Search Publications
Ionization state of the accretion disc in the neutron star low-mass X-ray binary 4U 1728-34
Méndez, Mariano; Xiang, Fu-Yuan; Lyu, Ming +1 more
We analysed an XMM-Newton plus a simultaneous Rossi X-ray Timing Explorer observation and a separate Suzaku observation of the neutron star low-mass X-ray binary 4U 1728-34. We fitted the X-ray spectra with the self-consistent reflection model RELXILL. We found that the inclination angle of 4U 1728-34 is 49 ± 5 degree, consistent with the upper li…
Swift, NuStar, and XMM-Newton observations of the NLS1 galaxy RX J2317.8-4422 in an extreme X-ray low flux state
Fabian, Andrew C.; Komossa, S.; Miniutti, Giovanni +6 more
We report the discovery of RX J2317.8-4422 in an extremely low X-ray flux state by the Neil Gehrels Swift observatory in 2014 April/May. In total, the low-energy X-ray emission dropped by a factor of 100. We have carried out multiwavelength follow-up observations of this narrow-line Seyfert 1 galaxy. Here we present observations with Swift, XMM-Ne…
Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy
Barmby, P.; Maccarone, T. J.; Bahramian, A. +2 more
We present an unprecedented, deep study of the primordial low-mass X-ray binary population in an isolated, lower metallicity environment. We perform follow-up observations of previously identified X-ray binary candidates in the Sculptor Dwarf Galaxy by combining a second Chandra observation with Spitzer and Gemini photometry, as well as Gemini spe…
Characteristics of solar wind rotation
Li, K. J.; Feng, W.
Over 54 yr of hourly mean value of solar wind velocity from 1963 November 27 to 2017 December 31 are used to investigate characteristics of the rotation period of solar wind through autocorrelation analysis. Solar wind of high velocity is found to rotate faster than low-velocity wind, while its rotation rate increases with increasing velocity, but…
The evolving X-ray spectrum of active galactic nuclei: Evidence for an increasing reflection fraction with redshift
Ballantyne, D. R.; Avirett-Mackenzie, M. S.
The cosmic X-ray background (XRB) spectrum and active galaxy number counts encode essential information about the spectral evolution of active galactic nuclei (AGNs) and have been successfully modelled by XRB synthesis models for many years. Recent measurements of the 8-24 keV AGN number counts by NuSTAR and Swift-BAT are unable to be simultaneous…
Explaining the asymmetric line profile in Cepheus X-4 with spectral variation across pulse phase
Fürst, Felix; Pottschmidt, Katja; Ballhausen, Ralf +4 more
The high mass X-ray binary Cepheus X-4, during its 2014 outburst, showed evidence for an asymmetric cyclotron line in its hard X-ray spectrum. The 2014 spectrum provides one of the clearest cases of an asymmetric line profile among all studied sources with Cyclotron Resonance Scattering Features (CRSF). We present a phase-resolved analysis of NuST…
Erratum: MHD simulation of the solar wind flow around the coma of comet Churyumov-Gerasimenko during Rosetta's flyby
Baranov, V. B.; Alexashov, D. B.; Lebedev, M. G.
On the saturation of acoustic mode frequencies at high solar activity
Rabello Soares, M. Cristina
Acoustic mode frequencies obtained by applying spherical harmonic decomposition to HMI, MDI, and GONG observations were analysed throughout the solar cycle. Evidence of a deviation from a linear relation with solar radio flux was found indicating a saturation effect at high solar activity. The Gompertz model, which is one of the most frequently us…
Search for exoplanetary transits in the Galactic bulge
Minniti, D.; Villanova, S.; Cortés, C. C.
A search for extrasolar planetary transits using extended Kepler mission (K2) campaigns 9 and 11 revealed five new candidates towards the Galactic bulge. The stars EPIC 224439122, 224560837, 227560005, 230778501 and 231635524 are found to have low-amplitude transits consistent with extrasolar planets, with periods P = 35.1695, 3.6390, 12.4224, 17.…
Molecular clumps towards compact H II regions
Gómez, M.; Rubio, M.; Cappa, C. E. +1 more
To better understand how the H II regions can affect their surrounding molecular clouds we have studied the molecular distribution towards three compact H II regions associated with IRAS sources (08140-3559, 09014-4736, and 09026-4842) by means of the observations of 12CO, 13CO, and C18O molecules in the J = 3-2 tr…