Search Publications
Runaway O-star Bow Shocks as Particle Accelerators? The Case of AE Aur Revisited
Rangelov, Blagoy; Federman, S. R.; Montmerle, Thierry +2 more
We present results of our Chandra/ACIS observations of the field centered on the fast, runaway O star AE Aur and its bow shock. Previous XMM-Newton observations revealed an X-ray “blob” near the IR arc tracing the bow shock, possibly a nonthermal source consistent with models of Inverse Compton scattering of dust IR photons by electrons accelerate…
Spectroscopy of NGC 4258 Globular Cluster Candidates: Membership Confirmation and Kinematics
González-Lópezlira, Rosa A.; Georgiev, Iskren Y.; Loinard, Laurent +9 more
We present multiobject spectroscopic observations of 23 globular cluster candidates (GCCs) in the prototypical megamaser galaxy NGC 4258, carried out with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy instrument at the 10.4 m Gran Telescopio Canarias. The candidates have been selected based on the (u* - i‧)…
Cassini UVIS Detection of Saturn's North Polar Hexagon in the Grand Finale Orbits
Lamy, L.; West, R. A.; Esposito, L. W. +6 more
Cassini's final orbits in 2016 and 2017 provided unprecedented spatial resolution of Saturn's polar regions from near-polar spacecraft viewing geometries. Long-wavelength channels of Cassini's Ultraviolet Imaging Spectrograph instrument detected Saturn's UV-dark north polar hexagon near 180 nm at planetocentric latitudes near 75°N. The dark polar …
X-ray and radio studies of SNR CTB 37B hosting the magnetar CXOU J171405.7-381031
Safi-Harb, Samar; Kothes, Roland; Gotthelf, Eric V. +2 more
We present a Chandra and XMM-Newton study of the supernova remnant (SNR) CTB 37B, along with archival radio observations. In radio wavelengths, the SNR CTB 37B is an incomplete shell showing bright emission from the eastern side, while the X-ray morphology shows diffuse emission from regions surrounding the magnetar CXOU J171405.7-381031. We used …
Multifractal detrended moving average analysis of Kepler stars with surface differential rotation traces
De Medeiros, J. R.; de Freitas, D. B.; Das Chagas, M. L. +2 more
A multifractal formalism is employed to analyse high-precision time-series data of Kepler stars with surface differential rotation (DR) traces. The multifractal detrended moving average (MFDMA) algorithm has been explored to characterize the multiscale behaviour of the observed time series from a sample of 662 stars selected with parameters close …
Detection of Hα emission from PZ Telescopii B using SPHERE/ZIMPOL
Henning, Thomas; Musso Barcucci, Arianna; Launhardt, Ralf +6 more
Hα is a powerful tracer of accretion and chromospheric activity, which has been detected in the case of young brown dwarfs and even recently in planetary mass companions (e.g. PDS70 b and c). Hα detections and characterisation of brown dwarf and planet companions can further our knowledge of their formation and evolution, and expanding such a samp…
SN 2016B a.k.a. ASASSN-16ab: a transitional Type II supernova
Pandey, S. B.; Benetti, S.; Kumar, Brajesh +12 more
We present photometry, polarimetry, and spectroscopy of the Type II supernova ASASSN-16ab/SN 2016B in PGC 037392. The photometric and spectroscopic follow-up commenced about 2 weeks after shock breakout and continued until nearly 6 months. The light curve of SN 2016B exhibits intermediate properties between those of Type IIP and IIL. The early dec…
Kinematics and dynamics of the luminous infrared galaxy pair NGC 5257/58 (Arp 240)
Rosado, M.; Amram, P.; Fuentes-Carrera, I. +6 more
Context. Encounters between galaxies modify their morphology, kinematics, and star formation history. The relation between these changes and external perturbations is not straightforward. The great number of parameters involved requires both the study of large samples and individual encounters where particular features, motions, and perturbations …
On ancient solar-type stars
Fuhrmann, Klaus; Chini, Rolf
We describe a survey of ancient solar-type stars down to main-sequence effective temperatures Teff ≥ 5300 K and within 42 pc of the Sun. The underlying Gaia-based, volume-complete parent sample consists of 1633 sources, dominated by Population I. The design of the survey is such that around 130 sources are expected to be members of Popu…
Acceleration of plasma in current sheet during substorm dipolarizations in the Earth's magnetotail: Comparison of different mechanisms
Parkhomenko, Elena I.; Malova, Helmi V.; Grigorenko, Elena E. +6 more
This work is devoted to the investigation of particle acceleration during magnetospheric dipolarizations. A numerical model is presented taking into account the four scenarios of plasma acceleration that can be realized: (A) total dipolarization with characteristic time scales of ≈3 min; (B) single peak value of the normal magnetic component …