Iranian Journal of Astronomy and Astrophysic
Volume:2 Issue: 1, Spring 2015

We review the variety of Active Galactic Nuclei (AGN) classes (so-called\AGN zoo") and classification schemes of galaxies by activity types based on their optical emission-line spectrum, as well as other parameters and other than optical wave-length ranges. A historical overview of discoveries of various types of active galaxies is given, including Seyfert galaxies, radio galaxies, QSOs, BL Lacertae objects, Star-bursts, LINERs, etc. Various kinds of AGN diagnostics are discussed. All known AGN types and subtypes are presented and described to have a homogeneous classification scheme based on the optical emission-line spectra and in many cases, also other parameters. Problems connected with accurate classifications and open questions related to AGN and their classes are discussed and summarized.

We study the structure and evolution of the horizontal proper motions in a regular sunspot penumbra, very close to the solar disc center, in active region NOAA 11092 using a 48 min time sequences of blue continuum images recorded by Hinode/SOT in 2010 August 3. During the day of the observation, the active region had a low activity level. We apply local correlation tracking (LCT) to the time series of the images to obtain the field of horizontal proper motions (flow field). The penumbra shows a slow (fast) flow field with an average speed of 0.2 (0.4) km/s starting at its middle towards the umbra (outer penumbral boundary) as an inward (outward) motion in accordance with previous findings. This behavior defines a continuous divergence line at the middle of the penumbra (r ≃ 2Rspot/3). A distorted ringlike feature with very slow flows (≈ 50 m/s; zero-flow ring: ZFR) co-spatial with the divergence line is clearly seen on the speed map of proper motions in logarithmic scale. Deep intrusion of coordinated penumbral filaments into the umbra can cause that the ZFR a) is significantly displaced towards the umbra (in most cases) or b) is discontinuous, showing considerable speeds there (≈ 150 m/s). Where the ZFR shows discontinuity, the divergence line does not move toward umbra. Also, because of the different evolutionary flows of adjacent penumbral filaments, the ZFR and the divergence line show a stable backward/forward displacement along itself during the 48 min observation. The radial variations of the azimuthally averaged brightness show a local bright ring with a weak contrast of 1% close to the ZFR. At the outer penumbra, we find that the converging filamentary flow occurs in a dark radial channel and the filamentary diverging flows are formed by the evolution of thin bight fibrils. Also, the large speeds at the penumbra boundary are produced by the displacement and/or the fragmentation of the bright fibrils in developing filamentary flows. At the near vicinity of the penumbra, in surrounding granulation, some divergence centers are strongly pushed away as a whole with an average speed of about 0.6 km/s by these developing filamentary flows.

Solar magnetic elds has an important role in the construction of the corona. In the coronal condition, the gas pressure and gravity are neglected as com- paired with the magnetic pressure. Here, the model of Linear Force-Free Field (LFFF) is introduced. Based on this model and appropriate boundary conditions, the structure of coronal magnetic eld is reconstructed. First, using semi-analytic Seehafer method, the LFFF is reconstructed using the Wiegel- mann code for the line of sight (LOS) magnetogram. Then, the magnetic eld lines and loops on a given magnetogram is plotted on the corresponding AIA image for es- timating the compatibility. Finally, by calculating the variance between a given traced loop and corresponding reconstructed loops, we nd a proper magnetic eld parameter for reconstructing a loop before and after aring.

In this study, we use three kinds of clustering methods based onc-means,k- means, and fuzzy c-means (FCM) algorithms to segment solar ultra-violet (UV) images. The methods are applied on a sequence of quiet-Sun photospheric observations at 525 nm images taken by Sunrise on 9 June 2009. The comparison between these three algorithms represents a little bit dierences in extraction of physical parameters (lling factors, brightness uctuations, size distribution, etc.) from images. On the basis of FCM algorithm, the mean value of granule sizes is found to be about 1.8 arcsec2 (0.85 Mm2). Granules with sizes smaller than 2.8 arcsec2 cover a wide range of brightness, while larger granules approaches a particular value. Granules may have lifetimes less than 10 minutes in this part of the Sun. Investigation of local fractal dimension of photospheric images shows that granulation pattern are approximately scale free in some resolutions.

We analyze the time series of Ca ii H-line obtained from Hinode/SOT on the solar limb. The time-distance analysis shows that the axis of spicule undergos quasi- periodic transverse displacement. We determined the period of transverse displacement as  40 _ 150±8 s and the mean amplitude as  0:1 _ 0:5 arc sec. For the oscillation wavelength of   1/0.06 arc sec  11500 km, the estimated kink speed is  13_ 83 km s -1. We obtained the magnetic eld strength in spicules as B0 = 2 _ 12:5±1 G and the energy ux as 7 { 227 Jm -2 s -1.

In this paper, we examine the effect of a hydrodynamical wind on the observational properties of supercritical accretion discs (slim discs) with thermal con- duction in the presence of magnetic field under a self similar treatment. The disk gas is assumed to be isothermal. In this flow, the mass-accretion rate ˙M decreases with radius r as ˙M / r(s ), where s is an arbitrary constant and indication of the effect of wind. Cooling effects of outflows or winds are noticeable in luminosity and effective temperature of advection dominated accretion flows. We apply this model to black-hole X-ray binary LMC X-3, which is supposed to be under critical accretion rate. Increas- ing the effect of wind decreases the disc’s temperature, luminosity and radiation flux of the disc, because of energy flux which is taken away by winds. The effect of thermal conduction is similar to the effect of wind in the disc’s temperature, luminosity and radiation flux of the disc, but the influence of wind on the observational properties is bigger than the effect of thermal conduction.

We monitored several multi Te V EAS events by a 4-fold small array of water cherenkov detectors. The square configuration of the detectors is used for detection of secondary particles of EAS events. We logged 476,675 true EAS events by the array in a period of 9 months. With the calculation of the local coordinates (ɵ/ɸ) of the logged events, we extracted a very good distribution of dN/dɵ = sinɵ(P0A0 cosɵ p90A90 sinɵ) cosn ɵ for the detected events with n=6.71±0.7. The parantese in the distribution is extracted from the water cherenkov detector geometry. By investigation of HWHM of the detector signals, we obtained a 7.2◦ accuracy in the direction of the EAS events. Also, we showed that the logged events are quite independent and random which is a good signature from EAS nature. Finally, we obtained 50 Te V for the threshold energy of the array with the first estimation and we obtained 95 Te V for the detection of the EAS events with a more accurate way.