Search Publications
20-100 keV properties of cataclysmic variables detected in the INTEGRAL/IBIS survey
Hill, A. B.; Knigge, C.; Bird, A. J. +5 more
Analysis of INTEGRAL/IBIS survey observations has revealed that the rare intermediate polar and asynchronous polar cataclysmic variables (CVs) are consistently found to emit in the 20-100 keV energy band, whereas synchronous polars and the common non-magnetic CVs rarely do so. From the correlation of a candidate INTEGRAL/IBIS survey source list wi…
Cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29
Homan, Jeroen; Miller, Jon M.; Cackett, Edward M. +3 more
We present Chandra and XMM-Newton X-ray observations that monitor the neutron star cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 for approximately 4 yr after these sources returned to quiescence from prolonged outbursts. In both sources the outbursts were long enough to significantly heat the neutron sta…
The interplay between star formation and the nuclear environment of our Galaxy: deep X-ray observations of the Galactic centre Arches and Quintuplet clusters
Wang, Q. Daniel; Dong, Hui; Lang, Cornelia
The Galactic centre (GC) provides a unique laboratory for a detailed examination of the interplay between massive star formation and the nuclear environment of our Galaxy. Here, we present a 100-ks Chandra Advanced CCD Imaging Spectrometer (ACIS) observation of the Arches and Quintuplet star clusters. We also report on a complementary mapping of t…
Constraints on dark matter and the shape of the Milky Way dark halo from the 511-keV line
Knödlseder, J.; Jean, P.; Ascasibar, Y. +1 more
About one year ago, it was speculated that decaying or annihilating light dark matter (LDM) particles could explain the flux and extension of the 511-keV line emission in the Galactic Centre. Here, we present a thorough comparison between theoretical expectations of the Galactic positron distribution within the LDM scenario and observational data …
Finding benchmark brown dwarfs to probe the substellar initial mass function as a function of time
Steele, I. A.; Pinfield, D. J.; Kendall, T. R. +5 more
Using a simulated disc brown dwarf (BD) population, we find that new large area infrared surveys are expected to identify enough BDs covering wide enough mass-age ranges to potentially measure the present day mass function down to ~0.03Msolar, and the BD formation history out to 10Gyr, at a level that will be capable of establishing if …
Late-type galaxies observed with SAURON: two-dimensional stellar and emission-line kinematics of 18 spirals
Emsellem, Eric; Peletier, Reynier F.; Cappellari, Michele +5 more
We present the stellar and gas kinematics of a sample of 18 nearby late-type spiral galaxies (Hubble types ranging from Sb to Sd), observed with the integral-field spectrograph SAURON at the 4.2-m William Herschel Telescope. SAURON covers the spectral range 4800-5380Å, allowing us to measure the Hβ, Fe, Mgb absorption features and the emission in …
Constraints on the initial mass function of the first stars
Ferrara, Andrea; Salvaterra, Ruben; Ciardi, Benedetta +1 more
Motivated by theoretical predictions that the first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop II/I stars by means of a numerically generated catalogue of dark matter haloes coupled with a self-consist…
A catalogue of close binaries located in the δ Scuti region of the Cepheid instability strip
Demircan, O.; Soydugan, F.; Soydugan, E. +1 more
A catalogue of close eclipsing binary systems (detached and semidetached) with at least one of the components located in the δ Scuti region of the Cepheid instability strip is presented. The positions of the stars in the instability strip are determined by their accurate temperatures and luminosities. Observationally detected binaries (20 semideta…
XMM-Newton observations of PSR B1259-63 near the 2004 periastron passage
Rodriguez, J.; Lutovinov, A.; Johnston, S. +2 more
PSR B1259-63 is in a highly eccentric 3.4-yr orbit with a Be star and crosses the Be star disc twice per orbit, just prior to and just after periastron. Unpulsed radio, X-ray and gamma-ray emission observed from the binary system is thought to be due to the collision of pulsar wind with the wind of Be star. We present here the results of new XMM-N…
The evolution of the cluster X-ray scaling relations in the Wide Angle ROSAT Pointed Survey sample at 0.6 < z < 1.0
Maughan, B. J.; Ebeling, H.; Jones, L. R. +1 more
The X-ray properties of a sample of 11 high-redshift (0.6 < z < 1.0) clusters observed with Chandra and/or XMM-Newton are used to investigate the evolution of the cluster scaling relations. The observed evolution in the normalization of the L-T, M-T, Mg-T and M-L relations is consistent with simple self-similar predictions, in whi…