Search Publications
Population study of astrophysical false positive detections in the southern PLATO field
Bray, J. C.; Kolb, U.; Rowden, P. +3 more
For the upcoming PLAnetary Transits and Oscillation of stars (PLATO) satellite mission, a large number of target stars are required to yield a statistically significant number of planet transits. Locating the centres of the long duration observational phase (LOP) fields closer to the Galactic plane will increase the target star numbers but also th…
NGTS clusters survey - IV. Search for Dipper stars in the Orion Nebular Cluster
Ramsay, Gavin; Wheatley, Peter J.; Henderson, Beth A. +13 more
The dipper is a novel class of young stellar object associated with large drops in flux on the order of 10-50 per cent lasting for hours to days. Too significant to arise from intrinsic stellar variability, these flux drops are currently attributed to disc warps, accretion streams, and/or transiting circumstellar dust. Dippers have been previously…
Transit timing variation analysis of the low-mass brown dwarf KELT-1 b
Southworth, J.; Mancini, L.; Evans, D. F. +8 more
We investigate whether there is a variation in the orbital period of the short-period brown dwarf-mass KELT-1 b, which is one of the best candidates to observe orbital decay. We obtain 19 high-precision transit light curves of the target using six different telescopes. We add all precise and complete transit light curves from open databases and th…
3D structure of H II regions in the star-forming complex S254-S258
Moiseev, Alexei V.; Kirsanova, Maria S.; Boley, Paul A.
The S254-258 star-forming complex is a place of massive star formation where five OB-stars have created H II regions, visible as optical nebulae, and disrupted the parental molecular gas. In this work, we study the 3D structure of these H II regions using optical spectroscopy and tunable-filter photometry with the 6- and 1-m telescopes of the Spec…
GlobULeS - V. UVIT/AstroSat studies of stellar populations in NGC 362: detection of blue lurkers in a globular cluster
Dattatrey, Arvind K.; Yadav, R. K. S.; Subramaniam, Annapurni +4 more
We report the discovery of four blue lurkers with low- and extremely low mass white dwarf (ELM WD) companions in the Galactic globular cluster NGC 362 using AstroSat's Ultra Violet Imaging Telescope (UVIT). We analysed the multiwavelength spectral energy distribution (SED) of far-ultraviolet-bright main-sequence stars using data from the UVIT, Ult…
Two large-scale sloshing cold fronts in the outskirts of the galaxy cluster Abell 3558
Walker, S. A.; Mirakhor, M. S.; Sundquist, M. +1 more
Previous studies of the massive nearby galaxy cluster Abell 3558 reported a cold front around the cluster core, which is attributed to the sloshing of the core as it responds to the gravitational disturbance created by a past minor merger. Here, using XMM-Newton mosaic, we report the detection of two rare large-scale sloshing cold fronts far outsi…
TOI-2498 b: a hot bloated super-Neptune within the Neptune desert
Cegla, Heather M.; Latham, David W.; Fernández Fernández, Jorge +39 more
We present the discovery and confirmation of a transiting hot bloated super-Neptune using photometry from the Transiting Exoplanet Survey Satellite (TESS) and the Las Cumbres Observatory Global Telescope (LCOGT) and radial velocity measurements from the High Accuracy Radial velocity Planet Searcher (HARPS). The host star TOI-2498 is a V = 11.2, G-…
Fundamental parameters of two O9-type giant stars: the (former) spectral classification standard HD 93249 A and ALS 12502 A
Simón-Díaz, S.; Gamen, R.; Maíz Apellániz, J. +5 more
The evolution of massive stars is not completely understood. Several phenomena affect their birth, life, and death, multiplicity being one of them. In this context, the OWN and MONOS projects are systematically observing O- and WN-type stars whose multiplicity status is unknown. Their major goal considers the necessity of determining absolute para…
Swift Deep Galactic Plane Survey classification of Swift J170800-402551.8 as a candidate intermediate polar cataclysmic variable
Mukai, K.; Cenko, S. B.; Hailey, C. +24 more
Here, we present the results of our multiwavelength campaign aimed at classifying Swift J170800-402551.8 as part of the Swift Deep Galactic Plane Survey (DGPS). We utilized Target of Opportunity (ToO) observations with the Neil Gehrels Swift Observatory, Chandra X-ray Observatory, Neutron star Interior Composition Explorer (NICER), X-ray Multi-Mir…
What can be learnt from a highly informative X-ray occultation event in NGC 6814? A marvellous absorber
Kang, Jia-Lai; Wang, Jun-Xian; Fu, Shu-Qi
A unique X-ray occultation event in NGC 6814 during an XMM-Newton observation in 2016 has been reported, providing useful information of the absorber and the corona. We revisit the event with the aid of the hardness ratio (HR)-count rate (CR) plot and comparison with two other absorption-free XMM exposures in 2009 and 2021. NGC 6814 exhibits a cle…