Search Publications
Observational determination of the galaxy bias from cosmic variance with a random pointing survey: clustering of z ∼ 2 galaxies from Hubble's BoRG survey
Cameron, Alex J.; Livermore, Rachael C.; Trenti, Michele +1 more
Gravitational clustering broadens the count-in-cells distribution of galaxies for surveys along uncorrelated (well-separated) lines of sight beyond Poisson noise. A number of methods have proposed to measure this excess `cosmic' variance to constrain the galaxy bias (i.e. the strength of clustering) independently of the two-point correlation funct…
A nuclear ionized gas outflow in the Seyfert 2 galaxy UGC 2024
Robinson, Andrew; Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa +15 more
As part of a high-resolution observational study of feeding and feedback processes occurring in the vicinity of the active galactic nucleus in 40 galaxies, we observed the inner 3{^''.}5 × 5 arcsec of the nearby spiral and Seyfert 2 galaxy UGC 2024 with the integral field unit of the Gemini-South Telescope. The observations enabled a st…
Detailed spectroscopic and photometric study of three detached eclipsing binaries
Kahraman Aliçavuş, F.; Aliçavuş, F.
Detached eclipsing binaries are remarkable systems to provide accurate fundamental stellar parameters. Fundamental stellar parameters and the metallicity values of stellar systems are needed to deeply understand stellar evolution and formation. In this study, we focus on the detailed spectroscopic and photometric studies of three detached eclipsin…
Search for the evolutionary relationship between Galactic globular and open clusters using data from the Gaia DR2 catalogue
Bobylev, V. V.; Bajkova, A. T.
Passing through the Galactic disc, a massive object such as a globular cluster, can trigger star formation process leading to the birth of open clusters. Here, we analyse such possible evolutionary relationship between globular and open clusters. To search for the closest rapprochement between objects we computed backwards the orbits of 150 Galact…
Long-term X-ray variation of the colliding-wind Wolf-Rayet binary WR 125
Sugawara, Yasuharu; Ebisawa, Ken; Midooka, Takuya
WR 125 is considered to be a colliding-wind Wolf-Rayet binary (CWWB), from which the most recent infrared flux increase was reported between 1990 and 1993. We observed the object four times from 2016 November to 2017 May with Swift and XMM-Newton, and carried out a precise X-ray spectral study for the first time. There were hardly any changes in t…
Radio-optical galaxy shape and shear correlations in the COSMOS field using 3 GHz VLA observations
Brown, Michael L.; Harrison, Ian; Hillier, Tom +1 more
We present a weak-lensing analysis of the 3 GHz Very Large Array radio survey of the COSMOS field, which we correlate with overlapping Hubble Space Telescope-Advanced Camera for Survey optical observations using both intrinsic galaxy shape and cosmic shear correlation statistics. After cross-matching sources between the two catalogues, we measure …
A slowly expanding torus associated with the candidate LBV MGE 042.0787+00.5084
Bordiu, Cristobal; Rizzo, J. Ricardo; Ritacco, Alessia
The luminous blue variable (LBV) phase is a poorly understood stage in the evolution of high-mass stars, characterized by its brevity and instability. The surroundings of LBV stars are excellent test beds to study their dense stellar winds and eruptive mass-loss events. Aiming to improve our knowledge of the LBV phase, we observed the J = 1 → 0 an…
Evidence for a TDE origin of the radio transient Cygnus A-2
Reynolds, C. S.; Rowlinson, A.; Siemiginowska, A. +3 more
In 2015, a radio transient named Cygnus A-2 was discovered in Cygnus A with the Very Large Array. Because of its radio brightness (νFν ≈ 6 × 1039 erg s-1), this transient likely represents a secondary black hole in orbit around the active galactic nucleus. Using Chandra ACIS observations from 2015 to 2017, we have …
The GALAH survey: unresolved triple Sun-like stars discovered by the Gaia mission
Lewis, Geraint F.; Ting, Yuan-Sen; Buder, Sven +17 more
The latest Gaia data release enables us to accurately identify stars that are more luminous than would be expected on the basis of their spectral type and distance. During an investigation of the 329 best solar twin candidates uncovered among the spectra acquired by the GALAH survey, we identified 64 such overluminous stars. In order to investigat…
Relativistic Fe Kα line in the composite X-ray spectra of radio-loud active galactic nuclei
Jin, Chichuan; Liu, Zhu; Yuan, Weimin +1 more
While a broad Fe Kα emission line is generally found in the X-ray spectra of radio quiet (RQ) active galactic nuclei (AGNs), this feature, commonly thought to be broadened by the relativistic effects near the central black hole, appears to be rare in their radio loud (RL) counterparts. In this paper, we carry out a detailed study of the ensemble p…