Search Publications
Forecasting cosmic acceleration measurements using the Lyman-α forest
Liske, Jochen; Gonzalez, Anthony; Dong, Chenxing +5 more
We present results from end-to-end simulations of observations designed to constrain the rate of change in the expansion history of the Universe using the redshift drift of the Lyman-α forest absorption lines along the lines of sight towards bright quasars. For our simulations, we take Lyman-α forest lines extracted from Keck/HIRES spectra of brig…
The centre-to-limb variation of non-thermal velocities using IRIS Si IV
Del Zanna, Giulio; Rao, Yamini K.; Mason, Helen E.
We study the non-thermal velocities in the quiet Sun using various high spatial, temporal, and spectral resolution observations from the Interface Region Imaging Spectrograph (IRIS). We focus our analysis on the transition region using the optically thin line (Si IV 1393.7 Å), and select line profiles that are nearly Gaussian. We find evidence of …
Spatially resolved gas flows around the Milky Way
Fox, Andrew J.; Bordoloi, Rongmon; Clark, Sean
We present spatially resolved measurements of cool gas flowing into and out of the Milky Way (MW), using archival ultraviolet spectra of background quasars from the Hubble Space Telescope/Cosmic Origins Spectrograph. We co-add spectra of different background sources at close projected angular separation on the sky. This novel stacking technique dr…
Gaia EDR3 bright star parallax zero-point using stellar clusters
Flynn, C.; Sekhri, R.; Venville, T. +4 more
We examine the zero-point of parallaxes in the Gaia EDR3 (Early Data Release 3, Gaia Collaboration (2021a)), using stars in open and globular clusters. Our aim is to check for zero-point systematics between bright stars G < 12 (which includes some important distance scale calibrators) and faint stars G > 14, for which the parallax scale has …
A selection function toolbox for subsets of astronomical catalogues
Everall, Andrew; Boubert, Douglas
Large catalogues are ubiquitous throughout astronomy, but most scientific analyses are carried out on smaller samples selected from these catalogues by chosen cuts on catalogued quantities. The selection function of that scientific sample - the probability that a star in the catalogue will satisfy these cuts and so make it into the sample - is thu…
New XMM-Newton observations of faint, evolved supernova remnants in the Large Magellanic Cloud
Haberl, F.; Filipović, M. D.; Maggi, P. +5 more
The Large Magellanic Cloud (LMC) hosts a rich population of supernova remnants (SNRs), our knowledge of which is the most complete of any galaxy. However, there remain many candidate SNRs, identified through optical and radio observations where additional X-ray data can confirm their SNR nature and provide details on their physical properties. In …
A pilot ASKAP survey for radio transients towards the Galactic Centre
Bannister, Keith W.; Kaplan, David L.; Lenc, Emil +8 more
We present the results of a radio transient and polarization survey towards the Galactic Centre, conducted as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients pilot survey. The survey region consisted of five fields covering $\sim 265\, {\rm deg}^2$ (350○ ≲ l ≲ 10○, |b| ≲ 10○).…
High-resolution ALMA observations of V4046 Sgr: a circumbinary disc with a thin ring
Garufi, Antonio; Pérez, Sebastián; Casassus, Simon +8 more
The nearby V4046 Sgr spectroscopic binary hosts a gas-rich disc known for its wide cavity and dusty ring. We present high resolution (~20 mas or 1.4 au) ALMA observations of the 1.3 mm continuum of V4046 Sgr which, combined with SPHERE-IRDIS polarised images and a well-sampled spectral energy distribution (SED), allow us to propose a physical mode…
A systematic comparison of galaxy cluster temperatures measured with NuSTAR and Chandra
Wik, D. R.; Gastaldello, F.; Maughan, B. J. +2 more
Temperature measurements of galaxy clusters are used to determine their masses, which in turn are used to determine cosmological parameters. However, systematic differences between the temperatures measured by different telescopes imply a significant source of systematic uncertainty on such mass estimates. We perform the first systematic compariso…
The distribution of dust in edge-on galaxies: I. The global structure
Gontcharov, George A.; Mosenkov, Aleksandr V.; Baes, Maarten +9 more
In this first paper in a series we present a study of the global dust emission distribution in nearby edge-on spiral galaxies. Our sample consists of 16 angularly large and 13 less spatially resolved galaxies selected from the DustPedia sample. To explore the dust emission distribution, we exploit the Herschel photometry in the range 100-500 $\mu …