Search Publications
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…
Quasi‑periodic oscillations are more than timing features: Applying the accretion‑ejection instability in super massive black‑holes
Varniere, Peggy
Low frequency quasi‑periodic oscillations (LFQPOs) have always been seen uniquely as a timing feature, with most models focused on reproducing only their timing behavior. Previously, the accretion‑ejection instability (AEI) predicted the existence of a more subtle effect on their energy spectrum. In the case of low mass X‑ray binaries (LMXB), that…
Soft excess in AGN with relativistic X‑ray reflection
Mathew, Blesson; Dewangan, Gulab C.; Ezhikode, Savithri H. +1 more
The soft X‑ray excess, emission below 2 keV over the X‑ray power‑law, is a marked spectral component in the X‑ray spectra of many Seyfert 1 galaxies. We investigate if the observed soft X‑ray excess in a sample of Seyfert 1s is in accordance with the prediction of the relativistic reflection model by analyzing the XMM‑Newton and NuSTAR spectra. Th…
Possible optical counterparts of ULXs in NGC 1672
Sonbas, Eda; Allak, Sinan; Akyuz, Aysun +1 more
In this study, we use archival data from Hubble Space Telescope (HST), Chandra, XMM‑Newton, and Swift‑XRT, to probe the nature of 9 (X1‑X9) candidate ultraluminous X‑ray sources (ULXs) in NGC 1672. Our study focuses on using the precise source positions obtained via improved astrometry based on Chandra and HST observations to search for and identi…
Searching for overlooked TDEs in the 4XMM catalogue
Risaliti, Guido; Sacchi, Andrea; Miniutti, Giovanni
Tidal disruption events (TDEs) are usually discovered as bright transients, either in the X‑ray or optical/UV band. These events are often characterized by a "super‑soft" emission in the X‑ray band, which has not been observed in any other extragalactic source, with few exceptions (novae and supersoft active galactic nuclei, AGN), which can howeve…
X‑HESS: A large sample of highly accreting serendipitous AGN under the XMM‑Newton microscope
Guainazzi, M.; Piconcelli, E.; Tombesi, F. +3 more
The bulk of X‑ray spectroscopic studies of active galactic nuclei (AGN) are focused on local () sources with low‑to‑moderate (<0.3) Eddington ratio (). It is then mandatory to overcome this limitation and improve our understanding of highly accreting AGN. In this work, we present the preliminary results from the analysis of a sample of high‑ ra…