Search Publications
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…
Understanding WASP-12b
Goodman, Jeremy; Bailey, Avery
The orbital period of the hot Jupiter WASP-12b is apparently changing. We study whether this reflects orbital decay due to tidal dissipation in the star, or apsidal precession of a slightly eccentric orbit. In the latter case, a third body or other perturbation would be needed to sustain the eccentricity against tidal dissipation in the planet its…
A catalogue of stellar diameters and fluxes for mid-infrared interferometry
Meisenheimer, K.; Matter, A.; Jaffe, W. +14 more
We present the Mid-infrared stellar Diameters and Fluxes compilation Catalogue (MDFC) dedicated to long-baseline interferometry at mid-infrared wavelengths (3-13 µm). It gathers data for half a million stars, i.e. nearly all the stars of the Hipparcos-Tycho catalogue whose spectral type is reported in the SIMBAD data base. We cross-match 26 …
Ages and masses of 0.64 million red giant branch stars from the LAMOST Galactic Spectroscopic Survey
Shi, Jianrong; Zhao, Gang; Wu, Yaqian +14 more
We present a catalogue of stellar age and mass estimates for a sample of 640 986 red giant branch (RGB) stars of the Galactic disk from the LAMOST Galactic Spectroscopic Survey (DR4). The RGB stars are distinguished from the red clump (RC) stars utilizing period spacing derived from the spectra with a machine-learning method based on kernel princi…