Search Publications
XMM-Newton Measurement of the Galactic Halo X-Ray Emission using a Compact Shadowing Cloud
Henley, David B.; Shelton, Robin L.; Stancil, Phillip C. +1 more
Observations of interstellar clouds that cast shadows in the soft X-ray background can be used to separate the background Galactic halo emission from the local emission due to solar wind charge exchange (SWCX) and/or the Local Bubble (LB). We present an XMM-Newton observation of a shadowing cloud, G225.60-66.40, that is sufficiently compact that t…
A complete radio study of SNR G15.4+0.1 from new GMRT observations
Surnis, M. P.; Castelletti, G.; Supan, L. +2 more
Aims: The supernova remnant (SNR) G15.4+0.1 is considered to be the possible counterpart of the γ-ray source HESS J1818-154. With the goal of getting a complete view of this remnant and understanding the nature of the γ-ray flux, we conducted a detailed radio study that includes the search for pulsations and a model of the broadband emission …
The Relationship Between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High-Resolution Hinode Observations
Hazra, Soumitra; Nandy, Dibyendu; Ravindra, B.
By using high-resolution observations of nearly co-temporal and co-spatial Solar Optical Telescope spectropolarimeter and X-Ray Telescope coronal X-ray data onboard Hinode, we revisit the problematic relationship between global magnetic quantities and coronal X-ray brightness. Co-aligned vector magnetogram and X-ray data were used for this study. …
Current-driven Langmuir oscillations and amplitude modulations—Another view on electron beam-plasma interaction
Sauer, K.; Sydora, R. D.
origin of Langmuir amplitude modulations and harmonic waves observed in the solar wind and in planetary foreshock regions is investigated in beam plasmas where the saturation process of the beam instability is accompanied with the formation of a plateau distribution. This saturated state represents a current which is shown to drive homogeneous ele…
The dayside magnetopause location during radial interplanetary magnetic field periods: Cluster observation and model comparison
Wang, H.; Shue, J. -H.; Huang, T. +2 more
The present work has investigated the midlatitudinal magnetopause locations under radial interplanetary field (RIMF) conditions. Among 262 (256) earthward (sunward) RIMF events from years of 2001 to 2009, Cluster satellites have crossed the magnetopause 22(12) times, with 10 (7) events occurring at midlatitudes. The observed midlatitudinal magneto…
MLS110213:022733+130617: a new eclipsing polar above the period gap
Costa, J. E. R.; Oliveira, A. S.; Rodrigues, C. V. +4 more
This study confirms MLS110213:022733+130617 as a new eclipsing polar. We performed optical spectroscopic, polarimetric and photometric follow-up of this variable source identified by the Catalina Real Time Transient Survey. Using the mid-eclipse times, we estimated an orbital period of 3.787 h, which is above the orbital period gap of the cataclys…
A statistical study of the low-altitude ionospheric magnetic fields over the north pole of Venus
Luhmann, J. G.; Russell, C. T.; Zhang, T. L. +3 more
Examination of Venus Express (VEX) low-altitude ionospheric magnetic field measurements during solar minimum has revealed the presence of strong magnetic fields at low altitudes over the north pole of Venus. A total of 77 events with strong magnetic fields as VEX crossed the northern polar region were identified between July 2008 and October 2009.…
The Earth's bow shock velocity distribution function
Maksimovic, M.; Meziane, K.; Hamza, A. M. +1 more
It is well established that interplanetary disturbances cause the Earth's bow shock to move sunward or earthward. Since the launch of the Cluster mission, precise determination of the shock velocity was carried out allowing for the possibility to perform sophisticated investigations about the shock dynamics. The shock normal and velocity are deter…
UrHip Proper Motion Catalog
Frouard, J.; Dorland, B. N.; Makarov, V. V. +2 more
Proper motions are computed and collected in a catalog using the Hipparcos positions (epoch 1991.25) and URAT1 positions (epoch 2012.3-2014.6). The goal is to obtain a significant improvement on the proper motion accuracy of single stars in the northern hemisphere, and to identify new astrometric binaries perturbed by orbital motion. For binaries …
Exploring the active galactic nuclei population with extreme X-ray-to-optical flux ratios (fx/fo > 50)
Ballo, L.; Carrera, F. J.; Watson, M. G. +8 more
The cosmic history of the growth of supermassive black holes in galactic centres parallels that of star formation in the Universe. However, an important fraction of this growth occurs inconspicuously in obscured objects, where ultraviolet/optical/near-infrared emission is heavily obscured by dust. Since the X-ray flux is less attenuated, a high X-…