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We report on detailed multi-wavelength observations and analysis of the very bright and long GRB 210619B, detected by the Atmosphere-Space Interactions Monitor (ASIM) installed on the International Space Station (ISS) and the Gamma-ray Burst Monitor (GBM) on-board the Fermi mission. Our main goal is to understand the radiation mechanisms and jet composition of GRB 210619B. With a measured redshift of $z$ = 1.937, we find that GRB 210619B falls within the 10 most luminous bursts observed by Fermi so far. The energy-resolved prompt emission light curve of GRB 210619B exhibits an extremely bright hard emission pulse followed by softer/longer emission pulses. The low-energy photon indices ($\alpha_{\rm pt}$) values obtained using the time-resolved spectral analysis of the burst suggest a transition between the thermal (during harder pulse) to non-thermal (during softer pulse) outflow. We examine the correlation between spectral parameters and find that both peak energy and $\alpha_{\rm pt}$ exhibit the flux tracking pattern. The late time broadband photometric dataset can be explained within the framework of the external forward shock model with $\nu_m$ $< \nu_c$ $< \nu_{x}$ (where $\nu_m$, $\nu_c$, and $\nu_{x}$ are the synchrotron peak, cooling-break, and X-ray frequencies, respectively) spectral regime supporting a rarely observed hard electron energy index ($p, Comment: 24 pages, 18 figures, 10 tables, accepted for publication in MNRAS

The Burst Optical Observer and Transient Exploring System (BOOTES) is a world-wide automatic telescope network which aims to repaid follow-up of transient and astrophysical sources in the sky for which the first station was installed in 1998. With the advent in 2015 of the LIGO/Virgo interferometers, as part of the new generation of detectors designed for the detection of the signal of gravitational waves, a new window to explore the Universe has been opened. Here we present the status of the BOOTES network, the related strategies regarding the follow-up of gravitational wave events and the developments in the Gravitational Wave Era. Some preliminary results regarding the BOOTES follow-up observations are presented.

We performed optical spectroscopy of the candidates inside the gravitational wave errorboxes (S190408an, S190425z, S190426c, S190510g, S190728q, S190814bv). The spectral classification of 34 transients observed with the 10.4m Gran Telescopio de Canarias prior to 1 Sep 2019 is presented. We ruled out the association of these candidates with gravitational wave events.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., We present a detailed prompt emission and early optical afterglow analysis of the two very-high-energy (VHE) detected bursts GRB 201015A and GRB 201216C, and their comparison with a subset of similar bursts. Time-resolved spectral analysis of multistructured GRB 201216C using the Bayesian binning algorithm revealed that during the entire duration of the burst, the low-energy spectral index (αpt) remained below the limit of the synchrotron line of death. However, statistically some of the bins supported the additional thermal component. Additionally, the evolution of spectral parameters showed that both the peak energy (Ep) and αpt tracked the flux. These results were further strengthened using the values of the physical parameters obtained by synchrotron modeling of the data. Our earliest optical observations of both bursts using the F/Photometric Robotic Atmospheric Monitor Observatorio del Roque de los Muchachos and Burst Observer and Optical Transient Exploring System robotic telescopes displayed a smooth bump in their early optical light curves, consistent with the onset of the afterglow due to synchrotron emission from an external forward shock. Using the observed optical peak, we constrained the initial bulk Lorentz factors of GRB 201015A and GRB 201216C to Γ0 = 204 and Γ0 = 310, respectively. The present early optical observations are the earliest known observations constraining outflow parameters and our analysis indicate that VHE detected bursts could have a diverse range of observed luminosity within the detectable redshift range of present VHE facilities. © 2023. The Author(s). Published by the American Astronomical Society., R.G. and S.B.P. acknowledge the financial support of ISRO under AstroSat archival Data utilization program (DS_2B-13013(2)/1/2021-Sec.2). A.A. acknowledges funds and assistance provided by the Council of Scientific & Industrial Research (CSIR), India with file No. 09/948(0003)/2020-EMR-I. A.J.C.T. acknowledges support from the Spanish Ministry project PID2020-118491GB-I00 and Junta de Andalucia grant P20_010168. Y.D.H. acknowledges support under the additional funding from the RYC2019-026465-I. M.C.G. acknowledges support from the Ramón y Cajal Fellowship RYC2019-026465-I (funded by the MCIN/AEI/10.13039/501100011033 and the European Social Funding). This research has used data obtained through the HEASARC Online Service, provided by the NASA-GSFC, in support of the NASA High Energy Astrophysics Programs. S.B.P. thankfully acknowledges inclusion of the photometric calibration data of GRB 201015A taken with the 4K × 4K CCD Imager acquired as a part of the present analysis and extends sincere thanks to the observing and support staff of the 3.6 m DOT for maintaining and running the observational facilities at Devasthal Nainital., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/., Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4,5,6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger. © 2022, The Author(s)., This work was supported by the European Research Council through the Consolidator grant BHianca (grant agreement ID 101002761) and by the National Science Foundation (under award number 12850). B.O’C. was partially supported by the National Aeronautics and Space Administration (NASA) through grants NNX16AB66G, NNX17AB18G and 80NSSC20K0389. N.K. was financially supported by Grants-in-Aid for Scientific Research 17H06362 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. This work was partially supported by the Optical and Near-Infrared Astronomy Inter-University Cooperation Program of the MEXT of Japan, and the joint research programme of the Institute for Cosmic Ray Research (ICRR), the University of Tokyo. Research at Perimeter Institute is supported in part by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Colleges and Universities. The development of afterglow models used in this work was partially supported by the European Union Horizon 2020 programme under the AHEAD2020 project (grant agreement number 871158). C.L.F., E.A.C. and R.W. are supported by the US Department of Energy through the Los Alamos National Laboratory (LANL), operated by Triad National Security, LLC, for the National Nuclear Security Administration of US Department of Energy (contract no. 89233218CNA000001). This work includes observations obtained at the international Gemini Observatory (principal investigator (PI): B.O’C.; GS-2022A-Q-141), a programme of NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the NSF on behalf of the Gemini Observatory partnership: the NSF (USA), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovacíon (Argentina), Ministério da Cieˆncia, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). The HST data (ObsID: 16846; PI: E.T.) used in this work was obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. This research is partially based on observations under our ToO proposal number DOT-2021-C2-P71 (PI: R.G.) and proposal number DOT-2021-C2-P54 (PI: S.B.P.) obtained at the 3.6-m Devasthal Optical Telescope (DOT), which is a National Facility run and managed by Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous Institute under the Department of Science and Technology, Government of India. R.G. and S.B.P. acknowledge all the observing and support staff of the 3.6-m DOT and 1.3-m DFOT for maintaining and running the observational facilities at Devasthal Nainital. R.G. is especially thankful to B. Kumar, A. K. Ror and M. Sarkar for the observations with the 3.6-m DOT and 1.3-m DFOT under the approved observing proposals: DOT-2021-C2-P71 (PI: R.G.), DFOT-2021B-P29 (PI: R.G.), and DOT-2021-C2-P54 (PI: S.B.P.). R.G., A.A., K.M. and S.B.P. acknowledge the BRICS grant (DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G)) for financial support. R.G. and S.B.P. also acknowledge the financial support of ISRO under the AstroSat archival data utilization programme (DS_2B-13013(2)/1/2021-Sec.2). A.A. acknowledges funds and assistance provided by the Council of Scientific & Industrial Research (CSIR), India with file no. 09/948(0003)/2020-EMR-I. M.D.C.-G. acknowledges support from the Ramón y Cajal Fellowship RYC2019-026465-I. Y.-D.H. acknowledges support under the additional funding from RYC2019-026465-I. A.J.C.-T. acknowledges support from the Spanish Ministry project PID2020-118491GB-I00, Junta de Andalucia project P20_01068 and the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). Based on observations collected at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (ToO Program 21B-2.2-028: PI: A.J.C.-T.), operated jointly by Junta de Andalucía and Consejo Superior de Investigaciones Científicas (IAA-CSIC). These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy and operates the LDT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University and Yale University. This research used resources provided by the LANL Institutional Computing Program. Figure 1 was created with the help of the NOIRLab/IPAC/ESA/STScI/CfA FITS Liberator. We made use of IRAF, which is distributed by the NSF NOIRLab. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.

The National Health and Nutrition Examination Survey (NHANES) of America has been running for more than 60 years and has achieved many significant achievements with international influence. The application of modern information technologies in NHANES provides a supplementary tool for the project's high quality and refined implementation. This paper introduces the information system of NHANES from seven aspects: project management, survey participant interview, physical examination, laboratory examination, field follow-up, data sharing, and social services. The construction and application prospects of the China National Health Survey Information System, suitable for China's native conditions, are also discussed in this article.美国健康与营养调查项目（NHANES）已历时六十余年，取得了许多具有国际影响力的重要成果。现代信息技术在NHANES中的应用为项目的高质量精细化实施提供了补充工具。本文从项目管理、受试者调查、体格检查、实验室检查、现场随访、数据共享和社会服务7个维度介绍NHANES的信息化系统应用状况，并进一步探讨了适合我国国情的国民健康调查信息化系统的建设与应用前景。.

Optical follow-up observations of optical afterglows of gamma-ray bursts are crucial to probe the geometry of outflows, emission mechanisms, energetics and burst environments. We performed the follow-up observations of GRB 210205A and ZTF21aaeyldq (AT2021any) using the 3.6m Devasthal optical telescope (DOT) around one day after the burst to deeper limits due to the longitudinal advantage of the place. This paper presents our analysis of the two objects using data from other collaborative facilities, i.e., 2.2m Calar Alto Astronomical Observatory (CAHA) and other archival data. Our analysis suggests that GRB 210205A is a potential dark burst once compared with the X-ray afterglow data. Also, comparing results with other known and well-studied dark GRBs samples indicate that the reason for the optical darkness of GRB 210205A could either be intrinsic faintness or a high redshift event. Based on our analysis, we also found that ZTF21aaeyldq is the third known orphan afterglow with a measured redshift except for ZTF20aajnksq (AT2020blt) and ZTF19abvizsw (AT2019pim). The multiwavelength afterglow modeling of ZTF21aaeyldq using the afterglowpy package demands a forward shock model for an ISM-like ambient medium with a rather wider jet opening angle. We determine circumburst density of n0=0.87 cm−3, kinetic energy Ek=3.80×1052 erg and the afterglow modeling also indicates that ZTF21aaeyldq is observed on-axis (θobs, RG, SBP, and KM acknowledge BRICS grant DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G) for the financial support. AA acknowledges funds and assistance provided by the Council of Scientific & Industrial Research (CSIR), India with file no. 09/948(0003)/2020-EMR-I. This research is based on observations obtained at the 3.6m Devasthal Optical Telescope (DOT) during observing cycles DOT-2021-C1 and DOT-2020-C2, which is a National Facility run and managed by Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous Institute under the Department of Science and Technology, Government of India. Based on observations collected at Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto, operated jointly by Junta de Andalucía and Consejo Superior de Investigaciones Científicas (IAA-CSIC). This research has made use of data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC) and the Leicester Database and Archive Service (LEDAS), provided by NASA’s Goddard Space Flight Center and the Department of Physics and Astronomy, Leicester University, UK, respectively., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

Following the detection of a long GRB 190919B by INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory), we obtained an optical photometric sequence of its optical counterpart. The light curve of the optical emission exhibits an unusually steep rise ∼100 s after the initial trigger. This behaviour is not expected from a ‘canonical’ GRB optical afterglow. As an explanation, we propose a scenario consisting of two superimposed flares: an optical flare originating from the inner engine activity followed by the hydrodynamic peak of an external shock. The inner-engine nature of the first pulse is supported by a marginal detection of flux in hard X-rays. The second pulse eventually concludes in a slow constant decay, which, as we show, follows the closure relations for a slow cooling plasma expanding into the constant interstellar medium and can be seen as an optical afterglow sensu stricto. © ESO 2022., The operation of the robotic telescope FRAM is supported by the grant of the Ministry of Education of the Czech Republic LM2018102. The data calibration and analysis related to the FRAM telescope is supported by the Ministry of Education of the Czech Republic MSMT-CR LTT18004, MSMT/EU funds CZ.02.1.01/0.0/0.0/16_013/0001402 and CZ.02.1.01/0.0/0.0/18_046/0016010. SK and MP acknowledge support from the European Structural and Investment Fund and the Czech Ministry of Education, Youth and Sports (Project CoGraDS – CZ.02.1.01/0.0/0.0/15_003/0000437). MT and MR acknowledge support from the Ministry of Education and Research of Italy via project PRIN-MIUR 2017 UnIAM (Unifying Isolated and Accreting Magnetars). YDH acknowledges support under the additional funding from the RYC2019-026465-I. AJCT acknowledges support from the Spanish Ministry Project PID2020-118491GB-I00 and the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709) as well as technical support from both NIWA Lauder and San Pedro Mártir Astronomical Observatory staff.

Full list of authors: Gupta, Rahul; Gupta, S.; Chattopadhyay, T.; Lipunov, V.; Castro-Tirado, A. J.; Bhattacharya, D.; Pandey, S. B.; Oates, S. R.; Kumar, Amit; Hu, Y. -D.; Valeev, A. F.; Minaev, P. Yu; Kumar, H.; Vinko, J.; Dimple; Sharma, V.; Aryan, A.; Castellón, A.; Gabovich, A.; Moskvitin, A.; Ordasi, A.; Pál, A.; Pozanenko, A.; Zhang, B. -B.; Kumar, B.; Svinkin, D.; Saraogi, D.; Vlasenko, D.; Fernández-García, E.; Gorbovskoy, E.; Anupama, G. C.; Misra, K.; Sárneczky, K.; Kriskovics, L.; Castro-Tirado, M. Á.; Caballero-García, M. D.; Tiurina, N.; Balanutsa, P.; Lopez, R. R.; Sánchez-Ramírez, R.; Szakáts, R.; Belkin, S.; Guziy, S.; Iyyani, S.; Tiwari, S. N.; Vadawale, Santosh V.; Sun, T.; Bhalerao, V.; Kornilov, V.; Sokolov, V. V., Multipulsed GRB 190530A, detected by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope onboard Fermi, is the sixth most fluent GBM burst detected so far. This paper presents the timing, spectral, and polarimetric analysis of the prompt emission observed using AstroSat and Fermi to provide insight into the prompt emission radiation mechanisms. The time-integrated spectrum shows conclusive proof of two breaks due to peak energy and a second lower energy break. Time-integrated (55.43 ± 21.30 per cent) as well as time-resolved polarization measurements, made by the Cadmium Zinc Telluride Imager (CZTI) onboard AstroSat, show a hint of high degree of polarization. The presence of a hint of high degree of polarization and the values of low energy spectral index (αpt) do not run over the synchrotron limit for the first two pulses, supporting the synchrotron origin in an ordered magnetic field. However, during the third pulse, αpt exceeds the synchrotron line of death in few bins, and a thermal signature along with the synchrotron component in the time-resolved spectra is observed. Furthermore, we also report the earliest optical observations constraining afterglow polarization using the MASTER (P < 1.3 per cent) and the redshift measurement (z = 0.9386) obtained with the 10.4 m GTC (Gran Telescopio Canarias) telescopes. The broad-band afterglow can be described with a forward shock model for an ISM (interstellar medium)-like medium with a wide jet opening angle. We determine a circumburst density of n0 ∼ 7.41, kinetic energy EK ∼ 7.24 × 1054 erg, and radiated gamma-ray energy Eγ,iso ∼ 6.05 × 1054 erg. © 2022 The Author(s)., RG, DB, SBP, KM, and VB acknowledge BRICS grant DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G) for the financial support. This publication uses data from the AstroSat mission of the Indian Space Research Organisation (ISRO), archived at the Indian Space Science Data Centre (ISSDC). CZT-Imager is built by a consortium of institutes across India, including the Tata Institute of Fundamental Research (TIFR), Mumbai, the Vikram Sarabhai Space Centre, Thiruvananthapuram, ISRO Satellite Centre (ISAC), Bengaluru, Inter University Centre for Astronomy and Astro-physics, Pune, Physical Research Laboratory, Ahmedabad, and Space Application Centre, Ahmedabad. This research also has used data obtained through the HEASARC Online Service, provided by the NASA-GSFC, in support of NASA High Energy Astrophysics Programmes. This work is based on data from the OSN Public Archive at IAA (IAA-CSIC) and the CAHA Archive at CAB (INTA-CSIC). The MASTER equipment is supported by Lomonosov MSU Development Programme. VL and VK are supported by RFBR 19-29-11011 grant. The research group of JV is supported by the project ‘Transient Astrophysical Objects’ GINOP 2.3.2-15-2016-00033 of the National Research, Development and Innovation Office (NKFIH), Hungary, funded by the European Union. AA acknowledges funds and assistance provided by the Council of Scientific and Industrial Research (CSIR), India with file number 09/948(0003)/2020-EMR-I. AP, SB, and PM acknowledge a support of the RSCF grant 18-12-00378. The GROWTH India Telescope (GIT) is a 70 cm telescope with a 0.7 deg field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the IAO (Hanle), operated by the Indian Institute of Astrophysics (IIA). MCG acknowledges support from the Ramón y Cajal Fellowship RYC2019-026465-I. YDH acknowledges support under the additional funding from the RYC2019-026465-I. BBZ acknowledges support by the National Key Research and Development Programme of China (2018YFA0404204), the National Natural Science Foundation of China (grant numbers 11833003, U2038105, and 12121003), the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-B11, and the Programme for Innovative Talents, Entrepreneur in Jiangsu. RSM acknowledges support under the CSIC-MURALES project with reference 20215AT009., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

Full list of authors: Castro-Tirado, A. J.; Østgaard, N.; Göǧüş, E.; Sánchez-Gil, C.; Pascual-Granado, J.; Reglero, V.; Mezentsev, A.; Gabler, M.; Marisaldi, M.; Neubert, T.; Budtz-Jørgensen, C.; Lindanger, A. Sarria, D.; Kuvvetli, I.; Cerdá-Durán, P.; Navarro-González, J.; Font, J. A.; Zhang, B. -B.; Lund, N.; Oxborrow, C. A.; Brandt, S.; Caballero-García, M. D.; Carrasco-García, I. M.; Castellón, A.; Castro Tirado, M. A.; Christiansen, F.; Eyles, C. J.; Fernández-García, E.; Genov, G.; Guziy, S.; Hu, Y. -D.; Nicuesa Guelbenzu, A.; Pandey, S. B.; Peng, Z. -K.; Pérez del Pulgar, C.; Reina Terol, A. J.; Rodríguez, E.; Sánchez-Ramírez, R.; Sun, T.; Ullaland, K.; Yang, S., Magnetars are strongly magnetized, isolated neutron stars1–3 with magnetic fields up to around 1015 gauss, luminosities of approximately 1031–1036 ergs per second and rotation periods of about 0.3–12.0 s. Very energetic giant flares from galactic magnetars (peak luminosities of 1044–1047 ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays4, and only one has been detected from outside our galaxy5. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed6–9, but their statistical significance has been questioned10. High-frequency QPOs have been seen only during the tail phase of the flare9. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare11 in the direction of the NGC 253 galaxy12–17, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere–Space Interactions Monitor instrument18,19 aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8–3.2 milliseconds) in the full energy range (50 × 103 to 40 × 106 electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares. © 2021, The Author(s), under exclusive licence to Springer Nature Limited., This work made use of data from ASIM. ASIM is an international experiment aboard the International Space Station. ASIM is a mission of the European Space Agency (ESA), funded by ESA and national grants from Denmark, Norway and Spain. ESA PRODEX contracts C 4000115884 (DTU) and 4000123438 (Bergen) support the ASIM Science Data Centre. The science analysis is supported by ESA Topical Team contract 4200019920/06/NL/VJ; European Research Council grant AdG-FP7/2007-2013: n 320839; Research Council of Norway contract 223252/F50 (CoE/BCSS); and Ministerio de Ciencia, Innovación y Universidades grants ESP 2017-86263-C4 and ESP2017-87676-C5-5-R. J.A.F. and P.C.-D. acknowledge support by the Spanish Agencia Estatal de Investigación (grant PGC2018-095984-B-I00) and by the Generalitat Valenciana (PROMETEO/2019/071). P.C.-D. acknowledges the Ramon y Cajal funding (RYC-2015-19074) for supporting his research. M.G. acknowledges support through the Generalitat Valenciana via the grant CIDEGENT/2019/031. A.J.C.-T., J.P.-G., M.D.C.-G. and E.R. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work is partly based on observations made with the Gran Telescopio Canarias (GTC), installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma. We thank J. D. Scargle for his help with the preliminary time-series analysis and his comments. J.P.-G. also acknowledges funding support from Spanish public funds for research from project PID2019-107061GB-C63 from the ‘Programas Estatales de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad’ from the Spanish Ministry of Science, Innovation and Universities (MCIU).

Introduction Abdominal aortic aneurysm (AAA) repair may be performed through open or endovascular approaches, but the factors influencing a patient's repair-type preference are not well characterized. Here we performed a qualitative analysis to better understand factors influencing patient preference within the Preference for Open Versus Endovascular Repair of AAA Trial. Methods Open-ended responses regarding primary (n = 21) and secondary (n = 47) factors influencing patient preference underwent qualitative analysis using the constant comparative method with iterative reviews. Codes were used to generate themes and themes grouped into categories, with each step conducted via consensus agreement between three researchers. Relative prevalence of themes were compared to ascertain trends in patient preference. Results Patient responses regarding both primary and secondary factors fell into four categories: Short-term concerns, long-term concerns, advice & experience, and other. Patients most frequently described short-term concerns (23) as their primary influence, with themes including post-op complications, hospitalization & recovery, and intraoperative concerns. Long-term concerns were more prevalent (20) as secondary factors, which included themes such as survival, and chronic management. The average age of patients voicing only long-term concerns as a primary factor was 11 years younger than those listing only short-term concerns. Conclusion Short-term concerns relating to the procedure and recovery are more often the primary factor influencing patient preference, while long term concerns play a more secondary role. Long-term concerns are more often a primary factor in younger patients. Vascular surgeons should consider this information in shared decision making to reach an optimal outcome.

Full list of authors: Gupta, Rahul; Oates, S. R.; Pandey, S. B.; Castro-Tirado, A. J.; Joshi, Jagdish C.; Hu, Y. -D; Valeev, A. F.; Zhang, B. B.; Zhang, Z.; Kumar, Amit; Aryan, A.; Lien, A ; Kumar, B.; Cui, Ch; Wang, Ch; Dimple; Bhattacharya, D.; Sonbas, E.; Bai, J.; Tello, J. C.; Gorosabel, J.; Castro Ceron, J. M.; Porto, J. R. F.; Misra, K.; De Pasquale, M.; Caballero-Garcia, M. D.; Jelinek, M.; Kubanek, P.; Minaev, P.; Cunniffe, R.; Sanchez-Ramirez, R.; Guziy, S.; Jeong, S.; Tiwari, S. N.; Razzaque, S.; Bhalerao, V.; Pintado, V. C.; Sokolov, V. V.; Zhao, X.; Fan, Y.; Xin, Y.

Gamma-ray bursts (GRBs) have been phenomenologically classified into long and short populations based on the observed bimodal distribution of duration1. Multi-wavelength and multi-messenger observations in recent years have revealed that in general long GRBs originate from massive star core collapse events2, whereas short GRBs originate from binary neutron star mergers3. It has been known that the duration criterion is sometimes unreliable, and multi-wavelength criteria are needed to identify the physical origin of a particular GRB4. Some apparently long GRBs have been suggested to have a neutron star merger origin5, whereas some apparently short GRBs have been attributed to genuinely long GRBs6 whose short, bright emission is slightly above the detector’s sensitivity threshold. Here, we report the comprehensive analysis of the multi-wavelength data of the short, bright GRB 200826A. Characterized by a sharp pulse, this burst shows a duration of 1 second and no evidence of an underlying longer-duration event. Its other observational properties such as its spectral behaviours, total energy and host galaxy offset are, however, inconsistent with those of other short GRBs believed to originate from binary neutron star mergers. Rather, these properties resemble those of long GRBs. This burst confirms the existence of short-duration GRBs with stellar core-collapse origin4, and presents some challenges to the existing models. © 2021, The Author(s), under exclusive licence to Springer Nature Limited., B.-B.Z. acknowledges support by the National Key Research and Development Programs of China (2018YFA0404204), the National Natural Science Foundation of China (grant nos. 11833003 and U2038105) and the Innovative and Entrepreneurial Talent Program in Jiangsu. Y.-Z.M. is supported by the National Postdoctoral Program for Innovative Talents (grant no. BX20200164). This work was supported in part by the Natural Science Foundation of China (grant nos. U1831135 (X.-H.Z.), 11922301 (H.-J.L.), 12041306 (Y.L.) and U1938201 (X.-G.W.)), the Guangxi Science Foundation (2017GXNSFFA198008 (H.-J.L.), 2017AD22006 (X.-G.W.) and 2016GXNSFFA380006 (X.-G.W.)) and the Bagui Young Scholars Program (H.-J.L.). Part of this work is based on observations made with the GTC installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, on the island of La Palma. We also acknowledge the use of public data from the Fermi Science Support Center., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

Aims. Gamma-ray burst (GRB) 190829A (z=0.0785) was detected by Fermi and Swift and also at very high energy (VHE) by the High-Energy Stereoscopic System (H.E.S.S.) telescopes. The prompt emission displayed two emission episodes separated by a quiescent gap of similar to 40 s. We present the 10.4 m Gran Telescopio Canarias (GTC) observations of the afterglow of GRB 190829A and its underlying supernova. We also compare GRB 190829A to GRB 180728A, a GRB with similar behaviour, and discuss the implications on underlying physical mechanisms producing these two GRBs.Methods. We present multi-band photometric data along with spectroscopic follow-up observations taken with the 10.4 m GTC telescope. Together with the data from the prompt emission, the 10.4 m GTC data are used to understand the emission mechanisms and possible progenitor.Results. A detailed analysis of the multi-band observations of the afterglow requires the cooling frequency to pass between the optical and X-ray bands at early epochs. The afterglow then transitions to the underlying supernova (SN) 2019oyw, which dominates later on.Conclusions. Although the prompt emission temporal properties of GRB 190829A and GRB 180728A are similar, the two pulses are different in the spectral domain. We find that SN 2019oyw associated with GRB 190829A is powered by Ni decay and is a Type Ic-BL SN. The spectroscopic and photometric properties of this SN are consistent with those observed for SN 1998bw, but evolved earlier. © ESO 2021., Based on observations made with the GTC telescope, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, part of them under Director's Discretionary Time. This work has made use of data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC) and the Leicester Database and Archive Service (LEDAS), provided by NASA's Goddard Space Flight Center and the Department of Physics and Astronomy, Leicester University, UK, respectively. Y.-D.H., A.J.C.-T., I.A. and D.A.K. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709). R.G, S.B.P., and A.A. acknowledge BRICS grant DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G) for part of the work. V.A.F. was supported by RFBR 18-29-21030 grant. S.B.P. also acknowledges DST/INT/JSPS/P/281/2018 for the present work. B.-B.Z. acknowledges the supported by the Fundamental Research Funds for the Central Universities (14380035). This work is supported by National Key Research and Development Programs of China (2018YFA0404204), the National Natural Science Foundation of China (Grant Nos. 11833003) and the Program for Innovative Talents, Entrepreneur in Jiangsu. D.A.K. acknowledges support from Spanish research project RTI2018-098104-J-I00 (GRBPhot). Finally, the authors extend their thanks to the anonymous referee for their valuable comments that helped to improve the manuscript substantially.

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.--Full list of authors: Ackley, K.; Amati, L.; Barbieri, C.; Bauer, F. E.; Benetti, S.; Bernardini, M. G.; Bhirombhakdi, K.; Botticella, M. T.; Branchesi, M.; Brocato, E.; Bruun, S. H.; Bulla, M.; Campana, S.; Cappellaro, E.; Castro-Tirado, A. J.; Chambers, K. C.; Chaty, S.; Chen, T. -W.; Ciolfi, R.; Coleiro, A.; Copperwheat, C. M.; Covino, S.; Cutter, R.; D'Ammando, F.; D'Avanzo, P.; De Cesare, G.; D'Elia, V.; Della Valle, M.; Denneau, L.; De Pasquale, M.; Dhillon, V. S.; Dyer, M. J.; Elias-Rosa, N.; Evans, P. A.; Eyles-Ferris, R. A. J.; Fiore, A.; Fraser, M.; Fruchter, A. S.; Fynbo, J. P. U.; Galbany, L.; Gall, C.; Galloway, D. K.; Getman, F. I.; Ghirlanda, G.; Gillanders, J. H.; Gomboc, A.; Gompertz, B. P.; González-Fernández, C.; González-Gaitán, S.; Grado, A.; Greco, G.; Gromadzki, M.; Groot, P. J.; Gutiérrez, C. P.; Heikkilä, T.; Heintz, K. E.; Hjorth, J.; Hu, Y. -D.; Huber, M. E.; Inserra, C.; Izzo, L.; Japelj, J.; Jerkstrand, A.; Jin, Z. P.; Jonker, P. G.; Kankare, E.; Kann, D. A.; Kennedy, M.; Kim, S.; Klose, S.; Kool, E. C.; Kotak, R.; Kuncarayakti, H.; Lamb, G. P.; Leloudas, G.; Levan, A. J.; Longo, F.; Lowe, T. B.; Lyman, J. D.; Magnier, E.; Maguire, K.; Maiorano, E.; Mandel, I.; Mapelli, M.; Mattila, S.; McBrien, O. R.; Melandri, A.; Michałowski, M. J.; Milvang-Jensen, B.; Moran, S.; Nicastro, L.; Nicholl, M.; Nicuesa Guelbenzu, A.; Nuttal, L.; Oates, S. R.; O'Brien, P. T.; Onori, F.; Palazzi, E.; Patricelli, B.; Perego, A.; Torres, M. A. P.; Perley, D. A.; Pian, E.; Pignata, G.; Piranomonte, S.; Poshyachinda, S.; Possenti, A.; Pumo, M. L.; Quirola-Vásquez, J.; Ragosta, F.; Ramsay, G.; Rau, A.; Rest, A.; Reynolds, T. M.; Rosetti, S. S.; Rossi, A.; Rosswog, S.; Sabha, N. B.; Sagués Carracedo, A.; Salafia, O. S.; Salmon, L.; Salvaterra, R.; Savaglio, S.; Sbordone, L.; Schady, P.; Schipani, P.; Schultz, A. S. B.; Schweyer, T.; Smartt, S. J.; Smith, K. W.; Smith, M.; Sollerman, J.; Srivastav, S.; Stanway, E. R.; Starling, R. L. C.; Steeghs, D.; Stratta, G.; Stubbs, C. W.; Tanvir, N. R.; Testa, V.; Thrane, E.; Tonry, J. L.; Turatto, M.; Ulaczyk, K.; van der Horst, A. J.; Vergani, S. D.; Walton, N. A.; Watson, D.; Wiersema, K.; Wiik, K.; Wyrzykowski, Ł.; Yang, S.; Yi, S. -X.; Young, D. R., Context. Gravitational wave (GW) astronomy has rapidly reached maturity, becoming a fundamental observing window for modern astrophysics. The coalescences of a few tens of black hole (BH) binaries have been detected, while the number of events possibly including a neutron star (NS) is still limited to a few. On 2019 August 14, the LIGO and Virgo interferometers detected a high-significance event labelled S190814bv. A preliminary analysis of the GW data suggests that the event was likely due to the merger of a compact binary system formed by a BH and a NS. Aims. In this paper, we present our extensive search campaign aimed at uncovering the potential optical and near infrared electromagnetic counterpart of S190814bv. We found no convincing electromagnetic counterpart in our data. We therefore use our non-detection to place limits on the properties of the putative outflows that could have been produced by the binary during and after the merger. Methods. Thanks to the three-detector observation of S190814bv, and given the characteristics of the signal, the LIGO and Virgo Collaborations delivered a relatively narrow localisation in low latency - a 50% (90%) credible area of 5 deg2 (23 deg2) - despite the relatively large distance of 267 ± 52 Mpc. ElectromagNetic counterparts of GRAvitational wave sources at the VEry Large Telescope collaboration members carried out an intensive multi-epoch, multi-instrument observational campaign to identify the possible optical and near infrared counterpart of the event. In addition, the ATLAS, GOTO, GRAWITA-VST, Pan-STARRS, and VINROUGE projects also carried out a search on this event. In this paper, we describe the combined observational campaign of these groups. Results. Our observations allow us to place limits on the presence of any counterpart and discuss the implications for the kilonova (KN), which was possibly generated by this NS-BH merger, and for the strategy of future searches. The typical depth of our wide-field observations, which cover most of the projected sky localisation probability (up to 99.8%, depending on the night and filter considered), is r ∼ 22 (resp. K ∼ 21) in the optical (resp. near infrared). We reach deeper limits in a subset of our galaxy-targeted observations, which cover a total ∼50% of the galaxy-mass-weighted localisation probability. Altogether, our observations allow us to exclude a KN with large ejecta mass M 0.1 M- to a high (> 90%) confidence, and we can exclude much smaller masses in a sub-sample of our observations. This disfavours the tidal disruption of the neutron star during the merger. Conclusions. Despite the sensitive instruments involved in the campaign, given the distance of S190814bv, we could not reach sufficiently deep limits to constrain a KN comparable in luminosity to AT 2017gfo on a large fraction of the localisation probability. This suggests that future (likely common) events at a few hundred megaparsecs will be detected only by large facilities with both a high sensitivity and large field of view. Galaxy-targeted observations can reach the needed depth over a relevant portion of the localisation probability with a smaller investment of resources, but the number of galaxies to be targeted in order to get a fairly complete coverage is large, even in the case of a localisation as good as that of this event. © K. Ackley et al. 2020., Based on observations collected at the European Southern Observatory under ESO programmes 1102.D-0353(E), 1102.D0353(F), 1102.D-0353(Q), 1102.D-0353(G), 0103.D-0070(A), 0103.D-0070(B), 0103.D-0703(A), 0103.D-0722(A), 0103.A-9099(A), 198.D-2010(D) and 60.A9285(A). ATLAS is primarily funded through NEO NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575. The ATLAS science products have been made possible through the contributions of the University of Hawaii IfA, the Queen's University Belfast, the Space Telescope Science Institute, and the South African Astronomical Observatory. PanSTARRS is primarily funded through NEO NASA grants NASA Grants NNX08AR22G, NNX14AM74G. The PanSTARRS science products for LIGO-Virgo follow-up are made possible through the contributions of the University of Hawaii IfA and the Queen's University Belfast. The Gravitational-wave Optical Transient Observer (GOTO) project acknowledges the support of the Monash-Warwick Alliance; Warwick University; Monash University; She ffield University; Leicester University; Armagh Observatory & Planetarium; the National Astronomical Research Institute of Thailand (NARIT); University of Portsmouth; Turku University and the Instituto de Astrofisica de Canarias (IAC). Part of the funding for GROND was generously granted from the Leibniz-Prize to Prof. G. Hasinger (DFG grant HA 1850/28-1). The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. The WHT and its override programme are operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias; part of these data were taken under program (19A)N3. FEB thanks CONICYT Basal AFB-170002 and Chile's Ministry of Economy fund IC120009. MGB, PDA and AM acknowledge support from ASI grant I/004/11/3. MBr, EC, AP and SPi acknowledge support from MIUR (PRIN 2017 grant 20179ZF5KS). EB, EM and MT acknowledge funding from GRAWITA. SHB is indebted to the Danish National Research Foundation (DNRF132) for support. SCa acknowledges support from grant MAE0065741. EC acknowledges the support of the H2020 OPTICON programme 730890. TWC acknowledges the Humboldt Foundation and Marie Sklodowska-Curie grant 842471. MDP thanks Istanbul University for support. PAE acknowledges UKSA support. RAJEF is supported by an STFC studentship. MF is supported by a Royal Society -SFI University Research Fellowship. LG was funded by the EU H2020 programme under MSCA grant no. 839090. CG, JH and LI were supported by a research grant from VILLUM FONDEN (project 16599). CG and LI were supported by a research grant from VILLUM FONDEN (25501). GGh acknowledges the PRIN MIUR "Figaro" for financial support. AGo acknowledges financial support from the Slovenian Research Agency (grants P1-0031, I0-0033, and J1-8136). BPG, AJL and JDL acknowledge support from ERC grant 725246 (TEDE, PI Levan). SGG acknowledges support by FCT Fundacao para a Ciencia e Tecnologia and by Project PTDC/FIS-AST-31546. GGr acknowledges the ESCAPE H2020 project no. 824064. MG is supported by the Polish NCN MAESTRO grant 2014/14/A/ST9/00121. PJG acknowledges support from NOVA and from the South African NRF SARChI grant 111692. CPG and MS acknowledge support from EU/FP7-ERC grant no. 615929. KEH acknowledges support by a Project Grant from The Icelandic Research Fund. YDH acknowledges support from the China Scholarships Council. JJ acknowledges support from NOVA and NWO-FAPESP grant for instrumentation. AJ acknowledges funding from the European Research Council (ERC). ZPJ was supported by the Foundation for Distinguished Young Scholars of Jiangsu Province (no. BK20180050). PGJ acknowledges funding from the ERC under Consolidator Grant agreement no. 647208. DAK acknowledges Spanish research project RTI2018-098104-J-I00 (GRBPhot). SKl acknowledges support by DFG grant Kl 766/16-3. ECK acknowledges support from the GREAT research environment. GPL acknowledges support from STFC via grant ST/N000757/1. GL was supported by a research grant (19054) from VILLUM FONDEN. KM acknowledges support from the ERC (grant no. 758638). IM is partially supported by OzGrav (ARC project CE17010000). MMacknowledges support from ERC through ERC-2017-CoG no. 770017. MJM acknowledges the National Science Centre, Poland, grant 2018/30/E/ST9/00208. BMJ and DW are supported by Independent Research Fund Denmark grant DFF-7014-00017. MN is supported by a Royal Astronomical Society Research Fellowship. ANG acknowledges support by grant DFG Kl 766/16-3. PTOB acknowledges funding from STFC. SRO gratefully acknowledges the support of the Leverhulme Trust. FO acknowledges the support of the H2020 Hemera program, grant no. 730970. MAPT was supported by grants RYC-2015-17854 and AYA201783216-P. EP aknowledges financial support from INAF. GP is supported by the Millennium Science Initiative through grant IC120009. MLP is partially supported by a "Linea 2" project of the Catania University. JQV acknowledges support from CONICYT folio 21180886. TMR acknowledges the support of the Vilho, Yrjo and Kalle Vaisala Foundation. ARo acknowledges support from Premiale LBT 2013. SR is supported by VR grants 2016-03657_3 and the research environment grant GREAT, Dnr. 2016-06012, and the Swedish National Space board, Dnr. 107/16. OSS acknowledges the Italian Ministry of Research (MIUR) grant 1.05.06.13. LSa acknowledges the Irish Research Council Scholarship no. GOIPG/2017/1525. SJS acknowledges support from STFC Grant ST/P000312/1. ERS and DS acknowledge funding from UK STFC CG ST/P000495/1. RLCS acknowledges funding from STFC. DS acknowledges support from STFC via grant ST/T007184/1. SDV acknowledges the support of the CNES. LWsupported by Polish NCN DAINA 2017/27/L/ST9/03221. The Cosmic DAWN center is funded by the Danish National Research Foundation.

Nature astronomy 387, 38 (2020). doi:10.1038/s41550-020-1183-3, LIGO and Virgo���s third observing run revealed the first neutron star���black hole (NSBH) merger candidates in gravitational waves. These events are predicted to synthesize r-process elements creating optical/near-infrared ���kilonova��� emission. The joint gravitational wave and electromagnetic detection of an NSBH merger could be used to constrain the equation of state of dense nuclear matter, and independently measure the local expansion rate of the Universe. Here, we present the optical follow-up and analysis of two of the only three high-significance NSBH merger candidates detected to date, S200105ae and S200115j, with the Zwicky Transient Facility. The Zwicky Transient Facility observed ~48% of S200105ae and ~22% of S200115j���s localization probabilities, with observations sensitive to kilonovae brighter than ���17.5 mag fading at 0.5 mag d$^{���1}$ in the g- and r-bands; extensive searches and systematic follow-up of candidates did not yield a viable counterpart. We present state-of-the-art kilonova models tailored to NSBH systems that place constraints on the ejecta properties of these NSBH mergers. We show that with observed depths of apparent magnitude ~22 mag, attainable in metre-class, wide-field-of-view survey instruments, strong constraints on ejecta mass are possible, with the potential to rule out low mass ratios, high black hole spins and large neutron star radii., Published by Nature Publishing Group, London

All authors: Kasliwal, Mansi M.; Anand, Shreya; Ahumada, Tomás; Stein, Robert; Carracedo, Ana Sagués; Andreoni, Igor; Coughlin, Michael W.; Singer, Leo P.; Kool, Erik C.; De, Kishalay; Kumar, Harsh; AlMualla, Mouza; Yao, Yuhan; Bulla, Mattia; Dobie, Dougal; Reusch, Simeon; Perley, Daniel A.; Cenko, S. Bradley; Bhalerao, Varun; Kaplan, David L.; Sollerman, Jesper; Goobar, Ariel; Copperwheat, Christopher M.; Bellm, Eric C.; Anupama, G. C.; Corsi, Alessandra; Nissanke, Samaya; Agudo, Iván; Bagdasaryan, Ashot; Barway, Sudhanshu; Belicki, Justin; Bloom, Joshua S.; Bolin, Bryce; Buckley, David A. H.; Burdge, Kevin B.; Burruss, Rick; Caballero-García, Maria D.; Cannella, Chris; Castro-Tirado, Alberto J.; Cook, David O.; Cooke, Jeff; Cunningham, Virginia; Dahiwale, Aishwarya; Deshmukh, Kunal; Dichiara, Simone; Duev, Dmitry A.; Dutta, Anirban; Feeney, Michael; Franckowiak, Anna; Frederick, Sara; Fremling, Christoffer; Gal-Yam, Avishay; Gatkine, Pradip; Ghosh, Shaon; Goldstein, Daniel A.; Golkhou, V. Zach; Graham, Matthew J.; Graham, Melissa L.; Hankins, Matthew J.; Helou, George; Hu, Youdong; Ip, Wing-Huen; Jaodand, Amruta; Karambelkar, Viraj; Kong, Albert K. H.; Kowalski, Marek; Khandagale, Maitreya; Kulkarni, S. R.; Kumar, Brajesh; Laher, Russ R.; Li, K. L.; Mahabal, Ashish; Masci, Frank J.; Miller, Adam A.; Mogotsi, Moses; Mohite, Siddharth; Mooley, Kunal; Mroz, Przemek; Newman, Jeffrey A.; Ngeow, Chow-Choong; Oates, Samantha R.; Patil, Atharva Sunil; Pandey, Shashi B.; Pavana, M.; Pian, Elena; Riddle, Reed; Sánchez-Ramírez, Rubén; Sharma, Yashvi; Singh, Avinash; Smith, Roger; Soumagnac, Maayane T.; Taggart, Kirsty; Tan, Hanjie; Tzanidakis, Anastasios; Troja, Eleonora; Valeev, Azamat F.; Walters, Richard; Waratkar, Gaurav; Webb, Sara; Yu, Po-Chieh; Zhang, Bin-Bin; Zhou, Rongpu; Zolkower, Jeffry, We present a systematic search for optical counterparts to 13 gravitational wave (GW) triggers involving at least one neutron star during LIGO/Virgo's third observing run (O3). We searched binary neutron star (BNS) and neutron star black hole (NSBH) merger localizations with the Zwicky Transient Facility (ZTF) and undertook follow-up with the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration. The GW triggers had a median localization area of 4480 deg2, a median distance of 267 Mpc, and false-alarm rates ranging from 1.5 to 10-25 yr-1. The ZTF coverage in the g and r bands had a median enclosed probability of 39%, median depth of 20.8 mag, and median time lag between merger and the start of observations of 1.5 hr. The O3 follow-up by the GROWTH team comprised 340 UltraViolet/Optical/InfraRed (UVOIR) photometric points, 64 OIR spectra, and three radio images using 17 different telescopes. We find no promising kilonovae (radioactivity-powered counterparts), and we show how to convert the upper limits to constrain the underlying kilonova luminosity function. Initially, we assume that all GW triggers are bona fide astrophysical events regardless of false-alarm rate and that kilonovae accompanying BNS and NSBH mergers are drawn from a common population; later, we relax these assumptions. Assuming that all kilonovae are at least as luminous as the discovery magnitude of GW170817 (-16.1 mag), we calculate that our joint probability of detecting zero kilonovae is only 4.2%. If we assume that all kilonovae are brighter than-16.6 mag (the extrapolated peak magnitude of GW170817) and fade at a rate of 1 mag day-1 (similar to GW170817), the joint probability of zero detections is 7%. If we separate the NSBH and BNS populations based on the online classifications, the joint probability of zero detections, assuming all kilonovae are brighter than-16.6 mag, is 9.7% for NSBH and 7.9% for BNS mergers. Moreover, no more than 10-4, or φ > 30° to be consistent with our limits. We look forward to searches in the fourth GW observing run; even 17 neutron star mergers with only 50% coverage to a depth of-16 mag would constrain the maximum fraction of bright kilonovae to, This work was supported by the Global Relay of Observatories Watching Transients Happen (GROWTH) project, funded by the National Science Foundation under PIRE grant No. 1545949. GROWTH is a collaborative project among the California Institute of Technology (USA), University of Maryland College Park (USA), University of Wisconsin Milwaukee (USA), Texas Tech University (USA), San Diego State University (USA), University of Washington (USA), Los Alamos National Laboratory (USA), Tokyo Institute of Technology (Japan), National Central University (Taiwan), Indian Institute of Astrophysics (India), Indian Institute of Technology Bombay (India), Weizmann Institute of Science (Israel), The Oskar Klein Centre at Stockholm University (Sweden), Humboldt University (Germany), Liverpool John Moores University (UK), and University of Sydney (Australia). Based on observations obtained with the Samuel Oschin Telescope 48 inch and the 60 inch telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. The ZTF is supported by the National Science Foundation under grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. The ZTF forced photometry service was funded under Heising-Simons Foundation grant No. 12540303 (PI: Graham). The SED Machine is based upon work supported by the National Science Foundation under grant No. 1106171. The GROWTH-India telescope is a 70 cm telescope with a 0.7 degrees field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). The GROWTH-India project is supported by SERB and administered by IUSSTF under grant No. IUSSTF/PIRE Program/GROWTH/2015-16. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France (doi: 10.26093/cds/vizier). The original description of the VizieR service was published in A&AS 143, 23. These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell is a private, nonprofit institution dedicated to astrophysical research and public appreciation of astronomy and operates the LDT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University, and Yale University. The Large Monolithic Imager was built by Lowell Observatory using funds provided by the National Science Foundation (AST-1005313). The upgrade of the DeVeny optical spectrograph has been funded by a generous grant from John and Ginger Giovale and a grant from the Mt. Cuba Astronomical Foundation. The KPED team thanks the National Science Foundation and the National Optical Astronomical Observatory for making the Kitt Peak 2.1 m telescope available. We thank the observatory staff at Kitt Peak for their efforts to assist Robo-AO KP operations. The KPED team thanks the National Science Foundation, the National Optical Astronomical Observatory, the Caltech Space Innovation Council, and the Murty family for support in the building and operation of KPED. In addition, they thank the CHIMERA project for use of the Electron Multiplying CCD (EMCCD). The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Some spectroscopic observations were obtained with the Southern African Large Telescope (SALT). The Photometric Redshifts for the Legacy Surveys (PRLS) catalog used in this paper was produced thanks to funding from the U.S. Department of Energy Office of Science, Office of High Energy Physics, via grant DE-SC0007914. This publication has made use of data collected at Lulin Observatory, partly supported by MoST grant 108-2112-M-008-001. Based on observations made with the Gran Telescopio Canarias (GTC), installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias on the island of La Palma. M.M.K. acknowledges generous support from the David and Lucille Packard Foundation. M.W.C. acknowledges support from the National Science Foundation with grant No. PHY-2010970. A.G. and J.S. acknowledge support from the Knut and Alice Wallenberg Foundation and GREAT research environment grant 2016-06012, funded by the Swedish Research Council. Some of the work by D.A.P. was performed at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY-1607611. D.A.P. was partially supported by a grant from the Simons Foundation. H.K. thanks the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant 1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. This work has been supported by the Spanish Science Ministry Centro de Excelencia Severo Ochoa Program under grant SEV-2017-0709. A.J.C.T. acknowledges support from the Junta de Andalucia (Project P07-TIC-03094) and Spanish Ministry Projects AYA2012-39727-C03-01, AYA2015-71718R, and PID-019-109974RB-I00. V.A.F. was supported by grant RFBR 19-02-00432. I.A. acknowledges support by a Ramon y Cajal grant (RYC-2013-14511) of the Ministerio de Ciencia, Innovacion, y Universidades (MICIU) of Spain. He also acknowledges financial support from MCIU through grant AYA2016-80889-P. A.A.M. is funded by the Large Synoptic Survey Telescope Corporation, the Brinson Foundation, and the Moore Foundation in support of the LSSTC Data Science Fellowship Program; he also receives support as a CIERA Fellow by the CIERA Postdoctoral Fellowship Program (Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University). A.C. acknowledges support from the National Science Foundation with grant No. 1907975. W.-H.I., A. K., K.-L.L., C.-C.N., A.P., H.T., and P.-C.Y. acknowledge support from Ministry of Science and Technology (MoST) Taiwan grants 104-2923-M-008-004-MY5, 107-2119-M-008-012, 108-2628-M-007-005-RSP, and 108-2112-M-007-025-MY3. D.D. is supported by an Australian Government Research Training Program Scholarship. S.A. is supported by the GROWTH project, funded by the National Science Foundation under PIRE grant No. 1545949. A.S.C. is supported by GREAT research environment grant 2016-06012, funded by the Swedish Research Council. E.C.K. acknowledges support from the G.R.E.A.T. research environment and the Wenner-Gren Foundations. A.J.C.T. is thankful for fruitful discussions with J. Cepa, E. Fernandez-Garcia, J. A. Font, S. Jeong, A. Martin-Carrillo, A. M. Sintes, and S. Sokolov. D.A.H.B. acknowledges research support from the National Research Foundation of South Africa. S.B.P. and V.B. acknowledge BRICS grant No. "DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G)" for part of the present work. J.S.B. was partially supported by a Gordon and Betty Moore Foundation Data-Driven Discovery grant and a grant from the National Science Foundation, "Conceptualization of a Scalable Cyberinfrastructure Center for Multimessenger Astrophysics."

Full list of authors: Lin, L.; Zhang, C. F.; Wang, P.; Gao, H.; Guan, X.; Han, J. L.; Jiang, J. C.; Jiang, P.; Lee, K. J.; Li, D.; Men, Y. P.; Miao, C. C.; Niu, C. H.; Niu, J. R.; Sun, C.; Wang, B. J.; Wang, Z. L.; Xu, H.; Xu, J. L.; Xu, J. W.; Yang, Y. H.; Yang, Y. P.; Yu, W.; Zhang, B.; Zhang, B. -B.; Zhou, D. J.; Zhu, W. W.; Castro-Tirado, A. J.; Dai, Z. G.; Ge, M. Y.; Hu, Y. D.; Li, C. K.; Li, Y.; Li, Z.; Liang, E. W.; Jia, S. M.; Querel, R.; Shao, L.; Wang, F. Y.; Wang, X. G.; Wu, X. F.; Xiong, S. L.; Xu, R. X.; Yang, Y. -S.; Zhang, G. Q.; Zhang, S. N.; Zheng, T. C.; Zou, J. -H., Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances1–3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources4–13, but no convincing evidence has been collected so far14. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft γ-ray bursts15. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft γ-ray/hard-X-ray flare18–21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-γ-ray repeater (SGR) bursts were detected in γ-ray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB–SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst. © 2020, The Author(s), under exclusive licence to Springer Nature Limited., This work is supported by the Natural Science Foundation of China (grants 11988101, 11673002, 11703002, 11543004, 11722324, 11690024, 11633001, 11920101003, 11833003, 11722324, 11633001, 11690024, 11573014, 11725314, 11690024, 11743002, 11873067, 11533003, 11673006, U1938201, 11725313, 11721303, 1172130, U15311243, U1831207, U1838201, U1838202, U1838113, U1938109), National Key Research and Development Programs of China (grants 2018YFA0404204, 2017YFA0402600), the Program for Innovative Talents and Entrepreneur in Jiangsu, the KIAA-CAS Fellowship, the China Postdoctoral Science Foundation (grants 2018M631242, 2016YFA0400800, 2018YFA0400802, E01S11BQ10, XDB23010200,XDB2304040, QYZDY-SSW-SLH008), the International Partnership Program of Chinese Academy of Sciences (grant number 114A11KYSB20160008), the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, the Max-Planck Partner Group, the Spanish Science Ministry “Centro de Excelencia Severo Ochoa” Program (grant SEV-2017-0709), the Junta de Andalucía (Project P07-TIC-03094) and the Spanish Ministry Projects AYA2012-39727-C03-01, AYA2015-71718R and PID2019-109974RB-I00. We thank E. Fernández-García (IAA-CSIC), I. M. Carrasco-García and C. Pérez del Pulgar (UMA) and the rest of the BOOTES Team for making the reported BOOTES Network observations possible. This work made use of data from FAST—a Chinese national mega-science facility, built and operated by the National Astronomical Observatories, Chinese Academy of Sciences. We also acknowledge the use of public data from the Fermi Science Support Center (FSSC).

Based on the Kirchoff plate theory and Hamiltonian principle, the magneto-aeroelastic nonlinear governing equation for the forced vibration of the rotating conductive circular plate is derived. According to principles of electromagnetic field combined with a simplified aerodynamic model, the expressions of electromagnetic force and aerodynamic load of rotating circular plate are presented. The transverse nonlinear forced vibration differential equation of simply edge rotating circular plate is achieved by Galerkin method, where Bessel functions are utilized to a mode shape. Amplitude–frequency response equation of the system is obtained by using averaging. By numerical calculation, the amplitude–frequency curves of circular plate are plotted, and the influences of different parameters on amplitude–frequency characteristics of systems are analyzed, respectively. The dynamic behaviors of the system are investigated by means of bifurcation diagrams, maximum Lyapunov exponents and system responses under different controlling parameters.

CuCr1−xMgxO2 (x = 0 and 0.02) epitaxial thin films were prepared on 5°/10° vicinal cut α-Al2O3 (000l) substrates using pulsed laser deposition. The laser-induced thermoelectric voltage (LITV) effect in these inclined delafossite thin films was observed for the first time. The thin films were characterized by resistivity temperature measurement and atomic force microscopy. Because of the enhanced resistivity anisotropy and high carrier concentration in the ab-plane owing to Mg doping, the 10°-tilted CuCr0.98Mg0.02O2 film exhibits an evident LITV signal with a maximum transverse thermoelectric voltage of 156 mV. Thermal conductivity results indicate that CuCr1−xMgxO2 (x = 0 and 0.02) films have a dominant phonon thermal conductivity, which may contribute to a long decay time for the LITV signal. These results indicate potential for future transverse thermoelectric applications based on transparent conductive oxides.

The magneto-elastic 1:3 principal-internal resonance of axially moving current-carrying beams in a magnetic field is investigated. With the elastic theory of Euler–Bernoulli beam and the basic theory of electromagnetic field taken into account, the magneto-elastic vibration equation of an axially moving beam in a magnetic field is therefore developed by the Hamiltonian principle. On the basis of the hypothetical two-order modal shape function satisfying the fixed-hinged boundary condition, amplitude–frequency response equations of the 1:3 principal-internal resonance are obtained by Galerkin and multi-scale method. Calculation results based on relevant MATLAB programming, show that: When the system first-order primary resonance occurs, the second-order modal amplitude that should be disappeared excited by internal resonance, but its value is smaller than the first-order modal amplitude. It has only two changing stages and lacks a small single-value area in the curve of amplitude and external excitation force amplitude for the first-order primary resonance of the system; the curves of amplitude versus magnetic field strength, influenced by applied current, exhibit an asymmetric distribution property along the longitudinal line where the value of the magnetic field strength is zero; the response can be dominated by the first mode in the second-order primary-internal resonance of the system, in which the amplitude of the external excitation must exceed a critical value before the first mode can be excited. In addition, such as the axial velocity, the magnetic field strength, the excitation amplitude and the tuning parameters have a significant effect on the amplitude of the system, especially the magnetic field has an obvious inhibitory effect on the vibration.

Based on the basic equations of electromagnetic elastic motion and the expression of electromagnetic force, the electromagnetic vibration equation of the rectangular thin plate in transverse magnetic field is obtained. For a rectangular plate with one side fixed and three other sides simply supported, its time variable and space variable are separated by the method of Galerkin, and the two-degree-of-freedom nonlinear Duffing vibration differential equations are proposed. The method of multiple scales is adopted to solve the model equations and obtain four first-order ordinary differential equations governing modulation of the amplitudes and phase angles involved via 1:1 or 1:3 internal resonances with different size ratios. With a numerical example, the time history response diagrams, phase portraits and 3-dimension responses of two order modal amplitudes are respectively captured. And the effects of initial values, thickness and magnetic field intensities on internal resonance characteristics are discussed respectively. The results also present obvious characteristics of typical nonlinear internal resonance in this paper.

On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulted from a neutron star-black hole (NSBH) merger, or potentially a low-mass binary BH merger. Due to the low false-alarm rate and the precise localization (23 deg at 90%), S190814bv presented the community with the best opportunity yet to directly observe an optical/near-infrared counterpart to an NSBH merger. To search for potential counterparts, the GROWTH Collaboration performed real-time image subtraction on six nights of public Dark Energy Camera images acquired in the 3 weeks following the merger, covering >98% of the localization probability. Using a worldwide network of follow-up facilities, we systematically undertook spectroscopy and imaging of optical counterpart candidates. Combining these data with a photometric redshift catalog, we ruled out each candidate as the counterpart to S190814bv and placed deep, uniform limits on the optical emission associated with S190814bv. For the nearest consistent GW distance, radiative transfer simulations of NSBH mergers constrain the ejecta mass of S190814bv to be M < 0.04 M at polar viewing angles, or M < 0.03 M if the opacity is κ < 2 cmg. Assuming a tidal deformability for the NS at the high end of the range compatible with GW170817 results, our limits would constrain the BH spin component aligned with the orbital momentum to be χ < 0.7 for mass ratios Q < 6, with weaker constraints for more compact NSs., This work was supported by the GROWTH (Global Relay of Observatories Watching Transients Happen) project funded by the National Science Foundation under PIRE grant No. 1545949. GROWTH is a collaborative project among California Institute of Technology (USA), University of Maryland College Park (USA), University of Wisconsin Milwaukee (USA), Texas Tech University (USA), San Diego State University (USA), University of Washington (USA), Los Alamos National Laboratory (USA), Tokyo Institute of Technology (Japan), National Central University (Taiwan), Indian Institute of Astrophysics (India), Indian Institute of Technology Bombay (India), Weizmann Institute of Science (Israel), The Oskar Klein Centre at Stockholm University (Sweden), Humboldt University (Germany), Liverpool John Moores University (UK), and University of Sydney (Australia). D.A.G. acknowledges support from Hubble Fellowship grant HST-HF2-51408.001-A. Support for program No. HST-HF251408.001-A is provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. We gratefully acknowledge Amazon Web Services, Inc., for a generous grant (PS_IK_ FY2019_Q3_ Caltech_Gravitational_Wave) that funded our use of the Amazon Web Services cloud computing infrastructure to process the DECam data. P.E.N. acknowledges support from the DOE through DE-FOA-0001088, Analytical Modeling for Extreme-Scale Computing Environments. D.A.P. and D.A.G. performed the work associated with this project at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY-1607611. This work was partially supported by a grant from the Simons Foundation. A.J.C.-T. thanks I. Agudo, J. Cepa, V. Dhillon, J. A. Font, A. MartinCarrillo, S. R. Oates, S. B. Pandey, E. Pian, R. Sanchez-Ramirez, A. M. Sintes, V. Sokolov, and B.-B. Zhang for fruitful conversations. F.F. gratefully acknowledges support from NASA through grant 80NSSC18K0565 and from the NSF through grant PHY1806278. M.B., A.G., E.K., S.D., and J.S. acknowledge support from the G.R.E.A.T research environment funded by the Swedish National Science Foundation. J.S. acknowledges support from the Knut and Alice Wallenberg Foundation. J.S.B. and K.Z. are partially supported by a Gordon and Betty Moore Foundation Data-Driven Discovery grant. D.A.H.B. acknowledges research support from the National Research Foundation of South Africa. M.W.C. is supported by the David and Ellen Lee Postdoctoral Fellowship at the California Institute of Technology. S.N. and G.R. are grateful for support from VIDI, Projectruimte, and TOP Grants of the Innovational Research Incentives Scheme (Vernieuwingsimpuls) financed by the Netherlands Organization for Scientific Research (NWO). H.K. and K.Z. thank the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining grant No. 1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. D.D. is supported by an Australian Government Research Training Program Scholarship. P.G. is supported by NASA Earth and Space Science Fellowship (ASTRO18F-0085). D.L.K. was supported by NSF grant AST-1816492. Y.D.H. thanks the support by the program of China Scholarships Council (CSC) under grant No. 201406660015. A.K.H.K. acknowledges support from the Ministry of Science and Technology of the Republic of China (Taiwan) through grants 107-2628-M-007-003 and 1082628-M-007-005-RSP. V.Z.G. acknowledges support from the University of Washington College of Arts and Sciences, Department of Astronomy, and the DIRAC Institute. University of Washington's DIRAC Institute is supported through generous gifts from the Charles and Lisa Simonyi Fund for Arts and Sciences and the Washington Research Foundation. M.J. and A.C. acknowledge the support of the Washington Research Foundation Data Science Term Chair fund and the UW Provost's Initiative in Data-Intensive Discovery. S.M. thanks the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant-1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. M.G. is supported by the Polish NCN MAESTRO grant 2014/14/A/ST9/00121. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France (doi:10.26093/cds/vizier). The original description of the VizieR service was published in A&AS 143, 23. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, University of California Santa Cruz, University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid, University of Chicago, University College London, DES-Brazil consortium, University of Edinburgh, ETH-Zurich, University of Illinois at Urbana-Champaign, Institut de Ciencies de l'Espai, Institut de Fisica d'Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, University of Michigan, National Optical Astronomy Observatory, University of Nottingham, Ohio State University, University of Pennsylvania, University of Portsmouth, SLAC National Lab, Stanford University, University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financiadora de Estudos e Projetos, Fundacao Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico and the Ministerio da Ciencia e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence "Origin and Structure of the Universe," and the DES collaborating institutions. The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. This work is partly based on data obtained with the instrument OSIRIS, built by a Consortium led by the Instituto de Astrofisica de Canarias in collaboration with the Instituto de Astronomia of the Universidad Autonoma de Mexico. OSIRIS was funded by GRANTECAN and the National Plan of Astronomy and Astrophysics of the Spanish Government. Some of the observations reported in this paper were obtained with the Southern African Large Telescope (SALT). Polish participation in SALT is funded by grant No. MNiSW DIR/WK/2016/07.

GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at z = 0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We present X-ray, optical/nIR, and radio observations of its counterpart and model them with two distinct components of emission: a standard afterglow, arising from the interaction of the relativistic jet with the surrounding medium, and a kilonova, powered by the radioactive decay of the sub-relativistic ejecta. Broadband modelling of the afterglow data reveals a weak reverse shock propagating backward into the jet, and a likely jet-break at 3.5 d. This is consistent with a structured jet seen slightly off-axis (theta(view) similar to theta(core)) while expanding into a low-density medium (n approximate to 10(-3) cm(-3)). Analysis of the kilonova properties suggests a rapid evolution towards red colours, similar to AT2017gfo, and a low-nIR luminosity, possibly due to the presence of a long-lived neutron star. The global properties of the environment, the inferred low mass (M-ej less than or similar to 0.006 M-circle dot) and velocities (v(ej) greater than or similar to 0.05c) of lanthanide-rich ejecta are consistent with a binary neutron star merger progenitor.© 2019 The Authors., Partial support of the DCT was provided by Discovery Communications. LMI was built by Lowell Observatory using funds from the National Science Foundation (AST-1005313). The work is partly based on the observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. ET acknowledges financial support provided by the National Aeronautics and Space Administration through HST-GO14357, HST-GO14087, HST-GO14607, and HST-GO14850 grants from the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Incorporated. AJCT, YDH e IM acknowledge financial support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). The development of CIRCE at GTC was supported by the University of Florida and the National Science Foundation (grant AST-0352664), in collaboration with IUCAA. RSR acknowledges support by Italian Space Agency (ASI) through the Contract no. 2015-046-R.0 and by AHEAD the European Union Horizon 2020 Programme under the AHEAD project (grant agreement no. 654215). YDH also acknowledges the support by the program of China Scholarships Council (CSC) under the grant no. 201406660015. JBG acknowledges the support of the Viera y Clavijo program funded by ACIISI and ULL. GN and AT acknowledge funding in the framework of the project ULTraS (ASI-INAF contract no. 2017-14-H.0). GR acknowledges the support of the University of Maryland through the Joint Space Science Institute Prize Postdoctoral Fellowship.

We investigate the prompt emission and the afterglow properties of short-duration gamma-ray burst (sGRB) 130603B and another eight sGRB events during 2012-2015, observed by several multiwavelength facilities including the Gran Canarias Telescope 10.4 m telescope. Prompt emission high energy data of the events were obtained by INTEGRAL-SPI-ACS, Swift-BAT, and Fermi-GBM satellites. The prompt emission data by INTEGRAL in the energy range of 0.1-10 MeV for sGRB 130603B, sGRB 140606A, sGRB 140930B, sGRB 141212A, and sGRB 151228A do not show any signature of the extended emission or precursor activity and their spectral and temporal properties are similar to those seen in case of other short bursts. For sGRB 130603B, our new afterglow photometric data constrain the pre-jet-break temporal decay due to denser temporal coverage. For sGRB 130603B, the afterglow light curve, containing both our new and previously published photometric data is broadly consistent with the ISM afterglow model. Modeling of the host galaxies of sGRB 130603B and sGRB 141212A using the LePHARE software supports a scenario in which the environment of the burst is undergoing moderate star formation activity. From the inclusion of our late-time data for eight other sGRBs we are able to: place tight constraints on the non-detection of the afterglow, host galaxy, or any underlying 'kilonova' emission. Our late-time afterglow observations of the sGRB 170817A/GW170817 are also discussed and compared with the sub-set of sGRBs.© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society, AJCT acknowledges support from the Junta de Andalucia (Project P07-TIC-03094) and support from the Spanish Ministry Projects AYA2012-39727-C03-01 and 201571718R. This work has been supported by the Spanish Science Ministry 'Centro de Excelencia SeveroOchoa' Program under grant SEV-2017-0709. FEDER funds are acknowledged. E.S. acknowledges assistance from the Scientific and Technological Research Council of Turkey (TUBITAK) through project 112T224. We thank TUBITAK for a partial support in using T100 telescope with project number 10CT100-95. A.S.P acknowledges partial support grants RFBR 17-02-01388, 17-51-44018, and 1752-80139. E.D.M., A.A.V., and P.Yu.M. are grateful to RSCF grant 18-12-00522 for support. B.-B.Z. acknowledges support from National Thousand Young Talents program of China and National Key Research and Development Program of China (2018YFA0404204). R.Ya.I. is grateful for partial support by the grant RUSTAVELI/FR/379/6-300/14. R.S.R. acknowledges support from ASI (Italian Space Agency) through the Contract No. 2015-046R.0 and from European Union Horizon 2020 Programme under the AHEAD project (grant agreement No. 654215). SJ acknowledges the support of the Korea Basic Science Research Program through NRF-2015R1D1A4A01020961.

The nonlinear free vibration of a conductive rotating thin circular plate subjected to static loads in magnetic field was investigated. The nonlinear vibration equations of the motion on a spinning circular thin plate were derived. According to the set of a displacement function, the approximate solution of the static problem and the magneto elastic axisymmetric vibration differential equation of the round plate were obtained through the application of Galerkin integral method. The characteristic formula between nonlinear frequency and amplitude using the static load as a parameter was obtained by the method of multiple scales. According to the numerical calculation, the characteristic curves of the relationship between frequency and the parameter such as the static load, the magnetic induction intensity and the speed of rotation were obtained. The nonlinear vibration characteristics of a spinning plate with clamped boundary condition were described according to the curves drawn by Matlab. We also showed that different parameters (including magnetic induction intensity, static load, time and spinning velocity.) have effect on the frequency of the plate.

This paper presents data on the simultaneous and complementary observations of the gamma-ray burst (GRB) GRB 161017A for optical, X-ray, and gamma wavelengths obtained by the Russian multi-messenger Lomonosov space observatory and supplemented by additional data from the Swift satellite as well as the ground-based MASTER Global Robotic Net and the 10 m Gran Telescopio Canarias. Multifrequency spectra of this very powerful explosion indicate that it originated at a distance of 10 billion light years from Earth. Here, we present the results of the prompt, early, and afterglow optical observations. The light curves and spectra suggest that the prompt optical and high-energy emissions occur in the same region near the GRB source. © 2018. The American Astronomical Society. All rights reserved., Analysis of the gamma-ray events observation during the BDRG experiment on board the Lomonosov satellite was fulfilled with the financial support of Ministry of Education and Science of Russia, grant No. RFMEFI60717X0175. A.J.C.T. acknowledges the Spanish Ministry Program AYA 2015-71718-R. MASTER Global Robotic Net is supported in part by the Development Program of Lomonosov Moscow State University. I.H.P. acknowledges National Research Foundation of Korea for Nos. 2018R1A2A1A05022685 and 2017K1A4A3015188. S.J. acknowledges the support of the Korea Basic Science Research Program through NRF-2018R1D1A1B07048993. This work was also supported in part by the RFBR grant 17-52-80133 and by Russian Science Foundation (RSF) grant 16-12-00085 (data analysis, interpretation, and discussion).

The ejecta composition is an open question in gamma-ray burst (GRB) physics . Some GRBs possess a quasi-thermal spectral component in the time-resolved spectral analysis , suggesting a hot fireball origin. Others show a featureless non-thermal spectrum known as the Band function , consistent with a synchrotron radiation origin and suggesting that the jet is Poynting-flux dominated at the central engine and probably in the emission region as well . There are also bursts showing a sub-dominant thermal component and a dominant synchrotron component , suggesting a probable hybrid jet composition . Here, we report an extraordinarily bright GRB 160625B, simultaneously observed in gamma-ray and optical wavelengths, whose prompt emission consists of three isolated episodes separated by long quiescent intervals, with the durations of each sub-burst being approximately 0.8 s, 35 s and 212 s, respectively. Its high brightness (with isotropic peak luminosity L ≈ 4 × 10 erg s) allows us to conduct detailed time-resolved spectral analysis in each episode, from precursor to main burst and to extended emission. The spectral properties of the first two sub-bursts are distinctly different, allowing us to observe the transition from thermal to non-thermal radiation between well-separated emission episodes within a single GRB. Such a transition is a clear indication of the change of jet composition from a fireball to a Poynting-flux-dominated jet., B.-B.Z. thanks Y.-Z. Fan, Y.-Z. Wang, H. Wang, K. D. Alexander and D. Lazzati for helpful discussions. We are grateful to K. Hurley, I. Mitrofanov, A. Sanin, M. Litvak and W. Boynton for the use of Mars Odyssey data in the triangulation. We acknowledge the use of the public data from the Swift and Fermi data archives. B.-B. Z. and A.J. C.-T. acknowledge support from the Spanish Ministry Projects AYA2012-39727-C03-01 and AYA2015-71718-R. Part of this work made use of B.-B.Z.'s personal Interactive Data Language (IDL) code library ZBBIDL and personal Python library ZBBPY. The computation resources used in this work are owned by Scientist Support LLC. B.Z. acknowledges NASA NNX14AF85G and NNX15AK85G for support. Z. G. D. acknowledges the National Natural Science Foundation of China(NSFC) (grant 11573014). Y.-D. H. acknowledges support by China Scholarships Council (grant 201406660015). Mini-MegaTORTORA belongs to Kazan Federal University, and the work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University. A. P., E.M., P. M. and A.V. are grateful to the Russian Foundation for Basic Research (grant 17-02-01388) for partial support. A. P. and S.B.P. acknowledge joint BRICS (Brazil, Russia, India, China and South Africa) grant RFBR 17-52-80139 and 388-ProFChEAP for partial support. R. I. is grateful to grant RUSTAVELI FR/379/6300/ 14 for partial support. Observations on Mini-MegaTORTORA are supported by the Russian Science Foundation (grant 14-50-00043). A.V.F. and A. M. thank the Russian Science Foundation (grant 14-50-00043). L.M. and A.F.Z. acknowledge support from INTA-CEDEA ESAt personnel hosting the Pi of the Sky facility at the BOOTES-1 station. H. G. and X.-Y.W. acknowledge NSFC (grants 11603003 and 11625312, respectively). Z. G. D., X.-F. W., B.Z., X.-Y. W.,L.S. and F.-W.Z. are also supported by the 973 program (grant 2014CB845800). F.-W.Z. is also supported in part by the NSFC (grants U1331101 and 11163003), the Guangxi Natural Science Foundation (grant 2013GXNSFAA019002) and the project of outstanding young teachers' training in higher education institutions of Guangxi. L.S. acknowledges support by the NSFC (grant 11103083) and the Joint NSFC-ISF Research Program (grant 11361140349). S.O. acknowledges the support of the Leverhulme Trust. S.J. acknowledges support from Korea Basic Science Research Program through NRF-2014R1A6A3A03057484 and NRF-2015R1D1A4A01020961, and I. H. P. through NRF-2015R1A2A1A01006870 and NRF-2015R1A2A1A15055344. R. A., D. F. and D. S. acknowledge support from RSF (grant 17-12-01378). A. K. acknowledges the Science and Education Ministry of Kazakhstan (grant 0075/GF4).

We present the extensive follow-up campaign on the afterglow of GRB 110715A at 17 different wavelengths, from X-ray to radio bands, starting 81 seconds after the burst and extending up to 74 days later. We performed for the first time a GRB afterglow observation with the ALMA observatory. We find that the afterglow of GRB 110715A is very bright at optical and radio wavelengths. We use optical and near infrared spectroscopy to provide further information about the progenitor's environment and its host galaxy. The spectrum shows weak absorption features at a redshift z = 0.8225, which reveal a host galaxy environment with low ionization, column density and dynamical activity. Late deep imaging shows a very faint galaxy, consistent with the spectroscopic results. The broadband afterglow emission is modelled with synchrotron radiation using a numerical algorithm and we determine the best fit parameters using Bayesian inference in order to constrain the physical parameters of the jet and the medium in which the relativistic shock propagates. We fitted our data with a variety of models, including different density profiles and energy injections. Although the general behaviour can be roughly described by these models, none of them are able to fully explain all data points simultaneously. GRB 110715A shows the complexity of reproducing extensive multi-wavelength broadband afterglow observations, and the need of good sampling in wavelength and time and more complex models to accurately constrain the physics of GRB afterglows., Accepted for publication in MNRAS

Zhang, B.B. et. al., Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA's Fermi Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low. The estimated event rate density above this luminosity is at least 190 Gpc yr, which is close to but still below the DNS merger event rate density. This event likely originates from a structured jet viewed from a large viewing angle. There are similar faint soft GRBs in the Fermi archival data, a small fraction of which might belong to this new population of nearby, low-luminosity sGRBs., We acknowledge support from National Basic Research Program of China (973 Program, Grant No. 2014CB845800). B.-B.Z. and A.J.C.T. acknowledge support from the Spanish Ministry Projects AYA 2012-39727-C03-01 and AYA2015-71718-R. B.-B.Z. acknowledges the support from the National Thousand Young Talents program of China. This work is also supported by the Strategic Pioneer Program on Space Science, Chinese Academy of Sciences (Grant No. XDA15052100). B.Z., H.S., H.G., and X.F.W. are supported by the Strategic Priority Research Program of the Chinese Academy of Sciences >Multi-waveband Gravitational Wave Universe> (Grant No. XDB23040000). H.G. acknowledges the National Natural Science Foundation of China under grants Nos. 11722324, 11603003, 11633001, and 11690024. H.J.L. and E. W. L. acknowledge the National Natural Science Foundation of China under grant 11603006 and 11533003. Y.D.H. acknowledges the support by China Scholarships Council (CSC) under the Grant No. 201406660015. X.-F.W. acknowledges the National Natural Science Foundation of China under grant 11625312. L.S. acknowledges the support by the Joint NSFC-ISF Research Program (No. 11361140349), jointly funded by the National Natural Science Foundation of China and the Israel Science Foundation. X.F. was supported by Natural Science Foundation of China under Grants Nos. 11725314, 11673068, and 11433009.

This is an erratum to the paper 'The afterglow and kilonova of the short GRB 160821B' (2019, MNRAS, 489, 2104-2116). In the original version of this article, the affiliations of K. Ackley were incorrect. They have now been corrected to: i) Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, VIC 3800, Australia ii) OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Clayton VIC 3800, Australia The authors apologise for this error.

The bifurcation and chaos of a clamped circular functionally graded plate is investigated. Considered the geometrically nonlinear relations and the temperature-dependent properties of the materials, the nonlinear partial differential equations of FGM plate subjected to transverse harmonic excitation and thermal load are derived. The Duffing nonlinear forced vibration equation is deduced by using Galerkin method and a multiscale method is used to obtain the bifurcation equation. According to singularity theory, the universal unfolding problem of the bifurcation equation is studied and the bifurcation diagrams are plotted under some conditions for unfolding parameters. Numerical simulation of the dynamic bifurcations of the FGM plate is carried out. The influence of the period doubling bifurcation and chaotic motion with the change of an external excitation are discussed.

In the version of this Letter originally published, the letter i was mistakenly omitted from the surname of the author R. Sanchez-Ramirez. This has now been corrected.

This paper studies the connectedness of the cone superefficient point set in locally convex topological vector spaces. First, we prove a scalarization theorem for a cone superefficient point set. From this result, we obtain the connectedness of a cone superefficient point set under the conditions that the set is cone convex and cone weakly compact.

Quasi-linear studies in the near-Earth (XGSE>-25 RE) central plasma sheet and plasma sheet boundary layer indicate that the ion cyclotron proton anisotropy instability may lead to significant ion heating in these regions. Saturation of the anisotropy instability can yield both narrow and broadband magnetic spectra below the proton gyrofrequency with amplitudes of the order of 1 nT. These waves then heat thermal and suprathermal He+ and O+ ions via resonant and nonresonant processes to energies above 1 keV for He+ ions and up to 100 eV for O+ ions. He++ ions also experience significant heating to temperatures that may exceed that of the unstable proton component. These results are consistent with in situ observations of magnetic noise and heavy ion distributions in the near-Earth magnetotail.

The evolution of particle velocity moments and wave spectra during the quasilinear saturation of the proton beam-anisotropy instability in a current carrying plasma is studied. For initial plasma moments characteristic of the near-Earth plasma sheet boundary layer, it is found that the saturation of the ion beam-anisotropy instability drives a field-aligned current, which self-consistently excites a kink-like mode. The driven current allows the wave fields of current driven mode to grow to amplitudes comparable to that of the anisotropy instability and facilitates more rapid isotropization of the unstable anisotropic beam components and saturation of the beam-anisotropy instability. This work has general relevance to the study of field-aligned instabilities in plasmas where the excited waves carry a net momentum density away from the source of instability.