Related papers: Probing Exotic Astrophysical Dark objects through …
We explore novel classes of exotic astrophysical sources capable of producing ultra-high-energy gamma rays extending beyond the PeV scale, motivated by quantum gravity scenarios and dark matter phenomenology. These sources include:…
Astrometric microlensing can be used to make precise measurements of the masses of lens stars that are independent of their assumed internal physics. Such direct mass measurements, obtained purely by observing the gravitational effects of…
We present a potential test of the origin of the $\gamma$-ray Galactic Centre Excess (GCE). We demonstrate how gravitational microlensing by stellar mass objects along the line of sight to the Galactic Bulge can distinguish between the…
We investigate gravitational microlensing signals produced by a spatially extended object transiting in front of a finite-sized source star. The most interesting features arise for lens and source sizes comparable to the Einstein radius of…
Small-scale dark matter structures lighter than a billion solar masses are an important probe of primordial density fluctuations and dark matter microphysics. Due to their lack of starlight emission, their only guaranteed signatures are…
Astrometric noise (AEN) in excess of parallax and proper motion is a potential signature of orbital wobble of individual components in binary star systems. The combination of X-ray selection with astrometric noise could then be a powerful…
Selection of extragalactic point sources, e.g. QSOs, is often hampered by significant selection effects causing existing samples to have rather complex selection functions. We explore whether a purely astrometric selection of extragalactic…
We investigate the microlensing detectability of extraterrestrial technosignatures originating from Dyson sphere \textendash like structures, such as Dyson Swarms surrounding primordial black holes (PBHs). These hypothetical swarms consist…
The gravitational pull of an unseen companion to a luminous star is well-known to cause deviations to the parallax and proper motion of a star. In a previous paper in this series, we argue that the astrometric mission Gaia can identify…
Gaia is an all sky, high precision astrometric and photometric satellite of the European Space Agency (ESA) due for launch in 2010-2011. Its primary mission is to study the composition, formation and evolution of our Galaxy. Gaia will…
Context: Astrometric gravitational microlensing is an excellent tool to determine the mass of stellar objects. Using precise astrometric measurements of the lensed position of a background source in combination with accurate predictions of…
Microlensing consists in two major effects: (1) variation in the apparent position of the background sources (astrometric component) and (2) flux variations of the background sources (photometric component). While the latter has been…
Due to dramatic improvements in the precision of astrometric measurements, the observation of light centroid shifts in observed stars due to intervening massive compact objects (`astrometric microlensing') will become possible in the near…
The Gaia satellite is cataloging the astrometric properties of an unprecedented number of stars in the Milky Way with extraordinary precision. This provides a gateway for conducting extensive surveys of transient astrometric lensing events…
Extrasolar planets found by gravitational microlensing often require assumptions on the source star distance and relative proper motion. Only in a few cases has it been possible to confirm these findings with space-based observations or…
The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of…
We investigate whether Gaia can specify the binary fractions of massive stellar populations in the Galactic disk through astrometric microlensing. Furthermore, we study if some information about their mass distributions can be inferred via…
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of $\sim 950$ microlensing events observed by the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a…
Context. Astrometric gravitational microlensing can be used to determine the mass of a single star (the lens) with an accuracy of a few percent. To do so, precise measurements of the angular separations between lens and background star with…
Given their extremely large distances and small apparent sizes, quasars are generally considered as objects with near-zero parallax and proper motion. However, some special quasars may have abnormal astrometric characteristics, such as…