List of all talks


[43] Topic: Generation, causes and effects of harmonics and surges on electrical/electronic systems

Speaker: Sandeep Upreti
Affiliation: NIT uttarakhand
Date (yyyy-mm-dd): 2015-07-24
Time: 12:00hr
Venue: Auditorium

Abstract: Power line disturbances are the most popular and prominent problems encountered in modern electrical and electronic systems which occurs mainly due to the rapid use of power conditioning modules in our systems. Harmonics and surges are one of the power line disturbances that occur in our electrical/electronic systems.Due to the increasing use of power electronics and decrease in the utility power supply of our electronic equipment.These disturbances degrade the quality of our power supply and thus leads to power quality issues. We have studied the generation ,causes and effects of these disturbances on our electrical/electronic systems and tried to explain various mitigation techniques.


About Speaker: Sandeep is studying electrical engineering in NIT Uttarakhand



[42] Topic: WITRICITY (i.e. Electricity without wire)

Speaker: UMESH PANDEY AND RAJWERDHAN ARYA
Affiliation: B.T.K.I.T. Dwarahat
Date (yyyy-mm-dd): 2015-07-15
Time: 15:30hr
Venue: AUDITORIUM

Abstract: Now a days Witricity is the most attractive, innovative topic of the Research.The transfer of electricity without using any wired connection is termed as Witricity. As most of the electronic devices rely on the chemical storage of battery charged with wired connection. The Witricity technology may become an alternative to power these devices. In our project we have studied about the basic principle of Witricity technology. We have simulated a thin compact planar Witricity device by using ROGER RO3010 substrate with the help of computer simulation technology (CST) microwave studio software.


About Speaker: Pursuing Bachelor of Engineering degree in Electronics and communication from B.T.K.I.T Dwarahat. The speakers has passed thir B.Tech.III year exam and are doing summer training in elecronics section of ARIES.



[41] Topic: Probing The Associated Environment of the BAL Quasar Q0059-2735

Speaker: Pritam J. Borah
Affiliation: Tejput Central University
Date (yyyy-mm-dd): 2014-07-22
Time: 12:30hr
Venue: ARIES Auditorium

Abstract: The outflows up to 30000-40000 km/s velocity offset are generally seen as broad absorption in about 10 percent of QSOs. Study of their physical properties give important insight about the environment of Active Galactic Nuclei. Here we have studied the nature of broad as well as narrow absorption line system at z_abs=1.5811 seen in the spectrum of Q0059-2735 with z_em=1.593. In our analysis we have used its high resolution ($sim 41,000$) data obtained Ultra-Violet Echelle Spectrograph(UVES) mounted on Very Large Telescope (VLT). We adopted Voigt profile decomposition method to compute the column densities of various ions considering the covering factor to be unity. The ratios of various ionic column densities have been used to constrain the photoionization models of the absorbing cloud. Given that Voigt profile decomposition intrinsically assumes unit covering factor, and our result by Inhomogeneous absorption model pretty much fits the observed spectrum,this allows us to approximate that this absorbing cloud responsible for the outflow should have covering factor very close to unity. Later electron density (n_e) has been calculated by using collisionally excited SiII lines and ionization parameter by photoionization modelling of the cloud.


About Speaker: Academy fellow, and INSPIRE fellow at Tejpur University Assam



[40] Topic: Review On Interstellar Grain Alignment

Speaker: RONIK KUMAR
Affiliation: IIT, Roorkee
Date (yyyy-mm-dd): 2014-07-04
Time: 12:30hr
Venue: ARIES Auditorium

Abstract: The work toward theoretical understanding of interstellar grain alignment began just after the discovery of polarization of starlight by Hiltner (Hiltner 1949) and Hall (Hall 1949) nearly half a century ago. Interstellar polarization is known to be caused by elongated dust grains aligned with respect to the Galactic magnetic field. Hence One of the easiest ways to determine the magnetic field direction is via polarization of radiation resulting from extinction on or/and emission by aligned dust grains. How reliable the interpretation of the polarization maps in terms of magnetic fields is the issue that the grain alignment theory addresses. Identifying the dominant grain alignment mechanism has proved to be an intriguing problem in grain dynamics (Lazarian et. al. 1997). The review on progress in the field of grain alignment since the work of David-Greenstein(Davis and Greenstein 1951), basic physical processes involved in grain alignment, and the niches in different alignment mechanisms in general interstellar medium and in dense molecular cloud regions are presented. The chemical composition of dust grains are also discussed in the later part because that determine the many properties of dust by studying the spectral features in the Interstellar extinction curve. Various grain models have been proposed to explain the interstellar extinction curve. Grain models are one of the important factors which determine the validity of different alignment mechanisms.


About Speaker: SUMMER FELLOW, INDIAN ACADEMY OF SCIENCE



[39] Topic: Astrophysical Line driven winds

Speaker: Ms Reetika Joshi
Affiliation: Kumaun University
Date (yyyy-mm-dd): 2014-07-02
Time: 15:30hr
Venue: ARIES Auditorium

Abstract: A subset of Active Galactic Nuclei(AGN) show broad absorption lines (BAL), with line width and velocity relative to AGN as large as few thousands km/s. These BAL are commonly interpreted as high velocity winds from accretion disks. Among many scenario, one possible mechanism of these high velocity winds is due to the line driven radiative acceleration. We have first explored theory of line driven radiative acceleration mechanism and with an aim to apply it to the recent BAL QSOs catalogs. We find a strong correlation of maximum relative velocity offset and BALQSOs luminosity as is expected in the model of radiation driven wind acceleration.


About Speaker: INSPIRE fellow at Kumaun University.



[38] Topic: Proposing a Method for Particle Accelerators

Speaker: Mukesh Kumar Vyas
Affiliation: Research Scholar, Aries
Date (yyyy-mm-dd): 2013-12-12
Time: 15:30hr
Venue: ARIES Auditorium

Abstract: The talk is designed to implement the concept of aberration of light into particle acceleration process. It provides an efficient method to accelerate charged particles up to advanced energy level. In another stage the theoretical treatment of the concept also presents some astrophysical process that can trigger protons up to enormous energy amount and results into cosmic rays.


About Speaker: Research Scholar, ARIES



[37] Topic: Single Scattering Albedo and Radiative Forcing Efficiency over Gangetic-Himalayan Region: The Role of the Particle Size

Speaker: Dr Umesh C Dumka
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-11-08
Time: 15:30hr
Venue: Auitorium

Abstract: We presents the extensive measurements of single scattering albedo (SSA), along with other aerosol parameters over the central Himalayan region. This study focuses on the SSA values and radiative forcing efficiency highlighting the role of the particle size in climate implications.


About Speaker: He is scientist at ARIES in atmospheric science division.



[36] Topic: Spectral variability of X-ray bright Hi-BALQSOs

Speaker: Jhilik Majumdar
Affiliation: Jadavpur University(IAS fellow)
Date (yyyy-mm-dd): 2013-08-22
Time: 12:30hr
Venue: Auditorium

Abstract: Broad Absorption Line Quasars (BALQSOs) enable study of the energetic outflows with velocities up to 0.2-0.3c accompanying the matter accreting to the super-massive black hole. The high absorbing columns in these outflowing winds (10^23 - 10^24 cm-2 ) forces the BALQSOs to be X-ray faint. Due to such reasons, almost all BALQSOs have been discovered by optical surveys, the X-ray properties of BALQSOs remain mostly unknown. However, recently there has been discovery of many X-ray loud BALQSOs, which are found to be very useful to understand their peculiar environments around the central engine, in conjunction to their optical properties such as variability of optical spectral absorption line associated with the quasars itself. Here we have used sample of well selected, 13 X-Ray bright Hi-ionization BALQSOs, having optical to X-ray slope > -1.80, to quantify their variability over 1yr to 10yr time scale. We will present our observation, spectral reductions, along with quantificatin of the percentage variation seen on the CIV and SiIV absorption troughs. Finally possible mechanism, which need further investigation will also be highlighted.


About Speaker: MSc student visiting from Jadavpur University, for her two month summer project under IAS summer fellowship program.



[35] Topic: The ILMT project : optical quality tests and prospective detection of gravitationally lensed QSOs.

Speaker: Dr. Francois Finet
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-08-21
Time: 15:30hr
Venue: Auditorium

Abstract: The International Liquid Mirror Telescope (ILMT) project is a joint collaboration between different universities and research institutes in Belgium, India, Canada and Poland, for the design, construction and operation of a 4 meter telescope at the Devasthal Observatory, that will use the liquid mirror technology. The first part of this talk will introduce the ILMT project, the telescope and its technology particularities, as well as an innovative instrument that has been designed for the measure of its primary mirror optical quality. The ILMT has been designed to perform a photometric variability survey of a narrow strip of sky, making it very suitable for the detection and follow-up of photometrically variable sources such as supernovae and quasars. The second part of the talk will present an estimate of the number of QSOs to be detected within the ILMT survey, and of the expected number of multiply imaged sources among these caused by the presence of a deflector near the lines-of-sight. We will then explain how this statistical sample of multiply imaged QSOs is intended to be used as cosmological probe, and we will therefore introduce a new mathematical approach for the estimate the lensing probabilities, based on the joined probability density of the observed QSOs.


About Speaker: Speaker is Visiting Scientist at ARIES.



[34] Topic: Probing the environment of BALQSO J0318-0600

Speaker: Pritam J. Borah
Affiliation: Tejpur University, Aasam
Date (yyyy-mm-dd): 2013-07-24
Time: 15:30hr
Venue: Auditorium

Abstract: The outflows up to 30000-40000 km/s velocity offset are generally seen as broad absorption in about 10 percent of QSOs. Study of their physical properties give important insight about the environment of Active Galactic Nuclei. Here we studied the nature of broad absorption line system at z_abs=1.9257 seen in the spectrum of J0318-0600 with z_em=1.967. In our analysis we have used its high resolution (R~ 40000) data obtained Ultra-Violet Echelle Spectrograph(UVES) mounted on Very Large Telescope (VLT). We adopted Voigt profile decomposition method to compute the column densities of various ions, in contrast to the power law method used in the literature. The ratios of various ions column densities have been used to constrain the photoionization models of the absorbing cloud. Further assuming a reasonable piece-wise power law spectral energy distribution we have estimated the distance of the absorbing cloud from the central engine to be around 6.5 kpc which is very close to the distance estimate obtained using pure power law column density distribution. Given that (i) Voigt profile decomposition intrinsically assumes unit covering factor, and (ii) our result matches with that obtained in literature using power law column density distribution, allow us to conclude that this absorbing cloud responsible for the outflow should have covering factor very close to unity.


About Speaker: Mr. Pritam J. Borah, is summer project student sponsored by India Science academies fellowship program. He is at present affiliate for his integrated MSc at Tejpur University Assam



[33] Topic: Study of Single Scattering Albedo over Central Himalayas

Speaker: Mr Chanchal Soni
Affiliation: IISc
Date (yyyy-mm-dd): 2013-07-24
Time: 11:30hr
Venue: ARIES Auditorium

Abstract: Single scattering albedo is one of the most important parameter in aerosol radiative forcing estimation. The exact knowledge of SSA is crucial and even small error in SSA can change the sign of aerosol radiative forcing.


About Speaker: He is pursuing two months summer project.



[32] Topic: Multi- Wavelength study of NGC 1931

Speaker: Abhijeet Anand
Affiliation: IISC Bangalore
Date (yyyy-mm-dd): 2013-07-23
Time: 15:30hr
Venue: Auditorium

Abstract: .


About Speaker: .



[31] Topic: Study of Single Scattering Albedo over Central Himalayas

Speaker: Mr Chanchal Soni
Affiliation: IISc
Date (yyyy-mm-dd): 2013-07-23
Time: 15:30hr
Venue: ARIES Lecture Hall

Abstract: Single scattering albedo is one of the most important parameter in aerosol radiative forcing estimation. The exact knowledge of SSA is crucial and even small error in SSA can change the sign of aerosol radiative forcing.


About Speaker: He is pursuing two month summer project.



[30] Topic: Study of a Super-flare, On the RS CVn Binary II PEG

Speaker: Ansul Kapoor
Affiliation: Project Student
Date (yyyy-mm-dd): 2013-07-15
Time: 15:30hr
Venue: New Lecture Room

Abstract: II Peg (HD 224085) is a well known 7.37 mag bright active binary system that displays evidence for star-spots covering a large fraction of the primary photosphere, and has signatures associated with vigorous magnetic activity across the entire electromagnetic spectrum. At a distance of 42 pc, this single lined spectroscopic binary is composed of a 0.8Mo (K2 IV) primary tidally locked in a 6.7 day orbit with a 0.4Mo secondary. On Dec. 16, 2005 a super-flare was observed in the primary sub-giant of this system. The strength of the flare was around 105 times an ordinary flare. The talk will focus on the various aspects of flares in general and primarily of this flare of 2005.


About Speaker: NASI Summer fellow



[29] Topic: The unprecedented 2012 outburst of SN 2009ip

Speaker: Kuntal Misra
Affiliation: ARIES, Nainital
Date (yyyy-mm-dd): 2013-07-10
Time: 15:30hr
Venue: Auditorium

Abstract: I will discuss the comprehensive campaigns that were undertaken by several groups to study the remarkable re-brightening(s) in SN 2009ip.


About Speaker: Scientist C



[28] Topic: Study of Black Carbon Over Dehradun

Speaker: Shreyash Srivastava
Affiliation: D.U
Date (yyyy-mm-dd): 2013-07-05
Time: 12:00hr
Venue: Lecture Room

Abstract: Temporal and diurnal variation of Black carbon is studied over Dehradun during the year 2009. Black carbon over Dehradun is also compared with high altitude site (i.e Nainital).


About Speaker: He is a pursuing one month summer project under Summer Training Program



[27] Topic: Various methods for distance measurement of extra-galactic objects

Speaker: Parth Shah
Affiliation: NIT, Surat
Date (yyyy-mm-dd): 2013-07-03
Time: 12:15hr
Venue: Auditorium

Abstract: The study has been made for measuring distances to extra galactic objects using various methods such as Parallax, Cepheid Variables, Type Ia Supernovae, Tully Fisher relation and Faber Jackson relation.


About Speaker: He is doing Integrated M.Sc. from NIT, Surat, Gujarat.



[26] Topic: Practical Telescope Optics and CCD detectors for astronomical observing

Speaker: Neha Gupta
Affiliation: Banasthali Vidyapeeth
Date (yyyy-mm-dd): 2013-06-27
Time: 15:30hr
Venue: Auditorium

Abstract: A study has been made regarding practical observational methods with 104 cm telescope at ARIES and associated CCD detector(s) being used in instruments at the Cassegrain focal plane. The same is complemented with principles and techniques of astronomical Telescope Optics, relevant to the above subject.


About Speaker: Neha Gupta is a 2nd year B Sc student at Banasthali Vidyapeeth, Rajasthan. She did a two year certificate course from ISRO and earned a gold medal in national mathematics olympiad contest, held by all India schools mathematics teachers association with state rank one. She is a summer project student at ARIES from 16 May 2013 to 30 June 2013.



[25] Topic: Display of IST, UT, LST and study of serial communication topology for hardware interface on PC using visual basic software.

Speaker: Vaibhav Savant
Affiliation: University of Pune
Date (yyyy-mm-dd): 2013-06-27
Time: 16:00hr
Venue: Auditorium

Abstract: Generate and display of time in different usable formates like IST, UT, LST is a part of up-gradation of the 104cm Sampurnanand Telescope s display system project. Existing display mechanism for 104cm ST shows RA, DEC, hour angle and LST in analog format. Conversion of this analog display to PC based digital display will perform better reading accuracy.


About Speaker: Master in Instrumentation



[24] Topic: Troposheric ozone: Variabilities in rural and cleaner sites

Speaker: A Vinod Kumar
Affiliation: Academies Project Student
Date (yyyy-mm-dd): 2013-06-27
Time: 12:00hr
Venue: ARIES Auditorium

Abstract: Presentation will be made on surface ozone observations at a rural site in central Indian and high altitude site in the central Himalayas.


About Speaker: He is a pursuing 2 months summer project under Summer Research Academies Fellowship Program



[23] Topic: Vertical profile of Temperature at Nainital from Space born sensor (AIRS) : A comparison with balloon born sensor

Speaker: Sayana Sai Brahmani
Affiliation: Academies Project Student
Date (yyyy-mm-dd): 2013-06-27
Time: 12:30hr
Venue: ARIES Auditorium

Abstract: Vertical distribution of the temperature is studied over Nainital using data from a Space-borne sensor (AIRS). These data are also compared with the radiosonde data.


About Speaker: She is a pursuing 2 months summer project under Summer Research Academies Fellowship Program.



[22] Topic: Discovery of a new class of hydrogen-rich supernovae from Indian optical telescopes

Speaker: Dr. Brijesh Kumar
Affiliation: ARIES, Nainital
Date (yyyy-mm-dd): 2013-06-26
Time: 15:30hr
Venue: Auditorium

Abstract: We use optical photometric and spectroscopic data from 1-2m class telescopes in India to discover a new class of hydrogen-rich supernovae. An overview of this scientific discovery and its physical significance will be described.


About Speaker: Scientist E



[21] Topic: Near-infrared polarimetric studies of star-forming regions.

Speaker: C. Eswaraiah
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-06-24
Time: 15:30hr
Venue: Audotorium

Abstract: I will present few important results based on NIR-polarimetric observations of few star-forming regions by the Japanese group. The discussion will mainly be focused on the dust properties and importance of magnetic fields in cloud and star-formation processes.


About Speaker: Speaker is PDF at ARIES working on star formation.



[20] Topic: X-Ray study of 3C273 with XMM-Newton

Speaker: Ms. Nibedita Kalita
Affiliation: Research Scholar
Date (yyyy-mm-dd): 2013-06-24
Time: 16:30hr
Venue: Audotorium

Abstract: I will present my work, search for variability and QPO in the quasar 3C273 with the help of XMM-Newton satellite.


About Speaker: Speaker is Ph.D Scholar in Dept. of physics , Gauhati University, Assam.



[19] Topic: Overview of black carbon studies: Indian perspective

Speaker: Hema Joshi
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-06-21
Time: 15:30hr
Venue: Auitorium

Abstract: Overview of black carbon studies: Indian perspective


About Speaker: Research Fellow at ARIES



[18] Topic: Weather Research and Forecasting Model with Chemistry (WRF-Chem) over South Asia

Speaker: Mr Narendra Ojha
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-06-14
Time: 15:30hr
Venue: Auditorium

Abstract: Weather Research and Forecasting Model with Chemistry (WRF-Chem) over South Asia


About Speaker: Researh Fellow at ARIES



[17] Topic: Central Engine of AGN

Speaker: Jai Bhagwan
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-06-12
Time: 15:30hr
Venue: Auditorium

Abstract: Very soon after the interpretation of 3C273 as a cosmologically redshifted object astrophysicists faced the dilemma of explaining its remarkable energetic output. The observed variability time scales limited its size to dimension of order light days. Thus, given that its inferred luminosity L~ 10^47 erg/sec is approximately one million times that of our own galaxy, it was immediately clear that some mechanism other than a dense conglomeration of stars had to be involved. The idea of the central massive object and accretion-powered radiation quickly emerged, primarily due to lack of any other tangible explanation. Hoyle and Fowler (1963) put forth the general concept considering scenarios where a hyperstar accreted from its ambient medium. More detailed models soon followed : Salpeter (1964), ZelDovich (1964), Lynden-Bell (1969). Estimates of AGN black hole masses from several independent methods are now available in the published literature and I will be discuss those results and their implication in this talk.


About Speaker: Research scholar at ARIES



[16] Topic: Weak emission lines quasars

Speaker: Dr. H. Chand
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-05-29
Time: 15:30hr
Venue: Auditorium

Abstract: The broad and strong emission line are the benchmark of bona-fied quasars. With the recent large survey such as SDSS many quasars having very weak emission lines has also been discovered. I shell sumarise the main features of such weak emission line quasars, along with the existing open questions about their nature.


About Speaker: Scientist at ARIES







[15] Topic: Radio-Far infrared correlation in dwarf galaxies

Speaker: Dr. Amitesh Omar
Affiliation: ARIES
Date (yyyy-mm-dd): 2013-05-15
Time: 15:30hr
Venue: Auditorium

Abstract: I will present an overview of much discussed very tight radio far infrared correlation in galaxies. The dwarf and low surface brightness galaxies reveal some evidences that radio-FIR correlation and its tightness in galaxies is a conspiracy. The new results and future prospects in the context of Wolf-Rayet galaxies studied by us will be presented.


About Speaker: Scientist at ARIES