Search Publications
A physical model of the broad-band continuum of AGN and its implications for the UV/X relation and optical variability
Done, Chris; Kubota, Aya
We develop a new spectral model for the broad-band spectral energy distribution (SED) of active galactic nuclei (AGN). This includes an outer standard disc, an inner warm Comptonizing region to produce the soft X-ray excess and a hot corona. We tie these together energetically by assuming Novikov-Thorne emissivity, and use this to define a size sc…
Imprints of cosmic rays in multifrequency observations of the interstellar emission
Orlando, E.
Ever since the discovery of cosmic rays (CRs), significant advancements have been made in modelling their propagation in the Galaxy and in the Heliosphere. However, propagation models suffer from degeneracy of many parameters. To complicate the picture, the precision of recent data have started challenging existing models. To tackle these issues, …
An INTEGRAL overview of High-Mass X-ray Binaries: classes or transitions?
Sidoli, L.; Paizis, A.
We analysed in a systematic way the public INTEGRAL observations spanning from December 2002 to September 2016, to investigate the hard X-ray properties of about 60 High Mass X-ray Binaries (HMXBs). We considered both persistent and transient sources, hosting either a Be star (Be/XRBs) or a blue supergiant companion (SgHMXBs, including Supergiant …
Spatial clustering and halo occupation distribution modelling of local AGN via cross-correlation measurements with 2MASS galaxies
Coil, Alison L.; Krumpe, Mirko; Miyaji, Takamitsu +1 more
We present the clustering properties and halo occupation distribution (HOD) modelling of very low redshift, hard X-ray-detected active galactic nuclei (AGN) using cross-correlation function measurements with Two-Micron All Sky Survey galaxies. Spanning a redshift range of 0.007 < z < 0.037, with a median z = 0.024, we present a precise AGN c…
The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features
Charles, P. A.; Armas Padilla, M.; Jiménez-Ibarra, F. +19 more
The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (! ∼ ! 90 s), which included a detailed coverage of the most active phase of the event. We present a data base consisting of 651 optical spectra obt…
The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows at 15.7 GHz
Wijers, R. A. M. J.; Fender, R. P.; van der Horst, A. J. +7 more
We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7 GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target …
Galactic binaries can explain the Fermi Galactic centre excess and 511 keV emission
Calore, F.; Bartels, R.; Storm, E. +1 more
The Fermi-LAT Galactic Centre excess and the 511 keV positron-annihilation signal from the inner Galaxy bear a striking morphological similarity. We propose that both can be explained through a scenario in which millisecond pulsars produce the Galactic Centre excess and their progenitors, low-mass X-ray binaries, the 511 keV signal. As a proof of …
The Fermi-LAT detection of magnetar-like pulsar PSR J1846-0258 at high-energy gamma-rays
Dekker, A.; Kuiper, L.; Hermsen, W.
We report the detection of the pulsed signal of the radio-quiet magnetar-like pulsar PSR J1846-0258 in the high-energy γ-ray data of the Fermi Large Area Telescope (Fermi LAT). We produced phase-coherent timing models exploiting RXTE PCA and Swift XRT monitoring data for the post- (magnetar-like) outburst period from 2007 August 28 to 2016 Septemb…
Where are Compton-thick radio galaxies? A hard X-ray view of three candidates
Bird, A. J.; Ubertini, P.; Malizia, A. +4 more
We present a broad-band X-ray spectral analysis of the radio-loud active galactic nuclei NGC 612, 4C 73.08 and 3C 452, exploiting archival data from NuSTAR, XMM-Newton, Swift and INTEGRAL. These Compton-thick candidates are the most absorbed sources among the hard X-ray selected radio galaxies studied in Panessa et al. We find an X-ray absorbing c…
Broad-band spectral study of the jet-disc emission in the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342
Dewangan, Gulab C.; Raychaudhuri, Biplab; Mallick, Labani +1 more
We present a broad-band spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 based on multi-epoch observations performed with Nuclear Spectroscopic Telescope Array on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray e…