Outputs (16)

Search for gravitational redshifted absorption lines in LMXB Serpens X-1 (2017)
Journal Article

The equation of state for ultradense matter can be tested from observations of the ratio of mass to radius of neutron stars. This could be measured precisely from the redshift of a narrow line produced on the surface. X-rays bursts have been intensiv... Read More about Search for gravitational redshifted absorption lines in LMXB Serpens X-1.

The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342 (2017)
Journal Article

The detection of several radio-loud narrow-line Seyfert 1 (NLS1) galaxies by the Fermi Gamma-Ray Space Telescope hints at the existence of a rare, new class of γ-ray emitting active galactic nuclei with low black hole masses. Like flat spectrum radio... Read More about The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342.

In search of a new era of UK X-ray astronomy (2017)
Journal Article

X-ray astronomy is our gateway to the hot universe. More than half of the baryons in the cosmos are too hot to be visible at shorter wavelengths. Studying the extreme environments of black hole and neutron star vicinities also requires X-ray data. Wi... Read More about In search of a new era of UK X-ray astronomy.

Evidence for higher black hole spin in radio-loud quasars (2017)
Journal Article

One of the major unsolved questions concerning the understanding of the active galactic nucleus population is the origin of the dichotomy between radio-quiet and radio-loud quasars. The most promising explanation is provided by the spin paradigm, whi... Read More about Evidence for higher black hole spin in radio-loud quasars.

What powers the most relativistic jets? – II. Flat-spectrum radio quasars (2017)
Journal Article

Flat Spectrum Radio Quasars (FSRQs) are the most powerful relativistic jets seen from supermassive black holes (BHs) accreting via a radiatively efficient thin disc. Their high energy emission is well modelled by highly relativistic electrons in the... Read More about What powers the most relativistic jets? – II. Flat-spectrum radio quasars.

Thermal winds in stellar mass black hole and neutron star binary systems (2017)
Journal Article

Black hole binaries show equatorial disc winds at high luminosities, which apparently disappear during the spectral transition to the low/hard state. This is also where the radio jet appears, motivating speculation that both wind and jet are driven b... Read More about Thermal winds in stellar mass black hole and neutron star binary systems.

Modelling the energy dependence of black hole binary flows (2017)
Journal Article

We build a full spectral-timing model for the low/hard state of black hole binaries assuming that the spectrum of the X-ray hot flow can be produced by two Comptonization zones. Slow fluctuations generated at the largest radii/softest spectral region... Read More about Modelling the energy dependence of black hole binary flows.

Determining the torus covering factors for a sample of type 1 AGN in the local Universe (2017)
Journal Article

In the unified scheme of active galactic nuclei, a dusty torus absorbs and then reprocesses a fraction of the intrinsic luminosity which is emitted at longer wavelengths. Thus, subject to radiative transfer corrections, the fraction of the sky covere... Read More about Determining the torus covering factors for a sample of type 1 AGN in the local Universe.

Super-Eddington QSO RX J0439.6-5311 – II. Multiwavelength constraints on the global structure of the accretion flow (2017)
Journal Article

We present a detailed multiwavelength study of an unobscured, highly super-Eddington Type-1 QSO RX J0439.6-5311. We combine the latest XMM–Newton observation with all archival data from infrared to hard X-rays. The optical spectrum is very similar to... Read More about Super-Eddington QSO RX J0439.6-5311 – II. Multiwavelength constraints on the global structure of the accretion flow.

Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing (2017)
Journal Article

Swift monitoring of NGC 4151 with an ~6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3–50 keV) and six in the ultraviolet (UV)/optical (1900–5500 Å). The three hardest X-ray... Read More about Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing.

The origin of the UV/optical lags in NGC 5548 (2017)
Journal Article

The new multiwavelength monitoring campaign on NGC 5548 shows clearly that the variability of the ultraviolet (UV)/optical light curves lags by progressively longer times at longer wavelengths, as expected from reprocessing off an optically thick dis... Read More about The origin of the UV/optical lags in NGC 5548.

Super-Eddington QSO RX J0439.6−5311 – I. Origin of the soft X-ray excess and structure of the inner accretion flow (2017)
Journal Article

We report the results from a recent 133 ks XMM–Newton observation of a highly super-Eddington narrow-line Type-1 quasi-stellar object RX J0439.6−5311. This source has one of the steepest active galactic nuclei hard X-ray slopes, in addition to a prom... Read More about Super-Eddington QSO RX J0439.6−5311 – I. Origin of the soft X-ray excess and structure of the inner accretion flow.

Revisiting the extremely fast disc wind in a gravitationally lensed quasar APM 08279+5255 (2017)
Journal Article

The gravitationally lensed quasar APM 08279+5255 has the fastest claimed wind from any active galactic nucleus, with velocities of 0.6–0.7c, requiring magnetic acceleration as special relativistic effects limit all radiatively driven winds to v < 0.3... Read More about Revisiting the extremely fast disc wind in a gravitationally lensed quasar APM 08279+5255.

Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy Cluster (2017)
Journal Article

High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E=3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Pe... Read More about Hitomi Constraints on the 3.5 keV Line in the Perseus Galaxy Cluster.

Black hole spin of Cygnus X-1 determined from the softest state ever observed (2017)
Journal Article

We show the softest ever spectrum from Cyg X-1, detected in 2013 with Suzaku. This has the weakest high-energy Compton tail ever seen from this object, so should give the cleanest view of the underlying disk spectrum, and hence the best determination... Read More about Black hole spin of Cygnus X-1 determined from the softest state ever observed.

Crossing the Eddington Limit: Examining Disk Spectra at High Accretion Rates (2017)
Journal Article

The faintest ultraluminous X-ray sources (ULXs), those with 0.3-10 keV luminosities 1 < L_X/10^39 < 3 erg s^-1, tend to have X-ray spectra that are disk-like but broader than expected for thin accretion disks. These `broadened disk' spectra are thoug... Read More about Crossing the Eddington Limit: Examining Disk Spectra at High Accretion Rates.