Following the discovery of the gravitational-wave source GW170817 by three Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo antennae (Abbott et al., 2017a), the MASTER Global Robotic ...Net telescopes obtained the first image of the NGC 4993 host galaxy. An optical transient, MASTER OTJ130948.10-232253.3/SSS17a was later found, which appears to be a kilonova resulting from the merger of two neutron stars (NSs). Here we describe this independent detection and photometry of the kilonova made in white light, and in B, V, and R filters. We note that the luminosity of this kilonova in NGC 4993 is very close to those measured for other kilonovae possibly associated with gamma-ray burst (GRB) 130603 and GRB 080503.
The early afterglow of GRB 190829A Dichiara, S; Troja, E; Lipunov, V ...
Monthly notices of the Royal Astronomical Society,
03/2022, Letnik:
512, Številka:
2
Journal Article
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ABSTRACT
GRB 190829A at z = 0.0785 is the fourth closest long GRB ever detected by the Neil Gehrels Swift observatory, and the third confirmed case with a very high-energy component. We present our ...multiwavelength analysis of this rare event, focusing on its early stages of evolution, and including data from Swift, the MASTER global network of optical telescopes, ALMA, and ATCA. We report sensitive limits on the linear polarization of the optical emission, disfavouring models of off-axis jets to explain the delayed afterglow peak. The study of the multiwavelength light curves and broad-band spectra supports a model with at least two emission components: a bright reverse shock emission, visible at early times in the optical and X-rays and, later, in the radio band; and a forward shock component dominating at later times and lower radio frequencies. A combined study of the prompt and afterglow properties shows many similarities with cosmological long GRBs, suggesting that GRB 190829A is an example of classical GRBs in the nearby universe.
Abstract
This article presents the early results of synchronous multiwavelength observations of one of the brightest gamma-ray bursts (GRBs) GRB 160625B with the detailed continuous fast optical ...photometry of its optical counterpart obtained by MASTER and with hard X-ray and gamma-ray emission, obtained by the Lomonosov and Konus-Wind spacecraft. The detailed photometry led us to detect the quasi-periodical emission components in the intrinsic optical emission. As a result of our analysis of synchronous multiwavelength observations, we propose a three-stage collapse scenario for this long and bright GRB. We suggest that quasiperiodic fluctuations may be associated with forced precession of a self-gravitating rapidly rotating superdense body (spinar), whose evolution is determined by a powerful magnetic field. The spinar’s mass allows it to collapse into a black hole at the end of evolution.
The Advanced LIGO observatory recently reported the first direct detection of the gravitational waves (GWs) predicted by Einstein & Sitzungsber. We report on the first optical observations of the GW ...source GW150914 error region with the Global MASTER Robotic Net. Between the optical telescopes of electromagnetic support, the covered area is dominated by MASTER with an unfiltered magnitude up to 19.9 mag (5s). We detected several optical transients, which proved to be unconnected with the GW event. The main input to investigate the final error box of GW150914 was made by the MASTER-SAAO robotic telescope, which covered 70 per cent of the final GW error box and 90 per cent of the common localization area of the LIGO and Fermi events. Our result is consistent with the conclusion (Abbott et al. 2016a) that GWs from GW150914 were produced in a binary black hole merger. At the same time, we cannot exclude that MASTER OT J040938.68-541316.9 exploded on 2015 September 14.
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).
The respiratory pathways of glycolysis, the tricarboxylic acid (TCA) cycle, and mitochondrial electron transport chain (miETC) are central features of carbon metabolism and bioenergetics in aerobic ...organisms. Respiration is essential for growth, maintenance, and carbon balance of all plant cells. Although the majority of respiratory enzymes are common to all organisms, plant respiration has evolved as a complex metabolic network endowed with a wide variety of unique characteristics. Plants have the option of employing alternative enzymes that bypass several of the conventional steps in cytosolic glycolysis, the TCA cycle, and miETC. The extent and conditions under which these bypasses operate is the subject of intensive research. The highly flexible nature of respiratory metabolism in plants has likely evolved in response to the crucial biosynthetic role played by respiration beyond its role in ATP generation; both functions must proceed if plants are to survive under varying and often stressful environmental and nutritional conditions. Additional complexity arises due to the existence of tissue- and/or developmental-specific isozymes of many plant respiratory enzymes, as well as the extensive interactions between photosynthesis and respiration, and plastidic, cytosolic, and mitochondrial metabolism in general. Recent progress in biochemistry, physiology, cell biology, genomics, transcriptomics, proteomics, metabolomics, and in vivo flux analyses have resulted in exciting new insights into many aspects of plant respiratory metabolism. Experiments on transgenic or mutant plants possessing significantly elevated or reduced levels of respiratory enzymes are augmenting our understanding of the functions, organization, and control of plant respiration. Metabolic engineering of plant respiration is of significant practical interest as it provides both an important approach to enhancing crop yields, as well as a potential mechanism for mitigating global climate change due to elevated atmospheric CO
2
levels.
Referee: Dr. Greg C. Vanlerberghe, University of Toronto at Scarborough, Department of Life Sciences and Department of Botany, 1265 Military
Trail, Scarborough, ON Canada M1C 1A4
•Proteomic adjustment after heat treatment is far more pronounced in Ellendale than Murcott.•Carbon derivation towards protective mechanisms is suggested as one immediate response.•Small HSPs play ...crucial roles in the immediate response to HT and long term cold storage.•Auxin downregulation and DNA structure protection are involved in Ellendale endurance.
Citrus is one of the most relevant horticultural crops worldwide. Among them, tangors are highly appreciated by their distinctively taste and aroma. However, both mandarins and tangors are especially susceptible to cold storage. Low temperature storage is generally used to delay fruit decay and reduce pathogen attack during the postharvest period and is necessary for long overseas transport to distant markets. Fruit quality can be protected by different physical methods aimed at improving the response to cold stress, such as heat treatment (HT). These strategies are also fostered as an environmentally sound option to the use of fungicides. The present work derives from previous studies in which metabolic profiling of two tangor varieties was related with their divergent performance after heat treatment and during postharvest cold storage. That work has been expanded and complemented by the study of the proteome of both type of fruit after heat treatment (HT), followed by 7 d of cold storage, in comparison with non-treated fruit. In contrast to Murcott, Ellendale accomplished an important adjustment of its protein contents when exposed to HT. Immediately after HT and at the beginning of postharvest storage at low temperature, proteome changes suggest that a metabolic shift of carbon toward the enhancement of protective mechanisms (such as the antioxidant system, membranes and protein structure protection and cell wall reinforcement), takes place in the less pathogen susceptible variety. Other defensive mechanisms involving nuclear and mitochondrial DNA preservation or auxin inactivation throughout the postharvest period are further discussed.
•Metabolite profiling demonstrates the observed divergence between cultivars.•Heat treatment improves both tangors performance after fungal innoculation.•Flavedo content of sugars and citric acid ...decay in Murcott during storage period.•Ellendale has higher content of hesperidin, putrescine and unsaturated fatty acids.•Ellendale may be better prepared to deal with stress with respect to Murcott.
Citrus growth and export are one of the most important agroeconomical activities in regions with Mediterranean-like climates. Among them, tangors in particular are appreciated by their sweet taste and delicate palatability. The current study describes the analysis of the metabolome of two tangor (Citrus reticulata × C. sinensis) cultivars, Murcott and Ellendale, broadly cultivated in Argentina and other countries, after heat treatment and postharvest storage. This investigation intended to shed light on the biochemistry behind some observed differences in the fruit of both cultivars, such as a distinctive response to cold storage. The differential response to heat treatments and their effectiveness for preventing fungal infection was also evaluated. Metabolite profiling carried out using several chromatographic techniques and differential methods allowed to comprehensively compare the levels of sugars, organic acids, amino acids, polyalcohols, phenylpropanoids and phospholipids among varieties. It was found that Ellendale possess lower content of turanose and melibiose, higher levels of putrescine, unsaturated fatty acids, ribonic and propionic acids, as well as a remarkably higher level of hesperidin than Murcott. After heat treatment, Ellendale was less prone to pathogen development during storage than Murcott. The results, analyzed in terms of the differential metabolome response between the two varieties, hint at a better competence, boosted by heat treatment, of Ellendale to withstand biotic and abiotic stress conditions.
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.
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