This paper considers latest highlights in simultaneous and follow-up optical observations of high energy astrophysical phenomena by MASTER Global Robotic Net. Such extreme Universe sources includes ...gamma-ray bursts, gravitational wave events, detected by LIGO/Virgo, fast radio bursts, high energy neutrino sources and others. Some of the neutrinos detected by ground-based facilities owe their births to supermassive black holes – blazars, which are in a special anxious state with high statistical reliability. We discovered the effect of a rapid decrease in the brightness of the blazar PKS 0735+17 at the time of the multiple detection of the high-energy neutrino event IceCube-211208A. This decrease in brightness within several hours was detected with a high confidence (SNR 10) in comparison with a multi-day brightening state of the blazar, which was accompanied not only by a maximum increase in the average brightness, but also by an increase in the amplitude of its brightness fluctuations. Additionally, we analyzed all cases of successful observation of blazars around neutrino events and obtained statistically reliable indications of the relationship between neutrino events and optical activity of blazars in the doubled error box at the 4.2
level.
We report on the earliest detection of the optical transient MASTER OT J123248.62-012924.5 coincident within the error box with the optical and X-ray transient AT2021lfa/ZTF21aayokph. In our images ...the brightness of the object rises monotonically with
confidence. We interpret this transient as a gamma-ray burst (GRB) characterized by smooth optical self-similar (SOSS) emission, while the nondetection of gamma-ray emission at space observatories is interpreted in terms of the hypothesis of a ‘‘failed’’ GRB. Thus, this is the first detection of a nonmonotonic orphan burst.
The study focuses on the impact of life excretion and mucus released by the “biological pollutants” invasive ctenophore Mnemiopsis leidyi and its predator Beroe ovata on the marine environment and ...lower trophic levels of the Black Sea ecosystem (bacteria, pico-phytoplankton, nano-autotrophic/heterotrophic flagellates, micro-phytoplankton, chlorophyll a, primary production (PP), micro-zooplankton). The chemical and biological variables were analysed in two sets of lab experiments with natural communities from mesotrophic (Gelendzhik) and eutrophic (Varna) coastal waters. While both species altered the chemical properties of experimental media, exerting structural and functional changes in the low food-web biological compartments, the results showed a stronger effect of B. ovata, most likely related to the measured higher rate of excretion and amount of released mucus. In addition the alterations in the Gelendzhik experiment were more pronounced, indicating that environmental implications on lower food-web are more conspicuous in mesotrophic than in eutrophic coastal waters.
•Experiments with invasive ctenophores in the NW and NE shelves of the Black Sea•Life excretions and mucus secretion of Mnemiopsis leidyi and Beroe ovata•Both ctenophores induced alterations in phytoplankton, chlorophyll and primary production•Both ctenophores caused changes in bacteria and micro-zooplankton biomass•The effect has been observed much more remarkable in Gelendzhik mesotrophic area.
ABSTRACT
We report on MASTER optical observations of an afterglow-like optical and X-ray transient AT2021lfa/ZTF21aayokph. We detected the initial steady brightening of the transient at 7σ confidence ...level. This allowed us to use smooth optical self-similar emission of GRBs model to constrain the explosion time to better than 14 min as well as to estimate its initial Lorentz factor Γ0 = 20 ± 10. Taking into consideration the low Γ0 and non-detection in gamma-rays, we classify this transient as the first failed GRB afterglow.
We present the earliest astronomical observation of a high-energy neutrino error box of which the variability was discovered after high-energy-neutrino detection. The one robotic telescope of the ...MASTER global international networks automatically imaged the error box of the very high-energy-neutrino event IceCube-170922A. Observations were carried out in minutes after the IceCube-170922A neutrino event was detected by the IceCube observatory at the South Pole. MASTER found the blazar TXS 0506+056 to be in the off-state after one minute and then switched to the on-state no later than two hours after the event. The effect is observed at a 50 significance level. We also present own a unique 16 yr light curve of blazar TXS 0506+056 (518 data set).
Aim.
To study the state of the marine ecosystem of the recreational‐tourist zone of the Caucasian sector of the Black Sea through the example of a beach near the mouth of the Agoy River.
Material and ...Methods
. Phytoplankton, heterotrophic bacterioplankton, infusoria, holoplankton, meroplankton, ichthyoplankton, zoobenthos of loose bottom sediments and hydrochemistry samples of the water and bottom sediments were collected in June 2012 on three sections from the mouth of the Agoy River to the coastal runoff zone (depths 2.5–7.5 m). The identification of species of plankton and of the zoobenthos and of the chemical parameters of water and sediments was carried out according to standard methods.
Results.
It was revealed that most of the beach area, where psammophilic biocenoses of Lucinella divaricate and Chamelea gallina (Bivalvia) were located, was in satisfactory condition. An increase in the density of Lucinella divaricate, a rare species in the late 1990s, was noted. In the runoff zone, there was observed the appearance of cyanobacteria and the suppression of zoobenthos, expressed through the replacement of mollusc biocenoses by the biocenosis of the polychaete, Capitella capitate, with a biomass two orders of magnitude lower than the average for the area. High numbers of heterotrophic bacterioplankton (4.5 million cell/ml) and infusoria (64 million ind./m3) could indicate bacterial contamination of this zone. The negative impact of waste water on plankton is manifested in a decrease in the population of netted zooplankton, their abnormal development, and the increasing role of microheterotrophs.
Conclusions.
The results obtained give an image of the state of marine coastal ecosystems of recreational‐tourist and cordoned areas of the Caucasus and can be useful for the further monitoring of this region.
Nutrients contents, dissolved oxygen, numerical density, abundance of phytoplankton, holoplankton and meroplankton were obtained in the harbour of Novorossiysk Bay in the autumn season. At the ...beginning of the autumn 2015, the optimal water temperature in the upper layer of water and the absence of zooplanktonophagous (ctenophore predators) led to the intensive development of plankton communities. The phytoplankton was represented mainly by diatoms algae and zooplankton – by cladoceran, copepods and larvae invertebrates. However, at the beginning of autumn no meaningful relationship between plant and animal components, contents of nutrients and phytoplankton can be found. The zooplankton contained metazoan organisms with a wide range of nutrition including detritophagous. During the autumn season, the phytoplankton community began to transit at the mixotrophic-heterotrophic phase of the annual cycle of development. Probably in the Novorossiysk harbor, the detritus is the most important component in the biotic cycle of matter and energy.
We present the results of the participation of the MASTER Global Robotic Network in the program to support the aLIGO (O1) and LIGO/Virgo (O2 and O3) gravitational-wave experiments in the ...electromagnetic channel. This study covers the first observing run O1 from September 2015 to January 2016, the second observing run O2 from November 2016 to August 2017 (only LIGO in January–July, joint LIGO/VIRGO (LVC) in August) and the third observing run O3 from April 2019 to April 2020. The main goal of these observations was to, for the first time in the history of astronomy, perform precise localization of gravitational-wave sources, which successfully resulted in the independent discovery of the kilonova using MASTER telescopes in the process of searching for the source of the GW170817 event. In many other events, dozens of optical transients unrelated to gravitational waves have been detected. Nevertheless, the experience of optical localization of gravitational waves is of exceptional importance for the development of a future successful strategy for the localization of gravitational wave events involving relativistic stars. In addition, objects detected in the analysis of huge areas in the sky, determined by the localization errors of the GW source, have been studied in particular detail by telescopes around the world. Objects such as supernovae, novae, active galactic nuclei, dwarf novae and other explosive phenomena in the Universe have been found and analyzed. More than 220 000 deg
2
within the region of the most probable localization of a gravitational wave source have been explored by the MASTER Global Robotic Network. This paper reports on the observations of the MA-STER Global Robotic Network for all alert events from the O1, O2, and O3 observing runs.
Long-duration gamma-ray bursts (GRBs) are powerful cosmic explosions, signaling the death of massive stars. Among them, GRB 221009A is by far the brightest burst ever observed. Because of its ...enormous energy (
≈ 10
erg) and proximity (
≈ 0.15), GRB 221009A is an exceptionally rare event that pushes the limits of our theories. We present multiwavelength observations covering the first 3 months of its afterglow evolution. The x-ray brightness decays as a power law with slope ≈
, which is not consistent with standard predictions for jetted emission. We attribute this behavior to a shallow energy profile of the relativistic jet. A similar trend is observed in other energetic GRBs, suggesting that the most extreme explosions may be powered by structured jets launched by a common central engine.
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