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Browsing IIAP Publications by Title

Browsing IIAP Publications by Title

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  • The optical emission line variability in T CrB: Based on ten years data from the Vainu Bappu Observatory 
    Anupama, G. C (Copernicus Foundation for Polish Astronomy, 1997)
  • Optical flux and colour variability of blazars in the ZTF survey 
    Negi, Vibhore; Joshi, Ravi; Chand, Krishan; Chand, Hum; Wiita, Paul; Ho, Luis C; Singh, Ravi S (Oxford University Press on behalf of Royal Astronomical Society, 2022-02)
    We investigate the temporal and colour variability of 897 blazars, comprising 455 BL Lacertae objects (BL Lacs) and 442 Flat Spectrum Radio Quasars (FSRQs), selected from the Roma-BZCAT catalogue, using the multiband light ...
  • Optical flux and spectral characterization of the blazar PG 1553 + 113 based on the past 15 years of data 
    Agarwal, Aditi; Mihov, B; Andruchow, I; Cellone, Sergio A; Anupama, G. C; Agrawal, V; Zola, S; Ergun Ege; Özdönmez, Aykut; Ege, Ergün (Indian Academy of Sciences, 2022-06)
    We study flux and spectral variability of the high energy peaked TeV blazar PG 1553 + 113 on diverse timescales using the data collected from 2005 to 2019 which also includes the intensive intra-night monitoring of the ...
  • Optical frequency standard with Sr+: a theoretical many-body approach 
    Sur, S; Latha, K. V. P; Chaudhuri, R. K; Das, B. P; Mukherjee, D (World Scientific Publishing Co, 2007)
    Demands from several areas of science and technology have lead to a worldwide search for accurate optical clocks with an uncertainty of 1 part in $10^{18}$, which is $10^{3}$ times more accurate than the present day cesium ...
  • Optical glass: its manufacture in India — a historical perspective 
    Saxena, A. K; Vagiswari, A; Manjula, M (Indian National Science Academy, 1991)
    A historical perspective of optical glass industry in India has been presented in this paper. In this introduction a clear definition and understanding of optical glass is given. This is followed by world perspective. The ...
  • Optical identification of XMM sources in the Canada-France-Hawaii telescope legacy survey 
    Stalin, C. S; Petitjean, P; Srianand, R; Fox, A. J; Coppolani, F; Schwope, A (Blackwell Publishing, 2010-01)
    We present optical spectroscopic identifications of X-ray sources in similar to 3 deg2 of the XMM-Large Scale Structure survey (XMM-LSS), also covered by the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS), obtained ...
  • Optical interferometer measurements of thermospheric temperature at Kavalur (12.5 deg N, 78.5 deg E), India 
    Sastri, J. H; Rao, H. N. R (Elsevier, 1994-02)
    First results on the behavior of thermospheric temperature over Kavalur (12.5 deg N, 78.5 deg E geographic; 2.8 deg N geomagnetic latitude) located close to the geomagnetic equator in the Indian zone are presented. The ...
  • Optical interferometric observations of a transient event of 1986 March 13 in the coma of Comet Halley 
    Prasad, D. C; Chandrasekhar, T; Desai, J. N; Ashok, N. M; Krishan, V (Indian Academy of Sciences, 1989-03)
    During the recent apparition of Comet Halley in 1985-86, a transient ionic event in the form of a blob of H2O(+) emission was recorded in the coma at about 0 h UT on March 13, 1986. Observations were carried out using a ...
  • Optical limiting in bacteriorhodopsin using a four-state model for two-beam illumination 
    Jagadish, C. S; Prashant, S. T; Prasad, B. R; Venkataramaniah, K; Sivasankara Sai, S (Department of Applied Optics and photonics, University of Calcutta, 2009)
    In this paper we have discussed a four state model in bacteriorhodopsin (bR) for two beam illumination. The paper presents simulation studies showing the change in the population levels of the various states in the bR ...
  • Optical linear polarization in ultra cool dwarfs: A tool to probe dust in the ultra cool dwarf atmospheres 
    Tata, R; Martin, E. L; Sengupta, S; Phan-Bao, N; Zapatero Osorio, M. R; Bouy, H (European Space Agency, 2009-12)
    Aims.Recent studies have detected linear polarization in L dwarfs in the optical I band. Theoretical models have been developed to explain this polarization. These models predict higher polarization at shorter wavelengths. ...
  • Optical metrology on primary mirror of visible emission line coronagraph on board Aditya-L1 mission 
    Venkata Suresh, Narra; Singh, Darshika; Venkatasubramanian, N; Budhiraju, Vishweshwar Rao; Hegde, Bhavana; Bhat, Nishchith; Utkarsha, D; Somasundaram, P. K; Ramaswamy, Venkateswaran; Kamath, P. U; Sriram, Kuppuswamy Venkatesan; Prasad, B. R (SPIE-Society of Photo-Optical Instrumentation Engineers, 2022-10)
    The visible emission line coronagraph (VELC) on board the Aditya-L1 mission is an internally occulted reflective coronagraph. It is capable of simultaneous observations of the solar corona in imaging, spectroscopic, and ...
  • Optical microvariability in radio quiet quasars 
    Wiita, P. J; Gopal-Krishna; Sagar, R (Kluwer Academic Publishers, 1994)
    We have observed 11 radio quiet QSOs (RQQSOs) to see if they exhibit intranight variability in the optical. The detection of such microvariability would support models in which flutuations on accretion disks are dominant, ...
  • Optical Microvariability of Blazars 
    Ghosh, K. K; Kim, C; Ramsey, B. D; Soundararajaperumal, S (Korean Astronomical Society, 2001-04)
    We present the results of optical differential photometry of five blazars [PKS 0219+428(3C66A), PKS 0235+164(AO 0235+16), H0414+019, PKS 0851+202(OJ 287), and QSO 1807+698(3C371)] that were observed on 7 nights between ...
  • Optical Nuclei of Radio-loud AGN and the Fanaroof-Riley Divide 
    Kharb, P; Shastri, P (EDP Sciences, 2004-10)
    We investigate the nature of the point-like optical nuclei that have been found in the centres of the host galaxies of a majority of radio galaxies by the Hubble Space Telescope. We examine the evidence that these optical ...
  • Optical observational programs at the Indian Institute of Astrophysics 
    Singh, J; Ravindra, B (Astronomical Society of India, 2011)
    The Indian Institute of Astrophysics has been making optical observations of the sun for more than a century by taking images of the sun in continuum to study the photosphere, Ca-K line and H-alpha line in order to study ...
  • Optical observations and dust modelling of comet 156P/Russell-LINEAR 
    Aravind, K; Halder, Prithish; Ganesh, Shashikiran; Sahu, D. K; Serra-Ricart, Miquel; Chambo, Jose J; Angchuk, D; Sivarani, T (Elsevier B.V., 2022-09-01)
    Comet 156P/Russell-LINEAR is a short period Jupiter family comet with an orbital period of 6.44 years. The results from spectroscopic, photometric, polarimetric observations and dust modelling studies are presented here. ...
  • Optical observations of GRB 060124 afterglow: a case for an injection break 
    Misra, K; Bhattacharya, D; Sahu, D. K; Sagar, R; Anupama, G. C; Castro-Tirado, A. J; Guziy, S. S; Bhatt, B. C (EDP Sciences, 2007-03)
    Aims.We present broad band optical afterglow observations of a long duration GRB 060124 using the 1.04-m Sampurnanand Telescope at ARIES, Nainital and the 2.01-m HCT at IAO, Hanle, including the earliest ground-based ...
  • Optical observations of star clusters NGC 1513 and NGC 4147; white dwarf WD 1145þ017 and K band imaging of star-forming region Sh 2-61 with the 3.6-m Devasthal optical telescope 
    Sagar, R; Yadav, R. K. S; Pandey, S. B; Sharma, Saurabh; Lata, Sneh; Joshi, Santosh (Indian Academy of Sciences, 2022-06)
    The UBVRI CCD photometric data of open star cluster NGC 1513 are obtained with the 3.6-m Indo-Belgian Devasthal optical telescope (DOT). Analyses of the GAIA EDR3 astrometric data have identified 106 possible cluster ...
  • Optical observations of supernova 2012aw 
    Bose, S; Kumar, B; Sutaria, F. K; Roy, Rupak; Kumar, B; Bhatt, V. K; Chakraborti, S (Cambridge University Press, 2014-01)
    We present optical UBVRI photometric and low-resolution spectroscopic follow-up observations of a type II SN 2012aw in a nearby (~10 Mpc) galaxy M95 during 4 to 270 days post-explosion. The evolution characteristics of ...
  • Optical observations of the fast declining Type Ib supernova iPTF13bvn 
    Srivastav, S; Anupama, G. C; Sahu, D. K (Oxford University Press on behalf of the Royal Astronomical Society, 2014-12-01)
    We present optical UBVRI photometry and medium resolution spectroscopy of the Type Ib supernova iPTF13bvn, spanning a phase of ∼−13 d to +71 d with respect to B-band maximum. The post-maximum decline rates indicate a fast ...

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