18 citations · 23 across the 8 of their papers we have counts for
8 papers
Earth-Projected Clustering of Historical Optical Transients in the Palomar Observatory Sky Survey-I (POSS-I)
Stephen Bruehl, Beatriz Villarroel, Hichem Guergouri +2
Palomar Observatory Sky Survey-I (POSS-I) images obtained before the launch of Sputnik contain star-like point sources consistent with sub-second flashes that are absent from all s…
Modelling Palomar Transients: Constraints from Reflection Geometry and Orbital Altitude
Beatriz Villarroel, Alina Streblyanska, Hichem Guergouri +3
Recent searches of digitised photographic plates from the Palomar Observatory have uncovered tens of thousands of short-lived transients, each visible in only a single exposure. Th…
Constraining Cosmological Parameters From Statistical Superluminal Effects Without a Distance Ladder
Hichem Guergouri, Omar Nemoul, Jamal Mimouni
We employ a statistical approach to study apparent superluminal motion of luminous sources in an expanding flat Friedmann--Lemaître--Robertson--Walker universe, explicitly incorpor…
Non-Radial Free Geodesics. II. In Spatially Curved FLRW Spacetime
Omar Nemoul, Hichem Guergouri, Jamal Mimouni
This paper presents an in-depth exploration of timelike free geodesics in spatially curved Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime. A unified approach for these geodes…
Non-Radial Free Geodesics. I. In Spatially Flat FLRW Spacetime
Omar Nemoul, Hichem Guergouri, Jamal Mimouni
This paper provides an analytical examination of non-radial geodesics within the context of the spatially flat Friedmann Lemaître Robertson Walker (FLRW) spacetime. Using the symme…
Studying the Behavior of Radial Free Geodesics in ΛCDM Model
Omar Nemoul, Hichem Guergouri, Jamal Mimouni
This paper presents an analytical study of the behavior of radial free-geodesics in the Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime within the Lambda Cold Dark Matter (ΛCD…
Is there a background population of high-albedo objects in geosynchronous orbits around Earth?
Beatriz Villarroel, Enrique Solano, Hichem Guergouri +11
Old, digitized astronomical images taken before the human spacefaring age offer a unique view of the sky devoid of known artificial satellites. In this paper, we have carried out t…
A glint in the eye: photographic plate archive searches for non-terrestrial artefacts
Beatriz Villarroel, Lars Mattsson, Hichem Guergouri +4
In this paper, we present a simple strategy to identify Non-Terrestrial artefacts \citep[NTAs;][]{Kopparapu} in or near geosynchronous Earth orbits (GEOs). We show that even the sm…