Search Publications
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…
Galaxy clustering in the VVV near-IR galaxy catalogue
Minniti, Dante; Alonso, M. Victoria; Valotto, Carlos +7 more
Mapping galaxies at low Galactic latitudes and determining their clustering status are fundamental steps in defining the large-scale structure in the nearby Universe. The VISTA Variables in the Vía Láctea (VVV) near-IR galaxy catalogue (VVV NIRGC) allows us to explore this region in great detail. Our goal is to identify galaxy overdensities and ch…
Identifying RR Lyrae in the ZTF DR3 data set
Koposov, Sergey E.; Huang, Kuan-Wei
We present an RR Lyrae (RRL) catalogue based on the combination of the third data release of the Zwicky Transient Facility (ZTF DR3) and Gaia EDR3. We use a multistep classification pipeline relying on the Fourier decomposition fitting to the multiband ZTF light curves and random forest classification. The resulting catalogue contains 71 755 RRLs …
An X-ray view of the ambiguous nuclear transient AT2019pev
Kochanek, C. S.; Grupe, D.; Mathur, S. +3 more
AT2019pev is a nuclear transient in a narrow-line Seyfert 1 galaxy at z = 0.096. The archival ultraviolet, optical, and infrared data showed features of both tidal disruption events and active galactic nuclei (AGNs), and its nature is not fully understood. We present detailed X-ray observations of AT2019pev taken with Swift, Chandra, and NICER ove…