Search Publications
A Lyman limit system associated with galactic winds
Bouché, Nicolas; Pettini, Max; York, Donald G. +9 more
Projected quasar galaxy pairs provide powerful means to study the circumgalactic medium (CGM) that maintains the relics of galactic feedback and the accreted gas from the intergalactic medium. Here, we study the nature of a Lyman Limit system (LLS) with N(H I) = 1019.1 ± 0.3 cm-2 and a dust-uncorrected metallicity of [Fe/H] =…
Centre-excised X-ray luminosity as an efficient mass proxy for future galaxy cluster surveys
Allen, Steven W.; Mantz, Adam B.; von der Linden, Anja +1 more
The cosmological constraining power of modern galaxy cluster catalogues can be improved by obtaining low-scatter mass proxy measurements for even a small fraction of sources. In the context of large upcoming surveys that will reveal the cluster population down to the group scale and out to high redshifts, efficient strategies for obtaining such ma…
Where are Compton-thick radio galaxies? A hard X-ray view of three candidates
Bird, A. J.; Ubertini, P.; Malizia, A. +4 more
We present a broad-band X-ray spectral analysis of the radio-loud active galactic nuclei NGC 612, 4C 73.08 and 3C 452, exploiting archival data from NuSTAR, XMM-Newton, Swift and INTEGRAL. These Compton-thick candidates are the most absorbed sources among the hard X-ray selected radio galaxies studied in Panessa et al. We find an X-ray absorbing c…
Three-dimensional structure of the Upper Scorpius association with the Gaia first data release
Moraux, Estelle; Galli, Phillip A. B.; Joncour, Isabelle
Using new proper motion data from recently published catalogues, we revisit the membership of previously identified members of the Upper Scorpius association. We confirmed 750 of them as cluster members based on the convergent point method, compute their kinematic parallaxes, and combined them with Gaia parallaxes to investigate the 3D structure a…
Methyl isocyanate (CH3NCO): an important missing organic in current astrochemical networks
Gratier, P.; Coutens, A.; Wakelam, V. +3 more
Methyl isocyanate (CH3NCO) is one of the important complex organic molecules detected on the comet 67P/Churyumov-Gerasimenko by Rosetta's Philae lander. It was also detected in hot cores around high-mass protostars along with a recent detection in the solar-type protostar IRAS 16293-2422. We propose here a gas-grain chemical model to fo…
The low-mass population of the Vela OB2 association from Gaia
Wright, Nicholas J.; Jeffries, R. D.; Armstrong, Joseph J.
The first Gaia Data Release presents an opportunity to characterize the low-mass population of OB associations, providing larger statistical samples and better constraints on the formation and evolution of clusters and associations. Using previously known low-mass members in a small region of Vela OB2, we have designed selection criteria that comb…
Twin radio relics in the nearby low-mass galaxy cluster Abell 168
Kale, R.; Parekh, V.; Dwarakanath, K. S. +1 more
We report the discovery of twin radio relics in the outskirts of the low-mass merging galaxy cluster Abell 168 (redshift=0.045). One of the relics is elongated with a linear extent ∼800 kpc and projected width of ∼80 kpc and is located ∼900 kpc towards the north of the cluster centre, oriented roughly perpendicular to the major axis of the X-ray e…
Star formation quenching in green valley galaxies at 0.5 ≲ z ≲ 1.0 and constraints with galaxy morphologies
Menéndez-Delmestre, K.; Sheth, K.; Gonçalves, T. S. +1 more
We calculate the star formation quenching time-scales in green valley galaxies at intermediate redshifts (z ∼ 0.5-1) using stacked zCOSMOS spectra of different galaxy morphological types: spheroidal, disc-like, irregular and merger, dividing disc-like galaxies further into unbarred, weakly barred and strongly barred, assuming a simple exponentiall…
Fluctuations of the gravitational field generated by a random population of extended substructures
Peñarrubia, Jorge
A large population of extended substructures generates a stochastic gravitational field that is fully specified by the function p(F), which defines the probability that a tracer particle experiences a force F within the interval F, F+d{F}. This paper presents a statistical technique for deriving the spectrum of random fluctuations directly from th…
Broad-band spectral study of the jet-disc emission in the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342
Dewangan, Gulab C.; Raychaudhuri, Biplab; Mallick, Labani +1 more
We present a broad-band spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 based on multi-epoch observations performed with Nuclear Spectroscopic Telescope Array on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray e…