1. Radio Astronomy Activities at RRI
N. Udaya Shankar
RRI
Indo-SA Astronomy Workshop
7 August 2012

2. The economically important Silk Road (red) and spice trade routes (blue)

3. SALT Pepper: MWA Precursor SKA EOI in SKA Low Science Case for SKA MID
Evolution of HI in the universe.
SALT

4. world-wide collaborations.
A&A group
Theoretical astrophysics (5)
Observational astronomy to (7)
Builders: specialized instruments .
Collaborations: Many body interactions
Lead to joint pursuit of problems in
Theory, Observations, Specialized instruments
world-wide collaborations.

5. Present Focus: Low Frequency Radio Astronomy. Frequencies Below: 1
Present Focus: Low Frequency Radio Astronomy. Frequencies Below: 1.4 GHz. Developing interest in the freq range: 2 to 4 GHz.

6. Evolution of HI atom in the universe
a. HI mass fluctuations using ORT;
327 MHz, z=3.3
b. EoR : I. Statistical Detection
Our participation in MWA
MHz, z=4-16
ii. Global Signal Detection
In-house Projects
87.5 – 175 MHz, z= 4-8
c. ERA : Epoch of Recombination array
2 – 4 GHz, z=1000
2.Transients and Pulsars, MWA and ORT

7. 2.Transients and Pulsars,
MWA and ORT
3. Halos and Relics in Galaxy Clusters GMRT and MWA
50 MHz system for GMRT
4. Multi-frequency observations of Compact objects ,
X-ray polarimeter.

8. 2. Murchison Wide Field Array (MWA)
MWA is a low-frequency imaging radio interferometer facility being built in the radio-quiet area of Western Australia

9. This is one exciting project …
Scientifically rich
EOR, Solar, Transients, Pulsars, RRLs, etc.
Technologically innovative
Leading the way in multiple simultaneous areas
Trailblazing!
Excellent partnership
Common goals + motivations
Abundance of talent and energy
Enormous growth potential
Inexpensive hardware, Moore’s law
LFD/xNTD synergy, path to SKA
Opportunities abound, for Australian, Indian, US, and Global community
MWA-LFD Kick-Off June 2006

10. MWA
Murchison

11. Antenna tile with 16 dipoles placed on a ground screen of 5 x 5 m

12. Physical Layout Antenna tile (~4m diam.) Cluster (50-100m diam.)
clusters
Array (~1.5km diam.)
tile
Cluster (50-100m diam.)
node
Coax out
Tile beamformer
Fiber out
Central Processing

13. A digital receiver for MWA has been developed and built in the Radio Astronomy laboratory at RRI.
RRI digital receivers operate between 80 and 300 MHz and are based on state-of- the-art Virtex-5 FPGA chips
The receivers operate at 655 MHz sampling, include poly-phase digital filters and fiber optic links.

14. MWA Digital Receiver
Each receiver receives outputs from 8 tiles , digitize them, do 512 CH PFB and send them through fiber links after serializing.

15. RRI contribution Development of
i) A/D and Filter Bank (ADFB) Architecture
ii) Firmware for ADFB board
i) Backplane and
ii) Clock for 32 T digital receiver
i) Hardware and firmware architecture for AGFO
ii) Design of Board and firmware development
Development of Imaging Algorithms: Nithya’s Talk

16. Current status
Actively involving in system testing under integrated environment
Planning to mass produce 16 digital receivers for 128 tiles by mid 2012
Development of hardware and firmware to combine in the digital receiver the outputs of all 8 tiles to form one beam and use the entire bandwidth available

17. Challenges for MWA, LOFAR, GMRT, Global Signal Detection Experiments are same

18. Receiver is a 2 element interferometer with a space beam splitter
Freq. range : 87.5 – 175 MHz
The screen is made resistive to ensure required phase diff. between transmitted and reflected signals exists and has equal transmission and reflected signals

19. Receiver system for EoR detection
Frequency Independent Antennas installed over absorber tiles
Well matched receivers with low noise figure
a digital receiver consisting of a high speed digitizers and a spectro-correlator

20. Take it to a radio quite zone Australia South Africa
Current Status
The Zero space interferometer has been completely characterized for all its properties and data acquired are being analyzed.
Next Phase:
Take it to a radio quite zone
Australia
South Africa

21. 5. X-Ray Polarimeter
X-ray polarimeter based on the principle of Thomson scattering is being developed at the Raman Research Institute (RRI)
The experiment has been proposed to the Indian Space Research Organization for a small satellite mission.

22. Scientific Objective Polarisation measurement gives insight about
The strength and the distribution of magnetic field in X-ray sources
Geometric anisotropies in the source
The nature of the accelerator responsible for energizing the electrons taking part in radiation and scattering.
The instrument is suitable for X-ray polarisation measurement of hard X-ray sources like
accretion powered pulsars,
black hole candidates in low-hard states etc.

23. Instrument Specifications
Energy band covered – 5-30keV
Detectors – Proportional counters
Photon collection area ~ 1018 cm2
Field of view - 33 degree with 0.5 degree flat response

24. Current Status The development of a Thomson polarimeter including
proportional counter detectors,
associated front-end electronics,
event processing logic,
data acquisition system, and
test and calibration system
have been completed successfully.
Engineering Model is being developed
For more details contact :

25. Sub-mm telescope Balasubramanyam, R, 2004, MNRAS, 354, 1189
New Optics design has been developed for constructing large sub-millimeter radio telescope economically.
Balasubramanyam, R, 2004, MNRAS, 354, 1189

27. Current Status
At present a 3m Submillimeter-wave telescope prototype (3mSTeP) is being built
The mechanical structure, design and optimization are completed
Work on 8 GHz wide band spectrometer is under progress.
For more details: contact :

28. Possible Future Collaborations

29. Studies of galaxy populations in merging galaxy clusters using SALT and GMRT.
Radio monitoring of transient X-ray sources, disk-jet connection.
3. Optical reprocessing of X-rays, simultaneous observations with ASTROSAT and SALT.
4. NIR-studies (in continuum and shocked molecular 2.1/2.2 um) of chosen southern massive star forming regions.
5. Observing for Global EoR signal detection in SKA site in SA.

30. Gauribidanur T Array

31. GBD_image

32. MRT Aerial View

35. Human Resource Development:
Hierarchical Interference mitigation.
Imaging with a non-coplanar array.
Imaging two steradinas of the sky.
Human Resource Development:
8 Ph.D. students
1 MS student
Several student projects

36. Major projects undertaken by RRI
Aperture Array for Low Frequency Radio astronomy
Development of Digital receivers for The Murchison Wide Field Array (MWA)
Multiband receiver system at Green Bank Telescope
Zero Spacing Interferometer to detect Cosmological Re-ionization Signatures
Development of an X-ray polarimeter for small satellite mission
Upgradation of Ooty Radio Telescope
Development of a 3m Submillimeterwave telescope Prototype(3mSTeP)