Search Publications
Extended corona models of X-ray reverberation in the AGN 1H 0707-495 and IRAS 13224-3809
Chainakun, P.; Young, A. J.; Hancock, S.
We fit a new vertically extended corona model to previously measured reverberation time lags observed by XMM-Newton in two extremely variable narrow-line Seyfert 1 active galactic nuclei, 1H 0707-495 and IRAS 13224-3809, in a variety of similarly observed flux groups and explore the model in all observations over a 16 yr period. The model employs …
Timing the formation of the galactic thin disc with asteroseismic stellar ages
Zhao, Gang; Wu, Yaqian; Xiang, Maosheng +3 more
The formation of the extended thin disc is the most spectacular event of our Galaxy in the past ~8 Gyr. To unveil this process, obtaining precise and accurate stellar ages for a large sample of stars is essential although challenging. In this work, we present the asteroseismic age determination of 5306 red giant branch stars using Kepler and LAMOS…
Minute-cadence observations of the LAMOST fields with the TMTS: II. Catalogues of short-period variable stars from the first 2-yr surveys
Filippenko, Alexei V.; Wang, Xiaofeng; Németh, Péter +25 more
Over the past few years, wide-field time-domain surveys such as Zwicky Transient Facility and Optical Gravitational Lensing Experiment have led to discoveries of various types of interesting short-period stellar variables, such as ultracompact eclipsing binary white dwarfs (WDs), rapidly rotating magnetized WDs, transitional cataclysmic variables …
Measuring the hot ICM velocity structure function using XMM-Newton observations
Pinto, C.; Federrath, C.; Sanders, J. S. +4 more
It has been shown that the gas velocities within the intracluster medium (ICM) can be measured by applying the novel XMM-Newton EPIC-pn energy scale calibration, which uses instrumental Cu Kα as reference for the line emission. Using this technique, we have measured the velocity distribution of the ICM for clusters involving AGN feedback and slosh…
Probing sub-galactic mass structure with the power spectrum of surface-brightness anomalies in high-resolution observations of galaxy-galaxy strong gravitational lenses - I. Power-spectrum measurement and feasibility study
Vegetti, S.; McKean, J. P.; Treu, T. +4 more
While the direct detection of the dark-matter particle remains very challenging, the nature of dark matter could be possibly constrained by comparing the observed abundance and properties of small-scale sub-galactic mass structures with predictions from the phenomenological dark-matter models, such as cold, warm, or hot dark matter. Galaxy-galaxy …
Peeking beneath the precision floor - I. Metallicity spreads and multiple elemental dispersions in the globular clusters NGC 288 and NGC 362
Monty, Stephanie; Marino, Anna F.; Karakas, Amanda I. +4 more
The view of globular clusters (GCs) as simple systems continues to unravel, revealing complex objects hosting multiple chemical peculiarities. Using differential abundance analysis, we probe the chemistry of the Type I GC, NGC 288 and the Type II GC, NGC 362 at the 2 per cent level for the first time. We measure 20 elements and find differential m…
A multiwavelength study of multiple spectral component jets in AGN: testing the IC/CMB model for the large-scale-jet X-ray emission
Georganopoulos, Markos; Breiding, Peter; Meyer, Eileen T. +3 more
Over ~150 resolved, kpc-scale X-ray jets hosted by active galactic nuclei have been discovered with the Chandra X-ray Observatory. A significant fraction of these jets have an X-ray spectrum either too high in flux or too hard to be consistent with the high-energy extension of the radio-to-optical synchrotron spectrum, a subtype we identify as Mul…
A search for transit timing variations within the exomoon corridor using Kepler data
Kipping, David; Yahalomi, Daniel A.
An exomoon will produce transit timing variations (TTVs) upon the parent planet and their undersampled nature causes half of such TTVs to manifest within a frequency range of two to four cycles, irrespective of exomoon demographics. Here, we search through published Kepler TTV data for such signals, applying a battery of significance and robustnes…
Accretion process, magnetic fields, and apsidal motion in the pre-main sequence binary DQ Tau
Kochukhov, Oleg; Ábrahám, Péter; Kóspál, Ágnes +3 more
Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and forces the material to leave the disc plane and fall onto the stellar surface by following the magnetic field lines. However, this …
Measuring the ICM velocity structure in the Ophiuchus cluster
Fabian, A. C.; Pinto, C.; Eckert, D. +8 more
We have found evidence of bulk velocities following active galactic nucleus (AGN) bubbles in the Virgo cluster and galaxy motions in the Centaurus cluster. In order to increase the sample and improve our understanding of the intracluster medium (ICM), we present the results of a detailed mapping of the Ophiuchus cluster with XMM-Newton to measure …