Search Publications
Luminosities and mass-loss rates of Local Group AGB stars and red supergiants
Groenewegen, M. A. T.; Sloan, G. C.
Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking.
Aims: We aim to investigate…
Surround and Squash: the impact of superbubbles on the interstellar medium in Scorpius-Centaurus OB2
Roccatagliata, Veronica; Diehl, Roland; Siegert, Thomas +7 more
Context. Feedback by massive stars shapes the interstellar medium and is thought to influence subsequent star formation. The details of this process are under debate.
Aims: We exploited observational constraints on stars, gas, and nucleosynthesis ashes for the closest region with recent massive-star formation, Scorpius-Centaurus OB2, and comb…
INTEGRAL/SPI γ-ray line spectroscopy. Response and background characteristics
Diehl, Roland; Greiner, Jochen; Siegert, Thomas +7 more
Context. The space based γ-ray observatory INTEGRAL of the European Space Agency (ESA) includes the spectrometer instrument "SPI". This is a coded mask telescope featuring a 19-element Germanium detector array for high-resolution γ-ray spectroscopy, encapsulated in a scintillation detector assembly that provides a veto for background from charged …
Discovery of 105 Hz coherent pulsations in the ultracompact binary IGR J16597-3704
Altamirano, D.; Sanna, A.; Degenaar, N. +15 more
We report the discovery of X-ray pulsations at 105.2 Hz (9.5 ms) from the transient X-ray binary IGR J16597-3704 using NuSTAR and Swift. The source was discovered by INTEGRAL in the globular cluster NGC 6256 at a distance of 9.1 kpc. The X-ray pulsations show a clear Doppler modulation that implies an orbital period of 46 min and a projected semi-…
NuSTAR and NICER reveal IGR J17591-2342 as a new accreting millisecond X-ray pulsar
Altamirano, D.; Sanna, A.; Ray, P. S. +21 more
We report the discovery by the Nuclear Spectroscopic Telescope Array (NuSTAR) and the Neutron Star Interior Composition Explorer (NICER) of the accreting millisecond X-ray pulsar IGR J17591-2342. Coherent X-ray pulsations around 527.4 Hz (1.9 ms) with a clear Doppler modulation were detected. This implies an orbital period of ∼8.8 h and a projecte…
XMM-Newton detection of the 2.1 ms coherent pulsations from IGR J17379-3747
Sanna, A.; Ferrigno, C.; Papitto, A. +7 more
We report the detection of X-ray pulsations at 2.1 ms from the known X-ray burster IGR J17379-3747 using XMM-Newton. The coherent signal shows a clear Doppler modulation from which we estimate an orbital period of 1.9 h and a projected semi-major axis of 8 lt-ms. Taking into account the lack of eclipses (inclination angle of <75°) and assuming …
IGR J17329-2731: The birth of a symbiotic X-ray binary
Sanna, A.; Gandhi, P.; Romano, P. +10 more
We report on the results of the multiwavelength campaign carried out after the discovery of the INTEGRAL transient IGR J17329-2731. The optical data collected with the SOAR telescope allowed us to identify the donor star in this system as a late M giant at a distance of 2.7-1.2+3.4 kpc. The data collected quasi-simultaneously…
Gamma-ray observations of Nova Sgr 2015 No. 2 with INTEGRAL
Starrfield, Sumner; Savchenko, Volodymyr; Diehl, Roland +11 more
Context. INTEGRAL observed Nova Sgr 2015 No. 2 (V5668 Sgr) around the time of its optical emission maximum on 21 March 2015. Studies at UV wavelengths showed spectral lines of freshly produced 7Be. This could also be measurable in gamma rays at 478 keV from the decay to 7Li. Novae are also expected to synthesise 22…
VLBA polarimetric monitoring of 3C 111
Gurwell, M.; Wilms, J.; Kadler, M. +17 more
Context. While studies of large samples of jets of active galactic nuclei (AGN) are important in order to establish a global picture, dedicated single-source studies are an invaluable tool for probing crucial processes within jets on parsec scales. These processes involve in particular the formation and geometry of the jet magnetic field as well a…
Extended VHE γ-ray emission towards SGR1806-20, LBV 1806-20, and stellar cluster Cl* 1806-20
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +242 more
Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) γ-ray source towards the luminous blue variable candidate LBV 1806-20, massive stellar cluster Cl* 1806-20, and magnetar SGR 1806-20. The new VHE source, HESS J1808-204, was detected at a statistical significance of >…