Search Publications
Fading of the X-ray flux from the black hole in the NGC 4472 globular cluster RZ 2109
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +1 more
We present the results of new X-ray observations of XMMU 122939.7+075333, the black hole (BH) in the globular cluster RZ 2109 in the Virgo cluster galaxy NGC 4472. A combination of non-detections and marginal detections in several recent Swift and Chandra observations show that the source has varied by at least a factor of 20 in the past 6 yr, and…
Investigation of Chromospheric Evaporation in a Neupert-type Solar Flare
Cao, Wenda; Ning, Zongjun
The Neupert effect implies a flare model in which the hard X-rays (HXRs) are produced by energetic electrons via electron-ion bremsstrahlung as they lose their energies in the chromosphere, while the soft X-rays (SXRs) are produced by thermal bremsstrahlung from "chromospheric evaporation" due to plasma being heated by those same electrons. Based …
Origin of the dust emission from Tycho's SNR
Onaka, T.; Furuzawa, A.; Lee, J. -J. +6 more
Aims: We investigate the spatial distribution of dust emission around Tycho's SNR to understand its origin. We distinguish the dust associated with the SNR from that of the surrounding ISM.
Methods: We performed mid- to far-infrared imaging observations of the remnant at wavelengths of 9, 15, 18, 24, 65, 90, 140, and 160 µm using t…
Comparative analysis and variability of the Jovian X-ray spectra detected by the Chandra and XMM-Newton observatories
Bhardwaj, Anil; Branduardi-Raymont, Graziella; Lisse, Carey M. +6 more
Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X-ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM-N…
Pickup hydrogen distributions in the solar wind at ∼11 AU: Do we understand pickup ions in the outer heliosphere?
McComas, D. J.; Schwadron, N. A.; Elliott, H. A.
This study examines the detailed distribution of interstellar pickup hydrogen ions measured by the Surface Wave Process Program instrument on the New Horizons spacecraft en route to Pluto. The observations cover an 8 h interval on 15 October 2008 when the craft was at ∼11.3 AU, constituting the first detailed pickup ion measurements in the outer h…
H2 reformation in post-shock regions
Kristensen, L. E.; Cuppen, H. M.; Gavardi, E.
H2 formation is an important process in post-shock regions, since H2 is an active participant in the cooling and shielding of the environment. The onset of H2 formation therefore has a strong effect on the temperature and chemical evolution in the post-shock regions. We recently developed a model for H2 …
Strong lensing as a probe of the mass distribution beyond the Einstein radius. Mass and light in SL2S J08544-0121, a galaxy group at z = 0.35
Kneib, J. -P.; Jullo, E.; Gavazzi, R. +6 more
Strong lensing has been employed extensively to obtain accurate mass measurements within the Einstein radius. We here use strong lensing to probe mass distributions beyond the Einstein radius. We consider SL2S J08544-0121, a galaxy group at redshift z=0.35 with a bimodal light distribution and with a strong lensing system located at one of the two…
Clathrate Hydrates Formation in Short-Period Comets
Petit, Jean-Marc; Marboeuf, Ulysse; Mousis, Olivier +1 more
The initial composition of current models of cometary nuclei is only based on two forms of ice: crystalline ice for long-period comets and amorphous ice for short-period comets. A third form of ice, i.e., clathrate hydrate, could exist within the short-period cometary nuclei, but the area of formation of this crystalline structure in these objects…
LoCuSS: Shedding new light on the massive lensing cluster Abell 1689 - the view from Herschel
Smith, G. P.; Egami, E.; Rex, M. +5 more
We present wide-field Herschel/PACS observations of A 1689, a massive galaxy cluster at z = 0.1832, from our open time key programme. We detect 39 spectroscopically confirmed 100 µm-selected cluster members down to 1.5×1010 L⊙. These galaxies are forming stars at rates in the range 1-10 M⊙/yr, and appear to c…
Wide-band Suzaku Analysis of the Persistent Emission from SGR 0501+4516 During the 2008 Outburst
Sakamoto, T.; Tiengo, A.; Hurley, K. +17 more
We observed the soft gamma repeater SGR 0501+4516 with Suzaku for ~51 ks on 2008 August 26-27, about 4 days after its discovery. Following the first paper, which reported on the persistent soft X-ray emission and the wide-band spectrum of an intense short burst, this paper presents an analysis of the persistent broadband (1-70 keV) spectra of this…