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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 ×…

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…

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

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…

Winds in ultraluminous X‑ray sources: New challenges

Pinto, C.; Kosec, P.

Ultraluminous X‑ray sources (ULXs) are extreme X‑ray binaries shining above 1039 erg/s, in most cases as a consequence of super‑Eddington accretion onto neutron stars and stellar‑mass black holes accreting above their Eddington limit. This was understood after the discovery of coherent pulsations, cyclotron lines, and powerful winds. The latter wa…

XMM2ATHENA, the H2020 project to improve XMM‑Newton analysis software and prepare for Athena

Ballet, Jean; Pouliasis, Ektoras; Maggi, Pierre +31 more

XMM‑Newton, a European Space Agency observatory, has been observing the X‑ray, ultra‑violet, and optical sky for 23 years. During this time, astronomy has evolved from mainly studying single sources to populations and from a single wavelength, to multi‑wavelength/messenger data. We are also moving into an era of time domain astronomy. New software…

The hyperluminous X‑ray source population

Roberts, T. P.; Walton, D. J.; MacKenzie, A. D. A.

We have recently published a catalog of 1843 candidate ultraluminous X‑ray sources (ULXs). This is the largest catalog of ULXs to date and was built by cross‑correlating recent serendipitous source catalogs from the XMM‑Newton, Swift, and Chandra observatories with a large sample of galaxies, primarily from HyperLEDA. The catalog contains 71 hyper…

Tidal disruption events and quasi‑periodic eruptions

Lin, Dacheng; Godet, Olivier; Webb, Natalie A. +4 more

Tidal disruption events (TDEs) occur when a star passes close to a massive black hole so that the tidal forces of the black hole exceed the binding energy of a star and cause it to be ripped apart. Part of the matter will fall onto the black hole, causing a strong increase in luminosity. Such events are often seen in the optical or the x‑ray (or b…

A novel "spectral‑ratio model fitting" to resolve complicated X‑ray spectral variations in active galactic nuclei

Ebisawa, Ken; Mizumoto, Misaki; Midooka, Takuya

Radiation‑magnetohydrodynamic simulation of the active galactic nuclei predicts the presence of the strong accretion disk wind, which gets unstable far from the central region and turns into gas clumps. These inner wind and outer clumps may be actually observed as the ultrafast outflows (UFOs) and the clumpy absorbers, respectively. We call this p…