Results for "R. Ojha"

total 127420took 0.14s
High resolution observations of 6.7-GHz methanol masers with the LBAMar 18 2004We have used the Australian Long Baseline Array (LBA) to produce milliarcsecond images of five sites of methanol maser emission at 6.7 GHz. These are all sites that have linear morphologies at arcsecond resolutions, which have been hypothesised to be ... More
The molecular complex associated with the Galactic HII region Sh2-90: a possible site of triggered star formationMar 31 2014We investigate the star formation activity in the molecular complex associated with the Galactic HII region Sh2-90, using radio-continuum maps obtained at 1280 MHz and 610 MHz, Herschel Hi-GAL observations at 70 -- 500 microns, and deep near-infrared ... More
Investigating the nuclear activity of barred spiral galaxies: the case of NGC 1672Apr 08 2011We have performed an X-ray study of the nearby barred spiral galaxy NGC1672, primarily to ascertain the effect of the bar on its nuclear activity. We use both Chandra and XMM-Newton observations to investigate its X-ray properties, together with supporting ... More
Polarimetric and photometric investigation of a dark globule LDN 1225: distance, extinction law, and magnetic fieldsDec 21 2018Feb 25 2019We present the results based on the optical $R$-band polarization observations of 280 stars distributed towards the dark globule LDN\,1225. {\it Gaia} data release 2 parallaxes along with the polarization data of $\sim$200 stars have been used to (a) ... More
Performance Analysis Of Neuro Genetic Algorithm Applied On Detecting Proportion Of Components In Manhole Gas MixtureAug 15 2012The article presents performance analysis of a real valued neuro genetic algorithm applied for the detection of proportion of the gases found in manhole gas mixture. The neural network (NN) trained using genetic algorithm (GA) leads to concept of neuro ... More
Simultaneous Optimization of Neural Network Weights and Active Nodes using MetaheuristicsJul 06 2017Optimization of neural network (NN) significantly influenced by the transfer function used in its active nodes. It has been observed that the homogeneity in the activation nodes does not provide the best solution. Therefore, the customizable transfer ... More
Ensemble of heterogeneous flexible neural trees using multiobjective genetic programmingMay 16 2017Machine learning algorithms are inherently multiobjective in nature, where approximation error minimization and model's complexity simplification are two conflicting objectives. We proposed a multiobjective genetic programming (MOGP) for creating a heterogeneous ... More
Statistical characterization of the forces on spheres in an upflow of airJun 30 2004Nov 09 2004The dynamics of a sphere fluidized in a nearly-levitating upflow of air were previously found to be identical to those of a Brownian particle in a two-dimensional harmonic trap, consistent with a Langevin equation [Ojha {\it et al.}, Nature {\bf 427}, ... More
Observational signatures of cloud-cloud collision in the extended star-forming region S235Sep 19 2017We present a multi-wavelength data analysis of the extended star-forming region S235 (hereafter E-S235), where two molecular clouds are present. In E-S235, using the 12CO (1-0) and 13CO (1-0) line data, a molecular cloud linked with the site "S235main" ... More
The Asymmetric Drift of the Thick Disk PopulationAug 21 1994We investigate the kinematics of the intermediate population using the photometric and astrometric sample surveys towards two opposite directions (galactic centre and anticentre) at intermediate latitude. A multivariate discriminant analysis (MDA) is ... More
Multi-Objective Geometric Programming Problem Being Cost Coefficients as Continous Function with Weighted Mean MethodFeb 21 2010Geometric programming problems occur frequently in engineering design and management. In multiobjective optimization, the trade-off information between different objective functions is probably the most important piece of information in a solution process ... More
Near infrared and gamma-ray monitoring of TANAMI gamma-ray bright sourcesJun 01 2013Spectral energy distribution and its variability are basic tools for understanding the physical processes operating in active galactic nuclei (AGN). In this paper we report the results of a one-year near infra red (NIR) and optical monitoring of a sample ... More
The embedded ring-like feature and star formation activities in G35.673-00.847Jan 23 2018We present a multi-wavelength study to probe the star formation (SF) process in the molecular cloud linked with the G35.673-00.847 site (hereafter MCG35.6), which is traced in a velocity range of 53-62 km/s. Multi-wavelength images reveal a semi-ring-like ... More
TANAMI - Multiwavelength and Multimessenger Observations of Active GalaxiesJun 12 2015Jul 08 2015Extragalactic jets launched from the immediate vicinity of supermassive black holes in radio-loud active galactic nuclei (AGN) are key objects in modern astronomy and astroparticle physics. AGN jets carry a fraction of the total gravitational energy released ... More
NAG: Network for Adversary GenerationDec 09 2017Mar 28 2018Adversarial perturbations can pose a serious threat for deploying machine learning systems. Recent works have shown existence of image-agnostic perturbations that can fool classifiers over most natural images. Existing methods present optimization approaches ... More
Evidence of interacting elongated filaments in the star-forming site AFGL 5142Mar 17 2019To probe the ongoing physical mechanism, we studied a wide-scale environment around AFGL 5142 (area ~25 pc x 20 pc) using a multi-wavelength approach. The Herschel column density (N(H_2)) map reveals a massive inverted Y-like structure (mass ~6280 M_sun), ... More
Embedded filaments in IRAS 05463+2652: early stage of fragmentation and star formation activitiesSep 01 2017We present a multi-wavelength data analysis of IRAS 05463+2652 (hereafter I05463+2652) to study star formation mechanisms. A shell-like structure around I05463+2652 is evident in the Herschel column density map, which is not associated with any ionized ... More
Optimizing Supply Chain Management using Gravitational Search Algorithm and Multi Agent SystemSep 03 2012Supply chain management is a very dynamic operation research problem where one has to quickly adapt according to the changes perceived in environment in order to maximize the benefit or minimize the loss. Therefore we require a system which changes as ... More
Kinematical Properties of the Thick Disk of the GalaxyOct 20 1994We try here to find new constraints on thick disk population using samples at intermediate latitude and North Galactic Pole, which include photometry and proper motions. The algorithm SEM (Stochastic-Estimation-Maximization; Celeux \& Deibolt 1986) was ... More
A Novel Service Oriented Model for Query Identification and Solution Development using Semantic Web and Multi Agent SystemAug 31 2012In this paper, we propose to develop service model architecture by merging multi-agentsystems and semantic web technology. The proposed architecture works in two stages namely, Query Identification and Solution Development. A person referred to as customer ... More
Parsec-scale structure of quasars: dawn of the golden age?Oct 03 2013Half a century after their discovery, the study of quasars remains one of the most fascinating intellectual challenges in astronomy. Quasars are laboratories for everything from relativity to magnetohydrodynamics and are perhaps the best available probes ... More
Detection of Knots and Jets in IRAS 06061+2151Feb 14 2004Feb 18 2004We report detection of a Young Stellar Object with an evidence for an outflow in the form of knots in the molecular hydrogen emission line (2.121 micron) towards the massive star forming region IRAS 06061+2151. Near-infrared images reveal IRAS 06061+2151 ... More
Structure and kinematical properties of the Galaxy at intermediate galactic latitudesNov 12 1995We have carried out a sample survey in UBVR photometry and proper motions in different directions in the Galaxy, as part of an investigation of galactic structure and evolution. Three fields in the direction of galactic anticentre, centre and antirotation ... More
Restricting Control Flow During Speculative Execution with VenkmanMar 26 2019Side-channel attacks such as Spectre that utilize speculative execution to steal application secrets pose a significant threat to modern computing systems. While program transformations can mitigate some Spectre attacks, more advanced attacks can divert ... More
Radio and infrared study of the star forming region IRAS 20286+4105Nov 09 2016A multi-wavelength investigation of the star forming complex IRAS 20286+4105, located in the Cygnus-X region, is presented here. Near-infrared K-band data is used to revisit the cluster / stellar group identified in previous studies. The radio continuum ... More
Steady and Transient Radio Emission from Ultracool DwarfsMay 26 2009We detect radio emission in an additional two epochs of the ultracool dwarf binary LP 349- 25, finding that the observed emission is broadband and steady on timescales between 10s and 10.7 hours, as well as on timescales of 0.6 and 1.6 years. This system ... More
TIRCAM2: The TIFR Near Infrared Imaging CameraNov 23 2012TIRCAM2 (TIFR Near Infrared Imaging Camera - II) is a closed cycle cooled imager that has been developed by the Infrared Astronomy Group at the Tata Institute of Fundamental Research for observations in the near infrared band of 1 to 3.7 microns with ... More
Consequences of a possible jet-star interaction in the inner central parsec of Centaurus AFeb 10 2015Apr 24 2015The jet-counterjet system of the closest radio-loud active galaxy Centaurus A (Cen A) can be studied with Very Long Baseline Interferometry (VLBI) on unprecedented small linear scales of ~0.018pc. These high-resolution observations provide essential information ... More
The molecular cloud S242: physical environment and star formation activitiesJul 03 2017We present a multi-wavelength study to probe the star formation (SF) processes on a larger scale (~1.05 deg x 0.56 deg) around the S242 site. The S242 molecular cloud is depicted in a velocity range from -3.25 to 4.55 km/s and has spatially elongated ... More
Star formation activity in the southern Galactic HII region G351.63-1.25Mar 19 2014The southern Galactic high mass star-forming region, G351.6-1.3, is a HII region-molecular cloud complex with a luminosity of 2.0 x 10^5 L_sun, located at a distance of 2.4 kpc. In this paper, we focus on the investigation of the associated HII region, ... More
The gamma-ray properties of radio-selected extragalactic jetsJun 13 2010Most extragalactic jets in radio-loud Active Galactic Nuclei are bright and variable gamma-ray sources, which are continuously monitored with Fermi/LAT. We present the gamma-ray properties of the MOJAVE and TANAMI AGN samples of radio-loud AGN. Both programs ... More
Study of morphology and stellar content of the Galactic HII region IRAS 16148-5011Dec 04 2014An investigation of the IRAS 16148-5011 region - a cluster at a distance of 3.6 kpc - is presented here, carried out using multiwavelength data in near-infrared (NIR) from the 1.4m Infrared Survey Facility telescope, mid-infrared (MIR) from the archival ... More
Southern-Hemisphere AGN Monitoring on (Sub-)Parsec Scales: The TANAMI ProgramMay 07 2012The Very Long Baseline Interferometry (VLBI) monitoring program TANAMI provides bi-monthly, dualfrequency (8GHz and 22GHz) observations of extragalactic jets with milliarcsecond resolution south of -30 deg declination using the Australian Long Baseline ... More
Star Formation and Young Population of the HII Complex Sh2-294Jun 25 2012The Sh2-294 HII region ionized by a single B0V star features several infrared excess sources, a photodissociation region, and also a group of reddened stars at its border. The star formation scenario in the region seems to be quite complex. In this paper, ... More
A study of the Galactic star forming region IRAS 02593+6016 / S 201 in infrared and radio wavelengthsNov 05 2003We present infrared and radio continuum observations of S 201 star forming region. A massive star cluster is observed in this region, which contains different classes of young stellar objects. The near-infrared colour-colour and colour-magnitude diagrams ... More
Infrared study of the Southern Galactic star forming region associated with IRAS 14416-5937Sep 30 2006Aims: We have carried out an infrared study of the southern Galactic massive star forming region associated with IRAS 14416-5937. Methods: This star forming region has been mapped simultaneously in two far infrared bands at ~ 150 & 210 micron using the ... More
Low-speed impact craters in loose granular mediaJan 28 2003Mar 25 2003We report on craters formed by balls dropped into dry, non-cohesive, granular media. By explicit variation of ball density $\rho_{b}$, diameter $D_{b}$, and drop height $H$, the crater diameter is confirmed to scale as the 1/4 power of the energy of the ... More
Infrared and radio study of star forming regions associated with IRAS 19111+1048 and IRAS 19110+1045Sep 29 2005A multiwavelength study of the star forming regions associated with IRAS 19111+1048 and IRAS 19110+1045 has been carried out. These have been simultaneously mapped in two far infrared bands at lambda_eff ~ 130 and 200 micron with ~1' angular resolution ... More
Star formation toward the H~II region IRAS 10427-6032Mar 16 2018The formation and properties of star clusters formed at the edges of H II regions are poorly known. We study stellar content, physical conditions, and star formation processes around a relatively unknown young H II region IRAS 10427-6032, located in the ... More
Infrared study of the southern Galactic star forming regions associated with IRAS 10049-5657 and IRAS 10031-5632Jul 18 2008The physical conditions of the interstellar medium and stellar components in the regions of the southern Galactic star forming complexes associated with IRAS 10049-5657 and IRAS 10031-5632 have been investigated. These regions have been mapped simultaneously ... More
A multiwavelength study of the ultracompact HII region associated with IRAS 20178+4046Feb 27 2007We present a multiwavelength study of the ultra compact HII region associated with IRAS 20178+4046. This enables us to probe the different components associated with this massive star forming region. The radio emission from the ionized gas was mapped ... More
Unveiling molecular clouds toward bipolar HII region G8.14+0.23Apr 24 2019Most recent numerical simulations suggest that bipolar HII regions, powered by O-type stars, can be formed at the interface of two colliding clouds. To observationally understand the birth of O-type stars, we present a detailed multi-wavelength analysis ... More
The MHz-peaked radio spectrum of the unusual gamma-ray source PMN J1603-4904Sep 07 2016Context. The majority of bright extragalactic gamma-ray sources are blazars. Only a few radio galaxies have been detected by Fermi/LAT. Recently, the GHz-peaked spectrum source PKS 1718-649 was confirmed to be gamma-ray bright, providing further evidence ... More
Sub-parsec scale imaging of Centaurus AJun 08 2010Jul 08 2010At a distance of about 3.8 Mpc, the radio galaxy Centaurus A is the closest active galaxy. Therefore it is a key target for studying the innermost regions of active galactic nuclei (AGN). VLBI observations conducted within the framework of the TANAMI ... More
Characterisation of Long Baseline Calibrators at 2.3 GHzJun 14 2011We present a detailed multi-epoch analysis of 31 potential southern hemisphere radio calibrators that were originally observed as part of a program to maintain the International Celestial Reference Frame (ICRF). At radio wavelengths, the primary calibrators ... More
High-Energy Polarimetry - a new window to probe extreme physics in AGN jetsMar 11 2019The constantly improving sensitivity of ground-based and space-borne observatories has made possible the detection of high-energy emission (X-rays and gamma-rays) from several thousands of extragalactic sources. Enormous progress has been made in measuring ... More
Characterizing the greater-than-bulk melting behaviour of Ga-Al nanoalloysMar 12 2015Mar 21 2015Phase diagrams are the most reliable way of predicting phase changes in a system. In this work, we create the phase diagram of the Ga(20-x)Al(x)+ bimetallic cluster system, for which the monometallic clusters display greater-than- bulk melting behaviour. ... More
Astrometric Plate Reduction with Orthogonal Functions and Milli-Arcseconds Accuracy in Deep Proper Motion SurveysAug 21 1994We have been doing a sample survey in UBV photometry and proper motions as part of an investigation of galactic structure and evolution. The programme is based on Schmidt plates (from OCA, Tautenburg, Palomar and ESO Schmidt telescopes) digitized with ... More
A multiwavelength study of Galactic HII region Sh2-294Aug 30 2007We present the observational results of Galactic HII region S294, using optical photometry, narrow-band imaging and radio continuum mapping at 1280 MHz, together with archival data from 2MASS, MSX and IRAS surveys. The stellar surface density profile ... More
Multiwavelength campaign of the gamma-ray flaring source PKS 2052-47Jan 10 2010The flat-spectrum radio quasar PKS 2052-47 experienced an optical flare in July-August, 2009. On August 9, the LAT detector onboard Fermi observed a flare from the source, which reached its active phase in the following two months. To further investigate ... More
A multiwavelength study of the massive star forming region IRAS 06055+2039 (RAFGL 5179)Jan 24 2006We present a multiwavelength study of the massive star forming region associated with IRAS 06055+2039 which reveals an interesting scenario of this complex where regions are at different stages of evolution of star formation. Narrow band near-infrared ... More
Circuit Complexity of Bounded Planar Cutwidth Graph MatchingJan 03 2018Recently, perfect matching in bounded planar cutwidth bipartite graphs (\BGGM) was shown to be in ACC$^0$ by Hansen et al.. They also conjectured that the problem is in AC$^0$. In this paper, we disprove their conjecture by showing that the problem is ... More
W40 region in the Gould Belt : An embedded cluster and H II region at the junction of filamentsSep 27 2013We present a multiwavelength study of W40 star-forming region using IR observations in UKIRT JHK bands, Spitzer IRAC bands & Herschel PACS bands; 2.12 micron H2 narrow-band imaging; & radio observations from GMRT (610 & 1280 MHz), in a FoV of ~34'x40'. ... More
Corrigendum to "Random grid-based visual secret sharing with abilities of OR and XOR decryptions"[Journal of Visual Communication and Image Representation. 24(2013) 48-62]Feb 17 2015It has been observed that the contrast values for (2, 3) VSS scheme, (2, 4) VSS scheme, (3, 5) VSS scheme and (4, 5) VSS scheme claimed by Wu and Sun (2013) are found to be incorrect. Since the same values are cited and compared by many other researchers ... More
English-Bhojpuri SMT System: Insights from the Karaka ModelMay 06 2019This thesis has been divided into six chapters namely: Introduction, Karaka Model and it impacts on Dependency Parsing, LT Resources for Bhojpuri, English-Bhojpuri SMT System: Experiment, Evaluation of EB-SMT System, and Conclusion. Chapter one introduces ... More
Pre-main-sequence population in NGC 1893 regionJul 24 2012In this paper we continued our efforts to understand the star formation scenario in and around the young cluster NGC 1893. We used a sample of the young stellar sources (YSOs) identified on the basis of multiwavelength data (optical, near-infrared (NIR), ... More
Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometerOct 12 1999The observational and operational efficiency of the TIFR 1 meter balloon borne far infrared telescope has been improved by incorporating a multielement solid state optical photometer (SSOP) at the Cassegrain focus of the telescope. The SSOP is based on ... More
Massive young stellar object W42-MME: The discovery of an infrared jet using VLT/NACO near-infrared imagesFeb 19 2015We report on the discovery of an infrared jet from a deeply embedded infrared counterpart of 6.7 GHz methanol maser emission (MME) in W42 (i.e. W42-MME). We also investigate that W42-MME drives a parsec-scale H2 outflow, with detection of bow shock feature ... More
The ionizing sources of luminous compact HII regions in the RCW106 and RCW122 cloudsJul 02 2013Feb 06 2014Given the rarity of young O star candidates, compact HII regions embedded in dense molecular cores continue to serve as potential sites to peer into the details of high-mass star formation. To uncover the ionizing sources of the most luminous and compact ... More
Near-Infrared Photometry and Radio Continuum Study of the Massive Star Forming Regions IRAS 21413+5442 and IRAS 21407+5441Aug 13 2008IRAS 21413+5442 and IRAS 21407+5441 are two massive star forming regions of high luminosity, likely associated with each other. Near-infrared photometry on these two IRAS sources was performed at UKIRT using the UFTI under excellent seeing conditions ... More
Near-IR spectra of ISOGAL sources in the Inner Galactic BulgeMar 27 2003In this work we present near-IR spectra (HK-band) of a sample of 107 sources with mid-IR excesses at 7 and 15 $\rm \mu$m detected during the ISOGAL survey. Making use of the DENIS interstellar extinction map from Schultheis et al. (1999) we derive luminosities ... More
The stellar contents and star formation in the NGC 7538 regionJan 04 2017Deep optical photometric data on the NGC 7538 region were collected and combined with archival data sets from $Chandra$, 2MASS and {\it Spitzer} surveys in order to generate a new catalog of young stellar objects (YSOs) including those not showing IR ... More
Star formation in bright-rimmed clouds and cluster associated with W5 E H{\sc ii} regionMar 17 2011The aim of this paper is to present the results of photometric investigations of the central cluster of the W5 E region as well as a follow-up study of the triggered star formation in and around bright-rimmed clouds (BRCs). We have carried out wide field ... More
Relational Crowdsourcing and its Application in Knowledge Graph EvaluationOct 21 2016Automatic construction of large knowledge graphs (KG) by mining web-scale text datasets has received considerable attention over the last few years, resulting in the construction of several KGs, such as NELL, Google Knowledge Vault, etc. These KGs consist ... More
A Multi-Wavelength High Resolution Study of the S255 Star Forming Region. General structure and kinematicsJun 26 2012We present observational data for two main components (S255IR and S255N) of the S255 high mass star forming region in continuum and molecular lines obtained at 1.3 mm and 1.1 mm with the SMA, at 1.3 cm with the VLA and at 23 and 50 cm with the GMRT. The ... More
Mapping of Large Scale 158 micron [CII] Line Emission: Orion AApr 14 2003We present the first results of an observational programme undertaken to map the fine structure line emission of singly ionized carbon ([CII] 157.7409 micron) over extended regions using a Fabry Perot spectrometer newly installed at the focal plane of ... More
Radio and Gamma-ray Properties of Extragalactic Jets from the TANAMI SampleJan 19 2016Using high-resolution radio imaging with VLBI techniques, the TANAMI program has been observing the parsec-scale radio jets of southern (declination south of -30{\deg}) gamma-ray bright AGN simultaneously with Fermi/LAT monitoring of their gamma-ray emission. ... More
The Gamma-Ray Blazar PKS 0208-512, a Multi-Wavelength InvestigationFeb 21 2012Jun 27 2012The gamma-ray blazar PKS 0208-512 has shown strong periods of flaring, at all frequencies from radio to gamma-ray. This has led to its inclusion in the TANAMI project, which tracks the jets of southern AGN using VLBI as well as supporting flux density ... More
A multiwavelength study of star formation in the vicinity of Galactic HII region Sh2-100Mar 23 2010We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of ultracompact ... More
Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino eventFeb 05 2016Mar 03 2016The discovery of extraterrestrial very-high-energy neutrinos by the IceCube collaboration has launched a quest for the identification of their astrophysical sources. Gamma-ray blazars have been predicted to yield a cumulative neutrino signal exceeding ... More
Oxygen vacancy mediated cubic phase stabilization at room temperature in pure nano-crystalline Zirconia films: A combined experimental and first-principles based investigationApr 08 2019We report the formation of cubic phase, under ambient conditions, in thin films of Zirconia synthesized by electron beam evaporation technique. The stabilization of the cubic phase was achieved without the use of chemical stabilizers and/or concurrent ... More
Enormous disc of cool gas surrounding the nearby powerful radio galaxy NGC 612 (PKS 0131-36)May 22 2008We present the detection of an enormous disc of cool neutral hydrogen (HI) gas surrounding the S0 galaxy NGC 612, which hosts one of the nearest powerful radio sources (PKS 0131-36). Using the Australia Telescope Compact Array, we detect M_HI = 1.8 x ... More
Low-mass young stellar population and star formation history of the cluster IC 1805 in the W4 H{\sc ii} regionMar 10 2017W4 is a giant H{\sc ii} region ionized by the OB stars of the cluster IC~1805. The H{\sc ii} region/cluster complex has been a subject of numerous investigations as it is an excellent laboratory for studying the feedback effect of massive stars on the ... More
Optical and Near-infrared survey of the stellar contents associated with the star-forming Complex Sh2-252Dec 29 2012We present the analyses of the stellar contents associated with the HII region Sh2-252 using UBVRI photometry, slit and slitless spectroscopy along with the NIR data from 2MASS for an area ~1 degree x 1 degree. We studied the sub-regions of Sh2-252 which ... More
The Algol triple system spatially resolved at optical wavelengthsMay 04 2010Interacting binaries typically have separations in the milli-arcsecond regime and hence it has been challenging to resolve them at any wavelength. However, recent advances in optical interferometry have improved our ability to discern the components in ... More
Rapid Gamma-ray flux variability during the 2013 March Crab Nebula flareAug 30 2013We report on a bright flare in the Crab Nebula detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The period of significantly increased luminosity occurred in 2013 March and lasted for approximately 2 weeks. During ... More
Certain properties of bounded variation of sequences of fuzzy numbers by using generalized weighted meanSep 09 2015The class of bounded variation $bv^F(u,v)$ of fuzzy numbers introduced by [8] has been investigated further with the help of the generalized weighted mean matrix $G(u,v)$. Imposing some restrictions on the matrix $G(u,v)$, we have established it's relation ... More
Sh2-138: Physical environment around a small cluster of massive starsSep 29 2015We present a multi-wavelength study of the Sh2-138, a Galactic compact H II region. The data comprise of optical and near-infrared (NIR) photometric and spectroscopic observations from the 2-m Himalayan Chandra Telescope, radio observations from the Giant ... More
Near-infrared Study of the Carina NebulaJun 13 2007We have carried out near-infrared (NIR) imaging observations of the Carina Nebula for an area of ~400 sq. arcmin. including the star clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16). With 10 sigma limiting magnitudes of J ~ 18.5, H ~ 17.5 and K_s ... More
Weighted $βγ$-summability of fuzzy functions of order $θ$Apr 15 2016The concept of weighted $\beta\gamma$ - summability of order $\theta$ in case of fuzzy functions is introduced and classified into ordinary and absolute sense. Several inclusion relations among the sets are investigated. Also we have found some suitable ... More
New class of sequences of fuzzy numbers defined by modulus function and generalized weighted meanFeb 10 2016In this paper, We have introduced a new class of sequences of fuzzy numbers defined by using modulus function and generalized weighted mean over the class defined in \cite{OS}. We have proved that this class form a quasilinear complete metric space under ... More
Parsec-Scale Blazar Monitoring: Proper MotionsSep 19 2000Oct 26 2000We present proper motions obtained from a dual frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 GHz and 22 GHz at bi-monthly intervals over 1996. Ten of the eleven sources for which ... More
The TANAMI Program: Southern-Hemisphere AGN on (Sub-)parsec ScalesJan 18 2013The Southern Hemisphere VLBI monitoring program TANAMI provides dual-frequency (8 GHz and 22 GHz), milliarcsecond monitoring of extragalactic jets south of -30 degrees declination. The TANAMI sample consists of a combined radio and gamma-ray selected ... More
A novel approach against E-mail attacks derived from user-awareness based techniquesSep 12 2012A large part of modern day communications are carried out through the medium of E-mails, especially corporate communications. More and more people are using E-mail for personal uses too. Companies also send notifications to their customers in E-mail. ... More
Some characterizations on weighted $αβ$-statistical convergence of fuzzy functions of order $θ$Aug 22 2015Based on the concept of new type of statistical convergence defined by Aktuglu, we have introduced the weighted $\alpha\beta$ - statistical convergence of order $\theta$ in case of fuzzy functions and classified it into pointwise, uniform and equi-statistical ... More
Star formation activity in the Galactic H II region Sh2-297Sep 15 2012We present a multiwavelength study of the Galactic H II region Sh2-297, located in Canis Major OB1 complex. Optical spectroscopic observations are used to constrain the spectral type of ionizing star HD 53623 as B0V. The classical nature of this H II ... More
Investigating source confusion in PMN J1603$-$4904Jan 05 2018PMN J1603$-$4904 is a likely member of the rare class of $\gamma$-ray emitting young radio galaxies. Only one other source, PKS 1718$-$649, has been confirmed so far. These objects, which may transition into larger radio galaxies, are a stepping stone ... More
The disk-outflow system in the S255IR area of high mass star formationJul 20 2015We report the results of our observations of the S255IR area with the SMA at 1.3 mm in the very extended configuration and at 0.8 mm in the compact configuration as well as with the IRAM-30m at 0.8 mm. The best achieved angular resolution is about 0.4 ... More
Star Formation Activity in the Galactic HII Complex S255-S257Jun 09 2011We present results on the star-formation activity of an optically obscured region containing an embedded cluster (S255-IR) and molecular gas between two evolved HII regions S255 and S257. We have studied the complex using optical, near-infrared (NIR) ... More
Structural studies of eight bright rimmed clouds in the southern hemisphereFeb 25 2016We carried out deep and wide-field near- and mid-infrared observations for a sample of 8 bright-rimmed clouds (BRCs). Supplemented with the $Spitzer$ archival data, we have identified and classified 44 to 433 young stellar objects (YSOs) associated with ... More
Development of ultra-thin polyethylene balloons for high altitude research upto mesosphereAug 19 2014Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group ... More
Why Do Compact Active Galactic Nuclei at High Redshift Scintillate Less?Jun 22 2012The fraction of compact active galactic nuclei (AGNs) that exhibit interstellar scintillation (ISS) at radio wavelengths, as well as their scintillation amplitudes, have been found to decrease significantly for sources at redshifts z > 2. This can be ... More
Young Stellar Population of the Bright-Rimmed Clouds BRC 5, BRC 7 and BRC 39Jun 24 2014Bright-rimmed clouds (BRCs), illuminated and shaped by nearby OB stars, are potential sites of recent/ongoing star formation. Here we present an optical and infrared photometric study of three BRCs: BRC 5, BRC 7 and BRC 39 to obtain a census of the young ... More
Young stellar population and ongoing star formation in the HII complex Sh2-252Apr 19 2013In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded ... More
Study of the filamentary infrared dark cloud G192.76+00.10 in the S254-S258 OB complexFeb 22 2018We present results of a high resolution study of the filamentary infrared dark cloud G192.76+00.10 in the S254-S258 OB complex in several molecular species tracing different physical conditions. These include three isotopologues of carbon monoxide (CO), ... More
Angular Broadening of Intraday Variable AGN. II. Interstellar and Intergalactic ScatteringJul 12 2007We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength intraday variability ... More
ATCA monitoring of gamma-ray loud AGNMay 10 2012As a critical part of the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry (TANAMI) program, in November 2007 the Australia Telescope Compact Array (ATCA) started monitoring the radio spectra of a sample of southern hemisphere ... More
Dual-Frequency Observations of 140 Compact, Flat-Spectrum Active Galactic Nuclei for Scintillation-Induced VariabilityJul 12 2011The 4.9 GHz Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey detected a drop in Interstellar Scintillation (ISS) for sources at redshifts z > 2, indicating an apparent increase in angular diameter or a decrease in flux density of the most ... More
Hunting for treasures among the Fermi unassociated sources: a multi-wavelength approachOct 23 2013The Fermi Gamma-ray Space Telescope has been detecting a wealth of sources where the multi-wavelength counterpart is either inconclusive or missing altogether. We present a combination of factors that can be used to identify multi-wavelength counterparts ... More
Young cluster Berkeley 59 : Properties, evolution and star formationNov 26 2017Berkeley 59 is a nearby ($\sim$1 kpc) young cluster associated with the Sh2-171 H{\sc ii} region. We present deep optical observations of the central $\sim$2.5$\times$2.5 pc$^2$ area of the cluster, obtained with the 3.58-m Telescopio Nazionale Galileo. ... More