Search Publications
The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters - XIV. Multiple stellar populations within M 15 and their radial distribution
Anderson, J.; Milone, A. P.; Marino, A. F. +6 more
In the context of the Hubble Space Telescope UV Survey of Galactic globular clusters (GCs), we derived high-precision, multi-band photometry to investigate the multiple stellar populations in the massive and metal-poor GC M 15. By creating for red-giant branch (RGB) stars of the cluster a `chromosome map', which is a pseudo two-colour diagram made…
Astrometric and photometric study of Dias 4, Dias 6, and other five open clusters using ground-based and Gaia DR2 data
Dias, W. S.; Monteiro, H.; Lépine, J. R. D. +3 more
We present a study of seven southern open clusters based on UBVRI CCD photometry (Johnsons-Cousins system) and Gaia DR2 data. Dias 4, Dias 6, and four other clusters had UBVRI photometric observations determined for the first time. From the observational UBVRI data we obtained photometric membership probability estimates and, using the proper moti…
Using principal component analysis to understand the variability of PDS 456
Fabian, A. C.; Buisson, D. J. K.; Reeves, J. N. +2 more
We present a spectral-variability analysis of the low-redshift quasar PDS 456 using principal component analysis. In the XMM-Newton data, we find a strong peak in the first principal component at the energy of the Fe absorption line from the highly blueshifted outflow. This indicates that the absorption feature is more variable than the continuum,…
A new powerful and highly variable disc wind in an AGN-star-forming galaxy, the case of MCG-03-58-007
Campana, S.; Turner, T. J.; Ballo, L. +7 more
We present the discovery of a new candidate for a fast disc wind, in the nearby Seyfert 2 galaxy MCG-03-58-007. This wind is discovered in a deep Suzaku observation that was performed in 2010. Overall the X-ray spectrum of MCG-03-58-007 is highly absorbed by a neutral column density of NH ∼1023 cm-2, in agreement w…
Flux rope breaking and formation of a rotating blowout jet
Joshi, Navin Chandra; Nishizuka, Naoto; Filippov, Boris +2 more
We analysed a small flux rope eruption converted into a helical blowout jet in a fan-spine configuration using multiwavelength observations taken by Solar Dynamics Observatory, which occurred near the limb on 2016 January 9. In our study, first, we estimated the fan-spine magnetic configuration with the potential-field calculation and found a sini…
Is there a UV/X-ray connection in IRAS 13224-3809?
Fabian, A. C.; Pinto, C.; Miniutti, G. +16 more
We present results from the optical, ultraviolet, and X-ray monitoring of the NLS1 galaxy IRAS 13224-3809 taken with Swift and XMM-Newton during 2016. IRAS 13224-3809 is the most variable bright AGN in the X-ray sky and shows strong X-ray reflection, implying that the X-rays strongly illuminate the inner disc. Therefore, it is a good candidate to …
CO excitation in the Seyfert galaxy NGC 34: stars, shock or AGN driven?
Cimatti, A.; Pozzi, F.; Massardi, M. +7 more
We present a detailed analysis of the X-ray and molecular gas emission in the nearby galaxy NGC 34, to constrain the properties of molecular gas, and assess whether, and to what extent, the radiation produced by the accretion on to the central black hole affects the CO line emission. We analyse the CO spectral line energy distribution (SLED) as re…
The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows at 15.7 GHz
Wijers, R. A. M. J.; Fender, R. P.; van der Horst, A. J. +7 more
We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7 GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target …
The Complete Local-volume Groups Sample - II. A study of the central radio galaxies in the high-richness sub-sample
Babul, Arif; Raychaudhury, Somak; Giacintucci, Simona +3 more
We present a study of the radio properties of the dominant early-type galaxies in 26 galaxy groups, the high-richness sub-sample of the Complete Local-volume Groups Sample (CLoGS). Combining new 610 and 235 MHz observations of 21 groups from the Giant Metrewave Radio Telescope (GMRT) with archival GMRT and Very Large Array (VLA) survey data, we fi…
Testing models of stellar structure and evolution - I. Comparison with detached eclipsing binaries
del Burgo, C.; Allende Prieto, C.
We present the results of an analysis aimed at testing the accuracy and precision of the PARSEC v1.2S library of stellar evolution models, combined with a Bayesian approach, to infer stellar parameters. We mainly employ the online DEBCat catalogue by Southworth, a compilation of detached eclipsing binary systems with published measurements of mass…