Hintze Centre for Astrophysical Surveys

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AutoSourceID-FeatureExtractor

Astronomy & Astrophysics EDP Sciences 680 (2023) A108-A108

Authors:

F Stoppa, R Ruiz de Austri, P Vreeswijk, S Bhattacharyya, S Caron, S Bloemen, G Zaharijas, G Principe, V Vodeb, PJ Groot, E Cator, G Nelemans

Abstract:

Aims. In astronomy, machine learning has been successful in various tasks such as source localisation, classification, anomaly detection, and segmentation. However, feature regression remains an area with room for improvement. We aim to design a network that can accurately estimate sources’ features and their uncertainties from single-band image cutouts, given the approximated locations of the sources provided by the previously developed code AutoSourceID-Light (ASID-L) or other external catalogues. This work serves as a proof of concept, showing the potential of machine learning in estimating astronomical features when trained on meticulously crafted synthetic images and subsequently applied to real astronomical data.Methods. The algorithm presented here, AutoSourceID-FeatureExtractor (ASID-FE), uses single-band cutouts of 32x32 pixels around the localised sources to estimate flux, sub-pixel centre coordinates, and their uncertainties. ASID-FE employs a two-step mean variance estimation (TS-MVE) approach to first estimate the features and then their uncertainties without the need for additional information, for example the point spread function (PSF). For this proof of concept, we generated a synthetic dataset comprising only point sources directly derived from real images, ensuring a controlled yet authentic testing environment.Results. We show that ASID-FE, trained on synthetic images derived from the MeerLICHT telescope, can predict more accurate features with respect to similar codes such as SourceExtractor and that the two-step method can estimate well-calibrated uncertainties that are better behaved compared to similar methods that use deep ensembles of simple MVE networks. Finally, we evaluate the model on real images from the MeerLICHT telescope and theZwickyTransient Facility (ZTF) to test its transfer learning abilities.
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Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

Astronomy & Astrophysics EDP Sciences 680 (2023) l16

Authors:

J Sánchez-Sierras, T Muñoz-Darias, SE Motta, RP Fender, A Bahramian, C Martínez-Sebastián, JA Fernández-Ontiveros, J Casares, M Armas Padilla, DA Green, D Mata Sánchez, J Strader, MAP Torres
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Minutes-duration optical flares with supernova luminosities

Nature Springer Nature 623:7989 (2023) 927-931

Authors:

Anna YQ Ho, Daniel A Perley, Ping Chen, Steve Schulze, Vik Dhillon, Harsh Kumar, Aswin Suresh, Vishwajeet Swain, Michael Bremer, Stephen J Smartt, Joseph P Anderson, GC Anupama, Supachai Awiphan, Sudhanshu Barway, Eric C Bellm, Sagi Ben-Ami, Varun Bhalerao, Thomas de Boer, Thomas G Brink, Rick Burruss, Poonam Chandra, Ting-Wan Chen, Wen-Ping Chen, Jeff Cooke, Michael W Coughlin, Kaustav K Das, Andrew J Drake, Alexei V Filippenko, James Freeburn, Christoffer Fremling, Michael D Fulton, Avishay Gal-Yam, Lluís Galbany, Hua Gao, Matthew J Graham, Mariusz Gromadzki, Claudia P Gutiérrez, K-Ryan Hinds, Cosimo Inserra, Nayana A J, Viraj Karambelkar, Mansi M Kasliwal, Shri Kulkarni, Tomás E Müller-Bravo, Eugene A Magnier, Ashish A Mahabal, Thomas Moore, Chow-Choong Ngeow, Matt Nicholl, Eran O Ofek, Conor MB Omand, Francesca Onori, Yen-Chen Pan, Priscila J Pessi, Glen Petitpas, David Polishook, Saran Poshyachinda, Miika Pursiainen, Reed Riddle, Antonio C Rodriguez, Ben Rusholme, Enrico Segre, Yashvi Sharma, Ken W Smith, Jesper Sollerman, Shubham Srivastav, Nora Linn Strotjohann, Mark Suhr, Dmitry Svinkin, Yanan Wang, Philip Wiseman, Avery Wold, Sheng Yang, Yi Yang, Yuhan Yao, David R Young, WeiKang Zheng
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The dense and non-homogeneous circumstellar medium revealed in radio wavelengths around the Type Ib SN 2019oys

(2023)

Authors:

Itai Sfaradi, Assaf Horesh, Jesper Sollerman, Rob Fender, Lauren Rhodes, David RA Williams, Joe Bright, Dave A Green, Steve Schulze, Avishay Gal-Yam
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WISDOM Project -- XVI. The link between circumnuclear molecular gas reservoirs and active galactic nucleus fuelling

(2023)

Authors:

Jacob S Elford, Timothy A Davis, Ilaria Ruffa, Martin Bureau, Michele Cappellari, Jindra Gensior, Satoru Iguchi, Fu-Heng Liang, Lijie Liu, Anan Lu, Thomas G Williams
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