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Statistical properties of Hipparcos 2, caveats on its use, and a recalibration of the intermediate astrometric data
Brandt, Timothy D.; Brandt, G. Mirek; Michalik, Daniel
We revisit the Hipparcos 2007 re-reduction and find improvements to the catalogue by leveraging Gaia EDR3. We show that including a constant residual offset and additional dispersion (two free parameters in total) in the Hipparcos 2007 Intermediate Astrometric Data (IAD) creates a new catalogue with significantly better agreement with Gaia EDR3. T…
Searching for quasi-periodic eruptions using machine learning
Young, A. J.; Webbe, Robbie
Quasi-periodic eruption (QPE) is a rare phenomenon in which the X-ray emission from the nuclei of galaxies shows a series of large amplitude flares. Only a handful of QPEs have been observed but the possibility remains that there are as yet undetected sources in archival data. Given the volume of data available a manual search is not feasible, and…
A reduction procedure and pipeline for the detection of trans-Neptunian objects using occultations
Ofek, Eran O.; Nir, Guy; Zackay, Barak
Kuiper belt objects smaller than a few kilometres are difficult to observe directly. They can be detected when they randomly occult a background star. Close to the ecliptic plane, each star is occulted once every tens of thousands of hours, and occultations typically last for less than a second. We present an algorithm, and companion pipeline, for…
Overcoming separation between counterparts due to unknown proper motions in catalogue cross-matching
Wilson, Tom J.
To perform precise and accurate photometric catalogue cross-matches - assigning counterparts between two separate data sets - we need to describe all possible sources of uncertainty in object position. With ever-increasing time baselines between observations, like 2MASS in 2001 and the next generation of surveys, such as the Vera C. Rubin Observat…
Extending time-series models for irregular observational gaps with a moving average structure for astronomical sequences
Elorrieta, F.; Eyheramendy, S.; Palma, W. +1 more
In this study, we introduce a novel moving-average model for analyzing stationary time-series observed irregularly in time. The process is strictly stationary and ergodic under normality and weakly stationary when normality is not assumed. Maximum likelihood (ML) estimation can be efficiently carried out through a Kalman algorithm obtained from th…
An investigation into the effect of exposing XMM-Newton's Optical Monitor to the light of Jupiter
Sullivan, S; Page, M J; Breeveld, A A +2 more
After nearly 18 yr of successful and safe operations, on 2017 July 17 and 18, XMM-Newton's Optical Monitor (OM) observed Jupiter - an object 10 magnitudes brighter than safe brightness limits - in its visual (V) filter. The object was exposed 40 arcsec from the nominal European Photon Imaging Cameras pn boresight in the negative Y direction, creat…