Search Publications
Multispacecraft Observations of the Simultaneous Occurrence of Magnetic Reconnection at High and Low Latitudes During the Passage of a Solar Wind Rotational Discontinuity Embedded in the April 9-11, 2015 ICME
Lugaz, Noé; Escoubet, C. Philippe; Wing, Simon +2 more
Numerous questions remain about how solar wind directional discontinuities, for example, rotational discontinuities (RDs), affect energy and transport processes at the magnetopause. The impact on the dayside magnetosphere of a solar wind RD is studied. The study shows that the RD leads to complex structures at the magnetopause, boundary layer, man…
Searching for New Globular Clusters in M31 with Gaia EDR3
Niu, Zexi; Liu, Jifeng; Huang, Song +5 more
We have found 50 new globular cluster (GC) candidates around M31 with Gaia Early Data Release 3 (EDR3), with the help of Pan-STARRS1 DR1 magnitudes and Pan-Andromeda Archaeological Survey (PAndAS) images. Based on the latest Revised Bologna Catalog and simbad, we trained two random forest (RF) classifiers, the first one to distinguish extended sou…
Diverse Chemo-Dynamical Properties of Nitrogen-Rich Stars Identified from Low-Resolution Spectra
Beers, Timothy C.; Lee, Young Sun; Kim, Young Kwang +1 more
The second generation of stars in the globular clusters (GCs) of the Milky Way (MW) exhibit unusually high N, Na, or Al, compared to typical Galactic halo stars at similar metallicities. The halo field stars enhanced with such elements are believed to have originated in disrupted GCs or escaped from existing GCs. We identify such stars in the meta…
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…
Backscattering and Line Broadening in Orion
O'Dell, C. R.; Ferland, G. J.; Méndez-Delgado, J. E.
Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region. This scattered light component has a weak wavelength dependence that is consistent with either general…
The brightness of the CO Cameron bands in the martian discrete aurora: A study based on revised cross sections
Daerden, F.; Neary, L.; Gérard, J. -C. +2 more
We analyze the consequences of the new laboratory measurements of the emissions cross sections of the Cameron bands excited by electron impact on CO2 and CO in the Mars aurora. We use Monte Carlo simulations to investigate the importance of these changes and their dependence on the initial electron energy. The Mars Climate Database (MCD…
Spectroscopic and photometric study of the pulsating eclipsing binary HIP 28271
Chen, Tao; Wang, Kun; Cao, Xingmei
We report the results of the detailed study of the single-lined eclipsing binary HIP 28271 with time-series high-resolution spectra and high-precision TESS photometry. The binary modeling indicates that HIP 28271 has a short orbital period of 2.7404254-4e-7+9e-7 days, with an eccentricity ofeorb = 0.0062-0.001…
3D ray tracing solver for communication blackout analysis in atmospheric entry missions
Poedts, Stefaan; Giangaspero, Vincent F.; Sharma, Vatsalya +4 more
During the atmospheric entry phase at hypersonic speed, the radio communication from/to a space vehicle can be disrupted due to the formation of a plasma sheath within the surrounding flow field. In order to characterize such communication blackout phases, this work presents a numerical methodology combining Computational Fluid Dynamic (CFD) simul…
Timing analysis of Swift J0243.6+6124 with NICER and Fermi/GBM during the decay phase of the 2017-2018 outburst
Santangelo, A.; Serim, M. M.; Baykal, A. +3 more
We present a timing and noise analysis of the Be/X-ray binary system Swift J0243.6+6124 during its 2017-2018 super-Eddington outburst using NICER/XTI observations. We apply a synthetic pulse timing analysis to enrich the Fermi/GBM spin frequency history of the source with the new measurements from NICER/XTI. We show that the pulse profiles switch …
A' view of the sunrise: boosting helioscopes with angular information
Frerick, Jonas; Kahlhoefer, Felix; Schmidt-Hoberg, Kai
The Sun may copiously produce hypothetical light particles such as axions or dark photons, a scenario which can be experimentally probed with so-called helioscopes. Here we investigate the impact of the angular and spectral distribution of solar dark photons on the sensitivity of such instruments. For the first time we evaluate this spectral and a…