Search Publications
X-Ray Tail in NGC 7619
Trinchieri, Ginevra; Fabbiano, Giuseppina; Kim, Dong-Woo +1 more
We present new observational results of NGC 7619, an elliptical galaxy with a prominent X-ray tail and a dominant member of the Pegasus group. With Chandra and XMM-Newton observations, we confirm the presence of a long X-ray tail in the southwest direction; moreover, we identify for the first time a sharp discontinuity of the X-ray surface brightn…
Are There Field-Free Gaps near τ = 1 in Sunspot Penumbrae?
Solanki, S. K.; Borrero, J. M.
The vertical stratification of the magnetic field strength in sunspot penumbrae is investigated by means of spectropolarimetric observations at high spatial resolution from the Hinode spacecraft. Assuming that the magnetic field changes linearly with optical depth we find that, in those regions where the magnetic field is more inclined and the Eve…
Broadband X-Ray Spectroscopy of A0535+262 with Suzaku
Mihara, T.; Takahashi, H.; Enoto, T. +9 more
The transient X-ray binary pulsar A0535+262 was observed with Suzaku on 2005 September 14 when the source was in the declining phase of the August-September minor outburst. The ~103 s X-ray pulse profile was strongly energy dependent, with a double-peaked profile in the soft X-ray energy band (<3 keV) and a single-peaked smooth profile in hard …
Optical Surface Brightness Fluctuations of Shell Galaxies toward 100 Mpc
Cantiello, M.; Brocato, E.; Raimondo, G. +1 more
We measure F814W surface brightness fluctuations (SBFs) for a sample of distant shell galaxies with radial velocities ranging from 4000 to 8000 km s-1. The distance at galaxies is then evaluated by using the SBF method. For this purpose, theoretical SBF magnitudes for the HST ACS filters are computed for single-burst stellar populations…
Latitudinal Gradients of Galactic Cosmic Rays during the 2007 Solar Minimum
Mewaldt, R. A.; Gómez-Herrero, R.; Ferreira, S. E. S. +6 more
Ulysses, launched in 1990 October in the maximum phase of solar cycle 22, completed its third out-of-ecliptic orbit in 2008 February. This provides a unique opportunity to study the propagation of cosmic rays over a wide range of heliographic latitudes during different levels of solar activity and different polarities in the inner heliosphere. Com…
Solar Observations of High-Temperature Emission with the Extreme-Ultraviolet Imaging Spectrometer on Hinode
Warren, Harry P.; Brown, Charles M.; Feldman, Uri
We present an analysis of solar coronal emission lines formed above 2.5 MK observed with the Extreme-Ultraviolet Imaging Spectrometer on Hinode during a small flare. Our main purpose is to evaluate the internal consistency of the atomic data available for the observed emission. We find that the observed emission from high-temperature Ca lines (Ca …
Discovery of Hot Gas in Outflow in NGC 3379
Zezas, A.; Gallagher, J.; King, A. R. +10 more
We report the discovery of a faint (LX ~ 4 +/- 1.5 × 1037 ergs s-1, 0.5-2 keV), outflowing gaseous hot interstellar medium (ISM) in NGC 3379. This represents the lowest X-ray luminosity ever measured from a hot phase of the ISM in a nearby early-type galaxy. The discovery of the hot ISM in a very deep Chandra obser…
A Comparison of Solar Open Field Regions Found by Type III Radio Bursts and the Potential Field Source Surface Model
DeRosa, Marc L.; Nitta, Nariaki V.
For heliophysics research and applications, the potential field source surface (PFSS) model is often employed to extrapolate the photospheric magnetic field to the corona. In an attempt to evaluate the performance of the PFSS model, we compare the computed footpoints of the heliospheric magnetic field with the locations of flares associated with t…
A Study of the Long-Term Evolution of Quasi-Periodic Oscillations in the Accretion-Powered X-Ray Pulsar 4U 1626-67
Paul, Biswajit; Kumar, Brijesh; Kaur, Ramanpreet +1 more
We report here a study of the long-term properties of quasiperiodic oscillations (QPOs) in an unusual accreting X-ray pulsar, 4U 1626-67. This is a unique accretion-powered X-ray pulsar in which we have found the QPOs to be present during all sufficiently long X-ray observations with a wide range of X-ray observatories. In the present spin-down er…
Anisotropy Signatures of Solar Energetic Particle Transport in a Closed Interplanetary Magnetic Loop
Sáiz, A.; Ruffolo, D.; Bieber, J. W. +2 more
Recent studies have stressed the importance of solar energetic particle (SEP) transport under disturbed interplanetary conditions, including the case of detection inside a closed interplanetary magnetic loop ejected by a preceding solar event. In this case, particles might be observed to arrive from the far leg of the loop, thus arriving at the de…