Search Publications
Classifying IGR J18007-4146 as an intermediate polar using XMM and NuSTAR
Hare, Jeremy; Mukai, Koji; Fornasini, Francesca M. +5 more
Many new and unidentified Galactic sources have recently been revealed by ongoing hard X-ray surveys. A significant fraction of these have been shown to be the type of accreting white dwarfs known as cataclysmic variables (CVs). Follow-up observations are often required to categorize and classify these sources, and may also identify potentially un…
Orphan optical flare as SOSS emission afterglow, localization in time
Zhirkov, K.; Gorbovskoy, E.; Serra-Ricart, M. +24 more
We report on MASTER optical observations of an afterglow-like optical and X-ray transient AT2021lfa/ZTF21aayokph. We detected the initial steady brightening of the transient at 7σ confidence level. This allowed us to use smooth optical self-similar emission of GRBs model to constrain the explosion time to better than 14 min as well as to estimate …
Forbush decreases caused by paired interacting solar wind disturbances
Belov, A. V.; Abunina, M. A.; Abunin, A. A. +3 more
The paper discusses changes in various characteristics of the solar wind, interplanetary magnetic field, geomagnetic activity, and cosmic rays during the registration of paired interacting solar wind disturbances on the Earth using the data base of Forbush effects and interplanetary disturbances - FEID. The cases of pair interaction are considered…
Discovery of an inflated hot Jupiter around a slightly evolved star TOI-1789
Howell, Steve B.; Fridlund, Malcolm; Guenther, Eike W. +11 more
We report here the discovery of a hot Jupiter at an orbital period of 3.208664 ± 0.000015 d around TOI-1789 (TYC 1962-00303-1, TESSmag = 9.1) based on the TESS photometry, ground-based photometry, and high-precision radial velocity (RV) observations. The high-precision RV observations were obtained from the high-resolution spectrographs…
fBLS - a fast-folding BLS algorithm
Mazeh, T.; Faigler, S.; Shahaf, S. +2 more
We present fBLS - a novel fast-folding technique to search for transiting planets, based on the fast-folding algorithm (FFA), which is extensively used in pulsar astronomy. For a given light curve with N data points, fBLS simultaneously produces all the binned phase-folded light curves for an array of Np trial periods. For each folded l…
First optical identification of the SRG/eROSITA-detected supernova remnant G 116.6 - 26.1. I. Preliminary results
Palaiologou, E. V.; Leonidaki, I.; Kopsacheili, M.
The supernova remnant (SNR) candidate G 116.6 - 26.1 is one of the few high Galactic latitude (|b| > 15°) remnants detected so far in several wavebands. It was discovered recently in the SRG/eROSITA all-sky X-ray survey and also displays a low-frequency weak radio signature. In this study, we report the first optical detection of G 116.6 - 26.1…
X-ray variability of transitional millisecond pulsars: a faint, stable, and fluctuating disc
Wijnands, Rudy; Linares, Manuel; van der Klis, Michiel +1 more
Transitional millisecond pulsars (tMSPs) have emerged in the last decade as a unique class of neutron stars at the crossroads between accretion- and rotation-powered phenomena. In their (sub-luminous) accretion disc state, with X-ray luminosities of order 1033-1034 erg s-1, they switch rapidly between two distinct …
Machine learning-based search for cataclysmic variables within Gaia Science Alerts
Copperwheat, C. M.; Darnley, M. J.; Mistry, D. +1 more
Wide-field time domain facilities detect transient events in large numbers through difference imaging. For example, Zwicky Transient Facility produces alerts for hundreds of thousands of transient events per night, a rate set to be dwarfed by the upcoming Vera C. Rubin Observatory. The automation provided by machine learning (ML) is therefore nece…
X-ray response to disc evolution in two γ Cas stars
Nazé, Yaël; Rauw, Gregor; Bohlsen, Terrence +4 more
The Hα emission of a set of southern γ Cas stars was monitored since 2019, with the aim of detecting transition events and examining how their peculiar X-ray emission would react in such cases. Two stars, namely HD 119682 and V767 Cen, were found to display slowly decreasing disc emissions. These decreases were not perfectly monotonic and several …
Spectral and temporal properties of ultra-luminous X-ray source NGC 55 ULX1
Jithesh, V.
We investigate the spectral and temporal properties of ultra-luminous X-ray source (ULX) NGC 55 ULX1 using Swift, XMM-Newton and NuSTAR observations conducted during 2013-2021. In these observations, the source flux varies by a factor of ~5-6, and we identify the source mainly in the soft ultraluminous (SUL) state of ULXs. We fit the X-ray spectra…