Search Publications
On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations
McClure-Griffiths, N. M.; Dickey, John M.; Staveley-Smith, L. +10 more
We use new high-resolution H I data from the Australian Square Kilometre Array Pathfinder to investigate the dynamics of the Small Magellanic Cloud (SMC). We model the H I gas component as a rotating disc of non-negligible angular size, moving into the plane of the sky, and undergoing nutation/precession motions. We derive a high-resolution (∼10 p…
Photodynamical analysis of the triply eclipsing hierarchical triple system EPIC 249432662
Vanderburg, A.; Haas, M.; Rappaport, S. +16 more
Using Campaign 15 data from the K2 mission, we have discovered a triply eclipsing triple star system: EPIC 249432662. The inner eclipsing binary system has a period of 8.23 d, with shallow ∼3 per cent eclipses. During the entire 80-d campaign, there is also a single eclipse event of a third body in the system that reaches a depth of nearly 50 per …
Radio frequency timing analysis of the compact jet in the black hole X-ray binary Cygnus X-1
Maccarone, T. J.; Gandhi, P.; Casella, P. +5 more
We present simultaneous multiband radio and X-ray observations of the black hole X-ray binary Cygnus X-1, taken with the Karl G. Jansky Very Large Array and the Nuclear Spectroscopic Telescope Array. With these data, we detect clear flux variability consistent with emission from a variable compact jet. To probe how the variability signal propagate…
Determining the recurrence time-scale of long-lasting YSO outbursts
Naylor, Tim; Morrell, Sam; Contreras Peña, Carlos
We have determined the rate of large accretion events in Class I and II young stellar objects (YSOs) by comparing the all-sky digitized photographic plate surveys provided by SuperCOSMOS with the latest data release from Gaia (DR2). The long mean baseline of 55 yr along with a large sample of Class II YSOs (≃15 000) allows us to study approximatel…
Search for RR Lyrae stars in DES ultrafaint systems: Grus I, Kim 2, Phoenix II, and Grus II
Bechtol, K.; Smith, M.; Annis, J. +58 more
This work presents the first search for RR Lyrae stars (RRLs) in four of the ultrafaint systems imaged by the Dark Energy Survey using SOAR/Goodman and Blanco/DECam imagers. We have detected two RRLs in the field of Grus I, none in Kim 2, one in Phoenix II, and four in Grus II. With the detection of these stars, we accurately determine the distanc…
Towards a complete understanding of the Magellanic Stream Formation
Hammer, Francois; Ripepi, Vincenzo; Cioni, Maria-Rosa L. +4 more
The Magellanic Clouds (MCs) have lost most of their gas during their passage by the Milky Way, a property that has never been successfully modelled. Here, we use accurate and mesh-free hydrodynamic simulations to reproduce the Magellanic Stream and the MCs in the frame of a `ram-pressure plus collision' model. This model reproduces many of the obs…
Reverberation reveals the truncated disc in the hard state of GX 339-4
Done, Chris; Mahmoud, Ra'ad D.; De Marco, Barbara
The nature and geometry of the hard state in black hole binaries is controversial. The broad-band continuum spectrum and fast variability properties can be explained in a model where the inner disc evaporates into a geometrically thick, hot flow. However, these models are challenged by the persistent detection of an extremely broad iron line, whic…
Systematic serendipity: a test of unsupervised machine learning as a method for anomaly detection
Giles, Daniel; Walkowicz, Lucianne
Advances in astronomy are often driven by serendipitous discoveries. As survey astronomy continues to grow, the size and complexity of astronomical data bases will increase, and the ability of astronomers to manually scour data and make such discoveries decreases. In this work, we introduce a machine learning-based method to identify anomalies in …
The first maps of κd - the dust mass absorption coefficient - in nearby galaxies, with DustPedia
Bianchi, S.; Madden, S. C.; Galliano, F. +17 more
The dust mass absorption coefficient, κd is the conversion function used to infer physical dust masses from observations of dust emission. However, it is notoriously poorly constrained, and it is highly uncertain how it varies, either between or within galaxies. Here we present the results of a proof-of-concept study, using the DustPedi…
Search for stellar companions of exoplanet host stars by exploring the second ESA-Gaia data release
Mugrauer, M.
A new survey is presented, which explores the second data release of the ESA-Gaia mission, in order to search for stellar companions of exoplanet host stars, located at distances closer than about 500 pc around the Sun. In total, 176 binaries, 27 hierarchical triples, and one hierarchical quadruple system are detected among more than 1300 exoplane…