Publications (39)
Searching for Electromagnetic Counterparts to Gravitational-wave Merger Events with the Prototype Gravitational-wave Optical Transient Observer (GOTO-4)
B. P. Gompertz, R. Cutter, D. Steeghs +49
We report the results of optical follow-up observations of 29 gravitational-wave triggers during the first half of the LIGO-Virgo Collaboration (LVC) O3 run with the Gravitational-…
Light curve classification with recurrent neural networks for GOTO: dealing with imbalanced data
U. F. Burhanudin, J. R. Maund, T. Killestein +42
The advent of wide-field sky surveys has led to the growth of transient and variable source discoveries. The data deluge produced by these surveys has necessitated the use of machi…
A second case of outbursts in a pulsating white dwarf observed by Kepler
J. J. Hermes, M. H. Montgomery, Keaton J. Bell +7
We present observations of a new phenomenon in pulsating white dwarf stars: large-amplitude outbursts at timescales much longer than the pulsation periods. The cool (Teff = 11,010…
Insights into internal effects of common-envelope evolution using the extended Kepler mission
J. J. Hermes, B. T. Gaensicke, A. Bischoff-Kim +14
We present an analysis of the binary and physical parameters of a unique pulsating white dwarf with a main-sequence companion, SDSS J1136+0409, observed for more than 77 d during t…
Processing GOTO data with the Rubin Observatory LSST Science Pipelines I : Production of coadded frames
J. R. Mullaney, L. Makrygianni, V. Dhillon +44
The past few decades have seen the burgeoning of wide field, high cadence surveys, the most formidable of which will be the Legacy Survey of Space and Time (LSST) to be conducted b…
Searching For Fermi GRB Optical Counterparts With The Prototype Gravitational-Wave Optical Transient Observer (GOTO)
Y. -L. Mong, K. Ackley, D. K. Galloway +45
The typical detection rate of gamma-ray burst (GRB) per day by the \emph{Fermi} Gamma-ray Burst Monitor (GBM) provides a valuable opportunity to further our understanding o…
MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light
E. Bachelet, I. -G. Shin, C. Han +138
Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant pla…
White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
J. J. Hermes, B. T. Gaensicke, Steven D. Kawaler +15
We present photometry and spectroscopy for 27 pulsating hydrogen-atmosphere white dwarfs (DAVs, a.k.a. ZZ Ceti stars) observed by the Kepler space telescope up to K2 Campaign 8, an…
High-speed photometry of the disintegrating planetesimals at WD1145+017: evidence for rapid dynamical evolution
B. T. Gaensicke, A. Aungwerojwit, T. R. Marsh +11
We obtained high-speed photometry of the disintegrating planetesimals orbiting the white dwarf WD1145+017, spanning a period of four weeks. The light curves show a dramatic evoluti…
Microlensing Discovery of a Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf
C. Han, Y. K. Jung, A. Udalski +67
Observations of accretion disks around young brown dwarfs have led to the speculation that they may form planetary systems similar to normal stars. While there have been several de…
A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251
N. Kains, R. Street, J. -Y. Choi +128
We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting micr…
A New Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-Magnification Gravitational Microlensing Events
J. -Y. Choi, I. -G. Shin, C. Han +118
High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet…
The Gravitational-wave Optical Transient Observer (GOTO): prototype performance and prospects for transient science
D. Steeghs, D. K. Galloway, K. Ackley +50
The Gravitational-wave Optical Transient Observer (GOTO) is an array of wide-field optical telescopes, designed to exploit new discoveries from the next generation of gravitational…
NGTS and HST insights into the long period modulation in GW Librae
P. Chote, B. T. Gaensicke, J. McCormac +17
Light curves of the accreting white dwarf pulsator GW Librae spanning a 7.5 month period in 2017 were obtained as part of the Next Generation Transit Survey. This data set comprise…
Using Orbital Effects to Break the Close/wide Degeneracy in Binary-lens Microlensing Events
I. -G. Shin, T. Sumi, A. Udalski +37
Microlensing can provide an important tool to study binaries, especially those composed of faint or dark objects. However, accurate analysis of binary-lens light curves is often ha…
The post-outburst pulsations of the accreting white dwarf in the cataclysmic variable GW Librae
P. Chote, D. J. Sullivan
We present new time-series photometry of the accreting pulsating white dwarf system GW Librae obtained in 2012 and 2013 at the University of Canterbury Mt John Observatory in New Z…
The Gravitational-wave Optical Transient Observer (GOTO) data pipeline and workflow for transient discovery
J. D. Lyman, D. O'Neill, T. Killestein +45
Wide-field and high-cadence sky surveys are the first step in the chain of discovery and characterisation of astrophysical transients such as supernovae, kilonovae, and tidal disru…
V1460 Her: A fast spinning white dwarf accreting from an evolved donor star
R. P. Ashley, T. R. Marsh, E. Breedt +6
We present time-resolved optical and ultraviolet spectroscopy and photometry of V1460~Her, an eclipsing cataclysmic variable with a 4.99\,h orbital period and an overluminous K5-ty…
Short timescale imaging polarimetry of geostationary satellite Thor-6: the nature of micro-glints
K. Wiersema, P. Chote, J. Marchant +8
Large constellations of orbiting communication satellites will become an important source of noise for present and future astronomical observatories. Mitigation measures rely on hi…
GOTO identification and broadband modelling of the counterpart to the SVOM GRB 250818B
S. Belkin, G. P. Lamb, K. Ackley +61
Rapid localisation and follow-up of gamma-ray bursts (GRBs) increasingly rely on low-latency triggers from new missions coupled to wide-field robotic optical facilities. We present…
Fast spectrophotometry of WD 1145+017
P. Izquierdo, P. RodrÃguez-Gil, B. T. Gänsicke +16
WD 1145+017 is currently the only white dwarf known to exhibit periodic transits of planetary debris as well as absorption lines from circumstellar gas. We present the first simult…
Transient-optimised real-bogus classification with Bayesian Convolutional Neural Networks -- sifting the GOTO candidate stream
T. L. Killestein, J. Lyman, D. Steeghs +45
Large-scale sky surveys have played a transformative role in our understanding of astrophysical transients, only made possible by increasingly powerful machine learning-based filte…
MOA-2010-BLG-523: "Failed Planet" = RS CVn Star
A. Gould, J. C. Yee, I. A. Bond +116
The Galactic bulge source MOA-2010-BLG-523S exhibited short-term deviations from a standard microlensing lightcurve near the peak of an Amax ~ 265 high-magnification microlensing e…
VLA Radio Observations of AR Sco
E. R. Stanway, T. R. Marsh, P. Chote +3
AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission…
MOA-2010-BLG-328Lb: a sub-Neptune orbiting very late M dwarf ?
K. Furusawa, A. Udalski, T. Sumi +119
We analyze the planetary microlensing event MOA-2010-BLG-328. The best fit yields host and planetary masses of Mh = 0.11+/-0.01 M_{sun} and Mp = 9.2+/-2.2M_Earth, corresponding to…
Interpretation of a Short-Term Anomaly in the Gravitational Microlensing Event MOA-2012-BLG-486
K. -H. Hwang, J. -Y. Choi, I. A. Bond +78
A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce per…
Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs
J. -Y. Choi, C. Han, A. Udalski +121
Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minim…
Multi-band photometry and spectroscopy of an all-sky sample of bright white dwarfs
R. Raddi, N. P. Gentile Fusillo, A. F. Pala +11
The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the e…
Outbursts in two new cool pulsating DA white dwarfs
Keaton J. Bell, J. J. Hermes, M. H. Montgomery +9
The unprecedented extent of coverage provided by Kepler observations recently revealed outbursts in two hydrogen-atmosphere pulsating white dwarfs (DAVs) that cause hours-long incr…
: the GOTO project for real-time citizen science in time-domain astrophysics
T. L. Killestein, L. Kelsey, E. Wickens +51
Time-domain astrophysics continues to grow rapidly, with the inception of new surveys drastically increasing data volumes. Democratised, distributed approaches to training sets for…
Processing GOTO data with the Rubin Observatory LSST Science Pipelines II: Forced Photometry and light curves
L. Makrygianni, J. Mullaney, V. Dhillon +45
We have adapted the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Science Pipelines to process data from the Gravitational-Wave Optical Transient Observer (GOTO)…
Self-Supervised Clustering on Image-Subtracted Data with Deep-Embedded Self-Organizing Map
Y. -L. Mong, K. Ackley, T. L. Killestein +45
Developing an effective automatic classifier to separate genuine sources from artifacts is essential for transient follow-ups in wide-field optical surveys. The identification of t…
MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection
J. C. Yee, L. -W. Hung, I. A. Bond +123
We analyze MOA-2010-BLG-311, a high magnification (A_max>600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit th…
Puoko-nui: a flexible high-speed photometric system
P. Chote, D. J. Sullivan, R. Brown +3
We describe a portable CCD-based instrumentation system designed to efficiently undertake high time precision fast photometry. The key components of the system are (1) an externall…
OGLE-2012-BLG-0455/MOA-2012-BLG-206: Microlensing event with ambiguity in planetary interpretations caused by incomplete coverage of planetary signal
H. Park, C. Han, A. Gould +55
Characterizing a microlensing planet is done from modeling an observed lensing light curve. In this process, it is often confronted that solutions of different lensing parameters r…
Searching for outbursts from Symbiotic Binaries in GOTO and ATLAS data
G. Ramsay, K. Ackley, S. Belkin +46
Symbiotic Binaries contain a white dwarf accreting material from a red giant star through a wind. We present the results of a search for outbursts from Symbiotic Binaries using pho…
Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events
I. -G. Shin, C. Han, J. -Y. Choi +119
Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to u…
MOA-2010-BLG-073L: An M-Dwarf with a Substellar Companion at the Planet/Brown Dwarf Boundary
R. A. Street, J. -Y. Choi, Y. Tsapras +129
We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remark…
Time series photometry of the helium atmosphere pulsating white dwarf EC 04207-474
P. Chote, D. J. Sullivan, M. H. Montgomery +1
We present the analysis of 71 hours of high quality time-series CCD photometry of the helium atmosphere pulsating white dwarf (DBV) EC 04207-4748 obtained using the facilities at M…