Search Publications
A search for transiting planets around hot subdwarfs. II. Supplementary methods and results from TESS Cycle 1
Van Grootel, V.; Charpinet, S.; Siess, L. +3 more
Context. Hot subdwarfs, which are hot and small He-burning objects, are ideal targets for exploring the evolution of planetary systems after the red giant branch (RGB). Thus far, no planets have been confirmed around them, and no systematic survey to find planets has been carried out.
Aims: In this project, we aim to perform a systematic tran…
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 …
Dust Emission as a Function of Stellar Population Age in the Nearby Galaxy M33
Calzetti, Daniela; Lin, Zesen; Mallory, Kate
Dust emission at 8 µm has been extensively calibrated as an indicator of current star formation rate for galaxies and ~kpc-size regions within galaxies. Yet, the exact link between the 8 µm emission and the young stellar populations in galaxies is still under question, as dust grains can be stochastically heated also by older field sta…
Testing the Cosmological Principle: Astrometric Limits on Systemic Motion of Quasars at Different Cosmological Epochs
Secrest, Nathan J.; Makarov, Valeri V.
A sample of 60,410 bona fide optical quasars with astrometric proper motions in Gaia Early Data Release 3 and spectroscopic redshifts above 0.5 in an oval 8400 square degree area of the sky is constructed. Using orthogonal Zernike functions of polar coordinates, the proper motion fields are fitted in a weighted least-squares adjustment of the enti…
H-band Light Curves of Milky Way Cepheids via Difference Imaging
Jones, David O.; Riess, Adam G.; Yuan, Wenlong +4 more
We present H-band light curves of Milky Way classical Cepheids observed as part of the Dark Energy, H 0, and peculiar Velocities using Infrared Light from Supernovae survey with the Wide-Field Infrared Camera on the United Kingdom Infrared Telescope. Due to the crowded nature of these fields caused by defocusing the Camera, we performed…
Alleviating the transit timing variation bias in transit surveys. II. RIVERS: Twin resonant Earth-sized planets around Kepler-1972 recovered from a Kepler false positive
Eggenberger, P.; Delisle, J. -B.; Alibert, Y. +4 more
Transit timing variations (TTVs) can provide useful information for systems observed in this way, putting constraints on the masses and eccentricities of the observed planets, and in some cases even revealing the existence of non-transiting companions. However, TTVs can also prevent the detection of small planets in transit surveys, or bias the re…
XMM-Newton and NuSTAR Observations of the Compact Millisecond Pulsar Binary PSR J1653-0158
Wu, Kinwah; Kong, Albert K. H.; Takata, Jumpei +4 more
We have presented the first joint XMM-Newton and NuSTAR analysis of the millisecond pulsar (MSP) binary PSR J1653-0158. The 75 minute orbital period inferred from optical and gamma-ray observations together with the 1.97 ms pulsation in the gamma-rays indicate that this system is the most compact Black Widow MSP system known to date. The orbital p…
Chemical weathering over hundreds of millions of years of greenhouse conditions on Mars
Michalski, Joseph R.; Ye, Binlong
Chemical weathering profiles on Mars which consist of an upper Al clay-rich, Fe-poor layer and lower Fe/Mg clay-rich layer are believed to have formed due to precipitation-driven top down leaching process in an ancient, reducing greenhouse climate. Here we use remote sensing imagery and spectroscopy coupled with topographic data and crater chronol…
FARWEST: Efficient Computation of Wave-Particle Interactions for a Dynamic Description of the Electron Radiation Belt Diffusion
Darrouzet, Fabien; Santolik, Ondrej; Pierrard, Viviane +5 more
In this paper, we present a new method to compute rapidly, wave particle interaction induced pitch angle and momentum diffusion coefficients. Those terms are normally obtained by the numerical solving of equations based on the quasi-linear theory. However, this bulk resolution leads to a high computational cost, preventing the integration of plasm…
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…