Search Publications
Analysing the spectral energy distributions of Galactic classical Cepheids
Groenewegen, M. A. T.
Spectral energy distributions (SEDs) were constructed for a sample of 477 classical Cepheids (CCs); including stars that have been classified in the literature as such but are probably not. The SEDs were fitted with a dust radiative transfer code. Four stars showed a large mid- or far-infrared excess and the fitting then included a dust component.…
Precision angular diameters for 16 southern stars with VLTI/PIONIER
White, Timothy R.; Casagrande, Luca; Ireland, Michael J. +2 more
In the current era of Gaia and large, high signal-to-noise stellar spectroscopic surveys, there is an unmet need for a reliable library of fundamentally calibrated stellar effective temperatures based on accurate stellar diameters. Here, we present a set of precision diameters and temperatures for a sample of 6 dwarf, 5 sub-giant, and 5 giant star…
PHEBUS on Bepi-Colombo: Post-launch Update and Instrument Performance
Korablev, Oleg; Belyaev, Denis; Chaufray, Jean-Yves +14 more
The Bepi-Colombo mission was launched in October 2018, headed for Mercury. This mission is a collaboration between Europe and Japan. It is dedicated to the study of Mercury and its environment. It will be inserted into Mercury orbit in December 2025 after a 7-year long cruise. Probing of Hermean Exosphere By Ultraviolet Spectroscopy (PHEBUS) is an…
Tidal Interaction between the UX Tauri A/C Disk System Revealed by ALMA
Palau, Aina; Zapata, Luis A.; Rodríguez, Luis F. +5 more
We present sensitive and high angular-resolution (∼0"2-0"3) (sub)millimeter (230 and 345 GHz) continuum and CO(2-1)/CO(3-2) line archive observations of the disk star system in UX Tauri carried out with the Atacama Large Millimeter/Submillimeter Array. These observations reveal the gas and dusty disk surrounding the young star UX Tauri A with a la…
Gaia and Hubble Unveil the Kinematics of Stellar Populations in the Type II Globular Clusters ω Centauri and M22
Da Costa, G. S.; Milone, A. P.; Cordoni, G. +8 more
The origin of multiple stellar populations in globular clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N-body simulations suggest that the present-day dynamics of GC stars can constrain the events that occurred at high redshift and led to the formation of multiple populations. Here, we combine multiband photometry f…
Exploiting Orbital Constraints from Optical Data to Detect Binary Gamma-Ray Pulsars
Clark, C. J.; Nieder, L.; Allen, B. +1 more
It is difficult to discover pulsars via their gamma-ray emission because current instruments typically detect fewer than one photon per million rotations. This creates a significant computing challenge for isolated pulsars, where the typical parameter search space spans wide ranges in four dimensions. It is even more demanding when the pulsar is i…
Optical, X-ray, and γ-ray observations of the candidate transitional millisecond pulsar 4FGL J0427.8-6704
Dhillon, V. S.; Kerr, M.; Marsh, T. R. +7 more
We present an optical, X-ray, and γ-ray study of 1SXPS J042749.2-670434, an eclipsing X-ray binary that has an associated γ-ray counterpart, 4FGL J0427.8-6704. This association has led to the source being classified as a transitional millisecond pulsar (tMSP) in an accreting state. We analyse 10.5 yr of Fermi LAT data and detect a γ-ray eclipse at…
Dust Environment Model of the Interstellar Comet 2I/Borisov
Fulle, M.; Cremonese, G.; Lazzarin, M. +27 more
2I/Borisov is the first interstellar comet discovered on 2019 August 30, and it soon showed a coma and a dust tail. This study reports the results of images obtained at the Telescopio Nazionale Galileo telescope, on La Palma - Canary Islands, in 2019 November and December. The images have been obtained with the R filter in order to apply our dust …
Solar Flare-CME Coupling throughout Two Acceleration Phases of a Fast CME
Veronig, Astrid M.; Dumbović, Mateja; Temmer, Manuela +8 more
Solar flares and coronal mass ejections (CMEs) are closely coupled through magnetic reconnection. CMEs are usually accelerated impulsively within the low solar corona, synchronized with the impulsive flare energy release. We investigate the dynamic evolution of a fast CME and its associated X2.8 flare occurring on 2013 May 13. The CME experiences …
Direct collapse to supermassive black hole seeds: the critical conditions for suppression of H2 cooling
Fang, Taotao; Nagamine, Kentaro; Shlosman, Isaac +1 more
Observations of high-redshift quasars imply the presence of supermassive black holes (SMBHs) already at z ∼ 7.5. An appealing and promising pathway to their formation is the direct collapse scenario of a primordial gas in atomic-cooling haloes at z ∼ 10-20, when the H2 formation is inhibited by a strong background radiation field, whose…