Features of Formation of the Cyclone Wakes (Fluctuations in Seawater Temperature) in the Area of Cape Svobodny, the Southeastern Part of the Sakhalin Island

Purpose. The purpose of this work is to study the particulars of the formation of cyclone wakes after the regular passage of cyclones over the area of the wave measurements, and to estimate the internal wave parameters along the track according to the field observations. Methods and Results. The analysis of data from the field observations of sea waves and water temperature is presented. The measurements were carried out by a ARW-K14 device (autonomous recorder of the waves and water temperature) in the area of the Cape Svobodny on the southeastern coast of the Sakhalin Island at a depth about 8 m. The recorded time series of the sea level and temperature fluctuations, lasting about one and a half months, were subjected to spectral analysis using specialized Kyma spectral analysis software. Dominant temperature fluctuations reaching 8.5 °C with a 13.1 h period were detected in the upper mixed layer of the ocean. These fluctuations were identified as the cyclone wakes in the stage of their relaxation. Taking into account the synoptic circumstances that existed during the passage of several cyclones and the associated storms in the observation area, the authors investigated the presence or absence of a trace. Conclusions. It is shown that if the next storm arrives earlier than 10 days after the previous one, the trace may be shorter or even absent due to active water mixing in the upper mixed layer of the ocean. For the data obtained, the value of the coefficient ∈ in the expression ω = (1 + ∈ ) f, which connects the dominant frequency ω of internal waves, i.e. almost inertial oscillations in the trace of each typhoon, with the inertial frequency f (the Coriolis parameter determined by the geographical latitude of the water area where the waves propagate), is close to the value proposed in the paper by E. Kunze. Using a formula due to J. F. Price, the characteristic horizontal lengths of internal waves in the direction of movement inside the wakes of cyclones moving at a speed 15–35 knots are determined. These lengths range from 304.6 to 1066.1 km

The Dependence of the Superconducting Transition Temperature of Organic Molecular Crystals on Intrinsically Non-Magnetic Disorder: a Signature of either Unconventional Superconductivity or Novel Local Magnetic Moment Formation

We give a theoretical analysis of published experimental studies of the effects of impurities and disorder on the superconducting transition temperature, T_c, of the organic molecular crystals kappa-ET_2X and beta-ET_2X (where ET is bis(ethylenedithio)tetrathiafulvalene and X is an anion eg I_3). The Abrikosov-Gorkov (AG) formula describes the suppression of T_c both by magnetic impurities in singlet superconductors, including s-wave superconductors and by non-magnetic impurities in a non-s-wave superconductor. We show that various sources of disorder lead to the suppression of T_c as described by the AG formula. This is confirmed by the excellent fit to the data, the fact that these materials are in the clean limit and the excellent agreement between the value of the interlayer hopping integral, t_perp, calculated from this fit and the value of t_perp found from angular-dependant magnetoresistance and quantum oscillation experiments. If the disorder is, as seems most likely, non-magnetic then the pairing state cannot be s-wave. We show that the cooling rate dependence of the magnetisation is inconsistent with paramagnetic impurities. Triplet pairing is ruled out by several experiments. If the disorder is non-magnetic then this implies that l>=2, in which case Occam's razor suggests that d-wave pairing is realised. Given the proximity of these materials to an antiferromagnetic Mott transition, it is possible that the disorder leads to the formation of local magnetic moments via some novel mechanism. Thus we conclude that either kappa-ET_2X and beta-ET_2X are d-wave superconductors or else they display a novel mechanism for the formation of localised moments. We suggest systematic experiments to differentiate between these scenarios.Comment: 18 pages, 5 figure

The spectral energy distribution of fermi bright blazars

We have conducted a detailed investigation of the broadband spectral properties of the γ-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi γ-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/γ-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these γ-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log ν-log ν Fν representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low- and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, αro, and optical to X-ray, αox, spectral slopes) and from the γ-ray spectral index. Our data show that the synchrotron peak frequency (νSpeak) is positioned between 1012.5 and 1014.5 Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10 13 and 1017 Hz in featureless BL Lacertae objects. We find that the γ-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter γ-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum γ-ray sources, the correlation between νSpeak and γ-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars. © 2010 The American Astronomical Society

Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society

Features of the Wave Processes in the South Kuril Strait Based on Observational Data

Purpose. The work is purposed at studying the waves in the South Kuril Strait within the period ranges from the wind waves to the tidal ones using the field observations data, and also at explaining the observed wave processes using the existing theories and models. Methods and Results. The results of the analyzed long-term (up to 12 months) time series of observations of waves and water temperature performed with the 1 s discreteness by the bottom autonomous wave recorders ARW-K14 at three points in the South Kuril Strait coastal zone are considered. To detect wave processes, the spectral analysis was applied. It showed the presence of significant maxima in the spectral densities that resulted in revealing the diurnal and semidiurnal tidal waves, and the time series of seawater temperature fluctuations made it possible to find out the waves with a period of the tidal harmonic K1. The seiche periods were calculated by the formula for a semi- open water area, and it showed the possibility of generating eigen oscillations of sea level in the South Kuril Strait with a period 5.0 hours, which was close to the period 4.8 hours derived from the observational data. It was revealed that the seiches amplitude are increased after the ebb reached its minimum level and further as the level grew. This effect (described by D. K. Chapman and G. S. Giese in their articles) is explained using the dynamic mechanism of generating the coastal seiches by deep-sea internal waves induced by a barotropic tide. Conclusions. It is shown that both seiches and tidal harmonics can contribute energy to the wave process with a period 4.8 hours. The level fluctuations with the periods varying from 0.4 to 3 hours do not depend on tidal harmonics and, possibly, they are the seiches or the edge waves. The results of a spectral analysis of three time series permitted to find out that seiches in the South Kuril Strait were of low energy and there were no conditions for their significant resonant amplification. It was shown that a part of the energy of tidal waves was transferred to the seiche oscillations in the Krabovaya and Malokurilskaya bays. Having being analyzed, the sea level fluctuations in the range of infragravity waves showed the possibility of the South Kuril Bay fluctuations to transform to the chaotic ones, which had been confirmed by modeling the behavior of the dynamic system – the water mass of the bay excited by the incoming swell waves