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Spectral Analysis of Forbush Decreases Using a New Yield Function
Livada, M.; Mavromichalaki, H.
The Forbush decreases of the cosmic ray intensity observed on 24 December 2014 and on 8 September 2017 were chosen for cosmic ray spectral analysis. At first an analytical study of the solar and geomagnetic parameters of these events was carried out due to the fact that both are typical cosmic ray events. Hourly cosmic ray data of the neutron moni…
Identifying the lens galaxy B 1152+199 as a ghostly damped Lyman α system by the cosmic origins spectrograph
Chen, Bin; Dai, Xinyu; Bhatiani, Saloni
Strong quasar-galaxy lensing provides a powerful tool to probe the interstellar medium (ISM) of the lens galaxy using radiation from the background quasar. Using the Cosmic Origins Spectrograph (COS) on board the Hubble Space Telescope, we study the cold ISM properties of the lens galaxy in B 1152+199 at a redshift of z = 0.4377. Since existing op…
Redshift Determinations from a Self-consistent Grid-based Lens Model for the Hubble Frontiers Field Cluster RXC J2248.7-4431 (AS1063)
Broadhurst, Tom; Coe, Dan; Lim, Jeremy +3 more
We present an iterative method to construct a freeform lens model that self-consistently reproduces the sky positions, geometrically inferred redshifts, and relative brightnesses of all multiply lensed images toward a galaxy cluster. This method is applied to the cluster RXC J2248.7-4431 (z = 0.348) from the Hubble Frontier Fields program, toward …
Solar physics in the 2020s: DKIST, parker solar probe, and solar orbiter as a multi-messenger constellation
Parenti, S.; Andretta, V.; Cranmer, S. R. +20 more
The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope (DKIST) is about to start operations at the summit of Haleakala (Hawaii). DKIST will join the early science phases of the NASA and ESA Parker Solar Probe and Solar Orbiter encounter missions. By combining in-situ measurements of the near-sun plasma environment and detail remote…
HP Cet and Swift J0820.6-2805: two candidate intermediate polars observed by XMM-Newton
Nucita, A. A.; De Paolis, F.; Strafella, F. +1 more
We report on the XMM-Newton observation of HP Cet and Swift J0820.6-2805, two X-ray photon sources that are candidates to be members of the intermediate polar class of cataclysmic variables. If the historical optical light curve of HP Cet shows a periodic feature at ≃96 min, a clear identification of such a signature in the high energy band (apart…
Domain of Influence analysis: implications for Data Assimilation in space weather forecasting
Poedts, Stefaan; Lapenta, Giovanni; Innocenti, Maria Elena +3 more
Solar activity, ranging from the background solar wind to energetic coronal mass ejections (CMEs), is the main driver of the conditions in the interplanetary space and in the terrestrial space environment, known as space weather. A better understanding of the Sun-Earth connection carries enormous potential to mitigate negative space weather effect…
BD+14°3061: A Luminous Yellow Post-AGB Star in the Galactic Halo
Bond, Howard E.
I report the discovery that the ninth-mag Galactic-halo star BD+14°3061 is a member of the rare class of luminous metal-poor "yellow post-AGB" stars. Its Gaia DR2 parallax implies an absolute magnitude of MV = -3.44 ± 0.27, and it is a very high-velocity star moving in a retrograde Galactic orbit. BD+14°3061 is a field analog of the hal…
Photometric study and kinematics of the EL CVn type eclipsing binary: WASP 1628+10
Luo, Yangping
1SWASP J162842.31+101416.7 (WASP 1628+10) is an EL CVn-type eclipsing binary system that is composed of a very low mass helium white dwarf precursor (WSAP 1628+10B) and an A-type dwarf star (WASP 1628+10A). We presented time-series BV photometric observations of WASP 1628+10. Six times of light minima were observed. The physical parameters of the …
Search for Evolutionary Changes in the Period the Cepheid ET Vul
Berdnikov, L. N.; Pastukhova, E. N.
The reduction of all the available photometry for the Cepheid ET Vul has allowed its $O-C$ diagram spanning a time interval of 130 years to be constructed. This has made it possible to calculate for the first time the rate of evolutionary decrease in the period, $dP/dt=-426.5(±{29.7})$ s yr${}^{-1}$, in agreement with the results of model calculat…
Plasma Turbulence at Comet 67P/Churyumov-Gerasimenko: Rosetta Observations
Halekas, J. S.; Howes, G. G.; Ruhunusiri, S.
We perform a power spectral analysis of magnetic field fluctuations measured by the Rosetta spacecraft's magnetometer at comet 67P/Churyumov-Gerasimenko. We interpret the power spectral signatures in terms of plasma turbulent processes and discover that different turbulent processes are prominent during different active phases of the comet. During…