Search Publications
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…
INTEGRAL/RXTE high-energy observation of a state transition of GX 339-4
Belloni, T.; Miller, J. M.; Homan, J. +7 more
On 2004 August 15, we observed a fast (shorter than 10 h) state transition in the bright black hole transient GX 339-4 simultaneously with Rossi X-Ray Timing Explorer (RXTE) and INTEGRAL. This transition was evident both in timing and spectral properties. Combining the data from the Proportional Counter Array (PCA), the High-Energy X-ray Timing Ex…
Rotation speed and stellar axis inclination from p modes: how CoRoT would see other suns
García, R. A.; Ballot, J.; Lambert, P.
In the context of future space-based asteroseismic missions, we have studied the problem of extracting the rotation speed and the rotation-axis inclination of solar-like stars from the expected data. We have focused on slow rotators (at most twice solar rotation speed), first, because they constitute the most difficult case and, secondly, because …
Gas and stellar dynamics in NGC 1068: probing the galactic gravitational potential
Schinnerer, Eva; Emsellem, Eric; Ferruit, Pierre +3 more
We present SAURON integral field spectrography of the central 1.5 kpc of the nearby Seyfert 2 galaxy NGC 1068, encompassing the well-known near-infrared (NIR) inner bar observed in the K band. We have successively disentangled the respective contributions of the ionized gas and stars, thus deriving their two-dimensional distribution and kinematics…