White dwarfs are compact stars, similar in size to Earth but approximately 200,000 times more massive. Isolated white dwarfs emit most of their power from...
A rapid optical and X-ray timing study of the neutron star X-ray binary Swift J1858.6-0814
We present a rapid timing analysis of optical (HiPERCAM and ULTRACAM) and X-ray (NICER) observations of the X-ray transient Swift J1858.6-0814 during 2018 and...
A reappraisal of the chemical composition of the Orion nebula based on Very Large Telescope echelle spectrophotometry
We present Very Large Telescope (VLT) UVES echelle spectrophotometry of the Orion nebula in the 3100-10400 Årange. We have measured the intensity of 555...
An accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local...
A recurrent nova super-remnant in the Andromeda galaxy
The accretion of hydrogen onto a white dwarf star ignites a classical nova eruption1,2—a thermonuclear runaway in the accumulated envelope of gas, leading to...
A Reemerging Bright Soft X-Ray State of the Changing-look Active Galactic Nucleus 1ES 1927+654: A Multiwavelength View
1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability...
A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664
Context. The observational mass-radius relation of main sequence stars with masses between 0.3 and 1.0 M⊙ reveals deviations between the stellar radii predicted...
A refined dynamical mass for the black hole in the X-ray transient XTE J1859+226
We present two contiguous nights of simultaneous time-resolved Gran Telescopio Canarias spectroscopy and William Herschel Telescope photometry of the black hole...
A refined sub-grid model for black hole accretion and AGN feedback in large cosmological simulations
In large-scale cosmological hydrodynamic simulations simplified sub-grid models for gas accretion on to black holes and AGN feedback are commonly used. Such...