Search Publications
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…
Statistics of the fractional polarization of compact radio sources in Planck maps
Toffolatti, Luigi; Bonavera, Laura; González-Nuevo, Joaquin +1 more
In this work, we apply the stacking technique to estimate the average fractional polarization from 30 to 353 GHz of a primary sample of 1560 compact sources - essentially all radio sources - detected in the 30 GHz Planck all-sky map and listed in the second version of the Planck Catalogue of Compact Sources (PCCS2). We divide our primary sample in…
Multiband study of RX J0838-2827 and XMM J083850.4-282759: a new asynchronous magnetic cataclysmic variable and a candidate transitional millisecond pulsar
D'Avanzo, P.; Campana, S.; Ribas, I. +23 more
In a search for the counterpart to the Fermi-LAT source 3FGL J0838.8-2829, we performed a multiwavelength campaign: in the X-ray band with Swift and XMM-Newton; in the infrared and optical with OAGH, ESO-NTT and IAC80; and in the radio with ATCA observations. We also used archival hard X-ray data obtained by INTEGRAL. We report on three X-ray sour…