Search Publications
How long can luminous blue variables sleep? A long-term photometric variability and spectral study of the Galactic candidate luminous blue variable MN 112
Gvaramadze, V. V.; Karpov, S. V.; Kniazev, A. Y. +1 more
Luminous blue variables (LBVs) are massive stars that show strong spectral and photometric variability. The questions of what evolutionary stages they represent and what exactly drives their instability are still open, and thus it is important to understand whether LBVs without significant ongoing activity exist, and for how long such dormant LBVs…
Optical polarization signatures of black hole X-ray binaries
Piirola, Vilppu; Poutanen, Juri; Veledina, Alexandra +7 more
Polarimetry provides an avenue for probing the geometry and physical mechanisms producing optical radiation in many astrophysical objects, including stellar binary systems. We present the results of multiwavelength (BVR) polarimetric studies of a sample of historical black hole X-ray binaries, observed during their outbursts or in the quiescent (o…
Multiple variability time-scales of the early nitrogen-rich Wolf-Rayet star WR 7
Koenigsberger, G.; Hamann, W. -R.; Estrada-Dorado, S. +7 more
We present the analysis of the optical variability of the early, nitrogen-rich Wolf-Rayet (WR) star WR 7. The analysis of multisector Transiting Exoplanet Survey Satellite (TESS) light curves and high-resolution spectroscopic observations confirm multiperiodic variability that is modulated on time-scales of years. We detect a dominant period of 2.…
Simulating nearly edge-on sloshing in the galaxy cluster Abell 2199
Laganá, T. F.; Machado, R. E. G.; Souza, G. S. +3 more
Off-axis collisions between galaxy clusters may induce the phenomenon of sloshing, causing dense gas to be dragged from the cool core of a cluster, resulting in a spiral of enhanced X-ray emission. Abell 2199 displays signatures of sloshing in its core and it is possible that the orbital plane of the collision is seen nearly edge-on. We aim to eva…
The GALAH Survey: improving our understanding of confirmed and candidate planetary systems with large stellar surveys
Lewis, Geraint F.; Casey, Andrew R.; Wittenmyer, Robert A. +24 more
Pioneering photometric, astrometric, and spectroscopic surveys is helping exoplanetary scientists better constrain the fundamental properties of stars within our galaxy and the planets these stars host. In this study, we use the third data release from the stellar spectroscopic GALAH Survey, coupled with astrometric data of eDR3 from the Gaia sate…
The young Galactic cluster NGC 225: binary stars' content and total mass estimate
Munari, U.; Ochner, P.; Carraro, G. +2 more
Galactic star clusters are known to harbour a significant amount of binary stars, yet their role in the dynamical evolution of the cluster as a whole is not comprehensively understood. We investigated the influence of binary stars on the total mass estimate for the case of the moderately populated Galactic star cluster NGC 225. The analysis of mul…
A search for hot subdwarf binaries in data from the Transiting Exoplanet Survey Satellite
Siwak, M.; Zola, S.; Krzesinski, J. +1 more
We present the results of a search for binary hot subdwarf stars in photometric data from the Transiting Exoplanet Survey Satellite (TESS). The sample of objects used in this work was a byproduct of another search for pulsating hot subdwarfs, which resulted in the discovery of nearly 400 non-pulsating variable candidates. The periodogram for each …
Investigation of Rocket Effect in BRC 18 using Gaia EDR3
Ojha, D. K.; Saha, Piyali; Neha, Sharma +1 more
Bright-rimmed clouds (BRCs) are ideal candidates to study radiation-driven implosion mode of star formation as they are potential sites of triggered star formation, located at the edges of HII regions, showing evidence of ongoing star formation processes. BRC 18 is located towards the eastern edge of relatively closer (~400 pc) H II region excited…
Selecting a complete sample of blazars in sub-millimetre catalogues
Bonavera, L.; González-Nuevo, J.; López-Caniego, M. +6 more
The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), which has covered about 642 sq. deg. in five bands from 100 to 500 $\mu \rm m$, allows a blind flux-limited selection of blazars at sub-mm wavelengths. However, blazars constitute a tiny fraction of H-ATLAS sources and therefore identifying them is not a trivial task. Using the data…
Investigating the nature and properties of MAXI J1810-222 with radio and X-ray observations
Pinto, C.; Motta, S. E.; Segreto, A. +10 more
We present results from radio and X-ray observations of the X-ray transient MAXI J1810-222. The nature of the accretor in this source has not been identified. In this paper, we show results from a quasi-simultaneous radio and X-ray monitoring campaign taken with the Australia Telescope Compact Array, the Neil Gehrels Swift Observatory X-ray Telesc…