The breakthrough listen search for intelligent life: a wideband data recorder system for the Robert C. Byrd green bank telescope

The Breakthrough Listen Initiative is undertaking a comprehensive search for radio and optical signatures from extraterrestrial civilizations. An integral component of the project is the design and implementation of wide-bandwidth data recorder and signal processing systems. The capabilities of these systems, particularly at radio frequencies, directly determine survey speed; further, given a fixed observing time and spectral coverage, they determine sensitivity as well. Here, we detail the Breakthrough Listen wide-bandwidth data recording system deployed at the 100-m aperture Robert C. Byrd Green Bank Telescope. The system digitizes up to 6 GHz of bandwidth at 8 bits for both polarizations, storing the resultant 24 GB/s of data to disk. This system is among the highest data rate baseband recording systems in use in radio astronomy. A future system expansion will double recording capacity, to achieve a total Nyquist bandwidth of 12 GHz in two polarizations. In this paper, we present details of the system architecture, along with salient configuration and disk-write optimizations used to achieve high-throughput data capture on commodity compute servers and consumer-class hard disk drives

SNOW COVER OF THE CENTRAL ANTARCTICA (VOSTOK STATION) AS AN IDEAL NATURAL TABLET FOR COSMIC DUST COLLECTION: PRELIMINARY RESULTS ON THE IDENTIFICATION OF MICROMETEORITES OF CARBONACEOUS CHONDRITE TYPE

During the 2010/11 season nearby the Vostok station the 56th Russian Antarctic Expedition has collected surface snow in a big amount from a 3 m deep pit using 15 220 L vol. containers (about 70 kg snow each). Snow melting and processing by ultra-centrifugation was performed in a clean (class 10 000 and 100) laboratory. Total dust concentrations were not exceeded 37.4 mkg per liter with particle dispersal mode around 2.5 mkm. To analyze the elemental composition of fine dust particles aimed to reveal Antarctic micrometeorites (AMM) two electron microscopy devices equipped with different micro-beams were implemented. As a preliminary result, three particles (of 107 analyzed) featured by Mg content clearly dominated over Al along with Si and Fe as major elements (a feature of carbonaceous chondrites) were observed. By this the Vostok AMM CS11 collection was established. The occurrence of given particles was averaged 2.8% – the factual value obtained for the first time for chondritic type AMM at Vostok which should be considered as the lowest estimate for all other families of AMM. Given the reference profile of total dust content in East Antarctic snow during Holocene (18 mkg/kg) the MM deposition in Antarctica was quantified for the first time – 14 tons per day for carbonaceous chondrites for the Vostok AMM CS11 collection and up to 245 tons per day for all MM types for the Concordia AMM DC02 collection. The results obtained allowed to prove that snow cover (ice sheet in total) of Central East Antarctica is the best spot (most clean of other natural locations and always below 0 ºC) for collecting native MM deposited on the Earth during the last million years and could be useful in deciphering the origin and evolution of solid matter in our Solar System and its effects on Earth-bound biogeochemical and geophysical processes including the life origin. The farther analyses of the Vostok AMMs are in a progress

СНЕЖНЫЙ ПОКРОВ ЦЕНТРАЛЬНОЙ АНТАРКТИДЫ (СТАНЦИЯ ВОСТОК) КАК ИДЕАЛЬНЫЙ ПРИРОДНЫЙ ПЛАНШЕТ ДЛЯ СБОРА КОСМИЧЕСКОЙ ПЫЛИ: ПРЕДВАРИТЕЛЬНЫЕ РЕЗУЛЬТАТЫ ПО ВЫЯВЛЕНИЕ МИКРОМЕТЕОРИТОВ ТИПА УГЛИСТЫХ ХОНДРИТОВ

During the 2010/11 season nearby the Vostok station the 56th Russian Antarctic Expedition has collected surface snow in a big amount from a 3 m deep pit using 15 220 L vol. containers (about 70 kg snow each). Snow melting and processing by ultra-centrifugation was performed in a clean (class 10 000 and 100) laboratory. Total dust concentrations were not exceeded 37.4 mkg per liter with particle dispersal mode around 2.5 mkm. To analyze the elemental composition of fine dust particles aimed to reveal Antarctic micrometeorites (AMM) two electron microscopy devices equipped with different micro-beams were implemented. As a preliminary result, three particles (of 107 analyzed) featured by Mg content clearly dominated over Al along with Si and Fe as major elements (a feature of carbonaceous chondrites) were observed. By this the Vostok AMM CS11 collection was established. The occurrence of given particles was averaged 2.8% – the factual value obtained for the first time for chondritic type AMM at Vostok which should be considered as the lowest estimate for all other families of AMM. Given the reference profile of total dust content in East Antarctic snow during Holocene (18 mkg/kg) the MM deposition in Antarctica was quantified for the first time – 14 tons per day for carbonaceous chondrites for the Vostok AMM CS11 collection and up to 245 tons per day for all MM types for the Concordia AMM DC02 collection. The results obtained allowed to prove that snow cover (ice sheet in total) of Central East Antarctica is the best spot (most clean of other natural locations and always below 0 ºC) for collecting native MM deposited on the Earth during the last million years and could be useful in deciphering the origin and evolution of solid matter in our Solar System and its effects on Earth-bound biogeochemical and geophysical processes including the life origin. The farther analyses of the Vostok AMMs are in a progress.В 2010/11 г. сотрудниками 56-й Российской антарктической экспедиции в районе станции Восток был отобран поверхностный снег из шурфа глубиной до 3 мв 15 контейнеров, около 70 кгснега в каждом. Плавление снега и концентрирование материала из воды путём ультрафильтрования проведено в помещениях, сертифицированных по классу чистоты (10 000 и 100). Общее содержание частиц пыли не превысило 37,4 мкг/л, а их распределение по размеру составило моду (значение признака, имеющее наибольшую частоту в статистическом ряду распределения) 2,5 мкм. Для выявления космической пыли микрометеоритного типа (КП-ММ) начат анализ микрочастиц пыли на элементный состав методами электронной сканирующей микроскопии с помощью микрозондов двух типов. Из 107 проанализированных частиц в трёх установлено содержание Mg больше чем Al, что позволяет рассматривать их в качестве кандидатов КП-ММ типа углистых хондритов (carbonaceous chondrites). Эти пробы положили начало созданию коллекции Восток КП-ММ CS11. Процентное содержание данных частиц в частицах общей пыли составило 2,8%, что следует рассматривать как нижнюю оценку встречаемости частиц КП-ММ в снежном покрове центральной части Восточной Антарктиды и как первую такого рода оценку для КП-ММ типа углистых хондритов. Исходя из референтной оценки содержания всей пыли в снежном покрове Восточной Антарктиды, равной 18 мкг/кг, рассчитан поток космической пыли на Землю в Антарктиде. Он составил для коллекции Восток КП-ММ CS11 – 14 т/сут (только для хондритов), а для коллекции Конкордия DC02 – до 245 т/сут (для всех типов микрометеоритов). Результаты выполненной работы позволяют считать снежный покров в центральной части Восточной Антарктиды наиболее чистым из природных планшетов для сбора и выявления микрочастиц космической пыли на протяжении последнего миллиона лет. В настоящее время продолжается детальный анализ этих и других частиц. Полученные результаты могут быть использованы для решения проблем происхождения и эволюции твёрдого вещества в Солнечной системе, его влияния на биогеохимические и геофизические процессы, а также зарождение жизни на Земле. Referenc