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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 …
Observations of multiple NH3 transitions in W33
Immer, K.; Henkel, C.; Wilson, T. L. +10 more
At a distance of 2.4 kpc, W33 is an outstanding massive and luminous 10 pc-sized star forming complex containing quiescent infrared dark clouds as well as highly active infrared bright cloud cores heated by young massive stars. We report measurements of ammonia (NH3) inversion lines in the frequency range 18-26 GHz obtained with the 40"…
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…
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…