Search Publications
Observing the metal-poor solar neighbourhood: a comparison of galactic chemical evolution predictions*†
Jordan, C.; Soubiran, C.; Korotin, S. A. +15 more
Atmospheric parameters and chemical compositions for 10 stars with metallicities in the region of -2.2 < [Fe/H] < -0.6 were precisely determined using high-resolution, high signal-to-noise, spectra. For each star, the abundances, for 14-27 elements, were derived using both local thermodynamic equilibrium (LTE) and non-LTE (NLTE) approaches. …
The Fan Region at 1.5 GHz - I. Polarized synchrotron emission extending beyond the Perseus Arm
Leahy, J. P.; Gaensler, B. M.; McClure-Griffiths, N. M. +12 more
The Fan Region is one of the dominant features in the polarized radio sky, long thought to be a local (distance ≲500 pc) synchrotron feature. We present 1.3-1.8 GHz polarized radio continuum observations of the region from the Global Magneto-Ionic Medium Survey and compare them to maps of Hα and polarized radio continuum intensity from 0.408 to 35…
High-precision optical polarimetry of the accreting black hole V404 Cyg during the 2015 June outburst
Miles-Páez, Paulo A.; Piirola, Vilppu; Tsygankov, Sergey S. +4 more
Our simultaneous three-colour (BVR) polarimetric observations of the low-mass black hole X-ray binary V404 Cyg show a small but statistically significant change of polarization degree (Δp ∼ 1 per cent) between the outburst in 2015 June and the quiescence. The polarization of V404 Cyg in the quiescent state agrees within the errors with that of the…
An atlas of exotic variability in IGR J17091-3624: a comparison with GRS 1915+105
Court, J. M. C.; Altamirano, D.; Belloni, T. +5 more
We performed an analysis of all Rossi X-ray Timing Explorer observations of the low-mass X-ray binary (LMXB) and black hole candidate IGR J17091-3624 during the 2011-2013 outburst of the source. By creating light curves, hardness-intensity diagrams and power density spectra of each observation, we have created a set of nine variability 'classes' t…
Modelling the ArH+ emission from the Crab nebula
Barlow, M. J.; Viti, S.; Priestley, F. D.
We have performed combined photoionization and photodissociation region (PDR) modelling of a Crab nebula filament subjected to the synchrotron radiation from the central pulsar wind nebula, and to a high flux of charged particles; a greatly enhanced cosmic-ray ionization rate over the standard interstellar value, ζ0, is required to acco…
The opposition effect of 67P/Churyumov-Gerasimenko on post-perihelion Rosetta images
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +45 more
High-resolution OSIRIS/Rosetta images of 67P/Churyumov-Gerasimenko acquired on the night run of 2016 April 9-10 show, at large scale, an opposition effect (OE) spot sweeping across Imhotep as the phase angle ranges from 0° to 17°. In this work, we fitted the phase curve of the whole surface imaged as well as three particular features using both th…
A study of halo and relic radio emission in merging clusters using the Murchison Widefield Array
Callingham, J. R.; Johnston-Hollitt, M.; Intema, H. T. +18 more
We have studied radio haloes and relics in nine merging galaxy clusters using the Murchison Widefield Array (MWA). The images used for this study were obtained from the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey which was carried out at five frequencies, viz. 88, 118, 154, 188 and 215 MHz. We detect diffuse radio emission in eight of th…
ALMA constraints on star-forming gas in a prototypical z = 1.5 clumpy galaxy: the dearth of CO(5-4) emission from UV-bright clumps
Daddi, E.; Elbaz, D.; Rujopakarn, W. +13 more
We present deep ALMA CO(5-4) observations of a main-sequence, clumpy galaxy at z = 1.5 in the HUDF. Thanks to the ∼0{^''.}5 resolution of the ALMA data, we can link stellar population properties to the CO(5-4) emission on scales of a few kiloparsec. We detect strong CO(5-4) emission from the nuclear region of the galaxy, consistent with…
Alignments of parity even/odd-only multipoles in CMB
Aluri, Pavan K.; Ralston, John P.; Weltman, Amanda
We compare the statistics of parity even and odd multipoles of the cosmic microwave background (CMB) sky from Planck full mission temperature measurements. An excess power in odd multipoles compared to even multipoles has previously been found on large angular scales. Motivated by this apparent parity asymmetry, we evaluate directional statistics …
Quasar lenses and galactic streams: outlier selection and Gaia multiplet detection
Agnello, Adriano
I describe two novel techniques originally devised to select strongly lensed quasar candidates in wide-field surveys. The first relies on outlier selection in optical and mid-infrared magnitude space; the second combines mid-infrared colour selection with Gaia spatial resolution, to identify multiplets of objects with quasar-like colours. Both met…