Search Publications
Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323
Zezas, Andreas; Drake, Jeremy J.; Wik, Daniel R. +4 more
We report the evidence for the anticorrelation between pulsed fraction (PF) and luminosity of the X-ray pulsar SXP 1323, found for the first time in a luminosity range 1035-1037 erg s-1 from observations spanning 15 yr. The phenomenon of a decrease in X-ray PF when the source flux increases has been observed in our…
Discovery of a 23.8 h QPO in the Swift light curve of XMMU J134736.6+173403
Jin, C.; Carpano, S.
XMMU J134736.6+173403 is an X-ray source discovered serendipitously by XMM-Newton, which was found to be spatially coincident with a pair of galaxies, including a Seyfert 2 galaxy, but presented in 2003 a very sharp persistent flux drop of a factor of 6.5 within 1 h. From the analysis of a set of 29 Swift observations conducted from 2008 February …
PSFGAN: a generative adversarial network system for separating quasar point sources and host galaxy light
Stark, Dominic; Launet, Barthelemy; Schawinski, Kevin +7 more
The study of unobscured active galactic nuclei (AGN) and quasars depends on the reliable decomposition of the light from the AGN point source and the extended host galaxy light. The problem is typically approached using parametric fitting routines using separate models for the host galaxy and the point spread function (PSF). We present a new appro…
Jets, arcs, and shocks: NGC 5195 at radio wavelengths
Muxlow, T. W. B.; Argo, M. K.; Williams, D. R. A. +10 more
We studied the nearby, interacting galaxy NGC 5195 (M 51b) in the radio, optical and X-ray bands. We mapped the extended, low-surface-brightness features of its radio-continuum emission; determined the energy content of its complex structure of shock-ionized gas; constrained the current activity level of its supermassive nuclear black hole. In par…
The origin of the LMC stellar bar: clues from the SFH of the bar and inner disc
Stetson, P. B.; Monelli, M.; Gallart, C. +2 more
We discuss the origin of the Large Magellanic Cloud (LMC) stellar bar by comparing the star formation histories (SFHs) obtained from deep colour-magnitude diagrams (CMDs) in the bar and in a number of fields in different directions within the inner disc. The CMDs, reaching the oldest main-sequence turn-offs in these very crowded fields, have been …
Polarization of seven MBM clouds at high Galactic latitude
Neha, S.; Soam, A.; Maheswar, G. +1 more
We made R-band polarization measurements of 234 stars towards the direction of the MBM 33-39 cloud complex. The distance of the MBM 33-39 complex was determined as 120 ± 10 pc using polarization results and near-infrared photometry from the 2MASS survey. The magnetic field geometry of the individual clouds inferred from our polarimetric results re…
Gaian bottlenecks and planetary habitability maintained by evolving model biospheres: the ExoGaia model
Nicholson, Arwen E.; Wilkinson, David M.; Williams, Hywel T. P. +1 more
The search for habitable exoplanets inspires the question - how do habitable planets form? Planet habitability models traditionally focus on abiotic processes and neglect a biotic response to changing conditions on an inhabited planet. The Gaia hypothesis postulates that life influences the Earth's feedback mechanisms to form a self-regulating sys…
Polarization light curve modelling of corotating interaction regions in the wind of the Wolf-Rayet star WR 6
Ignace, Richard; St-Louis, N.; Tremblay, Patrick
The intriguing WN4b star WR 6 has been known to display epoch-dependent spectroscopic, photometric and polarimetric variability for several decades. In this paper, we set out to verify if a simplified analytical model in which corotating interaction regions (CIRs) threading an otherwise spherical wind is able to reproduce the many broad-band conti…
A chemical study of M67 candidate blue stragglers and evolved blue stragglers observed with APOGEE DR14
Grebel, Eva K.; Pasquali, Anna; Caffau, Elisabetta +1 more
Within the variety of objects populating stellar clusters, blue straggler stars (BSSs) are among the most puzzling ones. BSSs are commonly found in globular clusters, but they are also known to populate open clusters of the Milky Way. Two main theoretical scenarios (collisions and mass transfer) have been suggested to explain their formation, alth…
A census of radio-selected AGNs on the COSMOS field and of their FIR properties
Popesso, P.; Salvato, M.; Brusa, M. +1 more
We use the new catalogue by Laigle et al. to provide a full census of VLA-COSMOS radio sources. We identify 90 per cent of such sources and sub-divide them into active galactic nuclei (AGNs) and star-forming galaxies on the basis of their radio luminosity. The AGN sample is complete with respect to radio selection at all z ≲ 3.5. Out of 704 AGNs, …