Search Publications
Temporal Gain Correction for X-ray Calorimeter Spectrometers
Tsujimoto, M.; Ishisaki, Y.; Yamada, S. +14 more
Calorimetric X-ray detectors are very sensitive to their environment. The boundary conditions can have a profound effect on the gain including heat sink temperature, the local radiation temperature, bias, and the temperature of the readout electronics. Any variation in the boundary conditions can cause temporal variations in the gain of the detect…
Ne X X-ray emission due to charge exchange in M82
Liu, L.; Cumbee, R. S.; Lyons, D. +4 more
Recent X-ray observations of star-forming galaxies such as M82 have shown the Ly β/Ly α line ratio of Ne X to be in excess of predictions for thermal electron impact excitation. Here, we demonstrate that the observed line ratio may be due to charge exchange and can be used to constrain the ion kinetic energy to be ≲ 500 eV/u. This is accomplished …
SAPS onset timing during substorms and the westward traveling surge
Mishin, Evgeny, V.
We present multispacecraft observations in the magnetosphere and conjugate ionosphere of the onset time of subauroral polarization streams (SAPS) and tens of keV ring current injections on the duskside in three individual substorms. This is probably the first unequivocal determination of the substorm SAPS onset timing. The time lag between the SAP…
X-ray/UV variability and the origin of soft X-ray excess emission from II Zw 177
Dewangan, Gulab C.; Pal, Main; Misra, Ranjeev +1 more
We study X-ray and UV emission from the narrow-line Seyfert 1 galaxy II Zw 177 using a 137 ks long and another 13 ks short XMM-Newton observation performed in 2012 and 2001, respectively. Both observations show soft X-ray excess emission contributing 76.9 ± 4.9 per cent in 2012 and 58.8 ± 10.2 per cent in 2001 in the 0.3-2 keV band. We find that b…
Evidence for a 36 ks phase modulation in the hard X-ray pulses from the magnetar 1E 1547.0-5408
Enoto, Teruaki; Makishima, Kazuo; Nakazawa, Kazuhiro +4 more
The Suzaku data for the highly variable magnetar 1E 1547.0-5408, obtained during the 2009 January activity, were reanalyzed. The 2.07 s pulsation, detected in the 15-40 keV HXD data, was found to exhibit phase modulation, which can be modeled by a sinusoid with a period of 36.0^{+4.5}_{-2.5}ks and an amplitude of 0.52 ± 0.14 s. While the effect is…
Hydrological and sedimentary analyses of well-preserved paleofluvial-paleolacustrine systems at Moa Valles, Mars
Hauber, Ernst; Di Achille, Gaetano; Ori, Gian Gabriele +2 more
Moa Valles is a well-preserved, likely Amazonian (younger than 2 Ga old), paleodrainage system that is nearly 300 km long and carved into ancient highland terrains west of Idaeus Fossae. The fluvial system apparently originated from fluidized ejecta blankets, and it consists of a series of dam breach paleolakes with associated fan-shaped sedimenta…
Where are all of the nebulae ionized by supersoft X-ray sources?
Gilfanov, M.; Woods, T. E.
Accreting, steadily nuclear-burning white dwarfs are associated with so-called close-binary supersoft X-ray sources (SSSs), observed to have temperatures of a few × 105 K and luminosities on the order of 1038 erg s-1. These and other types of SSSs are expected to be capable of ionizing their surrounding circumstell…
Turbulence-generated Proton-scale Structures in the Terrestrial Magnetosheath
Echim, Marius M.; Consolini, Giuseppe; Vörös, Zoltán +2 more
Recent results of numerical magnetohydrodynamic simulations suggest that in collisionless space plasmas, turbulence can spontaneously generate thin current sheets. These coherent structures can partially explain the intermittency and the non-homogenous distribution of localized plasma heating in turbulence. In this Letter, Cluster multi-point obse…
Globular Clusters, Ultracompact Dwarfs, and Dwarf Galaxies in Abell 2744 at a Redshift of 0.308
Lee, Myung Gyoon; Jang, In Sung
We report a photometric study of globular clusters (GCs), ultracompact dwarfs (UCDs), and dwarf galaxies in the giant merging galaxy cluster Abell 2744 at z = 0.308. Color-magnitude diagrams of the point sources derived from deep F814W (rest frame r‧) and F105W (rest frame I) images of Abell 2744 in the Hubble Space Telescope Frontier Field show a…
Insights into the location and dynamics of the coolest X-ray emitting gas in clusters of galaxies
Zhang, Y. -Y.; Finoguenov, A.; de Plaa, J. +10 more
We extend our previous study of the cool gas responsible for the emission of O VII X-ray lines in the cores of clusters and groups of galaxies. This is the coolest X-ray emitting phase and connects the 10 000 K H α emitting gas to the million degree phase, providing a useful tool to understand cooling in these objects. We study the location of the…