Search Publications
The origin of the high-mass X-ray binary 4U 2206+54/BD+532790
Neuhäuser, R.; Mugrauer, M.; Stoyanov, K. A. +7 more
Based on the Gaia EDR3 astrometric parameters and our new systemic radial velocity of the high-mass X-ray binary 4U 2206+54/BD+532790, we studied the trace back motion of the system and propose that it originated in the subgroup of the Cepheus OB1 association (Age ~4-10 Myr) with its brightest star, BD+532820 (B0V; ${\cal L}$~104.7${\ca…
Spectroscopic and imaging observations of transient hot and cool loops by IRIS and SDO
Gupta, Girjesh R.; Nayak, Sushree S.
Coronal loops are the basic building blocks of the solar atmosphere and are observed on various length scales. However, their formation mechanism is still unclear. In this paper, we present spectroscopic and imaging observations of small-scale transients and the subsequent formation of transient loops. For this purpose, we have utilized the multiw…
MeerKAT radio observations of the neutron star low-mass X-ray binary Cen X-4 at low accretion rates
Fender, R.; Miller-Jones, J. C. A.; van den Eijnden, J. +4 more
Centaurus X-4 (Cen X-4) is a relatively nearby neutron star low-mass X-ray binary that showed outbursts in 1969 and 1979, but has not shown a full outburst since. Due to its proximity and sustained period of quiescence, it is a prime target to study the coupling between accretion and jet ejection in quiescent neutron star low-mass X-ray binaries. …
Characterizing non-thermal equilibrium contact binaries
Wang, Z. H.; Zhu, L. Y.; Yuan, K.
Formation and evolution of marginal contact binaries with larger temperature difference between their two components remain inexplicable to date. To get a better understanding of the nature of such population we investigate on an individual, NSVS 7358116, by analysing observational data obtained from ground-based and space-based telescopes. It is …
Detection of spicules termed rapid blueshifted excursions as seen in the chromosphere via H α and the transition region via Si IV 1394 Å line emission
Shetye, Juie; Doyle, J. Gerry; Vilangot Nhalil, Nived
We show signatures of spicules termed rapid blueshifted excursions (RBEs) in the Si IV 1394 Å emission line using a semi-automated detection approach. We use the H α filtergrams obtained by the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope and co-aligned Interface Region Imaging Spectrograph data using the SJI 1400 Å channel …
External or internal companion exciting the spiral arms in CQ Tau?
Testi, Leonardo; Benisty, Myriam; Pinte, Christophe +9 more
We present new high-contrast images in near-infrared wavelengths (λc = 1.04, 1.24, 1.62, 2.18, and 3.78 µm) of the young variable star CQ Tau, aiming to constrain the presence of companions in the protoplanetary disc. We reached a Ks-band contrast of 14 mag with SPHERE/IRDIS at separations greater than 0${_{.}^{\prime\prime}}$4 fr…
Massive young stellar objects in the Local Group spiral galaxy M 33 identified using machine learning
van Loon, Jacco Th; Oliveira, Joana M.; Kinson, David A.
We present a supervised machine learning classification of stellar populations in the Local Group spiral galaxy M 33. The Probabilistic Random Forest (PRF) methodology, previously applied to populations in NGC 6822, utilizes both near and far-IR classification features. It classifies sources into nine target classes: young stellar objects (YSOs), …
On the origin of core radio emissions from black hole sources in the realm of relativistic shocked accretion flow
Stalin, C. S.; Rakshit, Suvendu; Nandi, Anuj +5 more
We study the relativistic, inviscid, advective accretion flow around the black holes and investigate a key feature of the accretion flow, namely the shock waves. We observe that the shock-induced accretion solutions are prevalent and such solutions are commonly obtained for a wide range of the flow parameters, such as energy (${\cal E}$) and angul…
NGTS-21b: an inflated Super-Jupiter orbiting a metal-poor K dwarf
Wheatley, Peter J.; Bayliss, Daniel; Worters, Hannah L. +29 more
We report the discovery of NGTS-21b , a massive hot Jupiter orbiting a low-mass star as part of the Next Generation Transit Survey (NGTS). The planet has a mass and radius of 2.36 ± 0.21 MJ and 1.33 ± 0.03 RJ, and an orbital period of 1.543 d. The host is a K3V (Teff = 4660 ± 41 K) metal-poor ([Fe/H] = -0.26 ± 0.07…
Redshift and stellar mass dependence of intrinsic shapes of disc-dominated galaxies from COSMOS observations below z = 1.0
Tallada-Crespí, P.; Teyssier, R.; Laigle, C. +4 more
The high abundance of disc galaxies without a large central bulge challenges predictions of current hydrodynamic simulations of galaxy formation. We aim to shed light on the formation of these objects by studying the redshift and mass dependence of their intrinsic 3D shape distributions in the COSMOS galaxy survey below redshift z = 1.0. This dist…