A new concept of the International Celestial Reference Frame: the epoch ICRF

Mei-ling, XU; Wang, G. L.; Zhao, Ming

doi:10.1093/mnras/stt044

Cited by 11 publications

(7 citation statements)

References 17 publications

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“…The detection of the secular aberration drift in the positions of extragalactic radio sources observed by very long baseline interferometry (VLBI) in accordance with the theoretical predictions (see, e.g., Fanselow 1983;Bastian 1995;Eubanks et al 1995;Sovers et al 1998;Mignard 2002;Kovalevsky 2003;Kopeikin & Makarov 2006) was announced recently by Titov et al (2011, hereafter TLG11), and Xu et al (2012Xu et al ( , 2013. These works provided direct measurements of the solar system acceleration in the Universe independent of a dynamical model of the Galaxy.…”

Section: Introductionmentioning

confidence: 57%

“…TLG11 found an acceleration vector pointing towards the Galactic center (α G = 266.4 • , δ G = −28.9 • ) within 10 • and an amplitude in agreement with predictions based on the Galactic parameters derived with other methods. Using a similar observational data set but an alternative estimation method, Xu et al (2012Xu et al ( , 2013 obtained an amplitude close to TLG11 but oriented about 18 • north and 23 • west from the Galactic center, and thus a significant acceleration of the Solar System perpendicularly to the Galactic plane. The authors raised the possibility of a companion star orbiting the Sun to explain the deviation.…”

Section: Introductionmentioning

confidence: 92%

“…Using a similar observational data set, but an alternative estimation method, Xu et al (2012Xu et al ( , 2013 obtained an amplitude similar to that of TLG11, but oriented about 18…”

Section: Introductionmentioning

confidence: 93%

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Improved VLBI measurement of the solar system acceleration

Titov

Lambert

2013

A&A

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Aims. We propose new estimates of the secular aberration drift, which is mainly caused by the rotation of the solar system about the Galactic center, based on up-to-date VLBI observations and improved method of outlier elimination. Methods. We fitted degree-2 vector spherical harmonics to the extragalactic radio source proper motion field derived from geodetic VLBI observations during 1979-2013. We paid particular attention to the outlier elimination procedure that removes outliers from (i) radio source coordinate time series and (ii) the proper motion sample. Results. We obtain more accurate values of the Solar system acceleration than in our previous paper. The acceleration vector is oriented towards the Galactic center within ∼7• . The component perpendicular to the Galactic plane is statistically insignificant. We show that an insufficient cleaning of the data set can lead to strong variations in the dipole amplitude and orientation, and hence to statistically biased results.

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Section: Introductionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 92%

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Improved VLBI measurement of the solar system acceleration

Titov

Lambert

2013

A&A

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“…The aberrational effect on the extragalactic sources attribute to the acceleration of the SSB has been called the 'secular aberration' (Kopeikin & Makarov 2006), 'secular aberration drift' (Titov 2010;Titov et al 2011;Xu et al 2013), 'Galactic aberration' (Malkin 2011;Liu et al 2012), and also a more concise term 'glide' (Mignard & Klioner 2012), which is as easy to be used as 'rotation'. Since the aberration in stellar proper motions in the Galaxy depends on both of the acceleration of the SSB and stars themselves, the above terms are not sufficient to distinguish these two phenomena, although they are quite similar, thus a proper terminology is necessary.…”

Section: Nomenclature Issuementioning

confidence: 99%

“…The systematic effect of the Galactic aberration on the present ICRF realized by extragalactic sources has been discussed by Liu et al (2012) using ICRF1/ICRF2 catalogues. More recently, a new concept of 'epoch ICRF' was proposed by Xu et al (2013) with a slightly different approach. Because the extragalactic sources are assumed to have no measurable motion (Petit & Luzum 2010), they can be regarded as free of acceleration, therefore only the acceleration of the SSB is necessarily be considered.…”

Section: Effect Of the Aberration On The Celestial Reference Frame Re...mentioning

confidence: 99%

Aberration in proper motions for stars in our Galaxy

Liu

Xie

Zhu

2013

Monthly Notices of the Royal Astronomical Society

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Accelerations of both the solar system barycenter (SSB) and stars in the Milky Way cause a systematic observational effect on the stellar proper motions, which was first studied in the early 1990s and developed by J. Kovalevsky (aberration in proper motions, 2003, A&A, 404, 743). This paper intends to extend that work and aims to estimate the magnitude and significance of the aberration in proper motions of stars, especially in the region near the Galactic center. We adopt two models for the Galactic rotation curve to evaluate the aberrational effect on the Galactic plane. Based on the theoretical developments, we show that the effect of aberration in proper motions depends on the galactocentric distance of stars; it is dominated by the acceleration of stars in the central region of the Galaxy. Within 200 pc from the Galactic center, the systematic proper motion can reach an amplitude larger than 1000 µas yr −1 by applying a flat rotation curve. With a more realistic rotation curve which is linearly rising in the core region of the Galaxy, the aberrational proper motions are limited up to about 150 µas yr −1 . Then we investigate the applicability of the theoretical expressions concerning the aberrational proper motions, especially for those stars with short period orbits. If the orbital period of stars is only a fraction of the light time from the star to the SSB, the expression proposed by Kovalevsky is not appropriate. With a more suitable formulation, we found that the aberration has no effect on the determination of the stellar orbits on the celestial sphere. The aberrational effect under consideration is small but not negligible with high-accurate astrometry in the future, particularly in constructing the Gaia celestial reference system realized by Galactic stars.

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The Galactic Aberration and Its Impact on Astronomical Reference Frames

Liu

2020

Chinese Astronomy and Astrophysics

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A new concept of the International Celestial Reference Frame: the epoch ICRF

Cited by 11 publications

References 17 publications

Improved VLBI measurement of the solar system acceleration

Improved VLBI measurement of the solar system acceleration

Aberration in proper motions for stars in our Galaxy

The Galactic Aberration and Its Impact on Astronomical Reference Frames

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