Search Publications
No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9
Turner, T. J.; Yaqoob, T.; Tatum, M. M. +2 more
Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe Kα emission line and Compton-reflection continuum in the X-ray spectrum. The method rests upon the interpretation of the Fe Kα line profile and associated …
Investigation of the energy dependence of the orbital light curve in LS 5039
Zhang, S.; Kretschmar, P.; Kuulkers, E. +5 more
LS 5039 is so far the best-studied γ-ray binary system at multiwavelength energies. A time-resolved study of its spectral energy distribution (SED) shows that above 1 keV its power output is changing along its binary orbit as well as being a function of energy. To disentangle the energy dependence of the power output as a function of orbital phase…
ALMA probes the molecular gas reservoirs in the changing-look Seyfert galaxy Mrk 590
Vestergaard, M.; Peterson, B. M.; Koay, J. Y. +2 more
We investigate if the active galactic nucleus (AGN) of Mrk 590, whose supermassive black hole was until recently highly accreting, is turning off due to a lack of central gas to fuel it. We analyse new subarcsecond resolution Atacama Large Millimetre/submilllimetre Array maps of the 12CO(3-2) line and 344 GHz continuum emission in Mrk 5…
Gamma-ray burst polarization reduction induced by the Lorentz invariance violation
Chang, Zhe; Li, Xin; Lin, Hai-Nan
It has been observed that photons in the prompt emission of some gamma-ray bursts (GRBs) are highly polarized. The high polarization is used by some authors to give a strict constraint on the Lorentz invariance violation (LIV). If the Lorentz invariance is broken, the polarization vector of a photon may rotate during its propagation. The rotation …
Limb-darkening coefficients from line-blanketed non-LTE hot-star model atmospheres
Howarth, I. D.; Reeve, D. C.
We present grids of limb-darkening coefficients computed from non-local thermodynamic equilibrium (non-LTE), line-blanketed TLUSTY model atmospheres, covering effective-temperature and surface-gravity ranges of 15-55 kK and 4.75 dex (cgs) down to the effective Eddington limit, at 2×, 1×, 0.5× (Large Magellanic Cloud), 0.2× (Small Magellanic Cloud)…
Searching for FUV line emission from 107 K gas in massive elliptical galaxies and galaxy clusters as a tracer of turbulent velocities
Anderson, Michael E.; Sunyaev, Rashid
Non-thermal pressure from turbulence and bulk flows is a fundamental ingredient in hot gaseous haloes, and in the intracluster medium, it will be measured through emission line kinematics with calorimeters on future X-ray spacecraft. In this paper, we present a complementary method for measuring these effects, using forbidden FUV emission lines of…
On the void explanation of the Cold Spot
Martínez-González, E.; Vielva, P.; Marcos-Caballero, A. +1 more
The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe…
The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex
White, G. J.; Marsh, K.; Ward-Thompson, D. +56 more
We present SCUBA-2 450 µm and 850 µm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spect…
Observational aspects of galactic accretion at redshift 3.3
Rauch, Michael; Haehnelt, Martin G.; Becker, George D.
We investigate the origin of extragalactic continuum emission and its relation to the stellar population of a recently discovered peculiar z = 3.344 Ly α emitter. Based on an analysis of the broad-band colours and morphology, we find further support for the idea that the underlying galaxy is being fed by a large-scale (L ≥ 35 kpc) accretion stream…
Accretion disc/corona emission from a radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504
Dewangan, G. C.; Ghosh, R.; Raychaudhuri, B.
Approximately 10-20 per cent of active galactic nuclei (AGN) are known to eject powerful jets from the innermost regions. There is very little observational evidence if the jets are powered by spinning black holes and if the accretion discs extend to the innermost regions in radio-loud AGN. Here, we study the soft X-ray excess, the hard X-ray spec…