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The Role of XMM–Newton in the Investigation of Persistent BeXRBs

Mereghetti, Sandro; Esposito, Paolo; Israel, Gian Luca +2 more

The persistent BeXRBs are a class of high-mass X-ray binaries (HMXRBs), which are characterized by persistent low X-ray luminosities ($$ {L}_{\mathrm{X}}\sim {10}^{34} $$ erg s$$ {}^{-1} $$) and wide ($$ {P}_{\mathrm{orb}}> $$ 30 days), almost circular orbits. In these sources the NS is slowly rotating (with $$ {P}_{\mathrm{spin}} $$ well above…

Beyond Accretion Limits: The Rise of Pulsating Gems

Wolter, Anna; Pintore, Fabio; Esposito, Paolo +23 more

The discovery of several ultraluminous X-ray sources exhibiting fast and rapidly evolving X-ray pulsations unequivocally associates these sources with accreting neutron stars orbiting relatively massive companion stars (> 8M$$ {}_{\odot } $$). Among these ULXs, the brightest pulsating ULX (PULX), NGC 5907 ULX-1, displays a peak luminosity (~2 ×…

Detection of Eclipses in the Cataclysmic Variable LAMOST J035913.61 + 405035.0

Kozhevnikov, V. P.

I conducted photometric observations of the cataclysmic variable LAMOST J035913.61 + 405035.0 and detected eclipses. During these observations, I recorded 14 eclipses over two groups of nights separated by 13 months. I accurately determined the orbital period of the system to be $$ {P}_{\mathrm{orb}}=0.228\kern0.1em 343\kern0.1em 85\pm 0.000\kern0…

XMM-Newton Observations of the Peculiar Be X-Ray Binary A0538-66

Mereghetti, Sandro; Rigoselli, Michela; Ducci, Lorenzo +1 more

A0538-66 is a neutron star/Be x-ray binary located in the Large Magellanic Cloud and, since its discovery in the 70s, it showed a peculiar behavior that makes it a unique object in the high-mass x-ray binaries scene: the extremely eccentric orbit ($$ e=0.72 $$), the short spin period of the neutron star ($$ P=69 $$ ms), the episodes of super-Eddin…

INTEGRAL Observations of Magnetars

Mereghetti, Sandro; Ducci, Lorenzo; Pacholski, Dominik Patryk +1 more

The INTEGRAL satellite has collected a large amount of data on magnetars in our Galaxy, spanning more than 20 years starting from 2003. The large data set obtained with the IBIS/ISGRI instrument at energies above 20 keV allows us to study both the properties and long-term evolution of their persistent hard X-ray emission and the population charact…

Modeling the Emission and Polarization Properties of Pulsating Ultraluminous X-Ray Sources

Israel, G. L.; Turolla, R.; Pintore, F. +4 more

Pulsating Ultraluminous X-ray Sources (PULXs) are a class of extragalactic sources with high X-ray luminosity, in excess of $$ {10}^{39} $$ erg $$ {\mathrm{s}}^{-1} $$, and showing pulsations that associate them with neutron stars accreting at a super-Eddington rate. A simplified model is presented, which describes the thermal emission from an acc…

Editor's Note: The X-Ray Mysteries of Neutron Stars and White Dwarfs

Schartel, Norbert

Revisiting Variable Stars Near Globular Clusters South of ‑29° Declination

Layden, Andrew C.; Evangelista, Julia; Gupta, Sakshi +5 more

We review an often-cited but seldom-accessed catalogue by Fourcade and Laborde (1966) of 785 variable stars near 47 southern Galactic globular clusters, and recover the locations of 85 stars that were not incorporated into subsequent variable star catalogues and hence have become "lost" to the literature. We match the positions of these stars with…

The Surprising Long-Term Evolution of the ULXP NGC 7793 P13

Fürst, Felix; Walton, Dominic J.; Brightman, Murray +2 more

The ultra-luminous x-ray pulsar (ULXP) NGC 7793 P13 has been regularly monitored with XMM-Newton, NuSTAR, and Swift for the last 8 years. Here, we present the latest results of this monitoring campaign with respect to the pulse period evolution and spectral variability. We find that since the source recovered from an x-ray low state in 2020–2022 t…

The HST Large Programme on NGC 6752 - V. Differences in luminosity and mass function among stellar populations

Vesperini, Enrico; Anderson, Jay; Salaris, Maurizio +8 more

We exploit the astro-photometric dataset of the multi-epoch infrared parallel field of a Hubble Space Telescope Large Programme aimed at studying the faintest stars of the globular cluster NGC 6752 to determine the luminosity and mass functions of the multiple stellar populations of this cluster. Thanks to the measurement of proper motions and dee…