Search Publications
On the Nonrelativistic Origin of Red-skewed Iron Lines in Cataclysmic Variable, Neutron Star, and Black Hole Sources
Laurent, Philippe; Titarchuk, Lev; Shaposhnikov, Nikolai
We perform the analysis of the iron Kα lines detected in three sources representing three types of accreting compact sources: cataclysmic variable (CV) GK Per, neutron star (NS) Serpens X-1, and black hole (BH) GX 339-4. We find, using data from Epic-PN Camera onboard XMM-Newton observatory, that the iron Kα emission line in …
Redshift Evolution in the Iron Abundance of the Intracluster Medium
Bregman, Joel N.; Anderson, Michael E.; Mullis, C. R. +1 more
Clusters of galaxies provide a closed box within which one can determine the chemical evolution of the gaseous baryons with cosmic time. We studied this metallicity evolution in the hot X-ray emitting baryons through an analysis of XMM-Newton observations of 29 galaxy clusters in the redshift range, 0.3 < z < 1.3. Taken alone, this data set …
AKARI Detection of Far-Infrared Dust Emission in the Halo of NGC 253
Onaka, Takashi; Yamagishi, Mitsuyoshi; Kaneda, Hidehiro +1 more
We present new far-infrared (FIR) images of the edge-on starburst galaxy NGC 253 obtained with the Far-Infrared Surveyor (FIS) onboard AKARI at wavelengths of 90 µm and 140 µm. We have clearly detected FIR dust emission extended in the halo of the galaxy; there are two filamentary emission structures extending from the galactic disk up…
Ion Temperature and Non-Thermal Velocity in a Solar Active Region: Using Emission Lines of Different Atomic Species
Hara, H.; Watanabe, T.; Imada, S.
We have studied the characteristics of the ion thermal temperature and non-thermal velocity in an active region observed by the EUV Imaging Spectrometer onboard Hinode. We used two emission lines of different atomic species (Fe XVI 262.98 Å and S XIII 256.69 Å) to distinguish the ion thermal velocity from the observed full width at half-maximum. W…
The Accuracy of Using the Ulysses Result of the Spatial Invariance of the Radial Heliospheric Field to Compute the Open Solar Flux
Lockwood, M.; Owens, M.
We survey observations of the radial magnetic field in the heliosphere as a function of position, sunspot number, and sunspot cycle phase. We show that most of the differences between pairs of simultaneous observations, normalized using the square of the heliocentric distance and averaged over solar rotations, are consistent with the kinematic "fl…
Triggered Star Formation and the Creation of the Supergiant H I Shell in IC 2574
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +4 more
Based on deep imaging from the Advanced Camera for Surveys aboard the Hubble Space Telescope (HST), we present new evidence that stellar feedback created a ~1 kpc supergiant H I shell (SGS) and triggered star formation (SF) around its rim in the M81 Group dwarf irregular galaxy IC 2574. Using photometry of the resolved stars from the HST images, w…
Evidence of Chromospheric Evaporation in the 2004 December 1 Solar Flare
Cao, Wenda; Ning, Zongjun; Yan, Yihua +3 more
In this paper, we present the radio and hard X-ray evidence of chromospheric evaporation during an M1.0 flare which occurred on 2004 December 1. The radio emission was observed by the Solar Broadband Radio Dynamic Spectrometer in China, which yielded dynamic spectra of decimetric emission. The hard X-ray emission was observed by RHESSI. In the rad…
Solar-like Oscillations in a Metal-poor Globular Cluster with the Hubble Space Telescope
Stello, Dennis; Gilliland, Ronald L.
We present analyses of variability in the red giant stars in the metal-poor globular cluster NGC 6397, based on data obtained with the Hubble Space Telescope. We use a nonstandard data reduction approach to turn a 23 day observing run originally aimed at imaging the white dwarf population, into time-series photometry of the cluster's highly satura…
Physical Conditions in the Inner Narrow-Line Region of the Seyfert 2 Galaxy Markarian 573
Kraemer, S. B.; Crenshaw, D. M.; Schmitt, H. R. +3 more
We have examined the physical conditions within a bright emission-line knot in the inner narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573 using optical spectra and photoionization models. The spectra were obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, through the 0farcs2 × 52farcs0 slit, at a position angle …
Resolving the Discrepancy Between Lensing and X-Ray Mass Estimates of the Complex Galaxy Cluster Abell 1689
Dahle, H.; Pedersen, K.; Limousin, M. +3 more
There is a long-standing discrepancy between galaxy cluster masses determined from X-ray and gravitational lensing observations of which Abell 1689 is a well studied example. In this work, we take advantage of 180 ks of Chandra X-ray observations and a new weak gravitational study based on a Hubble Space Telescope mosaic covering the central 1.8 M…