Search Publications
Searching for an intermediate-mass black hole in the blue compact dwarf galaxy MRK 996
Georgakakis, A.; Tsamis, Y. G.; Aloisi, A. +1 more
The possibility is explored that accretion on an intermediate-mass black hole contributes to the ionization of the interstellar medium of the compact blue dwarf galaxy MRK 996. Chandra observations set tight upper limits (99.7 per cent confidence level) in both the X-ray luminosity of the posited active galactic nucleus (AGN), LX(2-10 k…
The XMM-Newton view of the X-ray spectrum of WR140 across periastron passage
De Becker, Michaël; Pittard, Julian M.; Williams, Peredur. +1 more
An XMM-Newton campaign dedicated to the study of the X-ray emission of the colliding wind massive binary WR140 across its 2009 periastron passage has been undertaken. The high quality EPIC spectra revealed a strong phase-locked variability both in flux and in spectral shape. The observed variations are consistently explained by the varying emissio…
Real space CMB lensing reconstruction with point source masks
Carvalho, C. Sofia; Tereno, Ismael
An incomplete sky coverage poses difficulties in the extraction of the weak lensing information from the CMB. We test the reconstruction of the weak lensing convergence from CMB maps to which masks of point sources have been applied. We use the quadratic estimator with a kernel with finite support acting in real space for a Planck simulation. We r…
Numerical simulations to study solar wind turbulence
Sharma, R. P.; Kumar, Sanjay; Kumar, Sachin +2 more
Numerical simulation of coupled equations of kinetic Alfvén wave (KAW) and ion acoustic wave is presented in the solar wind. The nonlinear dynamical equations satisfy the modified Zakharov system of equations by taking the nonadiabatic response of the background density. The ponderomotive nonlinearity is incorporated in the wave dynamics. The effe…
An intrinsic source of reddening in the cataclysmic variable SS Cygni
Gaudenzi, S.; Giovannelli, F.; Lombardi, R. +2 more
By using the INES archive of the IUE satellite, we analyzed the spectra of SS Cygni in quiescence in order to determine the value of the reddening of the binary system. The reddening of the system is reported in the literature with values that vary significantly from one another. The results demonstrate that the reddening is comprised by two compo…
Four First and Two Recalculated Orbits for Binaries
Cvetković, Z.
In this paper, we analyze new orbital elements, and quantities that can be derived from them, for six binaries. For four of them, WDS 00251+4803 = HDS 56, WDS 01071-0036 = HDS 144 AB, WDS 06426+3955 = HDS 930, and WDS 21014+4037 = HDS 2995, the orbital elements are calculated for the first time. For the other two, WDS 04195+3800 = HDS 552 and WDS …
Modeling substorm ion injection observed by the THEMIS and LANL spacecraft in the near-Earth magnetotail
El-Alaoui, Mostafa; Walker, Raymond J.; Zhou, Meng +3 more
In this paper, we studied a substorm ion injection event by using magnetohydrodynamic (MHD) and large-scale kinetic (LSK) simulations. On 23 March 2007 the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite constellation provided us with a unique opportunity to study a substorm injection in the region beyond geo…
A photometric long-term study of chemically peculiar stars in open clusters
Fossati, L.; Heiter, U.; Paunzen, E. +5 more
Context. Photometric variability of chemically peculiar (CP) stars of the upper main sequence is closely connected to their local stellar magnetic field and their rotational period. Long term investigations, as presented here, help us to identify possible stellar cycles (as in the Sun). Furthermore, these data provide a basis for detailed surface …
Testing the Global Star Formation relation: An HCO+ (3-2) Mapping Study of Red MSX Sources in the Bolocam Galactic Plane Survey
Juneau, Stéphanie; Reiter, Megan; Shirley, Yancy L. +1 more
We present an analysis of the relation between the star formation rate (SFR) and mass of dense gas in Galactic clumps and nearby galaxies. Using the bolometric luminosity as a measure of SFR and the molecular line luminosity of HCO+ (3-2) as a measure of dense gas mass, we find that the relation between SFR and M dense is app…
Observations of dawn-dusk aligned polar cap aurora during the substorms of January 21, 2005
Tsurutani, B. T.; Du, A. M.; Sun, W. +2 more
A new type of polar cap aurora, dawn-dusk aligned polar cap aurora (DDAPCA), was detected during the exceptionally intense January 21, 2005 substorm (AEmax=3504 nT). The DDAPCA was located at very high latitude (>85° MLAT) in the polar cap region. As the interplanetary magnetic field (IMF) GSM By component rotated from a positive to …