Search Publications
Extragalactic fast X-ray transient candidates discovered by Chandra (2000-2014)
Bauer, F. E.; Brandt, W. N.; Xue, Y. Q. +7 more
Context. Extragalactic fast X-ray transients (FXRTs) are short flashes of X-ray photons of unknown origin that last a few seconds to hours.
Aims: Our ignorance about their physical mechanisms and progenitor systems is due in part to the lack of clear multiwavelength counterparts in most cases, because FXRTs have only been identified serendipi…
SRG/ART-XC all-sky X-ray survey: Catalog of sources detected during the first year
Sunyaev, R.; Krivonos, R.; Sazonov, S. +20 more
We present a first catalog of sources detected by the Mikhail Pavlinsky ART-XC telescope on board the SRG observatory in the 4-12 keV energy band during its ongoing all-sky survey. The catalog comprises 867 sources detected on the combined map of the first two 6-month scans of the sky (December 2019-December 2020), ART-XC sky surveys 1 and 2, or A…
Diffuse Galactic emission spectrum between 0.5 and 8.0 MeV
Calore, Francesca; Siegert, Thomas; Serpico, Pasquale D. +2 more
The last measurement of the diffuse emission spectrum of the Milky Way in the megaelectronvolt (MeV) photon energy range was performed by CGRO/COMPTEL more than 20 yr ago. We report a new analysis with the spectrometer SPI aboard INTEGRAL in the band 0.5-8.0 MeV, finally superseding the signal-to-noise ratio (S/N) of the historic observations. Thi…
Simultaneous X-ray and optical spectroscopy of V404 Cygni supports the multi-phase nature of X-ray binary accretion disc winds
Ponti, Gabriele; Muñoz-Darias, Teo
Observational signatures of accretion disc winds have been found in a significant number of low-mass X-ray binaries at either X-ray or optical wavelengths. The 2015 outburst of the black hole transient V404 Cygni provided a unique opportunity for studying both types of outflows in the same system. We used contemporaneous X-ray (Chandra Observatory…
Constraints to neutron-star kicks in high-mass X-ray binaries with Gaia EDR3
García, Federico; Chaty, Sylvain; Fortin, Francis +2 more
Context. All neutron star progenitors in neutron-star high-mass X-ray binaries (NS HMXBs) undergo a supernova event that may lead to a significant natal kick impacting the motion of the whole binary system. The space observatory Gaia performs a deep optical survey with exquisite astrometric accuracy, for both position and proper motions, that can …
A WISE view on extreme AGB stars
Groenewegen, M. A. T.
Context. Variability is a key property of stars on the asymptotic giant branch (AGB). Their pulsation period is related to the luminosity and mass-loss rate (MLR) of the star. Long-period variables (LPVs) and Mira variables are the most prominent of all types of variability of evolved stars. However, the reddest, most obscured AGB stars are too fa…
Constraining the overcontact phase in massive binary evolution. II. Period stability of known O+O overcontact systems
Mahy, Laurent; Abdul-Masih, Michael; Marchant, Pablo +2 more
Context. Given that mergers are often invoked to explain many exotic phenomena in massive star evolution, understanding the evolutionary phase directly preceding a merger, the overcontact phase, is of crucial importance. Despite this, large uncertainties exist in our understanding of the evolution of massive overcontact binaries.
Aims: We aim…
Peculiar X-ray transient SRGA J043520.9+552226/AT2019wey discovered with SRG/ART-XC
Gilfanov, M. R.; Medvedev, P. S.; Sunyaev, R. A. +24 more
Context. During its ongoing all-sky survey, the Mikhail Pavlinsky ART-XC (Astronomical Roentgen Telescope - X-ray Concentrator) telescope on board the Spectrum-Roentgen-Gamma (SRG) observatory is set to discover new X-ray sources, many of which can be transient. Here we report the discovery and multiwavelength follow-up of a peculiar X-ray source …
XMM-Newton and Swift observations of supergiant high mass X-ray binaries
Romano, P.; Ferrigno, C.; Bozzo, E.
Wind-fed supergiant X-ray binaries are precious laboratories not only to study accretion under extreme gravity and magnetic field conditions, but also to probe the still highly debated properties of massive star winds. These include clumps, originating from the inherent instability of line driven winds, and larger structures. In this paper we repo…
Turin-SyCAT: A multifrequency catalog of Seyfert galaxies
Capetti, A.; Masetti, N.; Chavushyan, V. +3 more
Aims: We present the first release of Turin-SyCAT, a multifrequency catalog of Seyfert galaxies.
Methods: We selected Seyfert galaxies considering criteria based on radio, infrared, and optical properties and starting from sources belonging to hard X-ray catalogs and surveys. We visually inspected optical spectra available for all select…