Precise CCD positions of Apophis in 2013

Wang, N.; Peng, Q. Y.; Zhang, Xinglai; Zhang, Qingfeng; Li, Z.; Xue, Meng

doi:10.1093/mnras/stv2236

Cited by 16 publications

(15 citation statements)

References 13 publications

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“…]. More recent estimates for the exponent γ, going up to distance scales of 100 M pc, range between 1.79 and 1.84[98,99,100,101,102,103].The conclusions are similar if one looks at the galaxy power spectrum data, which also suggestsa 0 ≈ (30 M pc) 2 assuming an exponent s = 1 exactly, again consistent in view of Eq. (113) with ξ ≈ 30 M pc, a value that seems rather low (again by two orders of magnitude) in view of the original identification of ξ as the vacuum condensate scale, Eqs.…”

supporting

confidence: 66%

Vacuum Condensate Picture of Quantum Gravity

Hamber

2019

Symmetry

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In quantum gravity perturbation theory in Newton's constant G is known to be badly divergent, and as a result not very useful. Nevertheless, some of the most interesting phenomena in physics are often associated with non-analytic behavior in the coupling constant and the existence of nontrivial quantum condensates. It is therefore possible that pathologies encountered in the case of gravity are more likely the result of inadequate analytical treatment, and not necessarily a reflection of some intrinsic insurmountable problem. The nonperturbative treatment of quantum gravity via the Regge-Wheeler lattice path integral formulation reveals the existence of a new phase involving a nontrivial gravitational vacuum condensate, and a new set of scaling exponents characterizing both the running of G and the long-distance behavior of invariant correlation functions. The appearance of such a gravitational condensate is viewed as analogous to the (equally nonperturbative) gluon and chiral condensates known to describe the physical vacuum of QCD. The resulting quantum theory of gravity is highly constrained, and its physical predictions are found to depend only on one adjustable parameter, a genuinely nonperturbative scale ξ in many ways analogous to the scaling violation parameter ΛM S of QCD. Recent results point to significant deviations from classical gravity on distance scales approaching the effective infrared cutoff set by the observed cosmological constant. Such subtle quantum effects are expected to be initially small on current cosmological scales, but could become detectable in future high precision satellite experiments.

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supporting

confidence: 66%

Vacuum Condensate Picture of Quantum Gravity

Hamber

2019

Symmetry

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“…For more instrumental details 18, 2014, November 3, 2015and November 21-23, 2016, no calibration fields could be used to derive the geometric distortion (called GD hereafter) patterns of the field of view. Then the GD pattern of the nearest date is applied for as it was done in our previous work Wang et al 2015).…”

Section: Observationsmentioning

confidence: 99%

“…Then the GD pattern of the nearest date is applied for as it was done in our previous work (Peng et al 2015;Wang et al 2015).…”

Section: Observationsmentioning

confidence: 99%

Precise CCD positions of Triton in 2014–2016 using the newest Gaia DR1 star catalogue

Wang

Peng

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Therefore, the DCR effect was usually not considered in the observation of satellites and asteroids (e.g. Gomes-Júnior et al 2015;Wang et al 2015;Yu et al 2018). But now the release of the Gaia star catalog has caused a revolution in astrometry.…”

Section: Introductionmentioning

confidence: 99%

Using Gaia DR2 to solve differential color refraction and charge transfer efficiency issues

Lin,

Peng,

Zheng

2020

Preprint

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The Gaia DR2 catalog released in 2018 gives information about more than one billion stars, including their extremely precise positions that are not affected by the atmosphere, as well as the magnitudes in the G, RP, and BP passbands. This information provides great potential for the improvement of the ground-based astrometry. Based on Gaia DR2, we present a convenient method to calibrate the differential color refraction (DCR). This method only requires observations with dozens of stars taken through a selected filter. Applying this method to the reduction of observations captured through different filters by the 1-m and 2.4-m telescopes at Yunnan Observatory, the results show that the mean of the residuals between observed and computed positions (O − C) after DCR correction is significantly reduced. For our observations taken through an N (null) filter, the median of the mean (O − C) for well-exposed stars (about 15 G-mag) decreases from 19 mas to 3 mas, thus achieving better accuracy, i.e. mean (O − C). Another issue correlated is a systematic error caused by the poor charge transfer efficiency (CTE) when a CCD frame is read out. This systematic error is significant for some of the observations captured by the 1-m telescope at Yunnan Observatory. Using a sigmoidal function to fit and correct the mean (O − C), a systematic error up to 30 mas can be eliminated.

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Precise CCD positions of Apophis in 2013

Cited by 16 publications

References 13 publications

Vacuum Condensate Picture of Quantum Gravity

Vacuum Condensate Picture of Quantum Gravity

Precise CCD positions of Triton in 2014–2016 using the newest Gaia DR1 star catalogue

Using Gaia DR2 to solve differential color refraction and charge transfer efficiency issues

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