Astronomy & Astrophysics Division
Physical Research Laboratory
Ahmedabad - 380 009
INDIA.


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Janardhan Padmanabhan


Janardhan Padmanabhan



Phone:   (+91) 79 2631 4505, 4610 (O);
              (+91) 79 2686 0261 (R);

e-mail :    jerry AT prl.res.in 


Summary of Research Interests:

Solar Wind and Solar Radio Studies at Meterwavelengths:

My current research interests are centered around studies of the Solar Wind and Space Physics with emphasis on "Space Weather" studies using observations of Interplanetary Scintillation (IPS). In recent times, I have been actively persuing Solar Radio Astronomical studies via meter wavelength solar imaging observations carried out mainly using the Giant Meterwave Radiotelescope (GMRT) facility at NCRA,TIFR, Pune.

Further details on the topics bulletted below cane be obtained fron the "Research Interests" link in the left hand column at the top of this page.

<sun>   IPS studies of the Solar Wind and Interplanetary Medium

<sun>   IPS studies of the Solar Wind at High Latitudes.

<sun>   VLA Imaging of Solar Flares and Compact Radio Sources.

<sun>   Solar Imaging Observations with the Giant Meterwave Radio Telescope (GMRT).

<sun>   IPS studies of Interstellar Scattering.

<sun>   IPS and Emission Line studies of Cometary Ion Tails and Coma.

<sun>   Very Long Baseline Interferometric (VLBI) Studies at 327 MHz.

<sun>   Studies of H-alpha Emission Line profiles of Be Stars.



Future Plans:


Recent work on combining visibilities obtained from the GMRT and the Nancay Radio Heliograph in France have yielded solar images with extraordinary dynamic range. This method therefore provides one the possibility of studying faint features that occur along with bright energetic phenomena on the solar disk like flares and CME's and is being actively followed up. Future possibilities for a space based payload for space weather and coronal studies is being looked into.

Selected Publications:


Some selected publications are listed below. Publications from years 2010 onwards can be accessed via the "Recent Publications" link in the left hand column at the top of this page and similarly, a complete list of publications in refereed journals including IAU circulars published can be accessed via the "All Publications" link at the top of the page.

  1. Travelling Interplanetary Disturbances Detected Using Interplanetary Scintillation at 327 MHz.
    Janardhan, P., Balasubramanian, V., Ananthakrishnan, S., Dryer, M., Bhatnagar, A. and McIntosh, P.S. (1996). Sol. Phys., 166, 379.

  2. K-Band Detection of Ammonia and (Possibly) Water in Comet Hale-Bopp.
    Bird, M. K., Janardhan, P., Wilson, T. L., Huchtmeier, W., Gensheimer, P., and Lemme, C. (1997). Earth Moon and Planets, 78, 21.

  3. Coronal Velocity Measurements with Ulysses: Multi-link Correlation Studies During two Superior Conjunctions.
    Janardhan, P., Bird, M K., Edenhofer, P, Plettemeier, D., Wohlmuth, R., Asmar, S W., Patzölt, M. and Karl, J. (1999). Sol. Phys.,184, 157.

  4. Radio Detection of a Rapid Disturbance Launched by a Solar Flare.
    White, S.M., Janardhan, P . and Kundu, M.R. (2000). ApJL., 533, L167.

  5. Giant Meter Wave Radio telescope Observations of an M2.8 Flare: Insights into the Initiation of a Flare-Coronal Mass Ejection Event.
    Prasad Subramanian, Ananthakrishnan, S., Janardhan, P. , Kundu, M.R., White, S.M., Garaimov, V.I. (2003). Sol. Phys. 218, 247-259.

  6. Combining Visibilities from the Giant Meterwave Radio Telescope and the Nancay Radio Heliograph.
    Mercier, C., Prasad Subramanian, Kerdraon, A., Pick, M., Ananthakrishnan, S. and Janardhan, P. (2006). A&A. 447,1189-1201.

  7. The Solar Wind Disappearance Event of 11 May 1999: Source Region Evolution.
    Janardhan, P. , Tripathi, D., and Mason, H. (2008). A&A Lett.  488, L1−L4.

  8. Solar Polar Fields During Cycles 21 - 23: Correlation with Meridional Flows.
    Janardhan, P., Susanta Kumar Bisoi and Gosain, S., (2010) Sol. Phys. 267, 267−277.

  9. Unique Observations of Geomagnetic SI+ - SI- pair and Solar Wind Fluctuations.
    Rastogi, R.G., Janardhan, P., Ahmed, K., Das, A.C. and Susanta Kumar Bisoi (2010) Jou. Geophys. Res. 115, A12110, doi:10.1029/2010JA015708.

  10. The Prelude to the Deep Minimum between Solar Cycles 23 and 24: Interplanetary Scintillation Signatures in the Inner Heliosphere
    Janardhan, P., Susanta Kumar Bisoi, Ananthakrishnan, S., Tokumaru, M., Fujiki, K., (2011) Geophys. Res. Lett.38,  L20108, doi:10.1029/2011GL049227.

  11. Deep GMRT 150 MHz observations of the DEEP2 fields: Searching for High Red-shift Radio Galaxies Revisited
    Susanta Kumar Bisoi., Ishwara-Chandra, C.H., Sirothia, S.K., and Janardhan, P. (2011).  Jou. Astrophys. Astr. 32, 613−614.  DOI: 10.1007/s12036-011-9116-2.

  12. Near-Infrared Monitoring and Modelling of V1647 Ori in its On-going 2008-12 Outburst Phase
    Venkata Raman, V., Anandarao, B.G., Janardhan, P. and Pandey, R.  (2013).  Res. Astron. Astrophys. 13, No. 9, 1107−1117. 

  13. Changes in quasi-periodic variations of solar photospheric fields: precursor to the deep solar minimum in the cycle 23?
    Susanta Kumar Bisoi, Janardhan,P., Chakrabarty, D., Ananthakrishnan, S. and Divekar,A. (2014).  Sol. Phys.  289,41−61, DOI: 10.1007/s11207-013-0335-3.

  14. Determination of mass and orbital parameters of a low-mass star HD 213597B/font>
    Priyanka Chaturvedi1, Rohit Deshpande, Vaibhav Dixit, Arpita Roy Abhijit Chakraborty, Suvrath Mahadevan, B.G. Anandarao, Leslie Hebb and P. Janardhan (2014).  MNRAS  442,3737−3744, DOI: 10.1093/mnras/stul127.

  15. Spread-F during the magnetic storm of 22 January 2004 at low latitudes: Effect of IMF-Bz in relation to local sunset time
    Rastogi,R.G., Chandra, H., Janardhan,P., Thai Lan Hoang, Louis Condori, Pant, T.K., Prasad, D.S.V.V.D. and Reinish, B.W. (2014).   Jou. Earth System Sci.  1231273−1285. 

  16. A study of density modulation index in the inner solar wind during solar cycle 23
    Susanta Kumar Bisoi, P. Janardhan, M. Ingale and P. Subramanian, and S. Ananthakrishnan  (2014).  Atrophysical Journal   [In Press]