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Thermodynamic performance of the 3-stage ADR for the Astro-H Soft-X-ray Spectrometer instrument
Kelley, Richard L.; Porter, Frederick S.; DiPirro, Michael J. +6 more
The Soft X-ray Spectrometer (SXS) instrument (Mitsuda et al., 2010) [1] on Astro-H (Takahashi et al., 2010) [2] will use a 3-stage ADR (Shirron et al., 2012) to cool the microcalorimeter array to 50 mK. In the primary operating mode, two stages of the ADR cool the detectors using superfluid helium at ⩽1.20 K as the heat sink (Fujimoto et al., 2010…
Transient effects in Herschel/PACS spectroscopy
Fadda, Dario; Appleton, Philip N.; Jacobson, Jeffery D.
Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident flux with a certain delay. This generates transient effects on the resulting signal which can be important and last for up to an hour.
Aims: The paper presents a study of the effects of transients on the detected si…
Suprathermal Electrons in Titan’s Sunlit Ionosphere: Model-Observation Comparisons
Coates, A. J.; Wahlund, J. -E.; Edberg, N. J. T. +8 more
The dayside ionosphere of the Saturnian satellite Titan is generated mainly from photoionization of N2 and CH4. We compare model-derived suprathermal electron intensities with spectra measured by the Cassini Plasma Spectrometer/Electron Spectrometer (CAPS/ELS) in Titan's sunlit ionosphere (altitudes of 970-1250 km) focusing o…
Ion injection at Quasi-parallel Shocks Seen by the Cluster Spacecraft
Dandouras, I.; Vaivads, A.; Khotyaintsev, Yu. V. +2 more
Collisionless shocks in space plasma are known to be capable of accelerating ions to very high energies through diffusive shock acceleration (DSA). This process requires an injection of suprathermal ions, but the mechanisms producing such a suprathermal ion seed population are still not fully understood. We study acceleration of solar wind ions re…
Seasonal Evolution on the Nucleus of Comet C/2013 A1 (Siding Spring)
Samarasinha, Nalin H.; A'Hearn, Michael F.; Bodewits, Dennis +6 more
We observed Comet C/Siding Spring using the Hubble Space Telescope (HST) during its close approach to Mars. The high spatial resolution images obtained through the F689M, F775W, and F845M filters reveal the characteristics of the dust coma. The dust production rate of C/Siding Spring, quantified by Afρ, is 590 ± 30, 640 ± 30, and 670 ± 30 cm in a …
Dipolarization front and current disruption
Lui, A. T. Y.
The modification of current density on the dawn-dusk cross section of the magnetotail with the earthward approach of a dipolarization front (DF) is examined through the recently published results of a three-dimensional (3-D) particle-in-cell (PIC) simulation. It is found that the current density intensifies by 37% abruptly within 1.5 ion gyrotime …
Star Formation in Ultraluminous Infrared Galaxies Probed with AKARI Near-infrared Spectroscopy
Nakagawa, Takao; Isobe, Naoki; Shirahata, Mai +1 more
We conducted systematic observations of the H I Brα line (4.05 µm) and the polycyclic aromatic hydrocarbon (PAH) feature (3.3 µm) in 50 nearby (z\lt 0.3) ultraluminous infrared galaxies (ULIRGs) with AKARI. The Brα line is predicted to be the brightest among the H I lines under conditions of high dust extinction ({A}V\gt 15 …
Accretion disc-corona and jet emission from the radio-loud narrow-line Seyfert 1 galaxy RX J1633.3+4719
Misra, R.; Dewangan, G. C.; Gandhi, P. +2 more
We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an ultrasoft component described by an accretion disc blackbody (kT_in = 39.6^{+11.2}_{-5.5} eV) and a power la…
Emission of hydrogen energetic neutral atoms from the Martian subsolar magnetosheath
Kallio, E.; Barabash, S.; Futaana, Y. +3 more
We have simulated the hydrogen energetic neutral atom (ENA) emissions from the subsolar magnetosheath of Mars using a hybrid model of the proton plasma charge exchanging with the Martian exosphere to study statistical features revealed from the observations of the Neutral Particle Detectors on Mars Express. The simulations reproduce well the obser…
Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters. II. NGC 5024, NGC 5272, and NGC 6352
Jefferys, W. H.; Stenning, D. C.; Wagner-Kaiser, R. +5 more
We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival Advanced Camera for Surveys Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three clusters, both single and double-population analyses are used to determine a best…