010020   Gopal Krishna;Sircar P;Dhurde S (National Centre for Radio Astrophysics, Tata Inst of Fundamental Res, Pune Univ Campus, Post Bag No.3, Pune-411 007, Email: krishna@ncra.tifr.res.in ) : Kinematical diagrams for conical relativistic jets. J Astrophys Astr 2007, 28(1), 29-40.

Presents diagrams depicting the expected inter-dependences of two key kinematical parameters of radio knots in the parsec-scale jets of blazers, deduced from VLBI observations. The two parameters are the apparent speed (<117>app = c/βapp) and the effective Doppler boosting factor (δeff>) of the relativistically moving radio knot. A novel aspect of these analytical computations of β-δ diagrams is that they are made for parsecªscale jets having a conical shape, with modest opening angles (ω up to 10°), in accord with the VLBI observations of the nuclei of the nearest radio galaxies. Another motivating factor is the recent finding that consideration of a conical geometry can have important implications for the interpretation of a variety of radio observations of blazar jets. In addition to uniform jet flows (i.e., those having a uniform bulk Lorentz factor, Γ), computational results are also presented for stratified jets where an ultra-relativistic central spine along the jet axis is surrounded by a slower moving sheath, possibly arising from a velocity shear.

6 illus, 72 ref

010019   Cui W;Zhang W;Zhang B (Phys Dep, Hebei Normal Univ, Shijiazhuang 050 016, P.R. China) : Evolution of the distribution of neutron exposures in the galaxy disc: an analytical model. J Astrophys Astr 2007, 28(1), 55-66.

In this work, based on the analytical model with delayed proªduction approximation developed by Pagel & TautvaiSiene (1995) for the Galaxy, the analytic solutions of the distribution of neutron exposures of the Galaxy (hereafter NEG) are obtained. The present results appear to reaªsonably reproduce the distribution of neutron exposures of the solar system (hereafter NES). The strong component and the main component of the NES are built up in different epochs. Firstly, the strong component is proªduced by the s-process nucleosynthesis in the metal-poor AGB stars, startªing from [FelH] ≈ -1.16 to [Fe/H] ≈ -0.66, corresponding to the time interval 1.06 <60> t <60> 2.6 Gyr. Secondly, the main component is produced by the s-process in the galactic disk AGB stars, starting from [FelH] ≈ -0.66 to [Fe/H] ≈ 0, corresponding to the time interval t <62> 2.6 Gyr. The anaªlytic solutions have the advantage of an understanding of the structure and the properties of the NEG. The NEG is believed to be an effective tool to study the s-process element abundance distributions in the Galaxy at difªferent epochs and the galactic chemical evolution of the neutron-capture elements.

4 illus, 27 ref

008055   Alladin S M;Hasan S N (Astronomy Dep, Osmania Univ, Hyderabad, Email: najam_hasan@yahoo.com) : Interactions and mergers of galaxies. Resonance 2007, 12(3), 13-26.

When two galaxies approach each other, we can witness the effects of the tidal forces On a gigantic scale. Peculiar features like galactic bridges and galactic tails may form, or the two galaxies may even merge into each other and form a single system. Merger of two spiral galaxies leads to the formation of an elliptical galaxy. The interaction of gas during such galaxy encounters triggers star formation and activity of the nucleus. It is generally being accepted that galaxy interactions and mergers play a vital role in galactic evolution.

4 ref

004001   Sujatha N V;Murthy J (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: sujaskm@yahoo.co.in) : Studies of diffuse UV radiation. Bull Astr Soc India 2007, 35(2), 295-300.

The upcoming TAUVEX mission is expected to provide us with high quality data from observations over large parts of the sky in different wavelength bands. Proposes to use this data for the study of diffuse radiation field and its sources in the UV, where much of the energy transfer between the stellar radiation field and the interstellar medium occurs. Describes method for development of tools and techniques to extract the astrophysical diffuse radiation using available GALEX data which will be used to analyse the data from the TAUVEX mission, future plans and expected science returns.

3 illus, 12 ref

004000   Subramaniam A (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: purni@iiap.res.in) : UV observations of globular clusters and nearby galaxies. Bull Astr Soc India 2007, 35(2), 223-8.

Proposes to identify the hot stellar population of the galactic globular clusters (GCs) using the TAUVEX. These stars can be easily identified in the core of the GCs where the crowding due to the main-sequence stars get dramatically reduced in the UV broad bands. Proposes to observe and create a first complete and homogeneous UV data on Magellanic Clouds. Studies of extra-galactic globular clusters in the UV is the only way to estimate their age and metallicity without ambiguity. Such studies have not been done even for M 31. Therefore, we propose that extra-galactic globular clusters should be observed in the UV broad band filters.

15 ref

003999   Sen A K;Mukai T;Gupta R;Okada Y (Physics Dep, Assam Univ, Silchar-788 011, Email: asokesen@sancharnet.in) : Proposal for UV observations of star forming clouds. Bull Astr Soc India 2007, 35(2), 239-47.

The small, compact dark clouds (also known as Bok Globules), are undergoing gravitational collapse that can result in the production of low mass stars. Light from background stars is scattered in forward direction by magnetically aligned dichroic dust grains. The degree and direction of alignment is proportional to the strength and direction of ambient magnetic field in the cloud. Background star polarimetry provides the technique to probe this field. In order to relate the physical conditions within the cloud to the background star polarization and to know the dust properties, we need to determine E(B - V) for each background star and relate it to the corresponding observed polarization (p). However, observed data, do not always show a correlation between polarization and extinction. Due to this the question arises whether the grains that produce polarization also produce observed extinction. The observation that the polarization is not related to the extinction, can be explained if polarization and extinction are caused by two different grain populations. Polarization is mainly caused by short grains, whereas the extinction is caused by larger ones. Based on these findings, justifications are made here to detect these small grains (0.0035-0.01 μm) in the star forming clouds through UV observations to be made by TAUVEX. These particles can be best detected through the UV observations, as they show far-UV excess and characteristic features of 2175 A bump. We propose imaging of these clouds through the three bandpass filters of TAUVEX. Expects to resolve many unanswered questions associated with star forming clouds, through this set of proposed observations.

3 illus, 20 ref

003998   Saxena P P (Mathematics and Astronomy Dep, Lucknow Univ, Lucknow-226 007, Email: pps1939@hotmail.com) : On the source of cometary N₂<. Bull Astr Soc India 2007, 35(2), 163-7.

The possibility of nitrous oxide (N₂O) molecules in Comet 1P/ Halley (Saxena 2004) is revisited in the light of theoretical considerations, its detection in hot molecular cores and observations of annealed Mg-silicate grains in comets to support its parent nature in other cornets as well. Having a photo-lifetime ≥10⁵s at 1 AU heliocentric distance (Huebner et al. 1992); N₂O may be the source of N₂⁺ ions in cometary tails. The detection of N₂O molecule in comets will have important implications on the nature of cometary parent molecules.

1 table, 17 ref

003997   Ranade A C;Singh H P;Gupta R;Ashok N M (NO, , Vigyan Prasar, A-50, Institutional Area, Sector-62, Noida-201 307, Email: rag@iucaa.ernet.in) : Infrared stellar spectral library: II. K-band spectra. Bull Astr Soc India 2007, 35(2), 87-109.

This is the second in the series of papers on near-infrared (NIR) stellar spectral library produced by reducing the observations carried out with 1.2 meter Gurushikhar Infrared Telescope (GIRT), at Mt. Abu, India using a NICMOS3 HgCdTe 256 x 256 NIR array based spectrometer. In (Ranade et al. 2004), H-band spectra of 135 stars at a resolution of <126> 16 angstrom were presented. The K-band library being released now consists of 114 stars covering spectral types O7-M7 and luminosity classes I-V. The spectra have a moderate resolution of <126> 22 angstrum in the K band and have been continuum shape corrected to their respective effective temperatures. We hope to release the remaining J-band spectra soon. The complete H and K-Band library is available online at: http:// vo.iucaa.eriiet.in/<126>voi/NIR_Header.html.

10 illus, 6 tables, 24 ref

003996   Prajval Shastri (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: pshastri@iiap.res.in) : Active galaxies and their importance: results from imaging them in the UV. Bull Astr Soc India 2007, 35(2), 249-54.

The current phenomenology of active galaxies is briefly outlined. Their significance in the larger context of galaxy formation and evolution is described. Recent ultraviolet imaging results are then summarized in the context of exploring the potential of TAUVEX in furthering AGN investigations.

16 ref

003995   Netzer H (School of Physics and Astronomy, Tel Aviv Univ, Tel Aviv-69978, Email: netzer@wise.tau.ac.il) : AGN research with TAUVEX. Bull Astr Soc India 2007, 35(2), 255-60.

Describes the major scientific issues related to the study of active galactic nuclei with TAUVEX. The physical motivatioruis briefly discussed and examples of projects suitable for the mission are given" with specific ideas about the optimal use of TAUVEX for achieving these goals.

1 illus, ref

003994   Murthy J;Safonova M;Mohan R;Gopakumar P (NO, Indian Institute of Astrophysics, Koramangala, Bangalore-560 034, Email: murthy@iiap.res.in) : TAUVEX-UV observations from geosynchronous orbit. Bull Astr Soc India 2007, 35(2), 175-85.

The TAUVEX Observatory consists of three identical co-aligned telescopes operating in several bands in the 1200 - 3500 A bandpass from geostationary orbit. The major science objectives of TAUVEX are (a) searches for QSOs and AGNs based on their UV properties, (b) surface photometry of galaxies in the UV, (c) studies of stars and nebulae within the Galaxy, (d) the nature of the UV background, and (d) studies of variable sources in the UV domain. The Principal Investigators and TAUVEX Science Team have created a coherent observing programme to address several key science objectives that will constitute the Core Science Programme projects. Along with this project, which will contribute up to 85% of observing time, the Science and Core Group teams have identified a small number of more modest programmes to pursue. Presents a description of the TAUVEX mission, including details of the instrument design and its estimated performance, assess the status of the mission development and describe in brief the main research categories. Additional information on the TAUVEX programme and development can be obtained on the World Wide Web at http://tauvex.iiap.res.in.

3 illus, 3 tables, 2 ref

003993   Maheswar G;Muthu C;Sujatha N V;Pandey G;Bhatt H C;Rao N Kameswara;Murthy J (NO, Aryabhatta Research Institute of Observational Sciences, Nainital-263 129, Email: maheswar@aries.ernet.in) : Interstellar dust studies with TAUVEX. Bull Astr Soc India 2007, 35(2), 233-8.

Proposes to carry out studies on the properties of interstellar dust using TAUVEX. Through the multi-band TAUVEX observations, particularly with the use of filters optimized for extinction observations of the 2175 A feature, combined with optical observations and 2MASS archived data, we can derive the extinction curve from UV to near-IR for stars located in different regions and environments. The extinction curve is a sensitive indicator of the properties of the interstellar dust and, as such, will allow us to trace the properties and evolution of the interstellar dust as a function of environment.

3 illus, 4 ref

003992   Joshi U C;Baliyan K S;Ganesh S (NO, Physical Research Laboratory, Ahmedabad-380 009, Email: joshi@prl.res.in) : Variability study of blazars with TAUVEX: scope and limitations. Bull Astr Soc India 2007, 35(2), 261-9.

The study of variability in blazars is an important tool to understand their energetics. Such a study is required to be made in all bands of spectral energy distribution. Hence, we propose to make UV observations of blazars using the TAUVEX facility for sources in the region /Dec/ <62> 50°. These observations will be complemented with simultaneous ground based observations in near IR, optical and radio frequencies using the facilities available in the country. The data will be used to study the nature of emission processes.

2 illus, 1 table, 52 ref

003991   Hota A;Saikia D J (NO, Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan, Email: hota@asiaa.sinica.edu.tw) : An H₁ study of three long-tailed irregular galaxies in the cluster Abells 1367. Bull Astr Soc India 2007, 35(2), 121-40.

Presents the results on the distribution and kinematics of HI gas with higher sensitivity and in one case of higher spectral resolution as well than reported earlier, of three irregular galaxies CGCG 097073, 097079 and 097087 (UGC 06697) in the cluster Abell 1367. These galaxies are known to exhibit long (50-75 kpc) tails of radio continuum and optical emission lines (Ha) pointing away from the cluster centre and arcs of starformation on the opposite sides of the tails. These features as well as the Hi properties, with two of the galaxies (CGCG 097073 and 097079) exhibiting sharper gradients in Hi intensity on the side of the tails, are consistent with the Hi gas being affected by the ram pressure of the intracluster medium. However the Hi emission in all the three galaxies extends to much smaller distances than the radio-continuum and Hα tails, and are possibly still bound to the parent galaxies. Approximately 20-30 per cent of the Hi mass is seen to accumulate on the downstream side due to the effects of ram pressure.

19 illus, 3 tables, 28 ref

003990   Herndon J M (NO, , Transdyne Corporation, 11044 Red Rock Drive, San Diego, California-92131, USA, Email: mherndon2san.rr.com) : Fundamental mass ratio relationships of whole-rock chondritic major elements: implications on ordinary chondrite formation and on planet Mercury's composition. Curr Sci 2007, 93(3), 394-9.

High occurrence on earth of ordinary chondritic meteorites and the making of models based upon assumptions has led to some confusion about the origin of ordinary chondrites and their role in planet fomation. Major element fractionation among chondrites has been discussed for decades as ratios relative to Si or Mg. Expressing ratios relative to Fe leads to a new relationship admitting the possibility that ordinary chon-drite meteorites are derived from two components: one is a relatively undifferentiated, primitive component, oxidized like the CI or Cl chondrites; the other is a somewhat differentiated, planetary component, with oxidation state like the reduced enstatit chondrites. Such a picture would seem to explain for the ordinary chondrites, their major element compositions, their intermediate states of oxidation, and their ubiquitous deficiencies of refractory siderophile elements. Suggests that the planetary component of ordinary chondrite formation consists of planet Mercury's missing complement of elements, presumably separated from protoplanetary Mercury during its formation.

2 illus, 3 tables, 28 ref

003989   Green D A (Mullard Radio Astronomy Observatory, , Cavendish Laboratory, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, United Kingdom) : Comments on the radio spectrum of HB 3. Bull Astr Soc India 2007, 35(2), 77-85.

It has recently been suggested that the radio spectrum of the Galactic supernova remnant HB 3 shows flattening at higher frequencies (above about 1 GHz).Review the radio spectrum of HB 3, noting the difficulties in deriving accurate flux densities for this remnant, particularly at high frequencies, due to the proximity of bright, thermal emission from W3 and its surroundings. A flux density for HB 3 at 2695 MHz is derived from Effelsberg survey data. The spectrum of HB 3 is well represented by a simple power-law spectrum from 22 to 2695 MHz, with a spectral index of 0.56 ± 0.03. It is concluded that contamination with thermal emission from adjacent regions is the cause for the reported spectral flattening of HB 3.

3 illus, 1 table, 26 ref

003988   Goyal A;Gopal Krishna;Ram Sagar;Anupama G C; Sahu D K (NO, Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital-263 129, Email: arti@aries.ernet.in) : Further evidence for intra-night optical variability of radio-quiet quasars. Bull Astr Soc India 2007, 35(2), 141-54.

Although well established for BL Lac objects and radio-loud quasars, the occurrence of intra-night optical variability (INOV) in radio-quiet quasars is still debated, primarily since only a handful of INOV events with good, statistical significance, albeit small amplitude, have been reported so far. This has motivated us to continue intra-night optical monitoring of bona-fide radio-quiet quasars (RQQs). Present the results for a sample of 11 RQQs monitored by us on 19 nights. On 5 of these nights a given RQQ was monitored simultaneously from two well separated observatories. In all, two clear cases and two probable cases of INOV events were detected. From these data, we estimate an INOV duty cycle of <126>8% for RQQs which would increase to 19% if the 'probable variable' cases are also included. Such comparatively small INOV duty cycles for RQQs, together with the small INOV amplitudes (<126>1%), are in accord with the previously deduced characteristics of this phenomenon.

4 illus, 2 tables, 54 ref

003987   Ebenezer E;Subramanian K R;Ramesh R; Sundararajan M S;Kathiravan C (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: subra@iiap.res.in) : Gauribidanur radio array solar spectrograph (Grass). Bull Astr Soc India 2007, 35(2), 111-9.

Describes the Gauribidanur radio array solar spectrograph (GRASS) and its various systems. The system consists of an array of 8 log periodic dipoles, a spectrum analyzer and a data acquisition system. The spec-trograph normally operates in the frequency range of 30 - 150 MHz with a frequency resolution of 250 KHz and a time resolution of 43 msec. The Gauribidanur radio array solar spectrograph operates approximately from 04:00 UT to 10:00 UT each day. Illustrates the working of the spectrograph with a few observations.

7 illus, 1 table, 13 ref

003986   Chandrasekhar T (Astronomy & Astrophysics Div, Physical Research Laboratory, Ahmedabad-380 009, Email: chandra@prl.res.in) : Chord lenghts across main belt asteroids from stellar occultations in the near infrared. Bull Astr Soc India 2007, 35(2), 155-61.

An asteroid occupation of a stellar source provides a direct measurement of the chord length across the asteroid with excellent precision. The method is independent of the brightness of the asteroid as well as its location anywhere in the solar system. At present stellar occultation predictions of main belt asteroids are available with sufficient precision to merit observations. At the 1.2 m telescope of Mt. Abu Observatory at Gurushikhar, a few well predicted main belt asteroidal occultations of stars mostly in the near IR J band (1.25 μm) have been successfully carried out in the last few years. The NIC-MOS IR array camera was used in the fast subarray mode for this purpose. Details of the observations and results are discussed.

5 illus, 2 tables, 5 ref

003985   Chakrabarti S K (NO, S.N. Bose National Center for Basic Sciences, JD-Block, Salt Lake, Kolkata-700 098, Email: chakraba@bose.res.in) : Quasi-periodic oscillations in quasars to nano-quasars. Bull Astr Soc India 2007, 35(2), 271-81.

TAUVEX brings us a unique opportunity to explore the temporal variability of UV emitting objects in the sky. One of the questions that we intend to resolve with TAUVEX is whether the 'variabilities' detected in active galaxies and quasars and in radiations around massive black holes in general are just random variations of the intensities or these are intrinsic to the disk system, and possibly due to the quasi-periodic oscillations (QPOs) which are well known to be observed in smaller black holes (nano-quasars). Presents a physical mechanism for the QPOs and show that this is a generic mechanism which should be manifested in all types of active compact objects, ranging from quasars to nano-quasars. Proposes some tests by which we may be able to tell if these are QPOs, even without waiting for a large number of cycles to test the periodicity. Presents a few examples to impress that perhaps we have already seen QPOs in some objects. Multi-wavelength observation capabilities in TAUVEX may be used to pinpoint the nature of the variable sources more accurately.

6 illus, 28 ref

003984   Brosch N;Almoznino E;Netzer H;Naaman M;Yacoby E R;Topaz J;Saar N (NO, , Elbit Systems Electro-Optics ELOP Ltd., Advanced Technology Park, P.O.Box 1165, Rehovot 76111, Israel, Email: noah@wise.tau.ac.il) : Calibrating TAUVEX: turning space hardware into a scientific instrument. Bull Astr Soc India 2007, 35(2), 187-208.

Explains the basic philosophy of calibrating TAU-VEX on the ground at the El-Op facilities in Israel, and in space after launch. We refer the reader to historical articles describing TAUVEX, its design and calibration, and update the knowledge base as to the modern testing and calibration procedures. Explicitly points out the products expected to result from the calibration process.

10 illus, 21 ref

003983   Brosch N;Almoznino E (Astronomy and Astrophysics Dep, Raymond and Beverly Sackler Faculty of, Tel Aviv Univ, Tel Aviv-69978, Israel, Email: noah@wise.tau.ac.il) : Galaxy surveys and science with TAUVEX. Bull Astr Soc India 2007, 35(2), 283-3.

One of the more interesting studies to be performed with TAU-VEX will be an unbiased survey of galaxies. Since the TAUVEX flight will occur when most of the results from GALEX will have been made available to the scientific community, it is important to select those types of studies that will extend significantly those done by GALEX and will complement them. Presents three different projects to be attempted in the field of galaxy UV observations: a general survey aimed at understanding the stellar populations in galaxies in a variety of environments based on deep TAUVEX exposures that should reach deeper than the GALEX mid-depth survey, a specific targeting of sky regions covered by HI measurements in order to detect the UV emission from low surface brightness galaxies detected through their 21-cm emission, and a unique project to measure the extragalactic extinction law by imaging early-type galaxies with dust lanes.

1 illus, 36 ref

003982   Bhatt H C (NO, Indian Institute of Astrophysics, Bangalore-560 034, Email: hcbhatt@iiap.res.in) : Some possible observing programmes in stellar and galactic astronomy with the TAUVEX. Bull Astr Soc India 2007, 35(2), 229-2.

While the major part of the survey observations with the TAU-VEX will be targeted on high galactic latitudes and celestial poles there are many observing proposals for stellar and galactic astronomy. Some of these on young stars, energetic outflows, flare stars, hot dwarfs, planetary nebulae are briefly discussed. A preferred sky area for Galactic observations is also suggested.

2 ref

003981   Almoznino E (Wise-Observatory, Tel-Aviv Univ, Israel, Email: nan@wise.tau.ac.il) : TAUVEX on Gsat4: observational prospects and constraints. Bull Astr Soc India 2007, 35(2), 209-22.

Describes the observational constraints imposed on the TAUVEX space telescope due to scattered light entering its telescopes from outside the field of view. This stray light is a sunlight reflected from various spacecraft components into TAUVEX apertures. Based on these constraints, a basic strategy of observation is suggested, in which the major part of the observational time will be dedicated to sky survey, while the rest will be aimed at specific targets.

11 illus, ref

003980   Ahmad A;Jeffery C S;Aerts C;Fontaine G; Charpinet S (Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland, Email: amir@star.arm.ac.uk) : Photometry of balloon 090100001 with the Himalayan Chandra telescope. Bull Astr Soc India 2007, 35(2), 67-75.

About one tenth of all hot subluminous B stars pulsate non-radially with periods of 80 - 600 s; the oscillations are identified with pressure modes. At lower effective temperatures, another group pulsates non-radially with periods <62> 3000s; these oscillations have been identified with gravity modes. If sufficient modes can be identified, such oscillations can provide information about the interior of a star. One pulsating sdB star - balloon 090100001 - lies at the boundary of the hot and cool groups, and shows both short and long-period oscillations. To study its interior structure in detail, we carried out a multi-site observing campaign in 2005 August in order to obtain a very precise light curve and hence to identify the modes of oscillation. This campaign involved four telescopes including the Himalayan Chandra Telescope (HCT), the William Herschel Telescope (in La Palma), the Canada France Hawaii Telescope and the Faulkes Telescope North (both in Hawaii). Here we report the HCT observations of balloon 090100001.

2 illus, 2 tables, 25 ref

003447   Patel K;Singh A K;Patel R P;Singh R P (Atmospheric Research Lab, Physics Dep, Banaras Hindu University, Varanasi-221 005) : Characteristics of low latitude ionospheric E-region irregularities linked with daytime VHF scintillations measured from Varanasi. J Earth Syst Sci 2009, 118(6), 721-32.

VHF amplitude scintillations recorded during the daytime period from January 1991 to December 1993, April 1998 to December 1999 and January 2008 to December 2008 at low latitude station Varanasi (geographic lat. = 25°15'N; long. = 82°59'E; geomagnetic lat. = 14°55'N, long. = 154°E, dip angle = 37.3°, sub-ionospheric dip = 34°) have been analyzed to study the behaviour of ionospheric E-region irregularities during the active solar and magnetic periods. The autocorrelation functions, power spectral densities, signal de-correlation times are computed to study the temporal features of ionospheric E-region irregularities linked with daytime scintillations. Derived spectral index ranges between -2 and -9. Assuming velocity of irregularities, the characteristic lengths of the E-region irregularities are estimated. Authors have estimated the minimum and maximum range of scale length of sporadic-E (E_s) irregularities to be observed over Varanasi. These results are in close agreement with those reported from this latitude region.

13 illus, 36 ref

003022   Narayan A;Shrivastava S (Mathematics Dep, Bhilai Institute of Technology, Durg-491 001) : Non liiner effects of the solar radiation pressure and magnetic field of the earth on the stability of cable connected satellite system in elliptical orbit. Bull Calcutta Mathl Soc 2007, 99(3), 209-22.

Combined effects of the solar radiation pressure and the magnetic field of the earth on the non-linear oscillations of two satellites connected by a light, flexible and inextensible cable in the central gravitational field of the earth have been studied. The motion of each of the satellite relative to their centre of mass has been studied, while the centre of mass of the system orbiting around the earth. The dipole of the earth has its axis inclined from the polar axis of the earth by 11°.4'. The presence of these perturbing forces enables the application of asymptotic method's of the theory of non-linear oscillations due to Bogoliubov, Krilov and Mitropolsky to the equations of motion of the system in non-resonance case. It is observed that the amplitude of oscillations varies, the variation is of the square of eccentricity.

3 illus, 14 ref

002112   Prasad A;Vinay Kumar K;Singh S;Singh R (Civil Engineering Dep, Indian Institute of Technology, Kanpur-208 016, Email: rpalka425@gmail.com) : Potentiality of multi-sensor satellite data in mapping flood hazard. J Indian Soc Remote Sens 2006, 34(2), 219-31.

5 illus, 33 ref

001083   Nichols A L (Physical and Chemical Sciences Div, Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, A-1400 Vienna, Austria, Email: a.l.nichols@iaea.org) : International efforts to improve atomic and nuclear databases for energy and non-energy applications. Curr Sci 2007, 93(1), 26-34.

Nuclear Data Section of the International Atomic Energy Agency has been involved in the formulation and maintenance of a wide range of atomic and nuclear databases for over 40 years. Much of the development work and the assembly of these dedicated databases require the involve-ment of external consultants and expertise from around the world, brought together to work in unison through well-defined IAEA coordinated research projects (CRPs) and more modest data development programmes (DDPs). A summary is given of the most recent CRPs and DDPs, and selected studies are described in detail to provide some indication of specific achievements that have been and are being made with respect to both energy and non-energy related applications.

4 illus, 4 tables, 33 ref

000091   Venkata Phani Kumar D;Chenna Reddy K;Yellaiah G (Astronomy Dep, Osmania University, Hyderabad-500 007, Email: gyh042000@yahoo.co.in) : MST radar observations of perseid meteor shower 2004. Bull Astr Soc India 2006, 34(3), 281-9.

There was a special attention for Perseid meteor shower observations in view of the predictions of an intense activity on 11th August 2004 caused by a filament of dust drifting across the Earth's orbit. Results of a systematic study of Perseid meteor shower observations, carried out during 12-15 August 2004 using Indian MST radar are presented. Based on over 27 hours of observing time, detected 2260 meteor echoes occurring between 80 km and 120 km with a mean height of 103 km. For observations, the peak activity of the shower occurred on 12/13 August, corresponding to solar longitude λ_° = 140.565 ± 0.16 with an average rate of 250 meteor echoes per hour. The SNR distribution of the echoes observed during the shower indicates that the smaller size meteoroids are more compared to larger size meteoroids in the perseid meteor stream. The three distinct peaks observed in the shower activity is presented and discussed.

4 illus, 16 ref

000090   Smith G H (NO, University of California/Lick Observatory, Santa Cruz, CA 95064, USA, Email: graeme@ucolick.org) : Primordial enrichment and nitrogen abundance inhomogeneties in globular clusters. Bull Astr Soc India 2006, 34(3), 235-53.

Globular clusters of the Milky Way tend to be markedly inhomoªgeneous with respect to the abundance of nitrogen, as well as other elements in the C-through-Al region of the Periodic Table. Stars within the same cluster may differ by as much as a factor of ten in nitrogen abundance. Discusses the possibility that globular clusters became enriched in nitrogen while they were still forming stars. Idealised equations describing the possible chemical evolution of a globular cluster are presented. They are used to elucidate several "supply and demand" requirements that must be met by a primordial enrichment model for the nitrogen inhomogeneity of these objects.

1 illus, 98 ref

000089   Mahendra Singh;Sanwal B B;Brijesh Kumar (NO, Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital-263 129, Email: msingh@aries.ernet.in) : Spectrophotometric study of the comet C/2001 Q4 (NEAT). Bull Astr Soc India 2006, 34(3), 273-9.

Spectrophotometric observations of the comet C/2001 Q4 (NEAT) were taken on three nights of May 13, 18 and 19, 2004 near its perihelion distance using 104-cm telescope of ARIES, Nainital. The Cassegrain HR-320 spectrograph with lK x lK CCD camera gives a visible spectral coverage of 3500-7000 Angstrom. The prominent emission bands CN (3888 Angstrom) and C₂ (4695, 5165 and 5538 Angstrom) were identified. An estimate of the CN and C₂ abundances and the production rates for these molecules and dust at those heliocentric distances were determined.

1 illus, 2 tables, 20 ref

000088   Jain H;Iqbal I Q;Taqvi Z A;Bhatnagar K B (NO, Jamia Millia Islamia, Delhi, Email: cfrsc@yahoo.com) : Stationary solutions and their stability in the magnetic-binary problem when the bigger primary is a triaxial rigid body. Bull Astr Soc India 2006, 34(3), 255-71.

Deals with the stationary-state in the planer magnetic-binary problem when the bigger primary is a triaxial rigid body with its equatorial plane coincident with the plane of motion by taking different values of semi axes of the triaxial rigid body. There exists five or seven equilibrium points (L₁, L₂, L₃ are collinear and L₄, L₅, L₆, L₇ are non-collinear) corresponding to certain values of mass parameter μ and magnetic parameter λ, the libration point L₁, does not exist when λ = 0, 2, 3 the libration point L₂ does not exist when λ = 2, 3. Founds that only L₂ is stable for given values of μ and <108.

3 illus, 9 tables

000087   Goto T;Ojha D (Infrared Astrophysics Dep, Institute of Space and Astronautical Science (ISAS), Japan Aerospace, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan, Email: tomo@ir.isas.jaxa.jp) : Deep J-band imaging of high redshift QSO candidates with the Himalayan Chandra Telescope. Bull Astr Soc India 2006, 34(3), 291-7.

High redshift QSOs (redshift<62>5.7) are highly important objects. If such QSOs may be found, their spectra will reveal the onset of reionization of the intergalactic medium (Gunn-Peterson trough), and provide precious insights into the re-ionization epoch in the very early universe. Reports the pilot attempt to follow-up high redshift QSOs with the Himalayan Chandra Telescope. Deep J-band imaging was performed on three high redshift QSO candidates colour-selected from the SDSS, using the near-infrared imager. Although none of the targets turned out to be likely high redshift QSOs, careful data reduction shows that the data reach the required depth, proving that the Himalayan Chandra Telescope is a powerful tool to follow-up high redshift QSO candidates.

4 illus, 1 table, 16 ref

000086   Chakrabarti S K;Das A;Acharyya K;Chakrabarti S (NO, S.N. Bose National Center for Basic Sciences, JD-Block, Salt Lake, Kolkata-700 098, Email: chakraba@bose.res.in) : Recombination efficiency of molecular hydrogen on intersteller grains-II A numerical study. Bull Astr Soc India 2006, 34(3), 299-31.

Knowledge of the recombination time on the grain surfaces has been a major obstacle in deciding the production rate of molecular hydroªgen and other molecules in the interstellar medium. Presents a numerical study to compute this time for molecular hydrogen for various cloud and grain parameters. Also finds the time dependence, particularly when a grain is freshly injected into the system. Apart from the fact that the recombination times seem to be functions of the grain parameters such as the activation barrier energy, temperature etc, the result also shows the dependence on the number of sites in the grain S and the effective accretion rate per site a_s of atomic hydrogen. Simply put, the average time that a pair of atomic hydrogens will take to produce one molecular hydrogen depends on how heavily the grain is alªready populated by atomic and molecular hydrogens and how fast the hopping and desorption times are. If the average recombination time is written as T_r <126> S^α/AH, where, A_H is the hopping rate, then α could be much greater than 1 for all astrophysically relevant accretion rates. Thus the average formation rate of H₂ is also dependent on the grain parameters, temperature and the accretion rate. The result will affect the overall rate of the formation of complex molecules such as methanol which require successive hydrogenation on the grain surfaces in the interstellar medium.

7 illus, 1 table, 18 ref

000091   Venkata Phani Kumar D;Chenna Reddy K;Yellaiah G (Astronomy Dep, Osmania University, Hyderabad-500 007, Email: gyh042000@yahoo.co.in) : MST radar observations of perseid meteor shower 2004. Bull Astr Soc India 2006, 34(3), 281-9.

There was a special attention for Perseid meteor shower observations in view of the predictions of an intense activity on 11th August 2004 caused by a filament of dust drifting across the Earth's orbit. Results of a systematic study of Perseid meteor shower observations, carried out during 12-15 August 2004 using Indian MST radar are presented. Based on over 27 hours of observing time, detected 2260 meteor echoes occurring between 80 km and 120 km with a mean height of 103 km. For observations, the peak activity of the shower occurred on 12/13 August, corresponding to solar longitude λ_° = 140.565 ± 0.16 with an average rate of 250 meteor echoes per hour. The SNR distribution of the echoes observed during the shower indicates that the smaller size meteoroids are more compared to larger size meteoroids in the perseid meteor stream. The three distinct peaks observed in the shower activity is presented and discussed.

4 illus, 16 ref

000090   Smith G H (NO, University of California/Lick Observatory, Santa Cruz, CA 95064, USA, Email: graeme@ucolick.org) : Primordial enrichment and nitrogen abundance inhomogeneties in globular clusters. Bull Astr Soc India 2006, 34(3), 235-53.

Globular clusters of the Milky Way tend to be markedly inhomoªgeneous with respect to the abundance of nitrogen, as well as other elements in the C-through-Al region of the Periodic Table. Stars within the same cluster may differ by as much as a factor of ten in nitrogen abundance. Discusses the possibility that globular clusters became enriched in nitrogen while they were still forming stars. Idealised equations describing the possible chemical evolution of a globular cluster are presented. They are used to elucidate several "supply and demand" requirements that must be met by a primordial enrichment model for the nitrogen inhomogeneity of these objects.

1 illus, 98 ref

000089   Mahendra Singh;Sanwal B B;Brijesh Kumar (NO, Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital-263 129, Email: msingh@aries.ernet.in) : Spectrophotometric study of the comet C/2001 Q4 (NEAT). Bull Astr Soc India 2006, 34(3), 273-9.

Spectrophotometric observations of the comet C/2001 Q4 (NEAT) were taken on three nights of May 13, 18 and 19, 2004 near its perihelion distance using 104-cm telescope of ARIES, Nainital. The Cassegrain HR-320 spectrograph with lK x lK CCD camera gives a visible spectral coverage of 3500-7000 Angstrom. The prominent emission bands CN (3888 Angstrom) and C₂ (4695, 5165 and 5538 Angstrom) were identified. An estimate of the CN and C₂ abundances and the production rates for these molecules and dust at those heliocentric distances were determined.

1 illus, 2 tables, 20 ref

000088   Jain H;Iqbal I Q;Taqvi Z A;Bhatnagar K B (NO, Jamia Millia Islamia, Delhi, Email: cfrsc@yahoo.com) : Stationary solutions and their stability in the magnetic-binary problem when the bigger primary is a triaxial rigid body. Bull Astr Soc India 2006, 34(3), 255-71.

Deals with the stationary-state in the planer magnetic-binary problem when the bigger primary is a triaxial rigid body with its equatorial plane coincident with the plane of motion by taking different values of semi axes of the triaxial rigid body. There exists five or seven equilibrium points (L₁, L₂, L₃ are collinear and L₄, L₅, L₆, L₇ are non-collinear) corresponding to certain values of mass parameter μ and magnetic parameter λ, the libration point L₁, does not exist when λ = 0, 2, 3 the libration point L₂ does not exist when λ = 2, 3. Founds that only L₂ is stable for given values of μ and <108.

3 illus, 9 tables

000087   Goto T;Ojha D (Infrared Astrophysics Dep, Institute of Space and Astronautical Science (ISAS), Japan Aerospace, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan, Email: tomo@ir.isas.jaxa.jp) : Deep J-band imaging of high redshift QSO candidates with the Himalayan Chandra Telescope. Bull Astr Soc India 2006, 34(3), 291-7.

High redshift QSOs (redshift<62>5.7) are highly important objects. If such QSOs may be found, their spectra will reveal the onset of reionization of the intergalactic medium (Gunn-Peterson trough), and provide precious insights into the re-ionization epoch in the very early universe. Reports the pilot attempt to follow-up high redshift QSOs with the Himalayan Chandra Telescope. Deep J-band imaging was performed on three high redshift QSO candidates colour-selected from the SDSS, using the near-infrared imager. Although none of the targets turned out to be likely high redshift QSOs, careful data reduction shows that the data reach the required depth, proving that the Himalayan Chandra Telescope is a powerful tool to follow-up high redshift QSO candidates.

4 illus, 1 table, 16 ref

000086   Chakrabarti S K;Das A;Acharyya K;Chakrabarti S (NO, S.N. Bose National Center for Basic Sciences, JD-Block, Salt Lake, Kolkata-700 098, Email: chakraba@bose.res.in) : Recombination efficiency of molecular hydrogen on intersteller grains-II A numerical study. Bull Astr Soc India 2006, 34(3), 299-31.

Knowledge of the recombination time on the grain surfaces has been a major obstacle in deciding the production rate of molecular hydroªgen and other molecules in the interstellar medium. Presents a numerical study to compute this time for molecular hydrogen for various cloud and grain parameters. Also finds the time dependence, particularly when a grain is freshly injected into the system. Apart from the fact that the recombination times seem to be functions of the grain parameters such as the activation barrier energy, temperature etc, the result also shows the dependence on the number of sites in the grain S and the effective accretion rate per site a_s of atomic hydrogen. Simply put, the average time that a pair of atomic hydrogens will take to produce one molecular hydrogen depends on how heavily the grain is alªready populated by atomic and molecular hydrogens and how fast the hopping and desorption times are. If the average recombination time is written as T_r <126> S^α/AH, where, A_H is the hopping rate, then α could be much greater than 1 for all astrophysically relevant accretion rates. Thus the average formation rate of H₂ is also dependent on the grain parameters, temperature and the accretion rate. The result will affect the overall rate of the formation of complex molecules such as methanol which require successive hydrogenation on the grain surfaces in the interstellar medium.

7 illus, 1 table, 18 ref

001117   Vishwakarma J P;Singh A K (Mathematics and Statistics Dep, D.D.U. Gorakhpur Univ, Gorakhpur-273 009, Email: jpv_univgkp@yahoo.com) : Self-similar flow behind a shock wave in a gravitating or non-gravitating gas with heat conduction and radiation heat-flux. J Astrophys Astr 2009, 30(1), 53-69.

The propagation of a spherical shock wave in an ideal gas with heat conduction and radiation heat-flux, and with or without self-gravitational effects, is investigated. The initial density of the gas is assumed to obey a power law. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density, and the total energy of the wave to vary with time. Similarity solutions are obtained and the effects of variation of the heat transfer parameters, the variation of initial density and the presence of self-gravitational field are investigated.

11 illus, 2 tables, 28 ref

001116   Sarkar A;Mahopatra S K;Sarkar A (NO, Flomerics India Private Limited., 1st Floor, Regent Sunnyside, 581/2, 8th Block, Koramangala, Bangalore-560 095, Email: anjansirkar@yahoo.com) : Influence of radiation on buoyancy induced transport phenomena inside horizontal cylindrical annulus in presence of particiopating medium. J Energy Heat Mass Transfer 2009, 31(1), 1-20.

In the investigation, the coupled phenomenon of natural convection and radiation within differentially heated cylindrical annulus has been numerically simulated. The radiation transfer contributed from the participating medium is obtained by solving the non-linear integro-differential radiative transfer equation (RTE) using discrete ordinate method (DOM). The participating gray medium is considered to be emitting, absorbing and isotropically scattering. Finite volume based finite difference method (FDM) is used as the numerical technique for solving governing equations. The vorticity-stream function formulation of N-S equation is discretized. The walls of the annulus are considered to be opaque, diffuse and gray. The influence of radiative parameters on the interaction phenomenon has been delineated through isotherm and streamline pattern.

11 illus, 3 tables, 19 ref

001115   Russell D G (NO, Owego free Academy, Owego, NY 13827, USA, Email: russeld1@oacsd.org) : The Ks-band tully-fisher relation-a determination of the hubble parameter from 218 ScI galaxies and 16 galaxy glusters. J Astrophys Astr 2009, 30(2), 93-118.

The value of Hubble parameter (H_-0) is determined using the morphologically type dependent Ks-band Tully-Fisher Relation (K-TFR). The slope and zero point are determined using 36 calibrator galaxies with Scl morphology. Calibration distances are adopted from direct Cepheid distances, and group or companion distances derived with the Surface Brightness Fluctuation Method or Type la Supernova. It is found that a small morphological type effect is present in the K-TFR such that Scl galaxies are more luminous at a given rotational velocity than Sa/Sb galaxies and Sbc/Sc galaxies of later luminosity classes. Distances are determined to 16 galaxy clusters and 218 Scl galaxies with minimum distances of 40.0 Mpc. From the 16 galaxy clusters a weighted mean Hubble parameter of HO = 84.2 ±6km s^-1 Mpc^-1 is found. From the 218 Scl galaxies a Hubble parameter of H₀ = 83.4 ± 8km s^-1 Mpc^-1 is found. When the zero point of K-TFR is corrected to account for recent results that find a Large Magellanic Cloud distance modulus of 18.39 ñ 0.05, a Hubble parameter of 88.0 ±6km s^-1 Mpc^-1 is found. Effects from Malmquist bias are shown to be negligible in this sample as galaxies are restricted to a minimum rotational velocity of 150 km s^-1. It is also shown that the results of this study are negligibly affected by the adopted slope for the K-TFR, inclination binning, and distance binning. A comparison with the results of the Hubble Key Project (Freedman et al. 2001) is made. Discrepancies between the K-TFR distances and the HKPI-TFR distances are discussed. Implications for A-CDM cosmology are considered with HO = 84km s^-1 Mpc^-1. It is concluded that it is very difficult to reconcile the value of H₀ found in this study with ages of the oldest globular clusters and matter density of the universe derived from galaxy clusters in the context of A-CDM cosmology.

7 illus, 12 Tables, 55 ref

001114   Razavi M;Dehghani A R;Khanmohammadi M (Mechanical Engineering Dep, Islamic Azad Univ, Science and Research Campus, Tehran, Iran) : Simulation of thermal stratification in cisterns using artificial neural network. J Energy Heat Mass Transfer 2009, 31(3), 201-10.

Cisterns were traditional parts of long-term and seasonal passive cooling systems which were used to supply and store cool and fresh water for warm and hot periods of the year. In this paper, the thermal behavior of a long-term cold-water underground reservoir is modeled using Artificial Neural Networks (ANN) and the results are compared with observations. Multi-Layer feed forward Perceptron Neural Network (MLP) with various calibration methods and architectures is used and results of performance functions of them are compared with observations. Afterwards, the best architecture and calibration methods are presented. With comparison between the obtained thermal layering from ANN and the experimental results, it is observed that a proper adoption between both layering during discharge period exists. Also, it is observed that the temperature distribution is linear in the lower area. On the contrary in the upper area, temperature distribution is exponential due to thermal exchange among upper layers of water and dome, transfer of mass, and evaporative heat resulted by entry air from wind towers.

4 illus, 1 table, 18 ref

001113   Rahoma W A;El-Salam F A A;Ahmed M K (Faculty of Science, Astronomy Dep, Cairo Univ, Cairo, Egypt, Email: walid_rahoma@yahoo.com) : Analytical treatment of the two-body problem with slowly varying mass. J Astrophys Astr 2009, 30(3-4), 187-205.

The work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.

37 ref

001112   Li L S (Physics Dep, Northeast Normal Univ, Changchum, China-130 024) : Method for judging decay or growth of the magnetic field of pulsar. J Astrophys Astr 2009, 30(3-4), 145-51.

This paper provides a method for judging growth or decay of the magnetic field of pulsar by using pulse period P, or frequency v, and its first and second derivatives P, P or v, v. The author uses this method to judge the growth or decay of the magnetic field of Crab pulsar. The judged result for Crab pulsar is that the magnetic field of Crab pulsar is growing now, but it is not decaying. The result corresponds with the actual case of Crab pulsar.

7 ref

001111   Karami K;Mohebi R (Physics Dep, Kurdistan Univ, Pasdaran St., Sanandaj, Iran, Email: rozitamohebi@yahoo.com) : Velocity curve studies of spectroscopic binary stars V380 cygni, V401 cyg, V523 cas, V373 cas and V2388 Oph. J Astrophys Astr 2009, 30(3-4), 153-63.

Using measured radial velocity data of five double lined spectroscopic binary systems V380 Cygni, V401 Cyg, V523 Cas, V373 Cas and V2388 Oph, we find corresponding orbital and spectroscopic elements via the method introduced by Karami & Mohebi (2007) and Karami & Teimoorinia (2007). Our numerical results are in good agreement with those obtained by others using more traditional methods.

15 illus, 5 tables, 10 ref