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Factor analysis of three-hour dynamics for the vegetation period of birch leaves from 01.05.2014 to 30.09.2014 of four meteorological parameters: atmospheric pressure; air temperature; relative humidity; dew point temperature was carried out by the method of identification of stable regularities (weather station Yoshkar-Ola, Russia, 2917WMO_ID=27485). Power sample consisted of 1222 of the row. The correlation coefficient 0.4677 is less than 0.5065 for the year between winter solstices, but slightly more than 0.4583 for the seven-year data set. It has been proved that the ontogenesis of birch leaves is most influenced by the relative humidity, the dew point temperature on the second and the air temperature on the third place. By the influence of air pressure the adequacy of the model by the correlation coefficient 0.7241, which is more than 0.6776 for one year. The first term shows the decrease in air pressure from the blooming of birch buds before leaf fall. But the second term shows the stress excitation of air pressure. As a result, the change in pressure in the dynamics of three-hour changes during the growing season are recession and excitation. And two wavelets with constant periods counteract the growth of air pressure the Third member has a cycle of oscillation of 56.3 days, and the second wavelet had a period of 15.4 days. For the influence of air temperature is characterized by two forces directed opposite. The first term according to the law of exponential growth shows an increase in positive temperatures due to increased solar radiation. And the second term of the trend according to the exponential law shows the influence of space on the temperature decrease. As a result of the action of the two forces, the maximum air temperature is observed near the summer equinox. Both wavelets on the sign are aimed at increasing the temperature of the air, which indicates global warming. With a minimum constant period of 0.5 days, a second oscillation with an adequacy of 0.6497 is observed. To this constant dynamics adapted leaves of plants. The influence of relative humidity is characterized by the fact that the first member is the law of death. The second term is the biotechnical law showing the limit of increase. The third term (the first wavelet) characterizes the daily fluctuation with a constant period of 0.5 days (correlation coefficient 0.6638). All four members of the model are aimed at increasing humidity. In comparison with the air temperature, the relative humidity has a more pronounced amplitude with the daily cycle of oscillatory perturbation (correlation coefficient 0.6638 in comparison with 0.6397). In this case, the daily fluctuation for relative humidity is the first oscillation, and for air temperature – the second. To affect the dew point temperature of the first member is the law of death, and the second – biotech law. This gives a maximum of about the summer equinox. Both wavelets are aimed at reducing the dew point temperature. The first oscillation in the form of a tremor can have a starting effect on the start of leaf vegetation with a constant period of 13 days. [ABSTRACT FROM AUTHOR]

Factor analysis of three-hour dynamics from 01.01.2012 to 31.10.2018 of four meteorological parameters: atmospheric pressure; air temperature; relative humidity; dew point temperature was carried out by the method of identification of stable regularities (weather station Yoshkar-Ola, Russia, WMO_ID=27485). The sampling rate was 19713 lines. It is proved that pair connections allow to study quanta of weather behavior for different periods of time: long-term, annual, seasonal and period of plant ontogenesis. There are two types of quanta of behavior: 1) in dynamics, the factor is divided into the sum of wavelets as a bundle of solitary waves (solitons), and this is characterized as quantum unraveling; 2) the mutual influence of the above four factors with the periodicity of measurements every three hours additionally obtains quantum entanglement in some boundaries. However, it turned out that there is no wave connection between these four factors, which indicates the presence of quantum entanglement of meteorological data. According to the first wavelet for 7 years, the oscillatory perturbation of pressure and relative humidity increases, and the amplitude of the temperature fluctuations of the air and the dew point, on the contrary, decreases. The second wavelet gives a decrease in the amplitude in the dynamics of the air pressure and dew point temperature, as well as an increase in the amplitude of fluctuations in temperature and relative humidity. The third member is the annual cycle of fluctuations, but it increases to normal within 182.63 days on the date of 01.01.2012 the half life in days 175.37 air pressure, 180.08 for air temperature, 181.15 days for relative humidity and 181.61 days for dew point temperature. The fourth term shows that the period of pressure fluctuation on 01.01.2012 is 102.28 days and it further increases, and for the dew point temperature it is 79.41 days and it decreases with time. The dynamics of air temperature occurs with a constant daily period, and the dynamics of relative humidity is approaching the daily cycle. [ABSTRACT FROM AUTHOR]

Factor analysis of three-hour dynamics from the winter solstice 22.12.2013 to 21.12.2014 of four meteorological parameters: atmospheric pressure; air temperature; relative humidity; dew point temperature was carried out by the method of identification of stable regularities (weather station Yoshkar-Ola, Russia, 2917WMO_ID=27485). The sample capacity was 2917 rows. The correlation coefficient increased to 0.5065, which is more than 0.4583 for a seven-year data set. The ranking of the factors changed only for dependent parameters: the air pressure was the third. 14 members of the model were accepted for all meteorological parameters. The article analyzed the first four terms. For the dynamics of air pressure, the first term shows a decrease from the beginning of the year to its end, and the second term – an increase in air pressure. And two wavelets counteract the growth of air pressure. The period of oscillation of the third member at the beginning of the year is 21.2 days. Second wavelet on 22.12.2013 had a period 33.0 days. For the dynamics of relative humidity, the first term is the law of death, and the second term of the trend is the biotechnical law showing the limit of increase. The third term characterizes the daily fluctuation with a constant period of 0.5 days. The maximum oscillation period of 129.4 days is in the 11th member of the model. At air pressure and dew point temperature daily fluctuations are observed. For the dynamics of the dew point temperature, the first term, as well as for the air temperature, has a negative sign and therefore shows the effect of space (global cooling). And the second member of the biotechnical law gives the growth of the meteorological parameter due to sunlight to the summer equinox. The third term gives a jerk of the oscillatory perturbation of the dew point temperature in the first 100 days. The quantum certainty of binary relations is different. [ABSTRACT FROM AUTHOR]

In a series of recent publications, scientists from ICRANet, led by professor Remo Ruffini, have reached a novel comprehensive picture of gamma-ray bursts (GRBs) thanks to their development of a series of new theoretical approaches. Among those, the induced gravitational collapse (IGC) paradigm explains a class of energetic, long-duration GRBs associated with Ib/c supernovae (SN), recently named binary-driven hypernovae (BdHNe). BdHNe have a well defined set of observational features which allow to identify them. Among them, the main two are: 1) long duration of the GRB explosion, namely larger than 2 s in the rest frame; 2) a total energy, released in all directions by the GRB explosion, larger than 1052 ergs. A striking result is the observation, in the BdHNe sources, of a universal late time power-law decay in the X-rays luminosity after 104 s, with typical decaying slope of ~ 1.5. This leads to the possible establishment of a new distance indicator having redshift up to z ~ 8. Thanks to this novel theoretical and observational understanding, it was possible for ICRANet scientists to build the firstst BdHNe catalog, composed by the 345 BdHNe identified up to the end of 2016. [ABSTRACT FROM AUTHOR]

In this study, orbital period variations of two eclipsing binary systems (NO Vul and EW Lyr) were discussed. Possible light time effects due to third bodies in these systems were re-examined. The mass function and orbital period of hypothetical third bodies were calculated to be 0.000627 ± 0.000003 Mʘ, 26.17 ± 0.05 years and 0.12682 ± 0.00003 Mʘ, 77.23 ± 0.72 years for NO Vul and EW Lyr, respectively. [ABSTRACT FROM AUTHOR]

Abstract. In this paper, orbital period variations of these two contact binaries (V700 Cyg and PY Lyr) were studied. O--C diagrams of these binaries were analyzed with the least-squares method by using all available times of minima. Apparent period changes of these two contact binaries were explained in terms of light-time effect due to a third body. Masses of third bodies were found to be 0.014 ± 0.001 M0 and 0.130 ± 0.006 M0 for V700 Cyg and PY Lyr. respectively. [ABSTRACT FROM AUTHOR]

The Eclipsing Binaries' Minima Monitoring Project (BIMA) is a joint project between Institut Teknologi Bandung (ITB) and National Astronomical Research Institute of Thailand (NARIT). This project is dedicated to observe minim of eclipsing binaries light curves to derived their time of minimum. Since its commissioning in 2012, this project has secured 71 minima of more than 30 eclipising binaries until September 2014. In the first year, BIMA project has established the observational technique, data handling system, calculation for determination time of minimum, and automatization for image reduction and analysis. In the second year, BIMA project began to combine its time of minimum data with other previous observations to analyze O-C (Observed-Calculated) Diagram of all observed systems. The O-C diagram is one of indispensable tools to study evolution in eclipsing binaries in which it indicates period change or correction for periode prediction. Period changes closely related to evolutionary phase of the systems can be detected. In this paper, we present and discuss preliminary analysis of O-C diagram from one particular eclipsing binary system, V566 Oph. [ABSTRACT FROM AUTHOR]

I discuss methods and current software packages for radio searches for pulsars and short-duration transients. I then describe the properties of the current pulsar population and the status of and predictions for ongoing and future surveys. The presently observed pulsar population numbers around 2000 and is expected to roughly double over the next five years, with the number of millisecond pulsars expected to more than triple. Finally, I discuss individual objects discovered in the Green Bank Telescope 350-MHz Drift-Scan Survey and the Arecibo Pulsar ALFA Survey. [ABSTRACT FROM AUTHOR]

The capabilities of XMM-Newton have been fully exploited to detect a broadened iron Kα emission line from the 2.5 ms Accreting Millisecond Pulsar, SAX J1808.4–3658. The energy of the transition is compatible with fluorescence from neutral/lowly ionized iron. The observed large width (FWHM more than 1 keV) can be explained through Doppler and relativistic broadening from the inner rings of an accretion disc close to the NS. From a fit of the line shape with a diskline model we obtain an estimate of the inner disc radius of 18.0-5.6+7.6 km for a 1.4 M⊙ neutron star. The disc is therefore truncated inside the corotation radius (31 km for SAX J1808.4–3658), in agreement with the observation of coherent pulsations. From our estimate of the inner disc radius, we infer that the magnetic field of the neutron star is in the range 1–5×108 G. [ABSTRACT FROM AUTHOR]

We present FUV observations of massive binary systems in the Galaxy, LMC and SMC. The binaries are High Mass X-ray binaries and double-line spectroscopic binaries. Many are eclipsing systems, with well-determined orbits and periods in the range 1.6–12 days. The far-UV spectra are used to determine spectrometric changes with phase and terminal velocities from species tracing a range of wind ionization states. We observed each system more than once to sample different orbital phases and spectral variability. All systems show significant changes in the P-Cygni wind profiles with phase. [ABSTRACT FROM AUTHOR]

Several colliding-wind massive binaries are known to be non-thermal emitters in the radio domain. This constitutes strong evidence for the fact that an efficient particle acceleration process is at work in these objects. The acceleration mechanism is most probably the Diffusive Shock Acceleration (DSA) process in the presence of strong hydrodynamic shocks due to the colliding-winds. In order to investigate the physics of this particle acceleration, we initiated a multiwavelength campaign covering a large part of the electromagnetic spectrum. In this context, the detailed study of the hard X-ray emission from these sources in the SIMBOL-X bandpass constitutes a crucial element in order to probe this still poorly known topic of astrophysics. It should be noted that colliding-wind massive binaries should be considered as very valuable targets for the investigation of particle acceleration in a similar way as supernova remnants, but in a different region of the parameter space. [ABSTRACT FROM AUTHOR]

Three-dimensional numerical simulations of the gas dynamics are used to study the structure and formation of circumbinary envelopes in close binary systems. It is shown that shape and position of a substantial part of the disk is specified by a precessional density wave. This spiral wave is due to the retrograde precession of flow lines in the binary system. On timescales comparable to the orbital period, this precessional wave (and hence an appreciable fraction of the disk) will be virtually stationary in the observer’s frame, whereas positions of other elements of the flow will vary due to the orbital rotation. The periodic variations of the positions of the disk and the bow shock formed when the inner parts of the circumbinary envelope flow around the disk result in variations in both the rate of angular-momentum transfer to the disk and the flow structure near Lagrange point L3. As a consequence outer parts of the circumbinary envelope are replenished by periodic ejections from the accretion disk and circum-disk halo through the vicinity of the Lagrange point L3. [ABSTRACT FROM AUTHOR]

A number of microquasars exhibit parsec-scale jets, which in some cases are known to interact with the interstellar medium (ISM). A famous example is the SS-433 system. Here, we summarise H.E.S.S. observations of three further examples in this category with arc-minute scale jets and/or jet/ISM interaction features. The small line-of-sight angle in the Cir X-1 jet makes this source a potential ‘microblazar’. An arc-minute bow-shock radio feature has been blown out by the Cyg X-1 jet, and the MAGIC telescope has also detected a VHE flare on 24 Sept. 2006 from Cyg X-1 (H.E.S.S. obs. were taken ∼1 month earlier). Persistent bi-lobal (∼7 arcmin long) ‘fossil’ jets of 4U1755-33 have been seen in X-rays. This report summarises our observations, searching for pointlike VHE emission at the central sources and for extended emission from their jets and/or jet/ISM interaction regions. [ABSTRACT FROM AUTHOR]

During our Swift/XRT program to obtain X-ray positions at arcsecond level for a sample of Galactic X-ray binaries, we discovered that SAX J0840.7+2248 is not a binary, but rather BeppoSAX/WFC+GRBM X-ray Rich GRB 980429. Here we report on this discovery and on the properties of this long, X-ray rich gamma-ray burst, from prompt to (very) late followup. [ABSTRACT FROM AUTHOR]

The HERES (Hamburg-ESO R-process Enhanced Stars) survey has targeted over 350 halo stars with a snapshot approach using UVES at VLT, finding 6 new strongly and 35 mildly r-enhanced objects (Barklem et a. 2005). It also yielded observations for a total of 94 C-enhanced stars, which make up the largest sample of this kind of objects observed at high resolution. We present the analysis of the C-rich stars in the HERES survey, which yielded measurements for C, N, Ba and Eu abundances, discuss the results and the consequences on our understanding of their formation scenarios. [ABSTRACT FROM AUTHOR]

We present results of a population synthesis study aimed at examining the role of spin-kick alignment in producing a correlation between the spin period of the first-born neutron star and the orbital eccentricity of observed double neutron star binaries in the Galactic disk. We find spin-kick alignment to be compatible with the observed correlation, but not to alleviate the requirements for low kick velocities suggested in previous population synthesis studies. Our results furthermore suggest low- and high-eccentricity systems may form through two distinct formation channels distinguished by the presence or absence of a stable mass transfer phase before the formation of the second neutron star. The presence of highly eccentric systems in the observed sample of double neutron stars may furthermore support the notion that neutron stars accrete matter when moving through the envelope of a giant companion. [ABSTRACT FROM AUTHOR]

The main objectives of modeling the Galactic pulsar population are (i) to understand underlying properties of various pulsar subclasses, and (ii) to probe physical conditions relevant to the formation and evolution of these objects. A theoretical approach is useful to explore various stellar populations, but introduces large systematic uncertainties in results. An empirical approach is known to be more reliable, but is limited only to known populations. Traditionally, the pulsar population studies focused on isolated, slowly rotating ‘normal’ pulsars that are the majority of the known pulsars. With improved pulsar search techniques and more sensitive instruments, the known pulsar sample has been greatly expanding, both in quality and quantity, over the past 40 years. The increased number of pulsar sample allows more rigorous statistical analysis on the normal population. Moreover, there are many new populations to be studied, such as relativistic pulsar binaries, millisecond pulsars, or pulsars in globular clusters. [ABSTRACT FROM AUTHOR]

We present system parameters for a small sample of short period, eclipsing CVs taken from the Sloan Digital Sky Survey. Three out of seven of the systems possess brown dwarf donor stars and have thus evolved past the orbital period minimum. This is broadly consistent with predictions that 40–70 per cent of CVs should have evolved past the orbital period minimum. The donor star masses themselves are inconsistent with model predictions, unless enhanced angular momentum loss (e.g. from circumbinary discs) is invoked. However, the mass transfer rates as deduced from white dwarf effective temperatures are not consistent with enhanced mass transfer rates. Solution of this conundrum will require independent estimates of the mass transfer rates in short period CVs. The white dwarfs show a strong tendency towards high masses. This may in part be due to selection effects. There is one Iron core white dwarf, and no Helium core white dwarfs in our sample, despite predictions that 30–80 per cent of short period CVs should contain Helium core white dwarfs. [ABSTRACT FROM AUTHOR]

We present an analysis of ULTRACAM light curves of the magnetic cataclysmic variable HU Aquarii which were taken at the VLT in May 2005. Since the light curves were serendipitously obtained during a low state, they allowed us to determine the binary and the stellar parameters with high accuracy. The light curve was decomposed into the components originating from the accretion spot, the photosphere surrounding it and the white dwarf itself, which allowed us to extract the eclipse light curve for the pure white dwarf. Combined with high-time resolution observations with different instruments over a 12 year baseline it was possible to get exact eclipse timings of the white dwarf and thus establish a significant deviation from a linear ephemeris. If described by a quadratic term, the period decreases by -1.13×10-11 ss-1. Interpreting this change in period as a pure angular momentum loss (AML) effect, the rate of J = -4.9×1035 erg is much too high to be explained by gravitational radiation alone. [ABSTRACT FROM AUTHOR]

Dwarf novae (DNe) are a subclass of Cataclysmic Variables (CVs) with outbursts powered by a disk instability leading to a sudden increase in the accretion rate. The Digital Access to a Sky Century at Harvard (DASCH) Collaboration is preparing to digitize over 500,000 Harvard plates from the 1880s to the 1980s with limiting magnitudes ranging from B∼14–19. As a demonstration project, we have scanned more than 500 plates in the fields centered on the galactic open cluster M44. There are 21 CVs in the fields within 10 degrees of M44 covered by the scans. Here we present the preliminary results of DN outbursts of the known CVs to derive long-term DN outburst duty cycles. In addition, a 100y lightcurve for a XMM–Newton source is also presented to demonstrate DASCH capabilities. [ABSTRACT FROM AUTHOR]

With current terrestrial gravitational wave detectors working at initial design sensitivities, and upgrades and space missions planned, it is likely that in the next five to ten years gravitational radiation will be detected directly from a variety of classes of objects. The most confidently expected of these classes is compact binaries, involving neutron stars or black holes. Detection of their coalescence, or their long-term orbits, has the potential to inform as about the evolutionary history of compact binaries and possibly even star formation over the past several billion years. I review what is currently known about compact binaries as sources of gravitational radiation, as well as the current uncertainties and what we expect to learn from future detections of gravitational waves from these systems. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Two light curve solutions for the close eclipsing binary II UMa, using Hipparcos data, are presented. The analysis was made using the PHOEBE program. The first solution was derived adopting the spectroscopic value q = 0.172 while the presence of third light was considered too. The second solution is based on the mass ratio value q = 0.13, derived by a q-search. It was found that II UMa is an A sub-class W UMa-type binary, and belongs to a class of systems with very low mass ratio that is expected to evolve in a single rapidly rotating star. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The great progress made during the last years in the field of close binary systems, and especially in the eclipsing binaries, is presented and discussed. The development of software for analyzing the huge amount of observational data sets, from both ground-based and space surveys, is presented. The latest achieved interesting results are mentioned, too. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

I summarize some aspects of the research at OAR on the neutron star population in Globular clusters. In particular I discuss the evolutionary stage of the interacting millisecond pulsar binary PSR J1740-5340 in the cluster NGC 6397 and point out that the donor component can not be a recently acquired low mass star. The precise mass derived for this star helps to constrain the loss of angular momentum during the radio-ejection phase which this system is traversing. I then discuss the problem of the large number of neutron stars present in globular clusters and show that it might be due to an atypical initial mass function, which is necessary to understand the chemical anomalies shown by the low mass stars evolving today. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In recent years proper motion measurements have been added to the set of observational constraints on the current properties of Galactic X-ray binaries. We develop an analysis that allows us to consider all this available information and reconstruct the full evolutionary history of X-ray binaries back to the time of core collapse and compact object formation. Here we present our analysis and results for GRO J1655-40. We find that a symmetric black hole (BH) formation event cannot be formally excluded, but that the associated system parameters are only marginally consistent with the currently observed binary properties. BH formation mechanisms involving an asymmetric supernova explosion with associated BH kick velocities of a few tens of km s-1, on the other hand, satisfy the constraints much more comfortably. We also derive an upper limit on the BH kick magnitude of ≃ 210km s-1. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A number of observations hints for the presence of an intermediate mass black hole (IMBH) in the core of three globular clusters: M15 and NGC 6752 in the Milky Way, and G1, in M31. However the existence of these IMBHs is far form being conclusive. In this paper, we review their main formation channels and explore possible observational signs that a single or binary IMBH can imprint on cluster stars. In particular we explore the role played by a binary IMBH in transferring angular momentum and energy to stars flying by. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We present a set of evolutionary computations for binaries with a B-type primary at birth. Some liberal computations including loss of mass and angular momentum during binary evolution are added to an extensive grid of conservative calculations. Our computations are compared statistically to the observed distributions of orbital periods and mass ratios of Algols. Conservative Roche Lobe Over Flow (RLOF) reproduces the observed distribution of orbital periods decently but fails to explain the observed mass ratios in the range ∈ [0.4–1]. In order to obtain a better fit the binaries have to lose a significant amount of matter, without transferring too much angular momentum. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Recent studies of chemical abundances of secondary stars in low mass X-ray binaries have opened a new window to obtain information on the progenitors of black holes and neutron stars. Secondary stars could have captured a significant amount of the ejected matter in the supernova explosions that originated compact objects in these systems. Thus, anomalous atmospheric abundances of these stars may be a signature of nucleosynthetic products in supernovae. The detailed chemical analysis of secondary stars may provide constraints on many parameters involved in supernova explosion models like the mass cut, the amount of fallback matter, possible mixing processes, and explosion energies and geometries. Such chemical analysis has been made in two black hole binaries: GRO J1655-40 (Israelian et al. 1999) and A0620-00 (González Hernández et al. 2004) where we have found several elements enhanced in the secondary stars. These element abundances compared with element yields in supernova explosion models suggest that the progenitors of compact objects were massive stars in the mass range 25–40 M⊙. We have also studied the neutron star binary Cen X-4 (González Hernández et al. 2005, submitted) where such strong anomalous abundances, with respect to element abundances in stars with similar Fe content, have not been found. However, element abundances appear to be super solar which might be explained if the secondary could be polluted by the ejected matter (also containing Fe) in a SN explosion of a progenitor with a He core of roughly 4 M⊙. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Cataclymic variables (CVs) are semi-detached binary systems in which a main sequence late-type star (the secondary) fills its Roche lobe and transfers matter to a white dwarf (the primary) through the inner Lagragian point L1. Evolutive models of CVs predicts that the orbital periods Porb of these systems would decrease on time scales of 108 – 109 years due to angular momentum losses either by magnetic braking via the secondary star’s wind (Porb > 3 hr) or by emission of gravitational radiation (Porb > 3 hr). These models try to explain the observed gap of systems with Porb in the range of ∼ 2 to 3 hr as the consequence of a sharp reduction of magnetic field open lines when the secondary star become fully convective (at Porb ∼ 3 hr). However, up to now no well-studied CVs show evidence of period decrease. Instead, most well-observed eclipsing CVs show cyclical period changes probably associated to solar-type (quasi-periodic and/or multiperiodic) magnetic activity cycles in the secondary star. The fast spinning secondaries of CVs, covering a range of masses and rotation periods, are an important laboratory to understand magnetic activities cycles in late type stars. In the present work, we report the investigation of cyclical period changes in IP Peg: CV with orbital periods of 3.8 hr. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The article focuses on cultural studies and the economy. Cultural studies is not just a subject for literary critics but it is a process of critical reflection that should be ongoing across university departments and schools. Every discipline of cultural studies is filled with great binaries and it needs deconstruction and reconstruction. The economy has a culture that exists inside the larger culture of society. It has principles like productivity and efficiency that are in concord and conflict with a larger culture.

Rapid mass transfer in a binary system can drive the accreting star out of thermal equilibrium, causing it to expand. This can lead to a contact system, strong mass loss from the system and possibly merging of the two stars. In low metallicity stars the timescale for heat transport is shorter due to the lower opacity. The accreting star can therefore restore thermal equilibrium more quickly and possibly avoid contact. We investigate the effect of accretion onto main sequence stars with radiative envelopes with different metallicities. We find that a low metallicity (Z<10-3)4M⊙ star can endure a 10 to 30 times higher accretion rate before it reaches a certain radius than a star at solar metallicity. This could imply that up to two times fewer systems come into contact during rapid mass transfer when we compare low metallicity. This factor is uncertain due to the unknown distribution of binary parameters and the dependence of the mass transfer timescale on metallicity. In a forthcoming paper we will present analytic fits to models of accreting stars at various metallicities intended for the use in population synthesis models. [ABSTRACT FROM AUTHOR]

The evolution of single stars at low metallicity has attracted great interest, while the effect of metallicity on binary evolution remains still relatively unexplored. We study the effect of metallicity on the number of binary systems that undergo different cases of mass transfer. We find that binaries at low metallicity are more likely to start transferring mass after the onset of central helium burning, often referred to as case C mass transfer. In other words, the donor star in a metal poor binary is more likely to have formed a massive CO core before the onset of mass transfer. At solar metallicity, the range of initial binary separations that result in case C evolution is very small for massive stars, because they do not expand much after the ignition of helium and because mass loss from the system by stellar winds causes the orbit to widen, preventing the primary star to fill its Roche lobe. This effect is likely to have important consequences for the metallicity dependence of the formation rate of various objects through binary evolution channels, such as long GRBs, double neutron stars and double white dwarfs. [ABSTRACT FROM AUTHOR]

We have computed the K-correction for emission lines formed on the irradiated face of the companion stars in X-ray binaries. Our results, combined with the detection of high excitation emission lines arising from the donor star can provide the first mass determinations for either neutron stars or black holes in active Low Mass X-ray Binaries (LMXBs). Here we present preliminary results of a high spectral resolution VLT+UVES campaign on the LMXB X-ray pulsar X1822-371. We measure a emission line velocity of Kem = 280±3 km s-1. The application of the K-correction to this Kem together with previous determinations of system parameters yields 1.52M⊙NS<1.85M⊙. [ABSTRACT FROM AUTHOR]

We present optical spectropolarimetric observations of three microquasars, Cyg X-1, LS 5039 and LS I +61d 303. For Cyg X-1, the observed polarization shows time variation correlated with the orbital phase. For LS 5039, there is no evidence of intrinsic polarization. For LS I +61d 303, the result is consistent with that of 2005 Jan, Oct and Nov, except for the systematic decrease in the intrinsic polarization and in the EWs of the Hα emission line. [ABSTRACT FROM AUTHOR]

We report on the analysis result of the X-ray pulsar V0332+53 (X0331+53) observed by RXTE in 2004-2005 outburst. This source is known to have the multiple cyclotron resonance lines at ~ 25 and ~ 50 keV. We have confirmed that the fundamental resonance energy increased from ~ 22 to ~ 27 keV as the source luminosity changed from 3.5×1038 ergs/s to 1.0×1038 ergs/s. In addition, we have revealed that the second resonance changed from ~ 49 to ~ 54 keV. The observed resonance energy ratio between the second and the fundamental cyclotron line was ~ 2.2 when the source was most luminous, whereas the ratio decreased to the nominal value of 2.0 at the least luminous state. This result implies that the second resonance shows a weaker fractional change compared to the fundamental line. The change of the resonance energy ratio may result from the different heights of the cyclotron scattering in the accretion column. [ABSTRACT FROM AUTHOR]

The Suzaku data of the galactic binary source LS 5039, which have continuous coverage of more than one orbital period, show strong modulation of the X-ray emission at the orbital period of this TeV gamma-ray emitting system. The X-ray radiation of LS 5039 is likely to be linked to very-high-energy electrons which are also responsible for the TeV gamma-ray emission. [ABSTRACT FROM AUTHOR]