Search Publications
The puzzling story of flare inactive ultra fast rotating M dwarfs. II. Searching for radial velocity variations
Ramsay, Gavin; Hakala, Pasi; Doyle, Lauren +2 more
Observations made using TESS revealed a sample of low-mass stars which show a periodic modulation on a period <0.2 d. Surprisingly, many of these ultra fast rotating (UFR) stars showed no evidence of flare activity which would be expected from such rapidly rotating stars. We present results from a spectroscopic survey of UFRs using the Nordic O…
A list of 49 new stellar twins from the Kepler catalogue of eclipsing binary stars
Bakış, Volkan; Yücel, Gökhan
49 new eclipsing twin binary candidates are identified and analysed based on the Kepler eclipsing binary light curves. Their colours and spectral types are calculated according to our classification. A comparison of the spectral type distribution of eclipsing twin binary systems showed that F-type twins dominate among others, which agrees well wit…
Photometric and spectroscopic study of the burst-like brightening of two Gaia-alerted young stellar objects
Moór, Attila; Ábrahám, Péter; Kóspál, Ágnes +18 more
Young stars show variability on different time-scales from hours to decades, with a range of amplitudes. We studied two young stars, which triggered the Gaia Science Alerts system due to brightenings on a time-scale of a year. Gaia20bwa brightened by about half a magnitude, whereas Gaia20fgx brightened by about two and half magnitudes. We analysed…
Decoding NGC 628 with radiative transfer methods
Popescu, C. C.; Pricopi, D.; Natale, G. +2 more
We present an axi-symmetric model for the ultraviolet (UV)-to-submillimetre (submm) images of the nearly face-on spiral galaxy NGC 628. It was calculated using a radiative transfer (RT) code, accounting for the absorption and re-emission of starlight by dust in the interstellar medium of this galaxy. The code incorporates emission from Polycyclic …
The rotation of planet-hosting stars
Feldmann, Robert; Helled, Ravit; Sibony, Yves
Understanding the distribution of angular momentum during the formation of planetary systems is a key topic in astrophysics. Data from the Kepler and Gaia missions allow to investigate whether stellar rotation is correlated with the presence of planets around Sun-like stars. Here, we perform a statistical analysis of the rotation period of 493 pla…
Monitoring observations of SMC X-1's excursions (MOOSE)-I. Programme description and initial high state spectral results
Clarkson, William I.; Dage, Kristen C.; Bahramian, Arash +8 more
SMC X-1 has exhibited three superorbital period excursions since the onset of X-ray monitoring beginning with the Rossi X-ray Timing Explorer's launch in 1995. TheNeutron star Interior Composition Explorer has recently probed a fourth observed excursion beginning in 2021 with our programme monitoring observations of SMC X-1's excursions (MOOSE). T…
A detailed star formation history for the extremely diffuse Andromeda XIX dwarf galaxy
Williams, Benjamin F.; Gilbert, Karoline M.; Dolphin, Andrew +3 more
We present deep imaging of the ultradiffuse Andromeda XIX dwarf galaxy from the Advance Camera for Surveys on the Hubble Space Telescope which resolves its stellar populations to below the oldest main-sequence turn-off. We derive a full star formation history for the galaxy using MATCH, and find no evidence of star formation in the past 8 Gyr. We …
XMM-Newton discovery of very high obscuration in the candidate supergiant fast X-ray transient AX J1714.1-3912
Sidoli, L.; Esposito, P.; Polletta, M. +2 more
We have analysed an archival XMM-Newton EPIC observation that serendipitously covered the sky position of a variable X-ray source AX J1714.1-3912, previously suggested to be a supergiant fast X-ray transient (SFXT). During the XMM-Newton observation the source is variable on a time-scale of hundred seconds and shows two luminosity states, with a f…
Forward and back: kinematics of the Palomar 5 tidal tails
Bernard, E. J.; Tolstoy, E.; Ferguson, A. M. N. +5 more
The tidal tails of Palomar 5 (Pal 5) have been the focus of many spectroscopic studies in an attempt to identify individual stars lying along the stream and characterize their kinematics. The well-studied trailing tail has been explored out to a distance of 15○ from the cluster centre, while less than 4° have been examined along the lea…
Spitzer and Herschel studies of dust in supernova remnants in the Small Magellanic Cloud
Filipović, M. D.; Matsuura, Mikako; Barlow, M. J. +6 more
With the entire Small Magellanic Cloud (SMC) mapped by the Spitzer Space Telescope and Herschel Space Observatory, we were able to search 8-250 $\mu$m images in order to identify infrared (IR) emission associated with SMC supernova remnants (SNRs). A valid detection had to correspond with known X-ray, H α, and radio emission from the SNRs. From th…