Search Publications
Weak solar flares with a detectable flux of hard X rays: Specific features of microwave radiation in the corresponding active regions
Livshits, M. A.; Grigor'eva, I. Yu.
The emission of very weak flares was registered at the Suzaku X-ray observatory in 2005–2009. The photon power spectrum in the 50–110 keV range for a number of these phenomena shows that some electrons accelerate to energies higher than 100 keV. The corresponding flares originate in active regions (ARs) with pronounced sunspots. As in the case of …
Exploring Hot Gas at Junctions of Galaxy Filaments with Suzaku
Mitsuishi, I.; Sousbie, T.; Sasaki, S. +3 more
We performed five pointing observations with Suzaku to search for hot gases associated with the junctions of galaxy filaments where no significant diffuse X-ray sources were previously detected. We discovered X-ray sources successfully in all five regions including merging groups of galaxies, Suzaku J0957+2610 and Suzaku J1134+2105, and analyzed t…
Ground calibrations of the Solar Intensity X-ray Spectrometer (SIXS) on board BepiColombo
Andersson, H.; Alha, L.; Huovelin, J. +4 more
In this paper we present the methods, results, and analysis of the BepiColombo SIXS instruments' ground calibrations. The aim of these calibrations was to characterize the performance of the three SIXS X-ray detectors to enable reliable spectral analysis of the solar X-ray data. The ground calibrations for characterizing the performance of the thr…
Constraints on dark matter annihilation and its equation of state after Planck data
Xu, Lixin
In this paper, the annihilation of dark matter (DM) fdɛ0 with nonzero equation of state (EoS) wdm was studied by using the currently available cosmic observations which include geometric and dynamic measurements. The constrained results show they are anti-correlated and are w dm = 0.000390-0.000753<…
The CMB derivatives of Planck's beam asymmetry
Rathaus, Ben; Kovetz, Ely D.
We investigate the anisotropy in cosmic microwave background Planck maps due to the coupling between its beam asymmetry and uneven scanning strategy. Introducing a pixel space estimator based on the temperature gradients, we find a highly significant (∼20σ) preference for these to point along ecliptic latitudes. We examine the scale dependence, mo…
Discovering a misaligned CO outflow related to the red MSX source G034.5964-01.0292
Rubio, M.; Ortega, M. E.; Paron, S. +1 more
Aims: The red MSX source G034.5964-01.0292 (MSXG34), catalogued as a massive young stellar object, was observed in molecular lines with the aim of discovering and studying molecular outflows.
Methods: We mapped a region of 3'× 3' centred at MSXG34 using the Atacama Submillimeter Telescope Experiment in the 12CO J = 3-2 and HCO…
Verification of the Spectral Classification of Stars Using the Hipparcos Catalogue
Deb, D.; Chakraborty, P.
The spectral classifications of the stars from spectral data have been corrected from time to time and new spectral and luminosity classes have been assigned. Identifying stars with wrong spectral and luminosity classification has been a stupendous task from the huge catalogue of stars. In this work we describe a simple statistical technique to id…
Interplanetary Field Enhancements: The Interaction between Solar Wind and Interplanetary Dusty Plasma Released by Interplanetary Collisions
Lai, Hairong
Interplanetary field enhancements (IFEs) are unique large-scale structures in the solar wind. During IFEs, the magnetic-field strength is significantly enhanced with little perturbation in the solar-wind plasma. Early studies showed that IFEs move at nearly the solar-wind speed and some IFEs detected at 0.72AU by Pioneer Venus Orbiter (PVO) are as…
A study of the relation between intensity oscillations and magnetic field parameters in a sunspot: Hinode observations
Venkatakrishnan, P.; Kumar, Brajesh; Mathew, Shibu K. +2 more
We present properties of intensity oscillations of a sunspot in the photosphere and chromosphere using G band and Ca II H filtergrams from Hinode. Intensity power maps as function of magnetic field strength and frequency reveal reduction of power in the G band with an increase in photospheric magnetic field strength at all frequencies. In Ca II H,…
Discovery of an overlapping cluster in the Abell 1674 field with Suzaku
Koyama, Katsuji; Hayashida, Kiyoshi; Akamatsu, Hiroki +5 more
We present the results of a Suzaku observation of Abell 1674, an optically very rich (richness class 3) cluster cataloged as z = 0.1066. We discover the He-like Fe K-shell line from the central region for the first time, and find that the X-ray spectrum yields a high redshift of 0.215^{+0.007}_{-0.006}. On the other hand, the spectrum of the south…