Search Publications
On why the iron K-shell absorption in AGN is not a signature of the local warm/hot intergalactic medium
Done, Chris; Terashima, Yuichi; Hayashida, Kiyoshi +5 more
We present a comparison between the 2001 XMM-Newton and 2005 Suzaku observations of the quasar, PG1211+143, at z = 0.0809. Variability is observed in the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which is significantly weaker in 2005 than during the 2001 XMM-Newton observation. From a recombination time-scale of <4 yr…
Constraints on decaying dark matter from XMM-Newton observations of M31
Boyarsky, Alexey; Ruchayskiy, Oleg; Iakubovskyi, Dmytro +1 more
We derive constraints on the parameters of the radiatively decaying dark matter (DM) particle, using the XMM-Newton EPIC spectra of the Andromeda galaxy (M31). Using the observations of the outer (5-13arcmin) parts of M31, we improve the existing constraints. For the case of sterile neutrino DM, combining our constraints with the latest computatio…
A systematic look at the very high and low/hard state of GX339-4: constraining the black hole spin with a new reflection model
Fabian, A. C.; Miller, J. M.; Miniutti, G. +3 more
We present a systematic study of GX 339-4 in both its very high and low hard states from simultaneous observations made with XMM-Newton and RXTE in 2002 and 2004. The X-ray spectra of both these extreme states exhibit strong reflection signatures, with a broad, skewed Fe Kα line clearly visible above the continuum. Using a newly developed, self-co…
The luminosities and distance scales of type II Cepheid and RR Lyrae variables
van Leeuwen, Floor; Whitelock, Patricia A.; Feast, Michael W. +2 more
Infrared and optical absolute magnitudes are derived for the type II Cepheids κ Pav and VY Pyx using revised Hipparcos parallaxes and for κ Pav, V553 Cen and SW Tau from pulsational parallaxes. Revised Hipparcos and HST parallaxes for RR Lyrae agree satisfactorily and are combined in deriving absolute magnitudes. Phase-corrected J, H and Ks
An XMM-Newton study of the environments, particle content and impact of low-power radio galaxies
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +2 more
We present a detailed study of the environments of a sample of nine low-power [Fanaroff-Riley type I (FRI)] radio galaxies, based on new and archival XMM-Newton observations. We report new detections of group-scale environments around three radio galaxies: 3C296, NGC1044 and 3C76.1. As with previous studies, we find that FRI radio galaxies inhabit…
Precision photometric redshift calibration for galaxy-galaxy weak lensing
Kneib, J. -P.; Cunha, C. E.; Bolzonella, M. +26 more
Accurate photometric redshifts are among the key requirements for precision weak lensing measurements. Both the large size of the Sloan Digital Sky Survey (SDSS) and the existence of large spectroscopic redshift samples that are flux-limited beyond its depth have made it the optimal data source for developing methods to properly calibrate photomet…
The type IIb SN 2008ax: the nature of the progenitor
Gal-Yam, A.; Smartt, S. J.; Maund, J. R. +9 more
A source coincident with the position of the type IIb supernova (SN) 2008ax is identified in pre-explosion Hubble Space Telescope (HST) Wide Field Planetary Camera 2 observations in three optical filters. We identify and constrain two possible progenitor systems: (i) a single massive star that lost most of its hydrogen envelope through radiatively…
Constraining dark matter properties with SPI
Boyarsky, Alexey; Ruchayskiy, Oleg; Malyshev, Denys +1 more
Using the high-resolution spectrometer SPI on board the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), we search for a spectral line produced by a dark matter (DM) particle with a mass in the range 40keV < MDM < 14MeV, decaying in the DM halo of the Milky Way. To distinguish the DM decay line from numerous instrumenta…
The evolution of the brightest cluster galaxies since z ~ 1 from the ESO Distant Cluster Survey (EDisCS)
Milvang-Jensen, B.; Noll, S.; Poggianti, B. M. +13 more
We present K-band data for the brightest cluster galaxies (BCGs) from the ESO Distant Cluster Survey (EDisCS). These data are combined with the photometry published by Aragón-Salamanca, Baugh & Kauffmann and a low-redshift comparison sample built from the BCG catalogue of von der Linden et al. BCG luminosities are measured inside a metric circ…
X-ray spectra from magnetar candidates - I. Monte Carlo simulations in the non-relativistic regime
Zane, S.; Nobili, L.; Turolla, R.
The anomalous X-ray pulsars (AXPs) and soft γ-repeaters (SGRs) are peculiar high-energy sources believed to host a magnetar, an ultramagnetized neutron star with surface magnetic field in the petagauss range. Their persistent, soft X-ray emission exhibits a two component spectrum, usually modelled by the superposition of a blackbody and a power-la…