Search Publications
The ASAS-SN catalogue of variable stars - VII. Contact binaries are different above and below the Kraft break
Kochanek, C. S.; Pinsonneault, M. H.; Stanek, K. Z. +11 more
We characterize ${\sim } 71\, 200$ W Ursae Majoris (UMa) type (EW) contact binaries, including ${\sim } 12\, 600$ new discoveries, using All-Sky Automated Survey for SuperNovae (ASAN-SN)V-band all-sky light curves along with archival data from Gaia, 2MASS, AllWISE, LAMOST, GALAH, RAVE, and APOGEE. There is a clean break in the EW period-luminosity…
Limits on the electromagnetic counterpart to S190814bv
Butler, N. R.; Lee, W. H.; Watson, A. M. +11 more
We derive limits on any electromagnetic counterpart to the compact binary merger S190814bv, whose parameters are consistent with the merger of a black hole and a neutron star. We present observations with the new wide-field optical imager DDOTI and also consider Swift/BAT observations reported by Palmer et al. We show that Swift/BAT would have det…
MOVES III. Simultaneous X-ray and ultraviolet observations unveiling the variable environment of the hot Jupiter HD 189733b
Vidotto, A. A.; Ehrenreich, D.; Lecavelier des Etangs, A. +8 more
In this third paper of the MOVES (Multiwavelength Observations of an eVaporating Exoplanet and its Star) programme, we combine Hubble Space Telescope far-ultraviolet (FUV) observations with XMM-Newton/Swift X-ray observations to measure the emission of HD 189733 in various FUV lines, and its soft X-ray spectrum. Based on these measurements we char…
Magnification, dust, and time-delay constraints from the first resolved strongly lensed Type Ia supernova iPTF16geu
Cenko, S. B.; Lee, W. H.; Kulkarni, S. R. +14 more
We report lensing magnifications, extinction, and time-delay estimates for the first resolved, multiply imaged Type Ia supernova iPTF16geu, at z = 0.409, using Hubble Space Telescope (HST) observations in combination with supporting ground-based data. Multiband photometry of the resolved images provides unique information about the differential di…
Identifying stellar streams in Gaia DR2 with data mining techniques
Martell, Sarah L.; Simpson, Jeffrey D.; Borsato, Nicholas W.
Streams of stars from captured dwarf galaxies and dissolved globular clusters are identifiable through the similarity of their orbital parameters, a fact that remains true long after the streams have dispersed spatially. We calculate the integrals of motion for 31 234 stars, to a distance of 4 kpc from the Sun, which have full and accurate 6D phas…
Detectability of embedded protoplanets from hydrodynamical simulations
Testi, L.; Rosotti, G.; Sanchis, E. +2 more
We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-sized planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts to being transparent to the planet flux in the infrared (IR…
Intensity interferometry of P Cygni in the H α emission line: towards distance calibration of LBV supergiant stars
Domiciano de Souza, A.; Vakili, F.; Rivet, J. -P. +7 more
We present intensity interferometry of the luminous blue variable P Cyg in the light of its H α emission performed with 1 m-class telescopes. We compare the measured visibility points to synthesized interferometric data based on the CMFGEN physical modelling of a high-resolution spectrum of P Cyg recorded almost simultaneously with our interferome…
Evidence for variability time-scale-dependent UV/X-ray delay in Seyfert 1 AGN NGC 7469
Peterson, Bradley M.; Horne, Keith; Gültekin, Kayhan +5 more
Using a month-long X-ray light curve from RXTE/PCA and 1.5 month-long UV continuum light curves from IUE spectra in 1220-1970 Å, we performed a detailed time-lag study of the Seyfert 1 galaxy NGC 7469. Our cross-correlation analysis confirms previous results showing that the X-rays are delayed relative to the UV continuum at 1315 Šby 3.49 ± 0.22 d…
Measuring the masses of magnetic white dwarfs: a NuSTAR legacy survey
Mukai, K.; Heinke, C. O.; Gandhi, P. +11 more
The hard X-ray spectrum of magnetic cataclysmic variables can be modelled to provide a measurement of white dwarf mass. This method is complementary to radial velocity measurements, which depend on the (typically rather uncertain) binary inclination. Here, we present results from a Legacy Survey of 19 magnetic cataclysmic variables with NuSTAR. We…
PSR J1012+5307: a millisecond pulsar with an extremely low-mass white dwarf companion
van Kerkwijk, M. H.; Breton, R. P.; Mata Sánchez, D. +2 more
Binaries harbouring millisecond pulsars (MSPs) enable a unique path to determine neutron star (NS) masses: radio pulsations reveal the motion of the NS, while that of the companion can be characterized through studies in the optical range. PSR J1012+5307 is an MSP in a 14.5-h orbit with a helium-core white dwarf (WD) companion. In this work we pre…