Transition from Fireball to Poynting-flux-dominated Outflow in Three-Episode GRB 160625B

The ejecta composition is an open question in gamma-ray bursts (GRB) physics. Some GRBs possess a quasi-thermal spectral component in the time-resolved spectral analysis, suggesting a hot fireball origin. Others show a featureless non-thermal spectrum known as the "Band" function, consistent with a synchrotron radiation origin and suggesting that the jet is Poynting-flux-dominated at the central engine and likely in the emission region as well. There are also bursts showing a sub-dominant thermal component and a dominant synchrotron component suggesting a likely hybrid jet composition. Here we report an extraordinarily bright GRB 160625B, simultaneously observed in gamma-rays and optical wavelengths, whose prompt emission consists of three isolated episodes separated by long quiescent intervals, with the durations of each "sub-burst" being $\sim$ 0.8 s, 35 s, and 212 s, respectively. Its high brightness (with isotropic peak luminosity L$_{\rm p, iso}\sim 4\times 10^{53}$ erg/s) allows us to conduct detailed time-resolved spectral analysis in each episode, from precursor to main burst and to extended emission. The spectral properties of the first two sub-bursts are distinctly different, allowing us to observe the transition from thermal to non-thermal radiation between well-separated emission episodes within a single GRB. Such a transition is a clear indication of the change of jet composition from a fireball to a Poynting-flux-dominated jet.Comment: Revised version reflecting the referees' comments. 27 pages, 11 figures, 5 tables. The final edited version will appear in Nature Astronom

Особенности течения менингоэнцефалита у ребенка со смешанной бактериальной инфекцией (клинический случай)

In the past decade the proportion of mixed infections has increased. The clinical aspects of mixed infections can be atypical, and the course of the disease depends on the type of pathogen-associants, their biological properties, relationships with each other and with the host. A clinical case, showing the possibility of mixed associations of Yersinia ana Listeria infections, caused the meningoencephalitis, is given. It is described the experience of the authors on neuroinfection diseases, according to which, a parallel study of blood and cerebrospinal fluid in molecular-genetic, serological as well as immunohistochemical diagnostic methods is required for the detection of mixed infection or co-infection in order to clarify the etiology of the disease.В последние десятилетия увеличился удельный вес смешанных (микст-) инфекций. Клинические проявления микст-инфекций, как правило, нетипичны, а течение заболевания зависит от вида возбудителей-ассоциантов, их биологических свойств, взаимоотношений друг с другом и с организмом хозяина. Представлен клинический случай, свидетельствующий о возможных микст-ассоциациях иерсиниозной и листериозной инфекций, вызвавших менингоэнцефалит. Описан опыт авторов по нейроинфекционным заболеваниям, согласно которому для уточнения этиологии необходимо параллельное исследование крови и цереброспинальной жидкости как молекулярно-генетическими, серологическими, так и иммуногистохимическими методами диагностики для обнаружения микст-инфекции или сопутствующей инфекции

Transition from fireball to Poynting-flux-dominated outflow in the three-episode GRB 160625B

The ejecta composition is an open question in gamma-ray burst (GRB) physics . Some GRBs possess a quasi-thermal spectral component in the time-resolved spectral analysis , suggesting a hot fireball origin. Others show a featureless non-thermal spectrum known as the Band function , consistent with a synchrotron radiation origin and suggesting that the jet is Poynting-flux dominated at the central engine and probably in the emission region as well . There are also bursts showing a sub-dominant thermal component and a dominant synchrotron component , suggesting a probable hybrid jet composition . Here, we report an extraordinarily bright GRB 160625B, simultaneously observed in gamma-ray and optical wavelengths, whose prompt emission consists of three isolated episodes separated by long quiescent intervals, with the durations of each sub-burst being approximately 0.8 s, 35 s and 212 s, respectively. Its high brightness (with isotropic peak luminosity L ≈ 4 × 10 erg s) allows us to conduct detailed time-resolved spectral analysis in each episode, from precursor to main burst and to extended emission. The spectral properties of the first two sub-bursts are distinctly different, allowing us to observe the transition from thermal to non-thermal radiation between well-separated emission episodes within a single GRB. Such a transition is a clear indication of the change of jet composition from a fireball to a Poynting-flux-dominated jet.B.-B.Z. thanks Y.-Z. Fan, Y.-Z. Wang, H. Wang, K. D. Alexander and D. Lazzati for helpful discussions. We are grateful to K. Hurley, I. Mitrofanov, A. Sanin, M. Litvak and W. Boynton for the use of Mars Odyssey data in the triangulation. We acknowledge the use of the public data from the Swift and Fermi data archives. B.-B. Z. and A.J. C.-T. acknowledge support from the Spanish Ministry Projects AYA2012-39727-C03-01 and AYA2015-71718-R. Part of this work made use of B.-B.Z.'s personal Interactive Data Language (IDL) code library ZBBIDL and personal Python library ZBBPY. The computation resources used in this work are owned by Scientist Support LLC. B.Z. acknowledges NASA NNX14AF85G and NNX15AK85G for support. Z. G. D. acknowledges the National Natural Science Foundation of China(NSFC) (grant 11573014). Y.-D. H. acknowledges support by China Scholarships Council (grant 201406660015). Mini-MegaTORTORA belongs to Kazan Federal University, and the work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University. A. P., E.M., P. M. and A.V. are grateful to the Russian Foundation for Basic Research (grant 17-02-01388) for partial support. A. P. and S.B.P. acknowledge joint BRICS (Brazil, Russia, India, China and South Africa) grant RFBR 17-52-80139 and 388-ProFChEAP for partial support. R. I. is grateful to grant RUSTAVELI FR/379/6300/ 14 for partial support. Observations on Mini-MegaTORTORA are supported by the Russian Science Foundation (grant 14-50-00043). A.V.F. and A. M. thank the Russian Science Foundation (grant 14-50-00043). L.M. and A.F.Z. acknowledge support from INTA-CEDEA ESAt personnel hosting the Pi of the Sky facility at the BOOTES-1 station. H. G. and X.-Y.W. acknowledge NSFC (grants 11603003 and 11625312, respectively). Z. G. D., X.-F. W., B.Z., X.-Y. W.,L.S. and F.-W.Z. are also supported by the 973 program (grant 2014CB845800). F.-W.Z. is also supported in part by the NSFC (grants U1331101 and 11163003), the Guangxi Natural Science Foundation (grant 2013GXNSFAA019002) and the project of outstanding young teachers' training in higher education institutions of Guangxi. L.S. acknowledges support by the NSFC (grant 11103083) and the Joint NSFC-ISF Research Program (grant 11361140349). S.O. acknowledges the support of the Leverhulme Trust. S.J. acknowledges support from Korea Basic Science Research Program through NRF-2014R1A6A3A03057484 and NRF-2015R1D1A4A01020961, and I. H. P. through NRF-2015R1A2A1A01006870 and NRF-2015R1A2A1A15055344. R. A., D. F. and D. S. acknowledge support from RSF (grant 17-12-01378). A. K. acknowledges the Science and Education Ministry of Kazakhstan (grant 0075/GF4).Peer reviewe

Гиперчувствительный пневмонит, сочетающийся с артериальной гипертензией: клинические, рентгенологические и функциональные особенности

The aim of the study was to explore the clinical, radiological, functional indicators of hypersensitivity pneumonitis (HP) in combination with arterial hypertension, to assess the effect of these diseases on each other.Methods. The study included 50 patients with hypersensitivity pneumonitis (HP) and 49 patients with arterial hypertension (AH). The patients were divided into three groups. The main group included 24 patients with hypersensitivity pneumonitis combined with AH. The comparison group was 26 patients with HP without AH; the control group was 25 patients with arterial hypertension alone. Clinical symptoms, radiological findings, and results of instrumental tests were analyzed.Results. The intensity of clinical symptoms (shortness of breath, cough) was significantly higher in the main group than in the control and comparison groups. Exercise tolerance estimated from the six-minute walk test was significantly lower in the main group. The clinical status correlated with the functional testResults. Volumetric and velocity spirometry values tended to decrease more in the main group compared to the other two groups. The lung diffusion capacity was significantly lower in the group of patients with HP in combination with AH compared to the group of patients with hypertension only. A similar trend was observed when assessing the chest CT: significantly more pronounced changes were found in the main group. EchoCG showed a significant increase in pulmonary hypertension and volumes of the right heart in the main group compared to the group of patients with AH alone.Conclusion. The present study provides evidence of the greater intensity of respiratory symptoms, decreased functional status, ventilation disorders, dilated heart cavities, greater risk of fatal vascular complications in patients with HP associated with hypertension.Целью исследования явилось изучение клинических, рентгенологических, функциональных показателей больных гиперчувствительным пневмонитом (ГЧП) в сочетании с артериальной гипертензией (АГ), а также оценка влияния этих заболеваний друг на друга. Материалы и методы. В исследование вошли больные ГЧП (n = 50) и АГ (n = 49). Пациенты были разделены на 3 группы: основную (n = 24) составили пациенты с ГЧП, сочетанным с АГ; группу сравнения (n = 26) – больные ГЧП без АГ; контрольную группу (n = 25) составили лица с изолированной АГ. Проанализированы клинические симптомы, данные лучевых и инструментальных исследований. Результаты. Установлена существенно более высокая интенсивность клинических симптомов (одышка, кашель) у лиц основной группы по сравнению с таковой у больных групп сравнения и контрольной. Также у пациентов основной группы выявлена существенно более низкая толерантность к физической нагрузке, оцененная по данным 6-минутного шагового теста. Характер клинического статуса коррелировал с данными функциональных исследований. При проведении спирометрии у больных основной группы отмечена тенденция к большему снижению объемных и скоростных показателей по сравнению с таковыми у лиц сравниваемых групп. Показатели диффузионной способности легких были существенно ниже в группе больных ГЧП в сочетании с АГ по сравнению с таковыми у больных с изолированной АГ. Аналогичная тенденция наблюдалась по данным компьютерной томографии органов грудной клетки – существенно более выраженные изменения выявлены у лиц основной группы. По данным эхокардиографии установлено существенное увеличение легочной гипертензии, объемов правых отделов сердца у больных основной группы по сравнению с таковыми при АГ. Заключение. Результаты исследования свидетельствуют о бóльшей интенсивности респираторной симптоматики, снижении функционального статуса, вентиляционных нарушениях, дилатации полостей сердца, большем риске фатальных сосудистых осложнений при ГЧП, ассоциированном с АГ

Transition from fireball to Poynting-flux-dominated outflow in three-episode GRB 160625B [submitted version]

The ejecta composition of gamma-ray bursts (GRBs) is an open question in GRB physics. Some GRBs possess a quasi-thermal spectral component in the time-resolved spectral analysis, suggesting a hot fireball origin. Some others show an essentially feature-less non-thermal spectrum known as the "Band" function, which can be interpreted as synchrotron radiation in an optically thin region, suggesting a Poynting-flux-dominated jet composition. Here we report an extraordinarily bright GRB 160625B, simultaneously observed in gamma-rays and optical wavelengths, whose prompt emission consists of three dramatically different isolated episodes separated by long quiescent intervals, with the durations of each "sub-burst" being ∼ 0.8 s, 35 s, and 212 s, respectively. The high brightness (with isotropic peak luminosity Lp,iso∼4×1053 erg/s) of this GRB allows us to conduct detailed time-resolved spectral analysis in each episode, from precursor to the main burst and extended emission. Interestingly, the spectral properties of the first two sub-bursts are distinctly different, which allow us for the first time to observe the transition from thermal to non-thermal radiation in a single GRB. Such a transition is a clear indication of the change of jet composition from a fireball to a Poynting-flux-dominated jet

The 999th Swift gamma-ray burst: Some like it thermal: A multiwavelength study of GRB 151027A

We present a multiwavelength study of GRB 151027A. This is the 999th GRB detected by the Swift satellite and it has a densely sampled emission in the X-ray and optical band and has been observed and detected in the radio up to 140 days after the prompt. The multiwavelength light curve from 500 s to 140 days can be modelled through a standard forward shock afterglow but requires an additional component to reproduce the early X-ray and optical emission. We present TNG and LBT optical observations performed 19.6, 33.9 and 92.3 days after the trigger which show a bump with respect to a standard afterglow flux decay and are possibly interpreted as due to the underlying SN and host galaxy (of 0.4 uJy in the R band). Radio observations, performed with SRT, Medicina, EVN and VLBA between day 4 and 140, suggest that the burst exploded in an environment characterised by a density profile scaling with the distance from the source (wind profile). A remarkable feature of the prompt emission is the presence of a bright flare 100 s after the trigger, lasting 70 seconds in the soft X-ray band, which was simultaneously detected from the optical band up to the MeV energy range. By combining Swift-BAT/XRT and Fermi-GBM data, the broadband (0.3-1000 keV) time resolved spectral analysis of the flare reveals the coexistence of a non-thermal (power law) and thermal blackbody components. The BB component contributes up to 35% of the luminosity in the 0.3-1000 keV band. The gamma-ray emission observed in Swift-BAT and Fermi-GBM anticipates and lasts less than the soft X-ray emission as observed by Swift-XRT, arguing against a Comptonization origin. The BB component could either be produced by an outflow becoming transparent or by the collision of a fast shell with a slow, heavy and optically thick fireball ejected during the quiescent time interval between the initial and later flares of the burst

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

The short-term changes of gully erosion forms in the context of the water level fluctuations in the Bratsk reservoir (Russia)

The results of investigations ascertain the influence of the water level regime on the erosion dynamics that was estimated according gullies volume change within the space-time between two measurements. The development of gullies in the shore zone is to a large extent influenced by the abrasion of shore slopes, which is intense at high water level in the reservoir. The minimum rate of gully development (4.5-54.7m3 yr-1) was due to the action of shore abrasion and eolian processes within the period of 2004-2007. A large positive dynamics can be attributed to the increasing number of erosion cuts. The maximum material loss from gullies (in total 627.66 m3 ) and the average volumetric retreat rate for all gullies (16.5 m3 yr-1) were recorded at the permanent lowering of the reservoir water level during the 2007-2008 period. Water level fluctuations cause cyclic changes in the dynamics of processes and initiate the new mechanism of erosion that is not typical of regular conditions

Features of a current meningoencefalitis at child with the mixed bacterial infection (clinical cases)

In the past decade the proportion of mixed infections has increased. The clinical aspects of mixed infections can be atypical, and the course of the disease depends on the type of pathogen-associants, their biological properties, relationships with each other and with the host. A clinical case, showing the possibility of mixed associations of Yersinia ana Listeria infections, caused the meningoencephalitis, is given. It is described the experience of the authors on neuroinfection diseases, according to which, a parallel study of blood and cerebrospinal fluid in molecular-genetic, serological as well as immunohistochemical diagnostic methods is required for the detection of mixed infection or co-infection in order to clarify the etiology of the disease

Egzogenic processes on shoreline of Brack Reservoir : stationary researches (South Part of East Siberia)

Strefa brzegowa Zbiornika Brackiego na rzece Angarze jest niezwykle ciekawym przykładem złożonego kompleksu procesów egzogenicznych z wyraźnym wpływem antropopresji, będącej wynikiem utworzenia zbiornika wodnego i jego eksploatacji. Badania monitoringowe, rozpoczęte jeszcze przed utworzeniem zbiornika, wskazują na transformację i intensyfikację przebiegu procesów egzogenicznych zachodzących na tym obszarze przed utworzeniem zbiornika (procesy osuwiskowe, procesy krasowe, erozja linijna), objęcie nimi kolejnych terenów, wcześniej pasywnych, jak również pojawienie się procesów nowych, przedtem nie występujących w tym regionie (procesy eoliczne, procesy abrazyjno-akumulacyjne). Badania te prowadzone są przez pracowników Instytutu Skorupy Ziemskiej RAN, a od kilku lat, w ramach dwustronnych umów, uczestniczą w nich również pracownicy Instytutu Geografii i Przestrzennego Zagospodarowania PAN.The Brack Reservoir on Angara river was created in 1967. It is the second in terms of capacity (170 km3) and surface (5,500 km2) man-made lake on Earth. Monitoring tests, that started before the reservoir has been created, gives the information about transformation and intensification of exogenous processes occurring in this area, in comparison to state before reservoir creation (landslides, karst, erosion processes). Those processes have taken new areas. Additionally on this area new processes have appeared as result of reservoir exploitation (eolian processes, accumulation-abrasive processes)