The Gravitational-wave Optical Transient Observer (GOTO): prototype performance and prospects for transient science

Steeghs, D.; Galloway, D. K.; Ackley, K.; Dyer, M.; Lyman, J.; Ulaczyk, K.; Cutter, R.; Mong, Y. L.; Dhillon, V. S.; O’Brien, P. T.; Ramsay, Gavin; Poshyachinda, S.; Kotak, R.; Nuttall, L. K.; Πάλλη, Ε.; Breton, R. P.; Pollacco, D.; Thrane, E.; Aukkaravittayapun, S.; Awiphan, S.; Burhanudin, U.; Chote, P.; Chrimes, A. A.; Daw, E. J.; Duffy, C.; Eyles-Ferris, R. A. J.; Gompertz, B.; Heikkilä, T.; Irawati, P.; Kennedy, Mark; Killestein, T.; Kuncarayakti, H.; Levan, A. J.; Littlefair, S.; Makrygianni, L.; Marsh, T. R.; Mata-Sanchez, D.; Mattila, S.; Maund, Justyn R.; McCormac, J.; Mkrtichian, D. E.; Mullaney, James; Noysena, K.; Patel, M.; Rol, E.; Sawangwit, U.; Stanway, Elizabeth R.; Starling, R. L. C.; Strøm, Paul A.; Tooke, S.; West, R. G.; White, David; Wiersema, K.

doi:10.1093/mnras/stac013

Cited by 40 publications

(20 citation statements)

References 107 publications

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“…Fits were performed on , the computing cluster of the Gravitational-wave Optical Transient Observer (GOTO) collaboration (Dyer et al 2020;Gompertz et al 2020;Steeghs et al 2022). The full table of results is shown in Table A1, with some example fits and corner plots in Figures A1 and A2.…”

Section: Afterglow Parameter Fittingmentioning

confidence: 99%

Towards an understanding of long gamma-ray burst environments through circumstellar medium population synthesis predictions

Chrimes

Gompertz

Канн

et al. 2022

Monthly Notices of the Royal Astronomical Society

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The temporal and spectral evolution of gamma-ray burst (GRB) afterglows can be used to infer the density and density profile of the medium through which the shock is propagating. In long-duration (core-collapse) GRBs, the circumstellar medium (CSM) is expected to resemble a wind-blown bubble, with a termination shock separating the stellar wind and the interstellar medium (ISM). A long standing problem is that flat density profiles, indicative of the ISM, are often found at lower radii than expected for a massive star progenitor. Furthermore, the presence of both wind-like environments at high radii and ISM-like environments at low radii remains a mystery. In this paper, we perform a ‘CSM population synthesis’ with long GRB progenitor stellar evolution models. Analytic results for the evolution of wind blown bubbles are adjusted through comparison with a grid of 2D hydrodynamical simulations. Predictions for the emission radii, ratio of ISM to wind-like environments, wind and ISM densities are compared with the largest sample of afterglow-derived parameters yet compiled, which we make available for the community. We find that high ISM densities of n ∼ 1000 cm−3 best reproduce observations. If long GRBs instead occur in typical ISM densities of n ∼ 1 cm−3, then the discrepancy between theory and observations is shown to persist at a population level. We discuss possible explanations for the origin of variety in long GRB afterglows, and for the overall trend of CSM modelling to over-predict the termination shock radius.

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Section: Afterglow Parameter Fittingmentioning

confidence: 99%

Towards an understanding of long gamma-ray burst environments through circumstellar medium population synthesis predictions

Chrimes

Gompertz

Канн

et al. 2022

Monthly Notices of the Royal Astronomical Society

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“…The Gravitational-Wave Optical Transient Observer (Steeghs et al 2021) is a wide-field optical array, designed specifically to rapidly survey large areas of sky in search of the weak kilonovae and afterglows associated with gravitational wave counterparts. The work we present in this paper was conducted during the GOTO prototype stage, using data taken with a single 'node' of telescopes situated at the Roque de los Muchachos observatory on La Palma.…”

Section: The Gravitational-wave Optical Transient Observer (Goto)mentioning

confidence: 99%

“…For now, we concentrate on a calendar year of prototype operations (spanning 01-01-2019 -01-01-2020) -which represents a significant dataset, comprising 44,789 difference images in total. Raw images are reduced with the GOTO pipeline (Steeghs et al 2021). Here we provide a very brief overview of the process for context, and delegate more in-depth discussion to the specific upcoming pipeline papers.…”

Section: The Gravitational-wave Optical Transient Observer (Goto)mentioning

confidence: 99%

Transient-optimised real-bogus classification with Bayesian Convolutional Neural Networks -- sifting the GOTO candidate stream

Killestein,

Lyman,

Steeghs

et al. 2021

Preprint

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Large-scale sky surveys have played a transformative role in our understanding of astrophysical transients, only made possible by increasingly powerful machine learning-based filtering to accurately sift through the vast quantities of incoming data generated. In this paper, we present a new real-bogus classifier based on a Bayesian convolutional neural network that provides nuanced, uncertainty-aware classification of transient candidates in difference imaging, and demonstrate its application to the datastream from the GOTO wide-field optical survey. Not only are candidates assigned a well-calibrated probability of being real, but also an associated confidence that can be used to prioritise human vetting efforts and inform future model optimisation via active learning. To fully realise the potential of this architecture, we present a fully-automated training set generation method which requires no human labelling, incorporating a novel data-driven augmentation method to significantly improve the recovery of faint and nuclear transient sources. We achieve competitive classification accuracy (FPR and FNR both below 1%) compared against classifiers trained with fully human-labelled datasets, whilst being significantly quicker and less labour-intensive to build. This data-driven approach is uniquely scalable to the upcoming challenges and data needs of next-generation transient surveys. We make our data generation and model training codes available to the community.

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“…A complete of grid tiles observed during the period from February 2019 to August 2020 is shown in Figure 5. Further details of the GOTO prototype phase will be in [20].…”

Section: The Goto-4 Prototypementioning

confidence: 99%

The Gravitational-wave Optical Transient Observer (GOTO)

Dyer,

Steeghs,

Galloway

et al. 2020

Preprint

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The Gravitational-wave Optical Transient Observer (GOTO) is a wide-field telescope project focused on detecting optical counterparts to gravitational-wave sources. GOTO uses arrays of 40 cm unit telescopes (UTs) on a shared robotic mount, which scales to provide large fields of view in a cost-effective manner. A complete GOTO mount uses 8 unit telescopes to give an overall field of view of 40 square degrees, and can reach a depth of 20th magnitude in three minutes. The GOTO-4 prototype was inaugurated with 4 unit telescopes in 2017 on La Palma, and was upgraded to a full 8-telescope array in 2020. A second 8-UT mount will be installed on La Palma in early 2021, and another GOTO node with two more mount systems is planned for a southern site in Australia. When complete, each mount will be networked to form a robotic, dual-hemisphere observatory, which will survey the entire visible sky every few nights and enable rapid follow-up detections of transient sources.

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The Gravitational-wave Optical Transient Observer (GOTO): prototype performance and prospects for transient science

Cited by 40 publications

References 107 publications

Towards an understanding of long gamma-ray burst environments through circumstellar medium population synthesis predictions

Towards an understanding of long gamma-ray burst environments through circumstellar medium population synthesis predictions

Transient-optimised real-bogus classification with Bayesian Convolutional Neural Networks -- sifting the GOTO candidate stream

The Gravitational-wave Optical Transient Observer (GOTO)

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