Search Publications

Double-cusp simulation during northward IMF using 3D PIC global code

Esmaeili, Amin; Kalaee, Mohammad Javad

The cusp has important effects on the transportation of particles and their energy from the solar wind to the magnetosphere, and ionosphere, and high-altitude atmosphere. The cusp can be considered to be a part of the magnetospheric boundary layer with weaker magnetic fields. It has been studied since 1971 by different satellite observations. Desp…

Quasi-periodic Pulse Amplitude Modulation in the Accreting Millisecond Pulsar IGR J00291+5934

van der Klis, Michiel; Bult, Peter; van Doesburgh, Marieke

We introduce a new method for analyzing the aperiodic variability of coherent pulsations in accreting millisecond X-ray pulsars (AMXPs). Our method involves applying a complex frequency correction to the time-domain light curve, allowing for the aperiodic modulation of the pulse amplitude to be robustly extracted in the frequency domain. We discus…

Observations of V0332+53 during the 2015 outburst using Fermi/GBM, MAXI, Swift and INTEGRAL

Rodi, James; Cherry, Michael L.; Baum, Zachary A.

We present the light curves, spectra and hardness-intensity diagram (HID) of the high-mass X-ray binary V0332+53 using Fermi/GBM, MAXI, Swift/BAT and INTEGRAL through its 2015 Type II outburst. We observe characteristic features in the X-ray emission (2-50 keV) due to periastron passages, the dynamical time-scale of the accretion disc, and changes…

Peak flux of flares associated with coronal mass ejections

Suryanarayana, Gadikere Sheshagiriyappa; Balakrishna, Kagalagodu Manjunathayya

Features of flares that occur in association with coronal mass ejections (CMEs) have often displayed variations compared to flares with no associated CMEs. A comparative estimation of peak flux values of flares associated with CMEs and those without CMEs is made. Peak flux values of flares associated with CMEs show distinctly higher values in comp…

Localization of whistler wave and turbulent spectra in the magnetotail region

Sharma, R. P.; Pathak, Neha; Sharma, Swati +2 more

Observations show that whistler waves play a very crucial role both in magnetic reconnection and turbulence. In this context, linear and nonlinear dynamical equations of whistler wave have been derived and further these equations have been solved numerically as well as semianalytically. For application purpose, magnetotail parameters have been cho…

Stellar X‑ray accretion signatures

Robrade, J.; Günther, H. M.; Schneider, P. C.

Structure and variability in the corona of the ultrafast rotator LO Pegasi

Schmitt, J. H. M. M.; Singh, K. P.; Lalitha, S.

Context. Low-mass ultrafast rotators show the typical signatures of magnetic activity and are known to produce flares, probably as a result of magnetic reconnection. As a consequence, the coronae of these stars exhibit very large X-ray luminosities and high plasma temperatures, as well as a pronounced inverse FIP effect.
Aims: To probe the re…

Young, active radio stars in the AB Doradus moving group

Ros, E.; Hormuth, F.; Ortiz, J. L. +5 more

Context. Precise determination of stellar masses is necessary to test the validity of pre-main-sequence (PMS) stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_⊙. To improve such a test, and based on our previous studies, we selected the AB Doradus moving group (AB Dor-MG) as the …

Gaia and VLT astrometry of faint stars: Precision of Gaia DR1 positions and updated VLT parallaxes of ultracool dwarfs

Sahlmann, J.; Lazorenko, P. F.

Aims: We compared positions of the Gaia first data release (DR1) secondary data set at its faint limit with CCD positions of stars in 20 fields observed with the Very Large Telescope (VLT) FORS2. We aim at an independent verification of the DR1 astrometric precision taking advantage of the FORS2 position uncertainties which are smaller than o…

Reconstructing the cosmic Horseshoe gravitational lens using the singular perturbative approach.

Alard, C.

The reconstruction of the cosmic horseshoe gravitational lens using the perturbative method reveals the presence of significant third-order terms. The presence of these higher order terms is apparent in the numerical expansion of the perturbative fields in Fourier series. The expansion of the fields at order 2 produces a higher value of the chi-sq…