Search Publications
Fermi GBM Observations of LIGO Gravitational-wave Event GW150914
McBreen, S.; Meegan, C. A.; McEnery, J. E. +32 more
With an instantaneous view of 70% of the sky, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent partner in the search for electromagnetic counterparts to gravitational-wave (GW) events. GBM observations at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914 reveal the presence of a weak transient above 5…
WATCHDOG: A Comprehensive All-sky Database of Galactic Black Hole X-ray Binaries
Heinke, C. O.; Sivakoff, G. R.; Gladstone, J. C. +1 more
With the advent of more sensitive all-sky instruments, the transient universe is being probed in greater depth than ever before. Taking advantage of available resources, we have established a comprehensive database of black hole (and black hole candidate) X-ray binary (BHXB) activity between 1996 and 2015 as revealed by all-sky instruments, scanni…
The Third Fermi GBM Gamma-Ray Burst Catalog: The First Six Years
Collazzi, Andrew C.; Preece, Robert D.; Kouveliotou, Chryssa +30 more
Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has triggered and located on average approximately two γ-ray bursts (GRBs) every three days. Here, we present the third of a series of catalogs of GRBs detected by GBM, extending the second catalog by two more years through the middle of 2014 July. The resulting list includes 1405 t…
Gamma-ray spectroscopy of positron annihilation in the Milky Way
Diehl, Roland; Greiner, Jochen; Siegert, Thomas +5 more
Context. The annihilation of positrons in the Galaxy's interstellar medium produces characteristic gamma-rays with a line at 511 keV. This gamma-ray emission has been observed with the spectrometer SPI on ESA's INTEGRAL observatory, confirming a puzzling morphology with bright emission from an extended bulge-like region, while emission from the di…
Regulation of black-hole accretion by a disk wind during a violent outburst of V404 Cygni
Ponti, G.; Charles, P. A.; Rodriguez, J. +7 more
Accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. In particular, black-hole transients have outflows whose properties are strongly coupled to those of the accretion flow. This includes X-ray winds of ionized material, expelled from the accretion disk encircling the black hole, and …
The IBIS Soft Gamma-Ray Sky after 1000 Integral Orbits
Hill, A. B.; Bird, A. J.; Fiocchi, M. +6 more
Here we report an all-sky soft gamma-ray source catalog based on IBIS observations performed during the first 1000 orbits of INTEGRAL. The database for the construction of the source list consists of all good-quality data available, from the launch in 2002, up to the end of 2010. This corresponds to ∼110 Ms of scientific public observations, with …
INTEGRAL Upper Limits on Gamma-Ray Emission Associated with the Gravitational Wave Event GW150914
Hanlon, L.; Mereghetti, S.; von Kienlin, A. +14 more
Using observations of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), we place upper limits on the gamma-ray and hard X-ray prompt emission associated with the gravitational wave event GW150914, which was discovered by the LIGO/Virgo Collaboration. The omnidirectional view of the INTEGRAL/SPI-ACS has allowed us to constrain the fra…
Positron annihilation signatures associated with the outburst of the microquasar V404 Cygni
Beloborodov, Andrei M.; Diehl, Roland; Greiner, Jochen +7 more
Microquasars are stellar-mass black holes accreting matter from a companion star and ejecting plasma jets at almost the speed of light. They are analogues of quasars that contain supermassive black holes of 106 to 1010 solar masses. Accretion in microquasars varies on much shorter timescales than in quasars and occasionally p…
On the Fermi-GBM Event 0.4 s after GW150914
Burgess, J. M.; Greiner, J.; Savchenko, V. +1 more
In view of the recent report by Connaughton et al., we analyze continuous time-tagged event (TTE) data of Fermi-gamma-ray burst monitor (GBM) around the time of the gravitational-wave event GW 150914. We find that after proper accounting for low-count statistics, the GBM transient event at 0.4 s after GW 150914 is likely not due to an astrophysica…
Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni
Ruiz, Javier; Enoto, Teruaki; Nogami, Daisaku +65 more
How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed…