View status of TGSS observations in Cycle 21 here .

View status of TGSS observations in Cycle 20 here .

View status of TGSS observations in Cycle 19 here .

View status of TGSS observations in Cycle 18 here .

September 2012: TGSS DR5 has moved to October 2012 due to two main reasons. First is all the fields from TGSS DR4 are being made with the modified analysis pipeline so that DR5 will include images made with the same algorithm and hence have uniform sensitivity to extended structure. Moreover the fields which were not included in the earlier releases by the team due to severe artifacts in the images caused by a combination of excess RFI resulting in excess editing of data; are also being reimaged using this modified pipeline. If this results in good quality images; these will also be released as part of DR5. If the image fidelity still continues to be low; then these fields will require compensatory time from the Observatory and will continue to appear as holes in the released TGSS coverage till the new data is obtained. This has increased the number of fields that are being imaged. Secondly, NCRA ran into power problems which also led to UPS problems in July 2012. This brought down the TGSS computing lab from 22 July to 27 July 2012 and crashed one of the hard disks. While about a week was lost in this and setting up the computers and pipelines; effective computing time lost was three weeks since recall that each computer takes 8-10 days to image a TGSS field.
We now have a new online book-keeping software to help us manage and keep track of the data releases and also help with the data quality checks. This tool is developed using a MqSQL database and has a user-friendly GUI. It also interfaces with SAO ds9 and gnuplot for generating plots.

April 2012: All the pointings required to cover the entire sky accessible to GMRT have been observed for the TGSS. These observations were completed in GMRT Observing Cycle 21 in March 2012.
The other important development has been modifications in the analysis pipeline. We had mentioned during our last data release that the analysis pipeline is undergoing some modifications which is expected to result in better image quality especially to extended. We are happy to say that this is indeed the case. In TGSS Data Release 4 which was on 20 April 2012; about 128 images have used this modified pipeline. The results are fairly encouraging. We plan to replace the old pipeline by this modified pipeline and in future - we plan to reimage all the fields released till DR4 with this modified pipeline.

October 2011: 35 more computers have been added to the TGSS computing lab. This takes the total number of computers to about 100 and all these have been set up by the team. The third data release will happen end-October. This will probably have a smaller number of images since in the last few months after DR2, the pipeline has been improved to deal with RFI and extended structure - both dependent on the central square baselines. In future, data analysis will use this pipeline. Although theoretically we should be sensitive to angular scales as large as 60' due to enhanced RFI on the short baselines leading to large flagging fractions for these short baselines, we are limited to angular scales of 7'-8'. The surface brightness sensitivity is about 3*local rms and ranges from 12 mJy/beam to 40 mJy/beam. In GMRT observing cycle 20, we were granted 150 hours of telescope time to observe the sky south of -30d. This extension to the original TGSS was proposed by the team after a couple of test regions at the southermost declinations accessible to GMRT were observed and successfully analysed. There was some confusion in granting time in GMRT observing cycle 21 which is the ongoing cycle but finally 100 hours of observing time is available to the team to complete the observations of the sky between -30 and -55d.

August 2011: Several important milestones have been achieved by the team since the last entry a year ago. The TGSS team has made two public data releases each covering about 1000 square degrees of the sky. TGSS DR1 was in October 2010 covering about 1000 square degrees of the southern sky and TGSS DR2 was in June 2011 covering a total of about 2000 square degrees which included the fields released in DR1. A mailing list has been set up for interested users to register and receive updates on TGSS data releases. In future, we plan to open up this forum for discussions. Additionally the TGSS computer lab has been extended and several more computers setup to run the data analysis pipeline. Observations in GMRT Observing Cycle 20 are in progress - while all the pointings covering the sky north of declination -30 degrees have been observed, the sky south of declination -30 degrees is being observed. Various scripts which help prepare the command files, select the phase calibrator and make sure all the pointings are observed have been developed in-house. Considering that on completion of the survey observations more than 5000 pointings will have been observed, book-keeping is an important part of the project. Data analysis of data from pointings in the southern sky is in progress and the third data release is planned for four months after DR2 as announced by the team. Several data checks for each field have been implemented. The first science paper from TGSS data has been published and can be found here . In this paper, the discovery of a giant radio relic seen in the TGSS data in a Planck Sunyaev-Zeldovich cluster - PLCK G287.0+32.9 has been published.

July 2010: The first images of the data obtained in Cycle 18 have been obtained using the newly installed TGSS computing lab. 36 fields which is about 225 square degrees of the sky have been imaged. These co-added images were generated using about five days of computing time with an optimal number of computers analysing the data. Basically cross-calibrated data of one field can be imaged and self-calibrated by one computer in about 3.5 days.

June 2010: The computers are checked, OS installed and the AIPS++ analysis pipeline installed and run on the computers. The images of the pointings observed in Cycle 16 and analysed by us were reanalysed on these computers and the working of the pipeline and machines verified by end June.

May 2010: 44 desktop computers required for the TGSS data analysis arrived at NCRA and set up in the TGSS computing lab.

April 2010: 770 hours are allocated by GTAC in GMRT Observing Cycle 18 (April - September 2010). Observations are presently in progress - the first run in the cycle was on 8 April 2010. Analysis of these data will begin in May 2010 when the new Survey lab with several computers has been set up. The group put in a new mid-term plan proposal to TIFR to fund this facility which has been approved.

January 2010: Using existing computing facilities at NCRA, we have analysed 32 pointings (ie about 10 hours) from the 100 hours of data acquired in the GMRT Observing Cycle 16. These data were acquired on 10 August 2009 using the hardware correlator. The pointing centres of these 32 pointings are listed here. Note that 16 of these close to the Galactic plane. Since these were the first set of pointings which were observed and analysed, we show in figure 1 and figure 2, the placement of the pointings in the sky with the naming convention that we follow. These images have been obtained using the data analysis pipeline developed in AIPS++ by the PI. The images for all these 32 pointings which can be obtained from our webpage have been primary beam corrected and the neighbouring images where available have been combined to generate maps of 4.5x4.5 degree large regions of the sky (HPBW at 150 MHz is 3 degrees). Shown alongside are a few collages obtained using SAO ds9 demonstrating the results. The median rms noise in all the above images is less than 9 mJy/beam with the rms noise being higher in the immediate vicinity of strong sources. Note that no system temperature correction has yet been applied for the pointings close to the Galactic plane.

General information:
5040 pointings are required to map the entire sky north of declination -30 degrees ie 32000 sq degrees. Each pointing is observed for 17.5m (3.5m X 5 HA) so this converts to a total time required for the pointings (excluding calibration overheads) to about 1500 hours. The following naming convention for the pointings is followed: an index for both right ascension (R) and declination (D) which increments with increase in RA and/or declination e.g. R01D20, R02D20.