Search Publications
The magnetic field and magnetosphere of Plaskett's star: a fundamental shift in our understanding of the system
Wade, G. A.; Neiner, C.; Alecian, E. +7 more
Plaskett's 'star' appears to be one of a small number of short-period binary systems known to contain a hot, massive, magnetic star. We combine an extensive spectropolarimetric (Stokes V) data set with archival photometry and spectropolarimetry to establish the essential characteristics of the magnetic field and magnetosphere of the rapidly rotati…
X-ray timing and spectral variability properties of blazars S5 0716 + 714, OJ 287, Mrk 501, and RBS 2070
Mohorian, Maksym; Bhatta, Gopal; Adhikari, Tek P. +6 more
The X-ray emission from blazars has been widely investigated using several space telescopes. In this work, we explored statistical properties of the X-ray variability in the blazars S5 0716+714, OJ 287, Mkn 501, and RBS 2070 using the archival observations from the XMM-Newton telescope between the period 2002-2020. Several methods of timing and sp…
Timing and spectral analysis of 2S 1417-624 during its 2018 outburst
Serim, M. M.; Şahiner, Ş.; Baykal, A. +4 more
We investigate timing and spectral characteristics of the transient X-ray pulsar 2S 1417-624 during its 2018 outburst with NICER follow up observations. We describe the spectra with high-energy cut-off and partial covering fraction absorption (PCFA) model and present flux-dependent spectral changes of the source during the 2018 outburst. Utilizing…
Sizing from the smallest scales: the mass of the Milky Way
Cooper, M. C.; Simon, J. D.; Ji, A. P. +6 more
As the Milky Way and its satellite system become more entrenched in near field cosmology efforts, the need for an accurate mass estimate of the Milky Way's dark matter halo is increasingly critical. With the second and early third data releases of stellar proper motions from Gaia, several groups calculated full 6D phase-space information for the p…
Asteroseismology of the double-radial mode δ Scuti star BP Pegasi
Daszyńska-Daszkiewicz, J.; Pamyatnykh, A. A.; Walczak, P. +1 more
Using the All-Sky Automated Survey data, we determine the pulsational frequencies of the high-amplitude δ Scuti star BP Pegasi. The analysis revealed only the two known, independent frequencies that we use to perform the seismic analysis of the star. On the basis of multicolour Strömgren photometry, we independently find that both frequencies can …
Globular Cluster UVIT Legacy Survey (GlobULeS) - I. FUV-optical colour-magnitude diagrams for eight globular clusters
Dalessandro, Emanuele; Hutchings, John; Stetson, Peter B. +22 more
We present the first results of eight globular clusters (GCs) from the AstroSat/UVIT Legacy Survey programme GlobULeS based on the observations carried out in two far-ultraviolet (FUV) filters (F148W and F169M). The FUV-optical and FUV-FUV colour-magnitude diagrams (CMDs) of GCs with the proper motion membership were constructed by combining the U…
Candidate isolated neutron stars in the 4XMM-DR10 catalogue of X-ray sources
Mereghetti, Sandro; Rigoselli, Michela; Tresoldi, Caterina
Most isolated neutron stars have been discovered thanks to the detection of their pulsed non-thermal emission, at wavelengths spanning from radio to gamma-rays. However, if the beamed non-thermal radiation does not intercept our line of sight or it is too faint or absent, isolated neutron stars can also be detected through their thermal emission, …
Multicomponent DHOST analysis in galaxy clusters
Umetsu, Keiichi; Salzano, Vincenzo; Laudato, Enrico
Extended theories of gravity with additional scalar degrees of freedom have recently acquired increasing interest due to the presence of a screening mechanism that allows suppressing at small scales (e.g. the Solar system scale) every modification restoring general relativity (GR). In this work, we consider a second-order extended theory of gravit…
7Be in the outburst of the ONe nova V6595 Sgr
Bonifacio, P.; Hernanz, M.; D'Odorico, V. +7 more
We report on the search for the 7Be II isotope in the outbursts of the classical nova V6595 Sgr by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations taken at the European Southern Observatory's Very Large Telescope in 2021 April, about two weeks after its discovery and under difficult circumstances…
The formation of the Milky Way halo and its dwarf satellites: A NLTE-1D abundance analysis. V. The Sextans galaxy
Jablonka, P.; Yakovleva, S. A.; Belyaev, A. K. +3 more
We present a homogeneous set of accurate atmospheric parameters for a sample of eleven very metal-poor (-3.32 ≤ [Fe/H] ≤-2.61) stars in the Sextans dwarf spheroidal galaxy (dSph) and the non-local thermodynamic equilibrium (NLTE) abundances of, at least, seven chemical elements based on high-resolution UVES/VLT and HDS/Subaru spectra. For each sta…