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Stellar laboratories . IX. New Se v, Sr iv-vii, Te vi, and I vi oscillator strengths and the Se, Sr, Te, and I abundances in the hot white dwarfs G191-B2B and RE 0503-289
Hoyer, D.; Rauch, T.; Werner, K. +4 more
Context. To analyze spectra of hot stars, advanced non-local thermodynamic equilibrium (NLTE) model-atmosphere techniques are mandatory. Reliable atomic data is crucial for the calculation of such model atmospheres.
Aims: We aim to calculate new Sr iv-vii oscillator strengths to identify for the first time Sr spectral lines in hot white dwarf…
Near-Infrared Knots and Dense Fe Ejecta in the Cassiopeia A Supernova Remnant
Koo, Bon-Chul; Lee, Jae-Joon; Moon, Dae-Sik +2 more
We report the results of broadband (0.95-2.46 µm) near-infrared spectroscopic observations of the Cassiopeia A supernova remnant. Using a clump-finding algorithm in two-dimensional dispersed images, we identify 63 “knots” from eight slit positions and derive their spectroscopic properties. All of the knots emit [Fe II] lines together with ot…
Absolute Magnitudes of Seismic Red Clumps in the Kepler Field and SAGA: The Age Dependency of the Distance Scale
Zhao, G.; Casagrande, L.; Bovy, J. +4 more
Red clump stars are fundamental distance indicators in astrophysics, although theoretical stellar models predict a dependence of absolute magnitudes with age. This effect is particularly strong below ∼2 Gyr, but even above this limit a mild age dependence is still expected. We use seismically identified red clump stars in the Kepler field for whic…
The Unusual Apparition of Comet 252P/2000 G1 (LINEAR) and Comparison with Comet P/2016 BA14 (PanSTARRS)
Samarasinha, Nalin H.; Tholen, David J.; Li, Jian-Yang +7 more
We imaged Comet 252P/2000 G1 (LINEAR; hereafter 252P) with the Hubble Space Telescope and both 252P and P/2016 BA14 (PanSTARRS; hereafter BA14) with the Discovery Channel Telescope in 2016 March and April, surrounding its close encounter to Earth. The r‧-band Afρ of 252P in a 0.″2-radius aperture were 16.8 ± 0.3 and 57 ± 1 cm…
High-latitude Conic Current Sheets in the Solar Wind
Tokumaru, Munetoshi; Fujiki, Ken'ichi; Malova, Helmi V. +7 more
We provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (CCSs) at high heliolatitudes. Long-lived CCSs were detected by Ulysses during its passages over the South Solar Pole in 1994 and 2007. The characteristic scale of these tornado-like structures is several times less than a typical width of…
INTEGRAL IBIS, SPI, and JEM-X observations of LVT151012
Sunyaev, R.; Hanlon, L.; Mereghetti, S. +18 more
During the first observing run of LIGO, two gravitational wave events and one lower-significance trigger (LVT151012) were reported by the LIGO/Virgo collaboration. At the time of LVT151012, the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) was pointing at a region of the sky coincident with the high localization probability area of th…
New constraints on Ganymede's hydrogen corona: Analysis of Lyman-α emissions observed by HST/STIS between 1998 and 2014
Alday, Juan; Saur, Joachim; Roth, Lorenz +4 more
Far-ultraviolet observations of Ganymede's atmospheric emissions were obtained with the Space Telescope Imaging Spectrograph (STIS) onboard of the Hubble Space Telescope (HST) on several occasions between 1998 and 2014. We analyze the Lyman-α emission from four HST campaigns in order to constrain the abundance and variation of atomic hydrogen in G…
Variegate galaxy cluster gas content: Mean fraction, scatter, selection effects, and covariance with X-ray luminosity
Andreon, S.; Moretti, A.; Wang, J. +2 more
We use a cluster sample selected independently of the intracluster medium content with reliable masses to measure the mean gas mass fraction and its scatter, the biases of the X-ray selection on gas mass fraction, and the covariance between the X-ray luminosity and gas mass. The sample is formed by 34 galaxy clusters in the nearby (0.050 < z &l…
Kinematics of the galaxy from Cepheids with proper motions from the Gaia DR1 catalogue
Bobylev, V. V.
A sample of classical Cepheids with known distances and line-of-sight velocities has been supplemented with proper motions from the Gaia DR1 catalogue. Based on the velocities of 260 stars, we have found the components of the peculiar solar velocity vector ( U, V, W)⊙ = (7.90, 11.73, 7.39) ± (0.65, 0.77, 0.62) km s-1 and the …
Swift, XMM-Newton, and NuSTAR Observations of PSR J2032+4127/MT91 213
Takata, J.; Kong, A. K. H.; Hui, C. Y. +3 more
We report our recent Swift, NuSTAR, and XMM-Newton X-ray and Lijiang optical observations on PSR J2032+4127/MT91 213, the γ-ray binary candidate with a period of 45-50 years. The coming periastron of the system was predicted to be in 2017 November, around which high-energy flares from keV to TeV are expected. Recent studies with Chandra and Swift …