Multi-Messenger Astronomy with Extremely Large Telescopes

The field of time-domain astrophysics has entered the era of Multi-messenger Astronomy (MMA). One key science goal for the next decade (and beyond) will be to characterize gravitational wave (GW) and neutrino sources using the next generation of Extremely Large Telescopes (ELTs). These studies will have a broad impact across astrophysics, informing our knowledge of the production and enrichment history of the heaviest chemical elements, constrain the dense matter equation of state, provide independent constraints on cosmology, increase our understanding of particle acceleration in shocks and jets, and study the lives of black holes in the universe. Future GW detectors will greatly improve their sensitivity during the coming decade, as will near-infrared telescopes capable of independently finding kilonovae from neutron star mergers. However, the electromagnetic counterparts to high-frequency (LIGO/Virgo band) GW sources will be distant and faint and thus demand ELT capabilities for characterization. ELTs will be important and necessary contributors to an advanced and complete multi-messenger network.Comment: White paper submitted to the Astro2020 Decadal Surve

Robotic equipment carrying RN detectors: requirements and capabilities for testing

77 pags., 32 figs., 5 tabs.-- ERNCIP Radiological and Nuclear Threats to Critical Infrastructure Thematic Group . -- This publication is a Technical report by the Joint Research Centre (JRC) . -- JRC128728 . -- EUR 31044 ENThe research leading to these results has received funding from the European Union as part of the European Reference Network for Critical Infrastructure Protection (ERNCIP) projec

Proactive strategies in personal dose monitoring, prevention and mitigation

At certain threshold, nuclear radiation (like x-rays and gamma-rays) may adversely impact the health of living tissues. The exposure to these radiations in nuclear facilities is measured by devices called dosimeters. The devices are generally worn on the torso and are monitored by health physics division to report the radiation dose received by the personnel. However, this approach is not proactive--since the dosimeters reflect the dose that has already been absorbed in the body of the wearer. This work presents a scheme to proactively avoid large dose acquisition at radiation-prone facilities. The work was divided into three major segments: (i) identify and characterize radioactive source(s), (ii) determine the impact of localized source(s), and (iii) estimate the integrated doses in traversing/evacuating the facility. The scope of this work does not extend to the development of proactive dosimeter. However, the approaches developed in these segments will be integrated into a dose monitoring system that would prevent or mitigate large dose acquisition. This work also has applications in nuclear facilities, hospitals, homeland security, and border protection --Abstract, page iv

Design and Development of Carborne Survey Equipment

In most nuclear and radiological emergencies involving the release of radioactive materials to environment, it is important that data on the geographic distribution of potentially hazardous radioactive materials be quickly presented to the authorities. The mobile radiation detection system makes it possible to measure radioactive materials in the environment at random places because of its easy mobility from place to place. The purpose of the work is to develop a mobile radiation detection system to measure gamma exposure rate, radioactive material on the ground and airborne radioactive particulate in the environment quickly. In this work, we have developed a carborne survey equipment system consisting of three gamma ray detectors, one airbome radioactive particulate sampler, a GPS (Global Positioning System), meteorological sensors, a data acquisition system and an operation software. Performance of the carborne survey equipment has been successfully demonstrated to measure iodine and argon release from medical isotope production facility on Serpong in western Java, Indonesia.Received: 04 October 2014; Revised:16 March 2015; Accepted: 23 March 201

Design and Development of Carborne Survey Equipment

In most nuclear and radiological emergencies involving the release of radioactive materials to environment, it is important that data on the geographic distribution of potentially hazardous radioactive materials be quickly presented to the authorities. The mobile radiation detection system makes it possible to measure radioactive materials in the environment at random places because of its easy mobility from place to place. The purpose of the work is to develop a mobile radiation detection system to measure gamma exposure rate, radioactive material on the ground and airborne radioactive particulate in the environment quickly. In this work, we have developed a carborne survey equipment system consisting of three gamma ray detectors, one airbome radioactive particulate sampler, a GPS (Global Positioning System), meteorological sensors, a data acquisition system and an operation software. Performance of the carborne survey equipment has been successfully demonstrated to measure iodine and argon release from medical isotope production facility on Serpong in western Java, Indonesia.Received: 04 October 2014; Revised:16 March 2015; Accepted: 23 March 2015 

The detection efficiency of on-axis short gamma ray burst optical afterglows triggered by aLIGO/Virgo

Assuming neutron star (NS) or neutron star/stellar-mass black hole (BH) mergers as progenitors of the short gamma ray bursts, we derive and demonstrate a simple analysis tool for modelling the efficiency of recovering on-axis optical afterglows triggered by a candidate gravitational wave event detected by the Advanced LIGO and Virgo network. The coincident detection efficiency has been evaluated for different classes of operating telescopes using observations of gamma ray bursts. We show how the efficiency depends on the luminosity distribution of the optical afterglows, the telescope features, and the sky localisation of gravitational wave triggers. We estimate a plausible optical afterglow and gravitational wave coincidence rate of 1 yr$^{-1}$ (0.1 yr$^{-1}$) for NS-NS (NS-BH), and how this rate is scaled down in detection efficiency by the time it takes to image the gravitational wave sky localization and the limiting magnitude of the telescopes. For NS-NS (NS-BH) we find maximum detection efficiencies of $>80$ when the total imaging time is less than 200 min (80 min) and the limiting magnitude fainter than 20 (21). We show that relatively small telescopes $(m<18)$ can achieve similar detection efficiencies to meter class facilities $(m<20)$ with similar fields of view, only if the less sensitive instruments can respond to the trigger and image the field within 10-15 min. The inclusion of LIGO India into the gravitational wave observatory network will significantly reduce imaging time for telescopes with limiting magnitudes $\sim20$ but with modest fields of view. An optimal coincidence search requires a global network of sensitive and fast response wide field instruments that could effectively image relatively large gravitational-wave sky localisations and produce transient candidates for further photometric and spectroscopic follow-up.Comment: 6 pages, 2 figures, version 2, reference added typo correction, Accepted by MNRA

A "kilonova" associated with short-duration gamma-ray burst 130603B

Short-duration gamma-ray bursts (SGRBs) are intense flashes of cosmic gamma-rays, lasting less than ~2 s, whose origin is one of the great unsolved questions of astrophysics today. While the favoured hypothesis for their production, a relativistic jet created by the merger of two compact stellar objects (specifically, two neutron stars, NS-NS, or a neutron star and a black hole, NS-BH), is supported by indirect evidence such as their host galaxy properties, unambiguous confirmation of the model is still lacking. Mergers of this kind are also expected to create significant quantities of neutron-rich radioactive species, whose decay should result in a faint transient in the days following the burst, a so-called "kilonova". Indeed, it is speculated that this mechanism may be the predominant source of stable r-process elements in the Universe. Recent calculations suggest much of the kilonova energy should appear in the near-infrared (nIR) due to the high optical opacity created by these heavy r-process elements. Here we report strong evidence for such an event accompanying SGRB 130603B. If this simplest interpretation of the data is correct, it provides (i) support for the compact object merger hypothesis of SGRBs, (ii) confirmation that such mergers are likely sites of significant r-process production and (iii) quite possibly an alternative, un-beamed electromagnetic signature of the most promising sources for direct detection of gravitational waves.Comment: preprint of paper appearing in Nature (3 Aug 2013