Janardhan Padmanabhan                                                                              
Astronomy & Astrophysics Division
Ahmedabad - 380 009
INDIA

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<aurora>

A display of the "Northern Lights" or Aurora Borealis.

























<Thaltej-Dipole-Array>

A view of the 20,000 m2 dipole array at Thaltej, Ahmedabad, that was operated by PRL and used for IPS observations of the solar wind at 103 MHz.

Click on the picture for a full size image of the array.
 
 

<elec-button>  Research Publications (1989  − Present):



    1989−1990:



  1. Quasar Enhanced.
    Alurkar, S.K., Sharma, A.K., Janardhan, P ., and Bhonsle, R.V. (1989). Nature , 338, 211−212.

  2. Three-Site Solar Wind Observatory.
    Alurkar, S.K.,Bobra, A.D., Nirman, N.S., Venat, P., and Janardhan, P. (1989). Ind. Jou. Pure and Appl. Phys., 27, 322−330.

  3. Interplanetary Scintillation Network for 3-Dimensional Space Exploration in India.
    Bhonsle, R.V., Alurkar, S.K., Bobra, A.D., Lali, K.S., Nirman, N.S., Venat, P., Sharma, A.K. and Janardhan, P. (1990). Acta Astronautica, 21, No. 3, 189−196.



    1991 - 1995:



  4. Estimation of electron density in the ion-tail of comet Halley using 103 MHz IPS observations.
    Sharma, A. K., Alurkar, S. K. and Janardhan, P. (1991). Bull. Astr. Soc. India, 19, 82.

  5. Enhanced scintillation of radio source 2204+29 by comet Austin (1989c1) at 103 MHz.
    Janardhan, P., Alurkar, S. K., Bobra, A. D., Slee, O. B. (1991). Bull. Astr. Soc. India, 19, 204.

  6. Enhanced Radio Source Scintillation Due to Comet Austin(1989 c1).
    Janardhan, P., Alurkar, S.K.,Bobra, A.D. and Slee, O.B. (1991). Aus. Jou. Phys., 44, 565−571.

  7. Power Spectral Analysis of Enhanced Scintillation of Quasar 3C459 Due to Comet Halley.
    Janardhan, P., Alurkar, S.K.,Bobra, A.D., Slee, O.B. and Waldron, D. (1992). Aust. J. of Phys., 45, No. 1, 115.

  8. Possible Contribution of a Solar Transient to Enhanced Scintillation Due to a Quasar.
    Janardhan, P. and Alurkar, S.K. (1992). Earth, Moon, and Planets, 58, 31−38.

  9. Comparison of Single-Site Interplanetary Scintillation Solar Wind Speed Structure With Coronal Features.
    Alurkar, S.K., Janardhan, P. and Vats, H.O. (1993). Sol. Phys., 144, No.2, 385−397.

  10. Angular Source Size Measurements and Interstellar Scattering at 103 MHz Using Interplanetary Scintillation.
    Janardhan, P. and Alurkar, S.K. (1993). Astronomy & Astrophys ., 269, 119−127.

  11. Measurements of Compact Radio Source Size and Structure of Cometary Ion Tails Using Interplanetary Scintillation at 103 MHz.
    Janardhan, P. (1993). Bull. Astr. Soc. India, 21, 381.

  12. IPS Survey at 327 MHz for Detection of Compact Radio Sources.
    Balasubramanian, V., Janardhan, P ., Ananthakrishnan, S., and Manoharan, P.K. (1993). Bull. Astr. Soc. India, 21, 469−471.

  13. Observations of PSR 0950+08 at 103 MHz.
    Deshpande, M.R., Vats, H.O., Janardhan, P ., and Bobra, A.D. (1993). Bull. Astr. Soc. India, 21, 613−614.

  14. Terrestrial Effects of PSR 0950+08.
    Vats, H.O., Deshpande, M.R., Janardhan, P ., Harish, C., and Vyas, G.D. (1993). Bull. Astr. Soc. India , 21, 615−617.

  15. Radio and X-ray burst from PSR 0950+08.
    Deshpande, M.R., Vats, H.O., Chandra Harish, Janardhan, P., Bobra, A.D. and, Vyas, G.D. (1994). Astrophys. Space Sci., 218, No.2, 249−265.

  16. Latitudinal Variation of Solar Wind Velocity.
    Ananthakrishnan, S., Balasubramanian, V., and Janardhan, P. (1995). Space Sci. Rev ., 72, 229−232.

  17. A 327-MHZ Interplanetary Scintillation Survey Of Radio Sources Over 6-Steradian.
    Balasubramanian, V., Janardhan, P . and Ananthakrishnan, S. (1995). Jou. Astrophys. & Astron., 16, 298.

  18. Unique Observations of PSR 0950+08 and Possible Terrestrial Effects.
    M.R. Deshpande, H.O. Vats, P. Janardhan, A.D. Bobra, Harish Chandra, and G.D.Vyas. (1995). Jou. Astrophys. & Astron ., 16, 253.



    1996 - 2000:



  19. Simultaneous Observations of Large Enhancement In the Flux of PSR 0950+08 Over a 200 KM Baseline at 103 MHz.
    Bobra, A. D., Chandra, H., Vats, H. O., Janardhan, P., Vyas, G. D., Deshpande, M. R., (1996). Proc. of the 160th IAU Colloquium− ASP Conf. Series.,  pp. 477−448.
    Eds.  S. Johnston, M.A. Walker and M. Bailes.

  20. On the Nature of Compact Components of Radio Sources at 327 MHz.
    Balasubramanian, V., Janardhan, P., Ananthakrishnan, S. and Srivatsan, R. (1996). Bull. Astr. Soc. India, 24, 829.

  21. IPS Observations of the Solar Wind at 327 MHz - A Comparison with Ulysses Observations.
    Janardhan, P ., Balasubramanian, V., Ananthakrishnan, S. and Srivatsan, R. (1996). Bull. Astr. Soc. India , 24, 645.

  22. 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, 379−401.

  23. Tracking Interplanetary Disturbances Using Interplanetary Scintillation.
    Janardhan, P., Balasubramanian, V. and Ananthakrishnan, S. (1997). Proc. 31st. ESLAB Symp., ESA SP−415 , pp. 177−181.

  24. Radio Detection of Ammonia in Comet Hale−Bopp.
    Bird, M. K., Huchtmeier, W., Gensheimer, P., Wilson, T. L., Janardhan, P. and Lemme, C. (1997). A&A Lett., 325, L5−L8.

  25. Ammonia in Comet Hale-Bopp.
    Wilson, T. L., Huchtmeier, W. K., Bird, M. K., Janardhan, P., Gensheimer, P. and Lemme, C., (1997). Bulletin of the American Astronomical Soc., 29, 1259.

  26. Detection and Tracking of IPS Disturbances Using Interplanetary Scintillation.
    Balasubramanian, V., Srivatsan, R., Janardhan, P., and Ananthakrishnan, S. (1998). Bull. Astr. Soc. India, 26, 225−229.

  27. Radio Observations of Transient Solar Wind Flows.
    Balasubramanian, V., Janardhan, P., Srivatsan, R. and Ananthakrishnan, S. (1998). Proc. of the 3rd. SOLTIP Symposium, pp. 319.
    Eds.  Feng, X.S., Wei, F.S., and Dryer, M.

  28. 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, 157−172.

  29. 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, 21−28.

  30. Study of Solar Wind Transients Using IPS.
    Ananthakrishnan, S., Kojima, M., Tokumaru, M., Balasubramanian, V., Janardhan, P., Manoharan, P.K., and Dryer, M. (1999). Proc. of Solar Wind 9 Conference, AIP, New York. pp 321.
    Eds.  S. R. Habbal

  31. Anisotropic Structure of the Solar Wind in its Region of Acceleration.
    Efimov, A.I., Rudash, V.K., Bird, M.K., Janardhan, P., Patzölt, M., Karl, J., Edenhofer, P. and Wohlmuth, R. (2000). Advances in Space Res., 26, 785−788.

  32. Radio Detection of a Rapid Disturbance Launched by a Solar Flare.
    White, S.M., Janardhan, P. and Kundu, M.R. (2000). ApJ Lett., 533 , L167−L170.

  33. Observations of Interplanetary Scintillation During the 1998 Whole Sun Month: A Comparison between EISCAT, ORT and Nagoya Data.
    Moran, P.J., Breen, A.R., Canals, A., Markkanen, J., Janardhan, P., Tokumaru, M. and Williams, P.J.S. (2000). Annales Geophysica, 18, 1003.

  34. H−alpha Observations of Be Stars.
    Banerjee, D.P.K., Rawat, S.D. and Janardhan, P. (2000). A&A Suppl., 147, 229.



    2001 − 2005:



  35. Near Infra−red and Optical Spectroscopy of Delta Scorpii.
    Banerjee, D.P.K., Janardhan, P. and Ashok, N.M. (2001). A&A Lett., 380, L13.

  36. Flow Sources and Formation Laws of Solar Wind Streams.
    Lotova, N.A., Obridko, V.N., Vladimirskii, K.V., Bird, M.K. and Janardhan, P. (2002). Sol. Phys., 205, 149.

  37. Fine Structure of the Solar Wind Turbulence Inferred from Simultaneous Radio Occultation Observations at Widely−Spaced Ground Stations.
    Bird, M.K., Janardhan, P., Efimov, A.I., Samoznaev, L.N., Andreev, V.E., Chashei, I.V., Edenhofer, P., Plettemeier, D., and Wohlmuth, R. (2003). Solar Wind 10, AIP Conf. Proc. 679, 465−468. AIP Press, Melville, New York, USA.
    Eds.  M. Velli et al.

  38. IPS Observations of the Solar Wind Disappearance Event of May 1999.
    Balasubramanian, V., Janardhan, P., Srinivasan, S., and Ananthakrishnan, S. (2003). Jou. Geophys. Res. 108, A3, 1121.

  39. 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.

  40. The Solar Wind and Interplanetary Disturbances.
    Janardhan, P., (2003). Solar Terrestrial Environment  − Space Weather, Allied Publishers, New Delhi., pp. 42−56.
    Eds.     R.P.Singh, Rajesh Singh & Ashok Kumar, Banaras Hindu University, Varanasi, India.
    ISBN:  81−7764−494−7.

  41. Radio Observations of Rapid Acceleration in a Slow Filament Eruption/Fast CME Event.
    Kundu, M.R., Garaimov, V.I., White, S.M., Manoharan, P.K., Subramanian, S., Ananthakrishnan, S., and Janardhan, P. (2004). Ap J. 607, 530−539.

  42. Resolving the Enigmatic Solar Wind Disappearance Event of 11 May 1999.
    Janardhan, P. , Fujiki, K., Kojima, M., Tokumaru, M., and Hakamada, K. (2005). Jou. Geophys. Res.110, A08101.



    2006 − 2010:



  43. 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.

  44. The Morphology of Decimetric Emission from Solar Flares: GMRT Observations.
    Kundu, M.R., White, S.M., Garaimov, V.I., Subramanian, S., Ananthakrishnan, S., and Janardhan, P. (2006). Sol. Phys. 236, 369−387.

  45. Enigmatic solar wind disappearance events: Do we understand them?.
    Janardhan, P., (2006). Jou. Astrophys. Astron. 27, 1−7.

  46. Locating the solar source of the extremely low−density, low−velocity solar wind flows of 11 May 1999.
    Janardhan, P., Fujiki, K., Kojima, M. and Tokumaru, M. (2007). Proc. of the ILWS Workshop 2006, p.132−138.
    Eds.    N. Gopalswamy and A. Bhattacharya
    ISBN:  81−87099−40−2

  47. Insights gained from Ground and Space Based Studies of Long Lasting Low Density Anomalies at 1 AU.
    Janardhan, P. , Ananthakrishnan, S., Balasubramanian, V., (2007). Asian Jou. Phys., 16, 209−232.
    Eds.   Janardhan, P., Vats, H.O., Iyer, K.N., & Anandarao, B.G.

  48. Prospects for GMRT to Observe Radio Waves from UHE Particles Interacting with the Moon.
    Sukanta P., Mohanty, S., Janardhan, P. , and Oscar, S., (2007). JCAP., 11, 022−038.

  49. The Source Regions of Solar Wind Disappearance Events.
    Janardhan, P. , Fujiki, K., Sawant, H.S., Kojima, M., Hakamada, K. and Krishnan, R., (2008). Jou. Geophys. Res. 113, A03102.

  50. 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.

  51. 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.

  52. 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.




    2011 − Present:



  53. 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.

  54. 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.

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   IAU Telegrams :

  1. PSR 0950+08.
    Janardhan, P., Deshpande, M. R., Bobra, A. D., Venat, P., Nirman, N. S. and Lali, K. S. (1992). IAU Circular No. 5575.

  2. Jupiter and Comet Shoemaker−Levy.
    O. P. N. Calla, V. Sukumaran, B. M. Darji, M. R. Deshpande, H. O. Vats, Janardhan, P., and N. M. Vadher., (1994). IAU Circular No. 6088.

  3. Comet C/1995 O1 (Hale−Bopp).
    Bird, M. K., Janardhan, P., Gensheimer, P., Huchtmeier, W. and Wilson, T. L., (1997). IAU Circular No. 6607.


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