Search Publications
The Gaia-ESO Survey: evidence of atomic diffusion in M67?
Gilmore, G.; Bayo, A.; Salaris, M. +37 more
Investigating the chemical homogeneity of stars born from the same molecular cloud at virtually the same time is very important for our understanding of the chemical enrichment of the interstellar medium and with it the chemical evolution of the Galaxy. One major cause of inhomogeneities in the abundances of open clusters is stellar evolution of t…
Improved distances and ages for stars common to TGAS and RAVE
Grebel, Eva K.; Steinmetz, Matthias; Bland-Hawthorn, Joss +15 more
We combine parallaxes from the first Gaia data release with the spectrophotometric distance estimation framework for stars in the fifth RAVE survey data release. The combined distance estimates are more accurate than either determination in isolation - uncertainties are on average two times smaller than for RAVE-only distances (three times smaller…
LoCuSS: The infall of X-ray groups on to massive clusters
Finoguenov, A.; Smith, G. P.; Okabe, N. +10 more
Galaxy clusters are expected to form hierarchically in a Λ cold dark matter (ΛCDM) universe, growing primarily through mergers with lower mass clusters and the continual accretion of group-mass haloes. Galaxy clusters assemble late, doubling their masses since z ∼ 0.5, and so the outer regions of clusters should be replete with accreting group-mas…
A quartet of black holes and a missing duo: probing the low end of the MBH-σ relation with the adaptive optics assisted integral-field spectroscopy
Krajnović, Davor; Sarzi, Marc; Cappellari, Michele +8 more
We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC 4339, NGC 4434, NGC 4474, NGC 4551, NGC 4578, and NGC 4762) with effective stellar velocity dispersion around 100 km s-1. We use near-infrared laser-guide adaptive optics observations with the GEMINI/NIFS to derive stellar kinemati…
Mass models of NGC 6624 without an intermediate-mass black hole
Jonker, Peter G.; Hénault-Brunet, Vincent; Gieles, Mark +4 more
An intermediate-mass black hole (IMBH) was recently reported to reside in the centre of the Galactic globular cluster (GC) NGC 6624, based on timing observations of a millisecond pulsar (MSP) located near the cluster centre in projection. We present dynamical models with multiple mass components of NGC 6624 - without an IMBH - which successfully d…
Searching for propeller-phase ULXs in the XMM-Newton Serendipitous Source Catalogue
Earnshaw, H. P.; Roberts, T. P.; Sathyaprakash, R.
We search for transient sources in a sample of ultraluminous X-ray sources (ULXs) from the 3XMM-DR4 release of the XMM-Newton Serendipitous Source Catalogue in order to find candidate neutron star ULXs alternating between an accreting state and the propeller regime, in which the luminosity drops dramatically. By examining their fluxes and flux upp…
Observational signatures of a warped disk associated with cold-flow accretion
Pettini, Max; Kacprzak, Glenn G.; York, Donald G. +9 more
We present MUSE observations of the field of the quasar Q0152$-$020 whose spectrum shows a Lyman limit system (LLS) at redshift $z_{\rm abs} = 0.38$, with a metallicity Z $\gtrsim 0.06$ Z$_\odot$. The low ionization metal lines associated with the LLS present two narrow distinct absorption components with a velocity separation of 26 km ${\rm s}^{-…
Lense-Thirring precession in ULXs as a possible means to constrain the neutron star equation of state
Gehrels, N.; Fabian, A. C.; Pinto, C. +11 more
The presence of neutron stars in at least three ultraluminous X-ray sources is now firmly established and offers an unambiguous view of super-critical accretion. All three systems show long-time-scale periods (60-80 d) in the X-rays and/or optical, two of which are known to be super-orbital in nature. Should the flow be classically super critical,…
An astrophysical interpretation of the remarkable g-mode frequency groups of the rapidly rotating γ Dor star, KIC 5608334
Li, Gang; Bedding, Timothy R.; Antoci, Victoria +5 more
The Fourier spectrum of the γ-Dor variable KIC 5608334 shows remarkable frequency groups at ∼3, ∼6, ∼9, and 11-12 d-1. We explain the four frequency groups as prograde sectoral g modes in a rapidly rotating star. Frequencies of intermediate-to-high radial order prograde sectoral g modes in a rapidly rotating star are proportional to |m|…
An INTEGRAL overview of High-Mass X-ray Binaries: classes or transitions?
Sidoli, L.; Paizis, A.
We analysed in a systematic way the public INTEGRAL observations spanning from December 2002 to September 2016, to investigate the hard X-ray properties of about 60 High Mass X-ray Binaries (HMXBs). We considered both persistent and transient sources, hosting either a Be star (Be/XRBs) or a blue supergiant companion (SgHMXBs, including Supergiant …