Search Publications
Revised cosmological parameters after BICEP 2 and BOSS
Das, Santanu; Souradeep, Tarun; Mukherjee, Suvodip
Estimation of parameters of the 'standard' model of cosmology have dramatically improved over past few decades due to increasingly exquisite measurements made by Cosmic Microwave Background (CMB) experiments. Recent data from Planck matches well with the minimal ΛCDM model. A likelihood analysis using Planck, WMAP and a selection of high resolutio…
Subdominant Dark Matter sterile neutrino resonant production in the light of PLANCK
Popa, L. A.; Tonoiu, D.
Few independent detections of a weak X-ray line at an energy of ~ 3.5 keV seen toward a number of astrophysical sites have been reported. If this signal will be confirmed to be the signature of decaying DM sterile neutrino with a mass of ~ 7.1 keV, then the cosmological observables should be consistent with its properties.
A young star cluster in the Leo A galaxy
Narbutis, D.; Vansevičius, V.; Bridžius, A. +2 more
We report a serendipitous discovery of a star cluster in the dwarf irregular galaxy Leo A. Young age ( ∼28 Myr) and low mass ( ∼510 M⊙) estimates are based on the isochrone fit assuming a metallicity derived for H II regions (Z=0.0007). The color-magnitude diagrams of the stars, located in and around the cluster area, and the results of…
Spacecraft Doppler tracking with possible violations of LLI and LPI: upper bounds from one-way measurements on MEX
Xie, Yi; Huang, Yong
We analyze the post-fit residuals of one-way Doppler tracking data from the Mars Express (MEX) spacecraft to test possible violations of local Lorentz invariance (LLI) and local position invariance (LPI). These one-way Doppler observations were carried out on 2011 August 7 for about 20 minutes at Sheshan Station of Shanghai Astronomical Observator…
Revealing the cold dust in low-metallicity environments (Corrigendum). I. Photometry analysis of the Dwarf Galaxy Survey with Herschel
Ciesla, L.; Boquien, M.; Roussel, H. +21 more
X-rays from the oxygen-type Wolf-Rayet binary WR 30a
Skinner, Stephen L.; Zhekov, Svetozar A.
We present an analysis of XMM-Newton X-ray data of WR 30a (WO+O), a close massive binary that harbours an oxygen-rich Wolf-Rayet star. Its spectrum is characterized by the presence of two well-separated broad peaks, or `bumps', one peaking at energies between 1 and 2 keV and the other between 5 and 7 keV. A two-component model is required to match…
Self-consistent electrostatic simulations of reforming double layers in the downward current region of the aurora
Gunell, H.; Andersson, L.; De Keyser, J. +1 more
The plasma on a magnetic field line in the downward current region of the aurora is simulated using a Vlasov model. It is found that an electric field parallel to the magnetic fields is supported by a double layer moving toward higher altitude. The double layer accelerates electrons upward, and these electrons give rise to plasma waves and electro…
Suzaku observations of Fe K α line in some Magnetic Cataclysmic Variables
Eze, R. N. C.
We resolved the 6.4 keV, 6.7 keV and 7.0 keV Fe K α lines in 19 Magnetic Cataclysmic Variables (mCVs) observed with the Suzaku satellite. The 6.7 keV and 7.0 keV emission lines are typically created by collisional excitation in the vicinity of the white dwarf arising from the shock front. The 6.4 keV iron emission line in contrast is formed in equ…
Prominence Visibility in Hinode/XRT Images
Heinzel, P.; Anzer, U.; Jejčič, S. +2 more
In this paper we study the soft X-ray (SXR) signatures of one particular prominence. The X-ray observations used here were made by the Hinode/X-Ray Telescope instrument using two different filters. Both of them have a pronounced peak of the response function around 10 Å. One of them has a secondary smaller peak around 170 Å, which leads to a conta…
Electrical interferences observed in the Cassini CIRS spectrometer
Flasar, F. Michael; Gorius, Nicolas; Guandique, Ever +6 more
The Composite Infrared Spectrometer (CIRS) carried onboard the Cassini spacecraft has now operated successfully for 17 years, following launch in 1997. Following insertion into Saturnian orbit in July 2004, the instrument has taken data nearly continuously, returning over 100 million interferograms (spectra) to date. Although of generally high qua…