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Simultaneous detection of an intrinsic absorber and a compact jet emission in the X-ray binary IGR J17091-3624 during a hard accretion state
Díaz Trigo, M.; Miller-Jones, J. C. A.; Migliari, S. +1 more
We present a detailed analysis of three XMM-Newton observations of the black hole low-mass X-ray binary IGR J17091-3624 taken during its 2016 outburst. Radio observations obtained with the Australia Telescope Compact Array indicate the presence of a compact jet during all observations. From the best X-ray data fit results, we concluded that the ob…
X-ray variability analysis of a large series of XMM-Newton +NuSTAR observations of NGC 3227
Turner, T. J.; Reeves, J. N.; Braito, V. +2 more
We present a series of X-ray variability results from a long XMM-Newton + NuSTAR campaign on the bright, variable AGN NGC 3227. We present an analysis of the light curves, showing that the source displays typically softer-when-brighter behaviour, although also undergoes significant spectral hardening during one observation which we interpret as du…
Realistic gravitational focusing of meteoroid streams
Vida, Denis; Moorhead, Althea V.; Clements, Tiffany D.
The number density and flux of a meteoroid stream is enhanced near a massive body due to the phenomenon known as gravitational focusing. The greatest enhancement occurs directly opposite the massive body from the stream radiant: as an observer approaches this location, the degree of focusing is unbound for a perfectly collimated stream. However, r…
First discovery of an ultra-cool white dwarf benchmark in common proper motion with an M dwarf
Hambly, N. C.; Harvey, E. J.; Lodieu, N. +5 more
Ultra-cool white dwarfs are among the oldest stellar remnants in the Universe. Their efficient gravitational settling and low effective temperatures are responsible for the smooth spectra they exhibit. For that reason, it is not possible to derive their radial velocities or to find the chemistry of the progenitors. The best that can be done is to …
Forward modelling the multiwavelength properties of active galactic nuclei: application to X-ray and WISE mid-infrared samples
Ruiz, Angel; Georgakakis, Antonis; LaMassa, Stephanie M.
An empirical forward-modelling framework is developed to interpret the multiwavelength properties of active galactic nuclei (AGNs) and provide insights into the overlap and incompleteness of samples selected at different parts of the electromagnetic spectrum. The core of the model are observationally derived probabilites on the occupation of galax…
The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition
Zhang, S. N.; Dai, Z. G.; Ge, M. Y. +6 more
In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n o…
The nature of the photometric variability of HgMn stars: a test of simulated light curves of φ Phe against the TESS data
Krtička, Jiří; Korhonen, Heidi; Prvák, Milan
The inhomogeneous surface distribution of heavy elements is known to cause periodic light variability of magnetic chemically peculiar stars. It is unclear to what extent the same paradigm applies to mercury-manganese (HgMn) stars. We aim to model the photometric variability of the HgMn star φ Phe using abundance maps obtained from high-resolution …
Searching for globular cluster chemical anomalies on the main sequence of a young massive cluster
Martocchia, S.; Dalessandro, E.; Salaris, M. +9 more
The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass, and age. Understanding this behaviour could bring us closer to the origin of these intriguing abundance spreads. In this work we use deep HST photometry to …
Validation of PSF models for HST and other space-based observations
Schrabback, Tim; Massey, Richard; Rhodes, Jason +4 more
Forthcoming space-based observations will require high-quality point spread function (PSF) models for weak gravitational lensing measurements. One approach to generating these models is using a wavefront model based on the known telescope optics. We present an empirical framework for validating such models to confirm that they match the actual PSF…
Soft X-ray emission lines in the X-ray binary Swift J1858.6-0814 observed with XMM-Newton Reflection Grating Spectrometer: disc atmosphere or wind?
Díaz Trigo, M.; Altamirano, D.; Knigge, C. +11 more
We find soft X-ray emission lines from the X-ray binary Swift J1858.6-0814 in data from XMM-NewtonReflection Grating Spectrometer (RGS): N VII, O VII, and O VIII, as well as notable residuals short of a detection at Ne IX and other higher ionization transitions. These could be associated with the disc atmosphere, as in accretion disc corona source…