Search Publications
An Almanac of Predicted Microlensing Events for the 21st Century
Nielsen, M. B.; Bramich, D. M.
Using Gaia data release 2 (GDR2), we present an almanac of 2509 predicted microlensing events, caused by 2130 unique lens stars, that will peak between July 25, 2026 and the end of the century. This work extends and completes a thorough search for future microlensing events initiated by Bramich and Nielsen using GDR2. The almanac includes 161 lens…
A Search for Black Hole Microlensing Signatures in Globular Cluster NGC 6656 (M22)
Anderson, J.; Casertano, S.; Kains, N. +3 more
We report the results of a study aiming to detect signs of astrometric microlensing caused by an intermediate-mass black hole (IMBH) in the center of globular cluster M22 (NGC 6656). We used archival data from the Hubble Space Telescope (HST) taken between 1995 and 2014 to derive long-baseline astrometric time series for stars near the center of t…
SETI with Gaia: The Observational Signatures of Nearly Complete Dyson Spheres
Zackrisson, Erik; Korn, Andreas J.; Wehrhahn, Ansgar +1 more
A star enshrouded in a Dyson sphere with a high covering fraction may manifest itself as an optically subluminous object with a spectrophotometric distance estimate significantly in excess of its parallax distance. Using this criterion, the Gaia mission will in coming years allow for Dyson sphere searches that are complementary to searches based o…
Mid-UV studies of the transitional millisecond pulsars XSS J12270-4859 and PSR J1023+0038 during their radio pulsar states
Altamirano, D.; Degenaar, N.; Wijnands, R. +7 more
We report mid-UV (MUV) observations taken with Hubble Space Telescope (HST)/WFC3, Swift/UVOT, and GALEX/NUV of the transitional millisecond pulsars XSS J12270-4859 and PSR J1023+0038 during their radio pulsar states. Both systems were detected in our images and showed MUV variability. At similar orbital phases, the MUV luminosities of both pulsars…
Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements
Gérard, J. -C.; Hubert, B.; Shematovich, V. I. +1 more
We present model results of the interaction of proton and hydrogen atom precipitation with the Martian atmosphere. We use a kinetic Monte Carlo model developed earlier for the analysis of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) Mars Express data. With the availability of Mars Atmosphere and Volatile Evolution Mission in situ m…
Longitudinal variability in Jupiter's zonal winds derived from multi-wavelength HST observations
Wong, Michael H.; Morales-Juberías, Raúl; Gaulme, Patrick +3 more
Multi-wavelength Hubble Space Telescope (HST) images of Jupiter from the Outer Planets Atmospheres Legacy (OPAL) and Wide Field Coverage for Juno (WFCJ) programs in 2015, 2016, and 2017 are used to derive wind profiles as a function of latitude and longitude. Wind profiles are typically zonally averaged to reduce measurement uncertainties. However…
Three-dimensional Magnetic Reconnection Triggering an X-class Confined Flare in Active Region 12192
Hou, Yijun; Li, Ting; Yang, Shuhong +1 more
We present an extensive analysis of the X2.0-class confined flare on 2014 October 27 in the great active region, AR 12192, observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The slipping motion of the substructures within the negative-polarity flare ribbon (R1) and continual reconnection-induced flows during …
The Effect of Spots on the Luminosity Spread of the Pleiades
Herczeg, Gregory J.; Guo, Zhen; Gully-Santiago, Michael
Cool spots on the surface of magnetically active stars modulate their observed brightnesses and temperatures, thereby affecting the stellar locus on the H-R diagram. Recent high-precision space-based photometric surveys reveal the rotational modulation from spots on stars in young clusters, including K2 monitoring of the 125 Myr old Pleiades clust…
ATHOS: On-the-fly stellar parameter determination of FGK stars based on flux ratios from optical spectra
Grebel, Eva K.; Hanke, Michael; Koch, Andreas +1 more
The rapidly increasing number of stellar spectra obtained by existing and future large-scale spectroscopic surveys feeds a demand for fast and efficient tools for the spectroscopic determination of fundamental stellar parameters. Such tools should not only comprise customized solutions for one particular survey or instrument, but, in order to enab…
Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation
Jarvinen, Riku; Vainio, Rami; Dimmock, Andrew P. +12 more
In this paper we present the first identification of foreshock cavitons and the formation of spontaneous hot flow anomalies (SHFAs) with the Vlasiator global magnetospheric hybrid-Vlasov simulation code. In agreement with previous studies we show that cavitons evolve into SHFAs. In the presented run, this occurs very near the bow shock. We report …