Search Publications
X-ray properties of high-richness CAMIRA clusters in the Hyper Suprime-Cam Subaru Strategic Program field
Oguri, Masamune; Fujimoto, Ryuichi; Okabe, Nobuhiro +13 more
We present the first results of a pilot X-ray study of 37 rich galaxy clusters at 0.1 < z < 1.1 in the Hyper Suprime-Cam Subaru Strategic Program field. Diffuse X-ray emissions from these clusters were serendipitously detected in the XMM-Newton fields of view. We systematically analyze X-ray images of 37 clusters and emission spectra of a su…
Variable stars in the field of intermediate-age open cluster NGC 559
Joshi, Y. C.; John, Ancy A.; Maurya, J. +3 more
This work presents the first long-term photometric variability survey of the intermediate-age open cluster NGC 559. Time series V-band photometric observations on 40 nights taken over more than 3 yr with three different telescopes are analysed to search for variable stars in the cluster. We investigate the data for the periodicity analysis and rev…
Cut-off features in interplanetary solar radio type IV emission
Pohjolainen, Silja; Talebpour Sheshvan, Nasrin
Solar radio type IV bursts can sometimes show directivity, so that no burst is observed when the source region in located far from the solar disk center. This has recently been verified also from space observations, at decameter wavelengths, using a 3D-view to the Sun with STEREO and Wind satellites. It is unclear whether the directivity is caused…
NaCo polarimetric observations of Sz 91 transitional disc: a remarkable case of dust filtering
Villaver, Eva; Pinte, Christophe; Zurlo, Alice +10 more
We present polarized light observations of the transitional disc around Sz 91 acquired with VLT/NaCo at H (1.7µm) and Ks (2.2µm) bands. We resolve the disc and detect polarized emission up to ∼0.5 arcsec (∼80 au) along with a central cavity at both bands. We computed a radiative transfer model that accounts for the main char…
Analysis of spiral structure in the accretion disc of the nova-like cataclysmic variable EC21178-5417
Groot, P. J.; Woudt, P. A.; Ruiz-Carmona, R. +1 more
We present an extensive Doppler tomography study of the eclipsing nova-like EC21178-5417, which exhibits the classic accretion disc signature in the form of double-peak emission lines in its spectrum. Doppler tomograms confirm the presence of a strong, two-armed spiral pattern visible in the majority of the spectral lines studied. This makes EC211…
Variability in Protoplanetary Nebulae: VII. Light-curve Studies of Five Medium-bright, Oxygen-rich, or Mixed-chemistry Post-AGB/Post-RGB Objects
Lu, Wenxian; Volk, Kevin; Hrivnak, Bruce J. +3 more
We have monitored over a 10-year interval the light variations of five evolved stars with very large mid-infrared excesses. All five objects appear to have oxygen-rich or mixed oxygen-rich and carbon-rich chemistries. They all vary in light: four over a small range of ∼0.2 mag and the fifth over a larger range of ∼0.7 mag. Spectral types range fro…
Using dimensionality reduction and clustering techniques to classify space plasma regimes
Verscharen, Daniel; Walsh, Andrew P.; Rae, I. Jonathan +2 more
Collisionless space plasma environments are typically characterised by distinct particle populations. Although moments of their velocity distribution functions help in distinguishing different plasma regimes, the distribution functions themselves provide more comprehensive information about the plasma state, especially at times when the distributi…
Boulder Fall Activity in the Jezero Crater, Mars
Vijayan, S.; Mangold, N.; Bhardwaj, Anil +5 more
Jezero crater is the landing site for the Mars 2020 Perseverance rover. We report 63 boulder fall tracks within the crater using High-Resolution Imaging Science Experiment (HiRISE) images. The boulder tracks have both fresh and faded morphologies similar to those reported elsewhere on Mars, but reported for the first time in Jezero crater. We comb…
Evolution of downflows in the transition region above a sunspot over short time-scales
Mathioudakis, M.; Krishna Prasad, S.; Nelson, C. J.
Context. Downflows with potentially super-sonic velocities have been reported to occur in the transition region above many sunspots; however, how these signatures evolve over short time-scales in both spatial and spectral terms is still unknown and requires further research.
Aims: In this article, we investigate the evolution of downflows det…
Continuation of the X-ray monitoring of Sgr A*: the increase in bright flaring rate confirmed
Mossoux, E.; Finociety, B.; Beckers, J. -M. +1 more
Context. The supermassive black hole Sagittarius A* (Sgr A*) is located at the dynamical center of the Milky Way. In a recent study of the X-ray flaring activity from Sgr A* using Chandra, XMM-Newton, and Swift observations from 1999 to 2015, it has been argued that the bright flaring rate has increased from 2014 August 31 while the faint flaring …