Search Publications
A kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy
Anderson, Jay; van der Marel, Roeland P.; Sparks, William B. +7 more
Jets of highly energized plasma with relativistic velocities are associated with black holes ranging in mass from a few times that of the Sun to the billion-solar-mass black holes at the centres of galaxies. A popular but unconfirmed hypothesis to explain how the plasma is energized is the `internal shock model', in which the relativistic flow is …
The evolution of the disc variability along the hard state of the black hole transient GX 339-4
Nandra, K.; Ponti, G.; De Marco, B. +1 more
We report on the analysis of hard-state power spectral density function (PSD) of GX 339-4 down to the soft X-ray band, where the disc significantly contributes to the total emission. At any luminosity probed, the disc in the hard state is intrinsically more variable than in the soft state. However, the fast decrease of disc variability as a functi…
Leptonic origin of the 100 MeV γ-ray emission from the Galactic centre
Walter, R.; Chernyakova, M.; Malyshev, D. +1 more
Context. The Galactic centre is a bright γ-ray source with the GeV-TeV band spectrum composed of two distinct components in the 1-10 GeV and 1-10 TeV energy ranges. The nature of these two components is not clearly understood.
Aims: We investigate the γ-ray properties of the Galactic centre to clarify the origin of the observed emission.
…
Star formation and quenching among the most massive galaxies at z ∼ 1.7
Berta, S.; Daddi, E.; Rodighiero, G. +5 more
We have conducted a detailed object-by-object study of a mass-complete (M* ≥ 1011 M⊙) sample of 56 galaxies at 1.4 ≤ z ≤ 2 in the Great Observatories Origins Deep Survey-South field, showing that an accurate deblending in 24 µm images is essential to properly assign to each galaxy its own star formation rate …
The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster
O'Dell, C. R.; Henney, W. J.; Ferland, G. J. +3 more
Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbi…
Hubble Space Telescope observations of the Kepler-field cluster NGC 6819 - I. The bottom of the white dwarf cooling sequence
Salaris, M.; Anderson, J.; Milone, A. P. +5 more
We use Hubble Space Telescope (HST) to reach the end of the white dwarf (WD) cooling sequence (CS) in the solar-metallicity open cluster NGC 6819. Our photometry and completeness tests show a sharp drop in the number of WDs along the CS at magnitudes fainter than mF606W = 26.050 ± 0.075. This implies an age of 2.25 ± 0.20 Gyr, consisten…
Upper atmosphere temperature structure at the Venusian terminators: A comparison of SOIR and VTGCM results
Wilquet, V.; Mahieux, A.; Brecht, A. S. +5 more
Venus Express SOIR terminator profiles of CO2 densities and corresponding temperatures have been determined for 132 selected orbits obtained between 2006 and 2013. These recently recalibrated measurements provide temperature profiles at the Venusian terminator over approximately 70-160 km, revealing a striking permanent temperature mini…
Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum
Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan +1 more
We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a pre-inflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We …
N49: The First Robust Discovery of Recombining Plasma in an Extra-galactic Supernova Remnant
Yamaguchi, Hiroya; Koyama, Katsuji; Uchida, Hiroyuki
Recent discoveries of recombining plasmas (RPs) in supernova remnants (SNRs) have dramatically changed our understanding of SNR evolution. To date, a dozen RP SNRs have been identified in the Galaxy. Here, we present Suzaku deep observations of four SNRs in the LMC, namely, N49, N49B, N23, and DEM L71, for accurate determination of their plasma st…
Plasmapause formation at Saturn
Coates, A. J.; Thomsen, M. F.; Jackman, C. M. +3 more
Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the den…