Search Publications
Spectroscopic and Photometric Monitoring of a Poorly Known Highly Luminous OH/IR Star: IRAS 18278+0931
Dutta, Somnath; Mondal, Soumen; Das, Ramkrishna +1 more
We present the time-dependent properties of a poorly known OH/IR star, IRAS 18278+0931 (hereafter IRAS 18+09), toward the Ophiuchus constellation. We have carried out long-term optical/near-infrared photometric and spectroscopic observations to study the object. From optical R- and I-band light curves, the period of IRAS 18+09 is estimated to be 5…
Desaturated EUV Flare Ribbons in an X-class Flare
Krucker, Säm; Schwartz, Richard A.; Torre, Gabriele
This paper studies the energy dissipation of nonthermal electrons in the chromospheric flare ribbons during the peak time of a Geostationary Operational Environmental Satellite X-class flare (SOL2011-09-06) using desaturated Solar Dynamics Observatory/Atmospheric Imaging Assembly extreme-ultraviolet (EUV) narrow-band images. The temperature distri…
ALMA Host Galaxy Observation of the Off-axis Gamma-Ray Burst XRF 020903
Urata, Yuji; Huang, Kuiyun; Chen, Jheng-Cyun
We investigated the radio properties of the host galaxy of X-ray flash, XRF 020903, which is the best example for investigating the off-axis origin of gamma-ray bursts (GRBs). Dust continuum at 233 GHz and CO are observed using the Atacama Large millimeter/submillimeter array. The molecular gas mass derived by applying the metallicity-dependent CO…
A Study of Variations in Correlation Between Rotation Residual and Meridional Velocity of Sunspot Groups
Javaraiah, J.
We analyzed the combined 142 years sunspot-group data from Greenwich Photoheliograpic Results (GPR) and Debrecen Photoheliographic Data (DPD) and determined the yearly mean residual rotation rate and the meridional velocity of sunspot groups in different 5∘ latitude intervals. We find that there exists a considerable latitude-time depen…
Atmospheric Parameters and Evolutionary CP Stars. I.21 COM from the Old Comae Berenices Cluster
Aliev, S. G.; Alishova, Z. M.
On the basis of Hipparcos observations and complex observations carried out at the Shamakhy Astrophysical Observatory named after N. Tusi of the National Academy of Sciences of Azerbaijan, the main parameters of the atmosphere and the evolutionary status of the magnetic CP star 21 Com from the old Comae Berenices cluster have been determined.Almos…
A search for distant, pulsating red giants in the southern halo
Kendall, T. R.; Mauron, N.; Gigoyan, K. S. +1 more
To investigate the asymptotic giant branch (AGB) population in the Galactic halo, we search for pulsating AGB stars at a heliocentric distance D > 50 kpc. Our research is based on the Catalina Southern Survey (CSS) catalogue of variables, comprising 1286 long-period variables (LPVs) with δ < −20°. We first focus on the 77 stars in the cap |b…
Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view
Michalek, Grzegorz; Ravishankar, Anitha
Solar energetic particles (SEPs) accelerated from shocks driven by coronal mass ejections (CMEs) are one of the major causes of geomagnetic storms on Earth. Therefore, it is necessary to predict the occurrence and intensity of such disturbances. For this purpose we analyzed in detail 38 non-interacting halo and partial halo CMEs, as seen by the So…
Clustered star formation toward Berkeley 87/ON2. I. Multiwavelength census and the population overlap problem
Alves, João; Garcia, Miriam; Jiménez-Bailón, Elena +3 more
Context. Disentangling line-of-sight alignments of young stellar populations is crucial for observational studies of star-forming complexes. This task is particularly problematic in a Cygnus-X subregion where several components, located at different distances, overlap: the Berkeley 87 young massive cluster, the poorly known [DB2001] Cl05 embedded …
Investigating Toroidal Flows in the Sun Using Normal-mode Coupling
Mani, Prasad; Hanasoge, Shravan
Helioseismic observations have provided valuable data sets with which to pursue the detailed investigation of solar interior dynamics. Among various methods to analyze these data, normal-mode coupling has proven to be a powerful tool, used to study Rossby waves, differential rotation, meridional circulation, and nonaxisymmetric multiscale subsurfa…
Results of the Electron Drift Instrument on Cluster
Baumjohann, W.; Torbert, R. B.; Matsui, H. +7 more
The electron drift instrument (EDI) on Cluster pioneered a new method of measuring electric fields, using a beam of electrons to sample the drift velocity over a km-scale gyro orbit. The technique is especially well suited to measuring weak, sub-mV/m, convection fields due to its sensitivity (to both components in the plane perpendicular to B) and…