Search Publications
Correlated variability of the reflection fraction with the X-ray flux and spectral index for Mrk 478
Jithesh, V.; Medhi, Biman J.; Misra, Ranjeev +2 more
The X-ray spectrum of Mrk 478 is known to be dominated by a strong soft excess that can be described using relativistic blurred reflection. Using observations from XMM-Newton, AstroSat, and Swift, we show that for the long-term (~years) and intermediate-term (days to months) variability, the reflection fraction is anticorrelated with the flux and …
Ionized filaments and ongoing physical processes in massive-star-forming sites around l = 345.°5
Dewangan, L. K.; Pirogov, L. E.; Bhadari, N. K. +1 more
Numerous research studies on dust and molecular filaments in star-forming sites have been conducted, but only a limited number have focused on ionized filaments. To observationally study this aspect, we present an analysis of multiwavelength data from an area of ~74.6 arcmin × 55 arcmin around l = 345${_{.}^{\circ}}$5. Using the 843-MHz continuum …
Dissipation of hydromagnetic waves in the viscous polytropic zone of the solar wind including FLR corrections, ohmic diffusion, and the Hall effect
Fok, Mei-Ching; Desta, Ephrem Tesfaye; Prajapati, Ram Prasad +1 more
In the polytropic zone of the solar wind, we have used the generalized polytrope pressure laws to investigate the dissipation of hydromagnetic waves and pressure-anisotropy-driven fluid instabilities in magnetized viscous plasmas, including finite Larmor radius (FLR) corrections and non-ideal magnetohydrodynamic (MHD) effects. The modified dispers…
Spatio-temporal bands of coronal bright points and their relation to solar torsional oscillations
Tsinamdzgvrishvili, Tamar; Chargeishvili, B. B.; Shergelashvili, Bidzina M. +1 more
Using automatic processing of daily FITS files from SOHO_EIT, we studied the temporal evolution of the latitudinal distribution of bright coronal points from 1995 to 2020. The study revealed homogeneous and inhomogeneous components of the latitudinal distribution. The homogeneous component has cyclical variations with a significant phase shift com…
Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
Guerrero, M. A.; Toalá, J. A.; Ramos-Larios, G. +2 more
We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC 4406. MUSE spectra are extracted from the rings to unambiguously…
A low-frequency pilot survey of southern H II regions in the vela constellation
Bourke, Tyler L.; Dickey, John M.; Wong, O. Ivy +3 more
Atomic ionized regions with strong continuum emission are often associated with regions of high-mass star formation and low-frequency (<2 GHz) observations of these regions are needed to help build star formation models. The region toward the Vela Supernova Remnant is particularly interesting as it is a complex structure of recent supernova exp…
The MOSDEF survey: towards a complete census of the z 2.3 star-forming galaxy population
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +16 more
We analyse the completeness of the MOSDEF survey, in which z ~ 2 galaxies were selected for rest-optical spectroscopy from well-studied HST extragalactic legacy fields down to a fixed rest-optical magnitude limit (HAB = 24.5). The subset of z ~ 2 MOSDEF galaxies with high signal-to-noise (S/N) emission-line detections analysed in previo…
A transient ultraluminous X-ray source in NGC 55
Cusumano, G.; Wolter, A.; Pinto, C. +14 more
Ultraluminous X-ray sources (ULXs) are a class of accreting compact objects with X-ray luminosities above 1039 erg s-1 . The average number of ULXs per galaxy is still not well-constrained, especially given the uncertainty on the fraction of ULX transients. Here, we report the identification of a new transient ULX in the gala…
Dark Energy Camera photometry reveals extra-tidal stars around the Milky Way globular cluster NGC 6864 (M75)
Piatti, Andrés E.
Globular clusters are prone to lose stars while moving around the Milky Way. These stars escape the clusters and are distributed throughout extended envelopes or tidal tails. However, such extra-tidal structures are not observed in all globular clusters, and yet there are no structural or dynamical parameters that can predict their presence or abs…
Simple interpretation of the seemingly complicated X-ray spectral variation of NGC 5548
Sugawara, Yasuharu; Ebisawa, Ken; Mizumoto, Misaki +1 more
NGC 5548 is a very well-studied Seyfert 1 galaxy in broad wavelengths. Previous multiwavelength observation campaigns have indicated that its multiple absorbers are highly variable and complex. A previous study applied a two-zone partial covering model with different covering fractions to explain the complex X-ray spectral variation and reported a…