Search Publications
An extreme ultraluminous X-ray source X-1 in NGC 5055
Mondal, Samaresh; De Marco, Barbara; Różańska, Agata +1 more
Aims: We analysed multi-epoch X-ray data of the ultraluminous X-ray source NGC 5055 X-1, with luminosity up to 2.32 × 1040 erg s-1, to constrain the physical parameters of the source.
Methods: We performed a timing and spectral analysis of Chandra and XMM-Newton observations. We used spectral models that assume the …
Unusually low density regions in the compressed slow wind: Solar wind transients of small coronal hole origin
Farrugia, Charles J.; Wang, Linghua; Fu, Hui +5 more
We report on two small solar wind transients embedded in the corotating interaction region, characterized by surprisingly lower proton density compared with their surrounding regions. In addition to lower density, these two small solar wind transients showed other interesting features like higher proton temperature, higher alpha-proton ratios, and…
The Wind beneath My Wings. I. Spectral Types and Multiplicity of the Central Stars Supporting Stellar Bow Shock Nebulae
Kobulnicky, Henry A.; Dixon, Don M.; Schurhammer, Danielle P. +9 more
Arcuate mid-infrared nebulae known as stellar bow shock nebulae (SBNe) have been previously hypothesized to be supported by the strong stellar winds and/or luminosity of massive early-type stars. We present an optical spectroscopic survey of 84 stars identified from mid-infrared images as candidate SBN-supporting stars. Eighty-one of 84 sources, 9…
XMM-Newton and NICER Measurement of the Rms Spectrum of the Millihertz Quasiperiodic Oscillations in the Neutron-star Low-mass X-Ray Binary 4U 1636-53
Altamirano, D.; Méndez, Mariano; Zhang, Guobao +4 more
We used two XMM-Newton and six Neutron Star Interior Composition Explorer observations to investigate the fractional rms amplitude of the millihertz quasiperiodic oscillations (mHz QPOs) in the neutron-star low-mass X-ray binary 4U 1636-53. We studied, for the first time, the fractional rms amplitude of the mHz QPOs versus energy in 4U 1636-53 dow…
Search for the optical counterpart of the GW170814 gravitational wave event with the VLT Survey Telescope
Covino, S.; Campana, S.; Della Valle, M. +30 more
We report on the search for the optical counterpart of the gravitational event GW170814, which was carried out with the VLT Survey Telescope (VST) by the GRAvitational Wave Inaf TeAm. Observations started 17.5 h after the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo alert and we covered an area of 99 deg2 that en…
Evolving pulsation of the slowly rotating magnetic β Cep star ξ1 CMa
Handler, G.; Wade, G. A.; Pigulski, A. +11 more
Recent BRITE-Constellation space photometry of the slowly rotating, magnetic β Cep pulsator ξ1 CMa permits a new analysis of its pulsation properties. Analysis of the two-colour BRITE data reveals the well-known single pulsation period of 0.209 d, along with its first and second harmonics. A similar analysis of SMEI and TESS observation…
Disturbed Flows in the Inner Solar Wind and Near Earth's Orbit
Pätzold, M.; Bird, M. K.; Efimov, A. I. +3 more
Coronal mass ejections from active regions on the Sun can be observed as series of individual events separated in time in the inner solar wind and near-Earth plasma. To find such events we have analyzed experimental data of dual-frequency solar wind radio sounding by the Rosetta and Mars Express spacecraft. The cycles of experiments performed in 2…
A white dwarf bound to the transiting planetary system WASP-98
Gänsicke, Boris T.; Močnik, Teo; Tremblay, Pier-Emmanuel +2 more
WASP-98 is a planetary system containing a hot Jupiter transiting a late-G dwarf. A fainter star, 12 arcsec away, has previously been identified as a white dwarf, with a distance and proper motion consistent with a physical association with the planetary system. We present spectroscopy of the white dwarf, with the aim of determining its mass, radi…
A search for pulsars in subdwarf B binary systems and discovery of giant-pulse emitting PSR J0533-4524
Ishwara-Chandra, C. H.; van Leeuwen, J.; Coenen, T. +2 more
Binary millisecond pulsars (MSPs) provide several opportunities for research of fundamental physics. However, finding them can be challenging. Several subdwarf B (sdB) binary systems with possible neutron star companions have been identified, allowing us to perform a targeted search for MSPs within these systems. Six sdBs with companions in the ne…
Simple, compact, high-resolution monochromatic x-ray source for characterization of x-ray calorimeter arrays
Eckart, M. E.; Kilbourne, C. A.; Leutenegger, M. A. +6 more
X-ray calorimeters routinely achieve very high spectral resolution, typically a few eV full width at half maximum (FWHM). Measurements of calorimeter line shapes are usually dominated by the natural linewidth of most laboratory calibration sources. This compounds the data acquisition time necessary to statistically sample the instrumental line bro…