Search Publications
Mapping dust in the giant molecular cloud Orion A
Magorrian, John; Gration, Amery
The Sun is located close to the Galactic mid-plane, meaning that we observe the Galaxy through significant quantities of dust. Moreover, the vast majority of the Galaxy's stars also lie in the disc, meaning that dust has an enormous impact on the massive astrometric, photometric and spectroscopic surveys of the Galaxy that are currently underway. …
Discovering changing-look AGN in the 6dF Galaxy Survey using ATLAS light curves
Wolf, Christian; Lai, Samuel; Tonry, John L. +4 more
Changing-look active galactic nuclei (CLAGNs) are characterized by extreme variations in line emission over short time-scales, mostly affecting broad H
X-rays from a newly discovered superbubble in M31
Li, Hui; Mao, Junjie; Cui, Wei +3 more
A superbubble is a hot, dilute, and X-ray-emitting gas cavity produced by stellar winds and supernova explosions. It is an intriguing feature for the study of stellar feedback processes. We report a study of possible superbubbles in the Andromeda Galaxy (M31). We identify one out of 83 extended sources as a strong superbubble candidate, SB1, from …
Mass segregation and velocity dispersion as evidence for a dark star cluster
Kroupa, Pavel; Pflamm-Altenburg, Jan; Wu, Wenjie
A dark star cluster (DSC) is a system in which the cluster potential is dominated by stellar remnants, such as black holes and neutron stars having larger masses than the long-lived low-mass stars. Due to mass segregation, these remnants are located in the central region of the cluster and form a dark core. We expect that at a few kpc from the Gal…
New Herbig-Haro objects associated with embedded sources
Movsessian, T. A.; Andreasyan, H. R.; Magakian, T. Yu +1 more
We continue to present the results of the Byurakan Narrow Band Imaging Survey (BNBIS). The main goal of this survey is to search for Herbig-Haro (HH) objects and jets in Galactic dark clouds. In this work we present the results of the search in the vicinity of infrared sources that are bright in the WISE survey and embedded in the dark clouds. The…
Orbits and masses in two triple systems
Tokovinin, Andrei; Nazor, Dinko
In an effort to determine accurate orbital and physical properties of a large number of bright stars, a method was developed to fit simultaneously stellar parameters (masses, luminosities, effective temperatures), distance, and orbits to the available data on multiple systems, namely the combined and differential photometry, positional measurement…
A catalogue of merging clusters of galaxies: cluster partners, merging subclusters, and post-collision clusters
Yuan, Z. S.; Han, J. L.; Wen, Z. L.
Clusters of galaxies are merging during the formation of large-scale structures in the Universe. Based on optical survey data, we identify a large sample of pre-mergers of galaxy clusters and merging subclusters in rich clusters. We find 39 382 partners within a velocity difference of 1500 km s$^{-1}$ and a projected separation of 5 $r_{500}$ arou…
Dynamical mass determination and partial eclipses of the heartbeat star HD 181793
Wilson, Thomas G.; Collier Cameron, Andrew; Uronen, Laura E.
We identify the bright Am-type star HD 181793 to be a previously unknown eclipsing, chemically peculiar heartbeat binary, the second of its kind known. The system carries an orbital period of $P = 11.47578275 \pm 0.00000055$ d. We use TESS photometry and LCOGT NRES radial velocity data to build a self-consistent orbital model and determine the fun…
Origin of extended main-sequence turn-off in open cluster NGC 2355
Zhang, Yu; Samal, M. R.; Amard, Louis +5 more
The presence of extended Main-Sequence Turn-Off (eMSTO) in the open clusters has been attributed to various factors, such as spread in rotation rates, binary stars, and dust-like extinction from stellar excretion discs. We present a comprehensive analysis of the eMSTO in the open cluster NGC 2355. Using spectra from the Gaia-European Southern Obse…
Simultaneous Chandra and HST observations of the quiescent neutron star low-mass X-ray binaries in 47 Tucanae
van den Berg, M.; Heinke, C. O.; Cohn, H. N. +6 more
We present simultaneous Chandra X-ray Observatory and Hubble Space Telescope observations of three certain (X5, X7, W37) and two likely (X4, W17) quiescent neutron star low-mass X-ray binaries (qLMXBs) in the globular cluster 47 Tuc. We study these systems in the X-ray, optical, and near-ultraviolet (NUV) using the simultaneous data and additional…