The clustering of Lα absorption lines in the QSO spectra

For nine published high-resolution QSO spectra a correlation analysis of their L forest lines has been performed. The two-point correlation functions show some quasi-periodic structure of magnitude ||0.3. Their characteristic separation along the line-of-sight amounts to s ₀=3×10^–3 or to s ₀=5×10^–3 for =1 and 0.2, respectively. Especially the distribution of nearest neighbouring line positions in two close QSO pairs allows for the interpretation that the absorption clouds lie in sheet-like structures as predicted by the pancake theory. The correlation data contain some hints on metal absorbers within the forest of unidentified lines.     

Stellar sources in the isogal inner galactic bulge field (l=0°,b= − 1°)

ISOGAL is a survey at 7 and 15 μm with ISOCAM of the inner galactic disk and bulge of our Galaxy. The survey covers ∼ 22 deg² in selected areas of the centrall = ±30 degree of the inner Galaxy. In this paper, we report the study of a small ISOGAL field in the inner galactic bulge (l = 0°,b = −1°, area = 0.033deg²). Using the multicolor nearinfrared data (IJK_s) of DENIS (DEep Near Infrared Southern Sky Survey) and mid-infrared ISOGAL data, we discuss the nature of the ISOGAL sources. The various color-color and color-magnitude diagrams are discussed in the paper. While most of the detected sources are red giants (RGB tip stars), a few of them show an excess in J-K_s and K_s-[15] colors with respect to the red giant sequence. Most of them are probably AGB stars with large mass-loss rates.     

The existence of long-lived rays of the coronal streamer belt – Radial density and velocity distributions of the solar wind flowing in them

A technique is proposed for separating the rays of the streamer belt with quasi-stationary and non-stationary solar wind (SW) flows. It is shown that the lifetime of rays with a quasi-stationary SW can exceed 20 days. A new method has been developed for measuring the relative density distribution of a quasi-stationary slow SW flowing along the streamer belt's ray of increased brightness, based on the LASCO/SOHO data. It is shown that the density n for such SW flows varies with the radius R according to the relationship nR ^–, where =₁3.3–3.9 within 4 R ₀ R 6 R ₀ (here R ₀ is the solar radius), and decreases gradually further away. It is also shown that the V(R)-profiles in some rays of the streamer belt differ little from each other, although the value of the mass flow density, j _E, at the Earth's orbit in them can vary more than by a factor of 4. This distinguishes in a crucial respect a slow SW in the streamer belt's rays from a fast SW originating in coronal holes, for which j _Econstant and the dependences V(R) in different fast flows can differ greatly.     

The excitation mechanism and the line-to-continuum intensity ratio of the [Fexiv] 5303 Å line in various coronal regions

The excitation mechanism of the coronal green line in various coronal regions is studied. The line-to-continuum intensity ratio is calculated using the model electron density values given by Newkirk (1961) and is compared with the observed values. Reasonably good agreement is found between the model calculations and observed values. The model calculations show that collisional excitation is more important in the innermost regions while radiative contribution progressively increases towards outer regions. The individual contributions depend strongly on the activity of the particular coronal region. An increased contribution from collisional excitation is seen in coronal active regions owing to the large electron density. A contour map of the line-to-continuum intensity ratio as derived from the observations, is plotted. At 1.10R the value is about 80 in active regions, 30–40 in coronal streamers, while it is less than 10 in polar regions.     

The mean transmission of the neutral intergalactic medium in the LYα -line from a sample of high-resolution quasar spectra

We present our measurements of the mean transmission \(\overline F \left( z \right)\) of the neutral intergalactic medium in the Lyα line. For this purpose we used the sample of 33 high-resolution (R = 5300…45 000) spectra selected from the public available archive of the European Southern Observatory with the help of the Virtual Observatory tools. For continuum determination in each spectra the points with maximum flux in Lyα-forest region were selected and fitted by spline. The obtained values of the mean transmission \(\overline F \left( z \right)\) was fitted by power-law τ_eff = α(1 + z)^β, where α = (4.4 _?0.2 ^+4.4 )× 10^–3, β = 3.278 _?0.054 ^+0.083 for averaging of the F(z) over the redshift bins Δz = 0.1 and α = (10.6 _?1.0 ^+1.1 )× 10^–3, β = 2.685 _?0.071 ^+0.081 for averaging over each quasar. The results were compared with those ones from previous studies of high- and low-resolution quasar spectra.     

The Origin and Acceleration of ~3He and Heavy Ions in the 2000 July 14 Event

1INTRODUCTIONEnrichment of3He and heavy ions(i.e.,Ne,Mg,Si and Fe),characteristic of impulsive?ares,have beenstudied for more than three decades.It is found that they are generally associated with nonthermal energeticelectron-rich events(Reames et al.1988;Reames1999and references therein;Ho et al.2001;Wang et al.2006)and are related to the peculiar ratio of charge to mass(Mazur et al.1996;Reames1999).Althoughthe abundance of3He ions is not correlated with the abundance of heavy ions,s…     

The East-West structure of mid-latitude geomagnetic pulsations in the 8–25 mHz band

We report results from 6 days' continuous recording of pulsation activity on a chain of magnetometers aligned East-West at 56.5°N geomagnetic latitude. We find phase differences between stations are relatively small. Signal propagation sense and horizontal polarisation correlate as low frequency inhomogeneous plasma theory predicts. There is no evidence of the Kelvin-Helmholtz instability being the major source. The most highly coherent signals often occur near midnight. We suggest the nightside may be the source region for a significant amount of dayside pulsation activity.     

The Role of T_(50) in the Classification of Gamma-ray Bursts

The role of T50 in classifying gamma-ray bursts (GRBs) is investigated. We take T50=0.7s as the line of division and find that some bursts belonging to the class of long bursts defined by T90≥2s now become short bursts (sample 1), while some belonging to the class of short bursts defined by T90 < 2 s now become long bursts (sample 2). We study how these sources are affected by the two methods of classification and find the change of classes of sample 1 is due to some peculiar properties of the light curves. Based on their characters, most of the bursts of sample 1 should be taken as short bursts.     

New satellite structure of the solar and laser plasma spectra in vicinity of the Lα (mg xii) line

Spectra in the narrow vicinity of the Mg xii resonance line at = 8.42 Å were obtained aboard the satellites Intercosmos-4, -7 and the rocket Vertical-2, as well as from laser-produced plasma. The high resolution in solar and laboratory spectra made it possible to reveal a new spectral structure close to the L (Mg xii) line from both short and long wavelength sides. The main features were observed in all the spectra and were interpreted as a single or group of dielectronic satellite lines due to 2l3l 1s3l transitions in the He-like ions according to theoretical calculations which were carried out by means of relativistic Z-expansion technique. The derived electron temperature of the emitting volumes seemed to be 3 × 10⁶ K for laser plasma and about 6 × 10⁶ K for the solar flares studied. The latter value is in good agreement with the temperature estimated with the help of the resonance line-to-continuum intensity ratios.Polish Academy of Science, Solar-Terrestrial Relations Laboratory, Wroclaw, Poland.     

North polar hood of Mars in 1969 (May 18–July 25). I. Blue light

The north polar hood has been mapped in its developing stages during 1969 using blue-filter, Planetary Patrol photography. Boundaries of the hood and associated clouds were plotted from hourly photographs for an interval of 69 days. The results are presented as summation maps, one covering the total interval and the others each covering one third of the interval. Each summation map shows, with isolines, the number of days that clouds were recorded within various areas. Several of the daily maps are also presented as examples of the plots of hourly coverage from which the summation maps were derived.     

Mercury: The Image of the Planet in the 210°–285° W Longitude Range Obtained by the Short-Exposure Method

For the purpose of obtaining images of the unknown portion of Mercury, we continued the previously started series of observations of this planet by the short exposure method. Several thousand electronic images of Mercury have been acquired on 1–2 May 2002 under good meteorological conditions at the high-altitude Skinakas Astrophysical Observatory of Iraklion University (Crete, Greece, 35°13 E, 24°54 N) during the evening elongation. The phase angle of Mercury was 95°–99° and the observed range of longitudes was 210°–285° W. Observations were carried out using Ritchy–Chrétien telescope (D = 1.29 m, F = 9.857 m) with the KS 19 filter cutting wavelengths shorter than about 700 nm. The planet's disk was seen, on average, at an angle of 7.75 arcsec. The image scale was equal to 47.8 m/arcsec. We used a CCD with a pixel size of 7.4 × 7.4 m in the regime of short exposures. By processing a great number of electronic images, we succeeded in obtaining a sufficiently distinct synthesized image of the unknown portion of Mercury's surface. The most prominent formation in this region is a giant basin (or cratered mare) centered at about 8° N, 280° W, which was given a working name Skinakas basin (after the name of the observatory where observations were made). By its size, the interior part of this basin exceeds the largest lunar Mare Imbrium. As opposed to Mare Imbrium, the Skinakas basin is presumably of impact origin. Its relief resembles that of Caloris Planitia but the size is much larger. A series of smaller formations are also seen on synthesized images. The resolution obtained on the surface of Mercury is about 100 km, which is close to the telescope diffraction limit. Also considered are the published theoretical estimations of the possible advantages offered by the short exposure method. Some results obtained by other research groups are discussed.     

The results of the photographic positional observations of Venus on the wide-field astrograph of the Sternberg Astronomical Institute,Moscow State University,in 1969–1988

A new technique for the reduction of the observed position of Venus with a correction for the phase effect and photographic irradiation is briefly described. For the first time, a method for bringing the observed position of Venus into the system of standard exposure is proposed that considerably diminishes the random errors of a session and the whole line of observations. Original Venus observational material is presented together with accuracy estimations. The O-C difference yielded by the reduction procedure is plotted along both coordinate axes.     

The LAMOST survey of background quasars in the vicinity of M31 and M33–Ⅲ.results from the 2013 regular survey

In this work, we report new quasars discovered in fields in the vicinity of the Andromeda(M31) and Triangulum(M33) galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST, also called the Guo Shou Jing Telescope) during the 2013 observational season, the second year of the regular survey. In total, 1330 new quasars are discovered in an area of ～133 deg2 around M31and M33. With i magnitudes ranging from 14.79 to 20.0 and redshifts from 0.08 to4.85, the 1330 new quasars represent a significant increase in the number of identified quasars in fields in the vicinity of M31 and M33. Up to now, there have been a total of 1870 quasars discovered by LAMOST in this area. The much enlarged sample of known quasars in this area can potentially be utilized to construct a precise astrometric reference frame for the measurement of minute proper motions of M31, M33 and their associated substructures, which are vital for understanding the formation and evolution of M31, M33 and the Local Group of galaxies. Moreover, in the sample,there are a total of 45, 98 and 225 quasars with i magnitudes brighter than 17.0, 17.5and 18.0 respectively. In the aforementioned brightness bins, 15, 35 and 84 quasars are reported here for the first time, and 6, 21 and 81 are reported in our pervious work. In addition, 0, 1 and 6 are from the Sloan Digital Sky Survey and 24, 41 and 54 are from the NED database. These bright quasars provide an invaluable sample to study the kinematics and chemistry of the interstellar/intergalactic medium of the Local Group.     

Connection between the appearance of γ-ray sources and Hα line impact linear polarization in the July 23, 2002 flare

Astronomy Letters - During our spectropolarimetric observations of the 2B/4.8X flare on July 23, 2002, with the Large Solar Vacuum Telescope (LSVT), we detected impact linear polarization in the...     

The Characteristics of the X-ray Flares (1-8, GOES) of the Different Classes and Their Variations in Two Cycles of Solar Activity

1　ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｌａｒｆｌａｒｅｓｒｅｆｌｅｃｔｔｈｅｅｎｅｒｇｅｔｉｃｓｏｆｃｏｒｒｅｓｐｏｎｄｉｎｇｍａｇｎｅｔｉｃｆｉｅｌｄｓ.Ｒｅｓｅａｒｃｈｉｎｇｔｈｅｓｏｌａｒｆｌａｒｅｐａｒａｍｅｔｅｒｓｉｎ 1 1 - ｙｅａｒｓｏｌａｒｃｙｃｌｅｓｃｏｕｌｄｔｈｒｏｗｌｉｇｈｔｏｎｔｈｅｅｎｅｒｇｅｔｉｃｓｏｆｍａｇｎｅｔｉｃｓｔｒｕｃｔｕｒｅｓｆｏｒｍｉｎｇｔｈｅｂａｓｉｓｏｆｔｈｅｃｈｒｏｍｏｓｐｈｅｒｉｃａｎｄｃｏｒｏｎａｌａｃｔｉｖｉｔｙ .Ｔｈｅｖａｒｉａｂｉｌｉｔｙｏｆｔｈｅ…     

Scientific Analysis within SEPServer – New Perspectives in Solar Energetic Particle Research: The Case Study of the 13 July 2005 Event

Solar energetic particle (SEP) events are a key ingredient of solar?Cterrestrial physics both for fundamental research and space weather applications. Multi-satellite observations are an important and incompletely exploited tool for studying the acceleration and the coronal and interplanetary propagation of the particles. While STEREO uses for this diagnostic two identical sets of instrumentation, there are many earlier observations carried out with different spacecraft. It is the aim of the SEPServer project to make these data and analysis tools available to a broad user community. The consortium will carry out data-driven analysis and simulation-based data analysis capable of deconvolving the effects of interplanetary transport and solar injection from SEP observations, and will compare the results with the electromagnetic signatures. The tools and results will be provided on the web server of the project in order to facilitate further analysis by the research community. This paper describes the data products and analysis strategies with one specific event, the case study of 13 July 2005. The release time of protons and electrons are derived using data-driven and simulation-based analyses, and compared with hard X-ray and radio signatures. The interconnection of the experimental and the simulation-based results are discussed in detail.     

Measurement of the 25Mg(p,γ)26Al reaction at stellar energies

Stellar nuclear reactions, generally occurring at energies well below the Coulomb barrier, have extremely low cross sections posing a very difficult task for their determination using the usual prompt γ-ray detection method. We describe here the application of the highly sensitive Accelerator Mass Spectrometry technique (AMS) as an alternative method for the determination of the resonance strengths of the ²⁵Mg(p,γ) reaction, by off-line counting of the produced ²⁶Al nuclei.     

The study of Gödel type solutions in f(R, ϕ) gravity

The aim of this paper is to study the Gödel type universe in modified f(R, ϕ) theory of gravity, where R stands for Ricci scalar and ϕ be the scalar potential. We investigate the modified field equations by using anisotropic and perfect fluid distributions. In particular, we consider two proposed models with some fixed values of parameters and investigate the exact solutions. The behaviour of energy conditions can be seen by a detailed graphical analysis. Furthermore, Tolman-Oppenheimer-Volkoff equation has been studied for both models in this theory. We have also discussed some exact solutions using perfect fluid. It is concluded that f(R, ϕ) theory of gravity support the phenomenon of cosmic expansion of the universe through Gödel type universe for both models.