MASTER Optical Polarization Variability Detection in the Microquasar V404 Cyg/GS 2023+33

On 2015 June 15, the Swift space observatory discovered that the Galactic black hole candidate V404 Cyg was undergoing another active X-ray phase, after 25 years of inactivity. The 12 telescopes of the MASTER Global Robotic Net located at six sites across four continents were the first ground-based observatories to start optical monitoring of the microquasar after its gamma-ray wake up at 18h 34m 09s U.T. on 2015 June 15. In this paper, we report, for the first time, the discovery of variable optical linear polarization, changing by 4%-6% over a timescale of ∼1 hr, on two different epochs. We can conclude that the additional variable polarization arises from the relativistic jet generated by the black hole in V404 Cyg. The polarization variability correlates with optical brightness changes, increasing when the flux decreases.Fil: Lipunov, V.. M.V.Lomonosov Moscow State University. Physics Department; RusiaFil: Gorbovskoy, E.. M.V.Lomonosov Moscow State University, Sternberg Astronomical Institute; RusiaFil: Krushinskiy, V.. Kourovka Astronomical Observatory, Ural Federal University; RusiaFil: Vlasenko, D.. M.V.Lomonosov Moscow State University, Sternberg Astronomical Institute; RusiaFil: Tiurina, N.. M.V.Lomonosov Moscow State University, Sternberg Astronomical Institute; RusiaFil: Balanutsa, P.. M.V.Lomonosov Moscow State University, Sternberg Astronomical Institute; RusiaFil: Kuznetsov, A.. M.V.Lomonosov Moscow State University, Sternberg Astronomical Institute; RusiaFil: Budnev, N.. Applied Physics Institute. Irkutsk State University; RusiaFil: Gress, O.. Applied Physics Institute, Irkutsk State University; RusiaFil: Tlatov, A.. Kislovodsk Solar Station of the Main (Pulkovo) Observatory RAS; RusiaFil: Rebolo Lopez, L.. Instituto de Astrofsica de Canarias; EspañaFil: Serra-Ricart, M.. Instituto de Astrofsica de Canarias; EspañaFil: Buckley, D. A. H.. South African Astronomical Observatory; SudáfricaFil: Israelyan, G.. Instituto de Astrofsica de Canarias; EspañaFil: Lodieu, N.. Instituto de Astrofisica de Canarias; EspañaFil: Ivanov, K.. Applied Physics Institute. Irkutsk State University; RusiaFil: Yazev, S.. Applied Physics Institute, Irkutsk State University; RusiaFil: Sergienko, Y.. Blagoveschensk State Pedagogical University; RusiaFil: Gabovich, A.. Blagoveschensk State Pedagogical University; RusiaFil: Yurkov, V.. Blagoveschensk State Pedagogical University; RusiaFil: Levato, Orlando Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Saffe, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Podesta, R.. Observatorio "Felix Aguiklar". Universidad Nacional de San Juan; ArgentinaFil: Lopez, C.. Observatorio "Felix Aguilar". Universidad nacional de San juan; Argentin

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Ранние оптические наблюдения семи гамма-всплесков в сравнении с их гамма-рентгеновскими характеристиками на глобальной сети телескопов-роботов МГУ МАСТЕР

Seven gamma-ray bursts – GRB 130907A, GRB 140311B, GRB 140129B, GRB 160227A, GRB 120404A, GRB 110801A, and GRB 120811C were observed by the MSU MASTER (Mobile Astronomical System of TElescope Robots) Global Network. Full automation of the observations provided for obtaining unique data on the properties of early optical radiation accompanying gamma-ray bursts. The data are compared in the optical (MASTER), X-ray (SWIFT X-ray Telescope, XRT) and gamma (SWIFT Burst Alert Telescope, BAT) ranges. Based on the data obtained, two groups are identified, and their radiation mechanisms are revealed. The effect of gamma-ray bursts on the biosphere of the Earth is determined, and the estimates and the scale of such an effect are considered.В статье представлены результаты наблюдений семи гамма-всплесков – GRB 130907A, GRB 140311B, GRB 140129B, GRB 160227A, GRB 120404A, GRB 110801A, GRB 120811C, полученные на телескопах-роботах глобальной сети МГУ «МАСТЕР». Полная автоматизация наблюдений позволила получить уникальные данные о свойствах раннего оптического излучения, сопровождавшего гамма-всплески. Выполнено сравнение данных в оптическом (МАСТЕР), рентгеновском (SWIFTX-rayTelescope (XRT)) и гамма (SWIFTBurstAlertTelescope (BAT)) диапазонах. На основании полученных данных выделены две группы, для которых определен механизм излучения. Также определено воздействие гамма-всплесков на биосферу Земли и рассмотрены оценки и масштаб такого влияния

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p