1_293

Cited by 44 publications

(81 citation statements)

References 1 publication

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“…Previous 43 GHz SiO maser and mIR observations show a linear correlation between the respective flux densities (Bujarrabal et al 1996(Bujarrabal et al , 1987Jiang 2002;Nyman et al 1993). This correlation argues in favor of radiative pump of the SiO masers, and against collisional pumping models.…”

Section: Line Intensitymentioning

confidence: 80%

“…Nyman et al (1993Nyman et al ( , 1986 found that the ratio of the 43 over 86 GHz (v = 1) SiO maser line flux is much higher for OH/IR stars, varying from 2 to 10 with increasing mass-loss rate, than for Mira stars (0.4) as found by Lane (1982). For typical 43 GHz maser line intensities measured for Galactic bulge OH/IR stars (Lindqvist et al 1991;Sjouwerman et al 2002a), and for the low 86 to 43 GHz line flux ratios generally seen towards OH/IR stars, such stars should be weak at 86 GHz and at the distance of the Galactic centre, while Mira stars should be stronger; -the SiO maser line flux correlates with the mIR continuum flux density (Alcolea et al 1989;Bujarrabal 1994;Bujarrabal et al 1987;Jiang 2002). Previous studies have shown that the 43 GHz (v = 1 and v = 2) line peak intensity correlates with the (∼7-12 µm) mIR continuum flux density (Bujarrabal 1994).…”

Section: Source Selectionmentioning

confidence: 99%

“…The mIR and maser intensities vary together during the stellar cycle. Measuring the respective flux densities at the maximum, Bujarrabal et al (1987) found that the IR 8 µm /SiO 43 GHz,v=1 ratio is ∼5 in O-rich Mira stars. The IR 12 µm /SiO 86 GHz,v=1 ratio was found to be ∼10, albeit with a large scatter, by Bujarrabal et al (1996) in a sample of O-rich late-type stars.…”

Section: Source Selectionmentioning

confidence: 99%

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86 GHz SiO maser survey of late-type stars in the Inner Galaxy

Messineo¹,

Habing²,

Sjouwerman³

et al. 2002

A&A

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Abstract. We present 86 GHz (v = 1, J = 2 → 1) SiO maser line observations with the IRAM 30-m telescope of a sample of 441 late-type stars in the Inner Galaxy (−4 • < l < +30 • ). These stars were selected on the basis of their infrared magnitudes and colours from the ISOGAL and MSX catalogues. SiO maser emission was detected in 271 sources, and their line-of-sight velocities indicate that the stars are located in the Inner Galaxy. These new detections double the number of line-of-sight velocities available from previous SiO and OH maser observations in the area covered by our survey and are, together with other samples of e.g. OH/IR stars, useful for kinematic studies of the central parts of the Galaxy.

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Section: Line Intensitymentioning

confidence: 80%

Section: Source Selectionmentioning

confidence: 99%

Section: Source Selectionmentioning

confidence: 99%

See 1 more Smart Citation

86 GHz SiO maser survey of late-type stars in the Inner Galaxy

Messineo¹,

Habing²,

Sjouwerman³

et al. 2002

A&A

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“…From the observational point of view, a radiative pumping model explains the observed correlation between SiO maser intensity and the infrared emission (e.g. Bujarrabal et al 1987), while the dependence on stellar pulsations could be explained by collisional pumping (e.g. Heske 1989).…”

Section: Sio Maser Pumpingmentioning

confidence: 99%

SiO maser emission from red supergiants across the Galaxy

Verheyen¹,

Messineo²,

Menten³

2012

A&A

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Aims. Red supergiants (RSGs) are among the most luminous of all stars, easily detectable in external galaxies, and may ideally serve as kinematic tracers of Galactic structure. Some RSGs are surrounded by circumstellar envelopes detectable by their dust and molecular and, in particular, maser emission. This study consists of a search for maser emission from silicon monoxide (SiO) toward a significant number of RSGs that are members of massive stellar clusters, many of which have only recently been discovered. Further, we aim to relate the occurrence of maser action to properties of the host stars. Methods. Using the IRAM 30 m telescope, we searched for maser emission in the J = 2−1 rotational transition within the first vibrationally excited state of SiO toward a sample of 88 RSGs. Results. With an average rms noise level of 0.25 Jy, we detected maser emission in 15% of the sample, toward most of the sources for the first time in this transition. The peak of the emission provides accurate radial velocities for the RSGs. The dependence of the detection rate on infrared colors supports a radiative pumping mechanism for the SiO masers.

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“…R Aqr is the symbiotic system presenting the beststudied molecular spectra. Its SiO maser intensity is normal, compared to that of standard Mira stars (Bujarrabal et al 1987;Pardo et al 2004) and has been studied relatively well, including high-resolution mapping using VLBI techniques. The SiO maser probably originates in the close surroundings of the Mira-type variable, forming the typical ring of spots (e.g.…”

Section: Introductionmentioning

confidence: 99%

VERA observations of SiO maser emission from R Aquarii

Kamohara¹,

Bujarrabal²,

Honma³

et al. 2010

A&A

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Aims. We aim to study the spatial distribution of the v = 1 and v = 2 J = 1−0 SiO maser emission from R Aqr, a well known stellar symbiotic system. In particular, we intend to determine the annual parallax and proper motion of the source by means of measurements of the absolute coordinates of the maser spots. Methods. We performed VLBI observations of the v = 1 and v = 2 J = 1−0 maser emission, at 7 mm wavelength, using VERA. We present observations made in 11 epochs, between December 2004 and October 2006, and observations by other authors are also discussed. VERA provides very high spatial resolution and accurate astrometric measurements, thanks to its double-beam observing system. From fitting ring-like structures to the maser spot distributions, we determine absolute J2000 coordinates of the central star.(SiO maser emission is known to be distributed around the star forming spot rings at a few stellar radii.) Results. Maps with accurate absolute coordinates were obtained in 8 epochs. From the coordinates determined for the central star, we measured parallax and linear proper motion. We obtain π = 4.7 ± 0.8 mas, compatible with, but much more accurate than, the Hipparcos value (5.07 ± 3.15 mas), and deduce a distance of R Aqr D = 214 +45 −32 pc. Our accurate astrometry also yields a reliable comparison between the spot distributions of both v = 1 and v = 2 J = 1−0 lines. We find that both masers come from similar regions, i.e. at similar distances from the star and defining common spot clusters, confirming previous results. But the coincidences between spots of both lines are very rare, within the spatial and spectral resolution of our experiments. This result is found for eight epochs, spanning more than one pulsation cycle (of the cool Mira-type component). We argue that explaining the finer details of the v = 1, 2 J = 1−0 distributions found here would require new theoretical efforts. Finally, our observations also allow the study of the structure and dynamics of the close circumstellar shells in R Aqr. We do not confirm the previous suggestion that these shells are rotating; instead, we conclude that the observed kinematics is very probably caused by pulsations and random movements. The spatial distribution of the maser spots is found to be variable, but to show a stable axial symmetry.

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Recent Work On SiO Masers at the Centro Astronómico de Yebes

Cited by 44 publications

References 1 publication

86 GHz SiO maser survey of late-type stars in the Inner Galaxy

86 GHz SiO maser survey of late-type stars in the Inner Galaxy

SiO maser emission from red supergiants across the Galaxy

VERA observations of SiO maser emission from R Aquarii

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