Astronomy & Astrophysics Division (A&A)


IR Telescope in Mt. Abu

A&A Faculty Staff Students/PDFs Publications Annual Report


Chair: Prof. T. Chandrasekhar

Overview

The Research in the Astronomy and Astrophysics Division involves investigations in the optical, infrared and the radio wavelength bands to understand some of the outstanding problems related to galactic and extragalactic cosmic phenomena, such as star formation, stellar evolution, interstellar medium, binary stars, pulsars, active galactic nuclei and giant radio galaxies. Solar activity and its impact on space weather are also being studied using radio techniques.

Research Programmes

The research activities in Optical and Infrared Astronomy optimally blend the capability of a moderately sized telescope (1.2m) with state-of-the-art instruments. Some of the key research areas include,

1. Infrared photometric and spectroscopic studies on Novae and Nova-like Stellar Phenomena,
2. Infrared photometric imaging studies of Massive Star Forming Regions in our galaxy for investigating the star formation processes,
3. Monitoring of short time (hour-day) variability of Active Galactic Nuclei.
4. High angular resolution (milli-arcsec) studies (in the infrared bands) of the atmospheres of Cool Giant Stars to resolve the structure of Dust Shells,
5. Spatio-kinematic studies of Planetary Nebulae of different morphologies,
6. Infrared surface photometric studies on Starburst Galaxies to understand the causes of high rate of star formation, and
7. Detection of extrasolar planetary systems.


The programmes of the radio astronomy group include

1. Space Weather investigations involving Interplanetary Scintillations, Solar Flare activity and Coronal Mass Ejections; and Studies on Pulsar bursting phenomena.
2. Investigationof Solar atmospheric (coronal) differential rotation to examine possible connections with photo-spheric differential rotation,
3. Investigation of high-z Quasars and Giant Radio Galaxies for understanding the morphologies of these objects and the nature of the Inter-Galactic Medium,



Space based observations of Sun

1. Studies of high resolution X-ray spectra of solar flares in the energy range 4-20 keV observed by SOXS low energy detector payload of PRL onboard GSAT-2

Facilities

The Division operates the Mt. Abu Observatory with the 1.2m Infrared Telescope having the back-end instruments, NICMOS Infrared Camera and Spectrograph, Imaging Fabry-Perot Spectrometer, high time resolution Infrared Photometer, Optical Polarimeter and Fibre-linked Grating Spectrograph. Occasionally, collaborative observations are being made using larger telescopes at national and international observatories at Hanle, Hawaii, La Palma, South Africa and Chile. Telescopes in space like Spitzer IR telescope are also used for observations. The Radio Astronomy programmes utilize the national facility Giant Metre Wave Radio Telescope and Ooty Radio Telescope of TIFR. A new high resolution optical spectrometer is being built for detecting extrasolar planets by the radial velocity technique.

Ph.D. Courses Offered

Astronomy & Astrophysics
Radio Astronomy
Solar Physics and Space Weather
Astronomical Instrumentation and Data Processing Techniques

Select List of Recent Publications

Ashok K. Singal : Maximum Brightness Temperature of an Incoherent Synchrotron Source : Inverse Compton Limit — A Misnomer, Astrophysical Journal Letters, 703, L109-L112 (2009)

P. Janardhan, K. Fujiki, H. S. Sawant, M. Kojima, K. Hakamada, and R. Krishnan : Source regions of solar wind disappearance events, Journal of Geophysical Research, 113, A03102 (2008)

D. P. K. Banerjee, K. A. Misselt, K. Y. L. Su, N. M. Ashok, and P. S. Smith : Spitzer observations of V4332 Sagittarii: Detection of Alumina Dust, Astrophysical Journal Letters, 666, L25-L28 (2007)

Lokesh Bharti, Rajmal Jain, S. N. A. Jaaffrey : Evidence for Magnetoconvection in Sunspot Umbral Dots, Astrophysical Journal Letters, 665, L79-L82 (2007)

R. K. Das, D. P. K. Banerjee, and N. M. Ashok : A near-infrared shock wave in the 2006 outburst of nova RS Ophiuchi, Astrophysical Journal Letters, 653, L141-L144 (2006)

D.P.K. Banerjee, K.Y.L. Su, K.A. Misselt and N.M. Ashok : Spitzer Observations of V838 Monocerotis : Detection of a rare Infrared Light Echo, Astrophysical Journal Letters, 644, L57-L61 (2006).

Rajmal Jain, Anil Pradhan, Vishal Joshi, K. J. Shah, Jayshree Trivedi, S. L. Kayasth, V. M. Shah, and M. R. Deshpande : The Fe-line feature in X-ray spectrum of solar flares: First results from SOXS mission; Solar Physics, 239, 217-237 (2006)

N.M. Ashok, D.P.K. Banerjee, W.P. Varricatt and U.S. Kamath, Near-infrared and Optical Studies of the Fast Nova V4643 Sgr (Nova Sagittarii 2001) Mon. Not. R. Astron. Soc., 368, 592-598 (2006).

G. Koshy, D.P.K. Banerjee, T. Chandrasekhar and N.M. Ashok, A Late, Infrared Flash from the Afterglow of GRB 050319 Astrophysical Journal Letters, 640, L13-L16 (2006).

Rajmal Jain, Hemant Dave, A. B. Shah, N. M. Vadher, Vishal M. Shah, G. P. Ubale, K. S. B. Manian, Chirag M. Solanki, K. J. Shah, Sumit Kumar, S. L. Kayasth, V. D. Patel, Jayshree J. Trivedi and M. R. Deshpande : Solar X-Ray Spectrometer (SOXS) Mission onboard GSAT-2 Indian Spacecraft: The Low Energy Payload; Solar Physics, 227, 89-122 (2005)

D.P.K. Banerjee, R.J. Barber, N.M. Ashok and J. Tennyson, Near-Infrared Water Lines in V838 Monocerotis Astrophysical Journal Letters, 627, L141-L144 (2005).

S. Mondal and T. Chandrasekhar, Angular Diameter Measurements of Evolved Variables by Lunar Occultations at 2.2 and 3.8 microns Astronomical Journal, 130, 842-852 (2005).

A.C. Gupta and U.C. Joshi, Intra-night Optical Variability of Luminous Radio-quiet QSOs Astronomy & Astrophysics, 440, 855-865 (2005).

P. Janardhan, Resolving the Enigmatic Solar Wind Disappearance Event of 11 May 1999 Journal of Geophysical Research, 110, A08101 (2005).

D P. K. Banerjee, W.P. Varricatt, N.M. Ashok, L and M Band Infrared Studies of V4332 Sagittarii : Detection of the Water Ice Absorption Band at 3.05 m and the CO Fundamental Band in Emission Astrophysical Journal Letters, 615, L53-L56 (2004).

D.P.K. Banerjee and N.M. Ashok, Optical Studies of V4332 Sagittarii : Detection of Unusually Strong K I and Na I Lines in Emission Astrophysical Journal Letters, 604, L57-L60 (2004).

D.P.K. Banerjee and N.M. Ashok, A Search for Radioactive A1 in the Nova-Like Variable V4332 Sagittarii The Astrophysical Journal Letters, 610, L29-L32 (2004).

B.G. Anandarao, A. Chakraborty, D.K. Ojha and L. Testi, Detection of Knots and Jets in IRAS 06061+2151 Astronomy & Astrophysics, 421, 1045-1050 (2004).

A.K. Singal, C. Konar and D.J. Saikia, J1432+158 : the Most Distant Giant Quasar Mon. Not. R. Astron. Soc., 347, L79-L82 (2004).

D.P.K. Banerjee, W.P. Varricatt, N.M. Ashok and O. Launila, Remarkable Changes in the Near-Infrared Spectrum of the Nova-like Variable V4332 Sagittarii Astrophysical Journal Letters, 598, L31-L34 (2003).

N.M. Ashok and D.P.K. Banerjee, The Enigmatic Outburst of V445 Puppis – A Possible Helium Nova? Astronomy & Astrophysics, 409, 1007-1015 (2003).

C. Muthu and B.G. Anandarao, A Spatiokinematic Study of the Planetary Nebula NGC 1514 Astronomical Journal, 126, 2963-2979 (2003).

U.C. Joshi, K.S. Baliyan and S. Ganesh, Polarization Studies of Comet C/2000 WM1 (Linear) Astronomy & Astrophysics, 405, 1129-1135 (2003).

M.S. Nandakumar and B.G. Anandarao, Ongoing Star Formation Activity in the L1340 Dark Cloud Astronomical Journal, 123, 2583-2589 (2002).

S. Mondal and T. Chandrasekhar, Dust Structure around the Wolf-Rayet Star WR104 from Lunar Occultation Observations at 2.2 μm Mon. Not. R. Astron. Soc., 334, 143-148 (2002).

C. Muthu and B.G. Anandarao, A Spatiokinematic Study of the Planetary Nebula NGC 4361 : Evidence for Quadrupolar Flows Astronomical Journal, 121, 2106-2114 (2001).

T. Chandraseakhar and S. Mondal, Fine Structure in the Inner Dust Shell of IRC + 10216 from Lunar Occultation Observations at 2.2 μm Mon. Not. R. Astron. Soc., 322, 356-360 (2001).

Hari Om Vats, J.R. Cecatto, M. Mehta, H.S. Sawant and J.A.C.F., Neri Discovery of Variation in Solar Coronal Rotation with Altitude Astrophysical Journal Letters, 548, L87-L89 (2001).