Search Publications
Accretion of a clumped wind from a red supergiant donor on to a magnetar is suggested by the analysis of the XMM-Newton and NuSTAR observations of the X-ray binary 3A 1954+319
Ducci, L.; Ferrigno, C.; Bozzo, E. +1 more
3A 1954+319 has been classified for a long time as a symbiotic X-ray binary, hosting a slowly rotating neutron star and an aged M red giant. Recently, this classification has been revised thanks to the discovery that the donor star is an M supergiant. This makes 3A 1954+319 a rare type of high-mass X-ray binary consisting of a neutron star and a r…
A 6D view of stellar shells
Evans, N. W.; Vasiliev, E.; Dong-Páez, C. A.
Stellar shells are low surface brightness features, created during nearly head-on galaxy mergers from the debris of the tidally disrupted satellite. Here, we investigate the formation and evolution mechanism of shells in six dimensions (3D positions and velocities). We propose a new description in action-angle coordinates which condenses the seemi…
Differences in star formation activity between tidally triggered and isolated bars: a case study of NGC 4303 and NGC 3627
Okamoto, Takashi; Pettitt, Alex R.; Iles, Elizabeth J.
Galactic bars are important drivers of galactic evolution, and yet how they impact the interstellar medium and correspondingly star formation, remains unclear. We present simulation results for two barred galaxies with different formation mechanisms, bars formed in isolation or via a tidal interaction, to consider the spatially and temporally vary…
A Roche lobe-filling hot subdwarf and white dwarf binary: possible detection of an ejected common envelope
Wang, Luqian; Han, Zhanwen; Chen, Xuefei +12 more
Binaries consisting of a hot subdwarf star and an accreting white dwarf (WD) are sources of gravitational wave radiation at low frequencies and possible progenitors of Type Ia supernovae if the WD mass is large enough. Here, we report the discovery of the third binary known of this kind: It consists of a hot subdwarf O (sdO) star and a WD with an …
A chemical map of the outbursting V883 Ori system: vertical and radial structures
Kastner, J. H.; Williams, J. P.; Cieza, L. +3 more
We present the first results of a pilot program to conduct an Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 (211-275 GHz) spectral line study of young stellar objects (YSOs) that are undergoing rapid accretion episodes, i.e. FU Ori objects (FUors). Here, we report on molecular emission line observations of the FUor system, V883 Ori. I…
Hard X-ray luminosity functions of cataclysmic variables: joint Swift/BAT and Gaia data
Doroshenko, Victor; Suleimanov, Valery F.; Werner, Klaus
Cataclysmic variables (CVs) are the most numerous population among the Galactic objects emitting in hard X-rays. Most probably, they are responsible for the extended hard X-ray emission of the Galactic ridge and the central Galactic regions. Here, we consider the sample of CVs detected in the all-sky hard X-ray Swift/BAT survey, which were also de…
Eclipse mapping of EXO 0748-676: evidence for a massive neutron star
Ingram, Adam; Middleton, Matthew; Knight, Amy H. +1 more
Determining the maximum possible neutron star (NS) mass places limits on the equation of state (EoS) of ultra-dense matter. The mass of NSs in low-mass X-ray binaries can be determined from the binary mass function, providing independent constraints are placed on both the binary inclination and mass ratio. In eclipsing systems, they relate via the…
A new look at the frequency-dependent damping of slow-mode waves in the solar corona
Nakariakov, Valery M.; Kolotkov, Dmitrii Y.
Being directly observed in the Doppler shift and imaging data and indirectly as quasi-periodic pulsations in solar and stellar flares, slow magnetoacoustic waves offer an important seismological tool for probing many vital parameters of the coronal plasma. A recently understood active nature of the solar corona for magnetoacoustic waves, manifeste…
OGLE-2018-BLG-0799Lb: a q 2.7 × 10-3 planet with Spitzer parallax
Maoz, Dan; Han, Cheongho; Udalski, Andrzej +73 more
We report the discovery and analysis of a planet in the microlensing event OGLE-2018-BLG-0799. The planetary signal was observed by several ground-based telescopes, and the planet-host mass ratio is q = (2.65 ± 0.16) × 10-3. The ground-based observations yield a constraint on the angular Einstein radius θE, and the microlensi…
Mass segregation in the hyades cluster
Evans, N. Wyn; Oh, Semyeong
Using the Gaia colour-magnitude diagram, we assign masses to a catalogue of 979 confirmed members of the Hyades cluster and tails. By fitting the cumulative mass profile, stars within the tidal radius have a Plummer-like profile with half-mass radius rh of 5.75 pc. The tails are extended with rh = 69.35 pc and fall off more s…