The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, tempo... more The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, temporal, and spatial details of solar hard X-ray flares in the 15–150 keV range. Above this energy (and upto 1000 keV), it also acts as an omni-directional gamma-ray detector with a capability to study gamma-ray bursts (GRB), bright solar flares, and X-ray pulsars. With an ensemble of
We present the results of an analysis of hard X-ray observations of the C2.7 solar flare detected... more We present the results of an analysis of hard X-ray observations of the C2.7 solar flare detected by the RT -2 Experiment onboard the Coronas − P hoton satellite. We detect hard X-ray pulsations at periods of ∼12 s and ∼15 s. We find a marginal evidence for a decrease in period with time. We have augmented these results using the publicly available data from the RHESSI satellite. We present a spectral analysis and measure the spectral parameters.
We present the results of an analysis of the prompt gamma-ray emission from GRB 090618 using the ... more We present the results of an analysis of the prompt gamma-ray emission from GRB 090618 using the RT -2 Experiment onboard the Coronas − P hoton satellite. GRB 090618 shows multiple peaks and a detailed study of the temporal structure as a function of energy is carried out. As the GRB was incident at an angle of 77 • to the detector axis, we have generated appropriate response functions of the detectors to derive the spectrum of this GRB. We have augmented these results using the publicly available data from the Swif t BAT detector and show that a combined spectral analysis can measure the spectral parameters quite accurately. We also attempt a spectral and timing analysis of individual peaks and find evidence for a systematic change in the pulse emission characteristics for the successive pulses. In particular, we find that the peak energy of the spectrum, E p , is found to monotonically decrease with time, for the successive pulses of this GRB.
The RT-2 detectors onboard the Coronas-Photon satellite are designed for solar flare obser-vation... more The RT-2 detectors onboard the Coronas-Photon satellite are designed for solar flare obser-vations and they provide omni-directional gamma-ray sensitivity above 100 keV. We present the results of the detection of several gamma-ray bursts from February to November 2009. In particular, we present the temporal and spectral results of the multi-peaked GRB 090618.
Imaging in hard X-rays of any astrophysical source with high angular resolution is a challenging ... more Imaging in hard X-rays of any astrophysical source with high angular resolution is a challenging job. Shadow-casting technique is one of the most viable options for imaging in hard X-rays. We have used two different types of shadow-casters, namely, Coded Aperture Mask (CAM) and Fresnel Zone Plate (FZP) pair and two types of pixellated solid-state detectors, namely, CZT and CMOS in RT-2/CZT payload, the hard X-ray imaging instrument onboard the CORONAS-PHOTON satellite. In this paper, we present the results of simulations with different combinations of coders (CAM This work was made possible in part from a grant from Indian Space Research Organization (ISRO). Upendra Desai initiated the Zone Plate work and his contribution in the form of suggestions and discussions has proved quite valuable for this work. The whole-hearted support from G. Madhavan Nair, Ex-Chairman, ISRO, who initiated the RT-2 project, is gratefully acknowledged.
RT-2 instruments will cover the energy range of 15 keV to 150 keV extendable up to ∼1 MeV. It con... more RT-2 instruments will cover the energy range of 15 keV to 150 keV extendable up to ∼1 MeV. It consists of three detectors (two Phoswich detectors, namely, RT-2/S, RT-2/G and one solidstate imaging detector RT-2/CZT) and one processing electronic device (RT-2/E). Both Phoswich detectors will have time resolved spectrum, whereas the solid-state imaging detector will have high resolved image of the solar flares in hard X-rays. We have used Co-57 (122 keV) radio-active source for onboard calibration of all three detectors. In this paper, we briefly discuss the in-flight performance of RT-2 instruments and present initial flight data from the instruments.
The RT-2 detectors onboard the Coronas-Photon satellite have detected several solar flares from F... more The RT-2 detectors onboard the Coronas-Photon satellite have detected several solar flares from February to November 2009. RT-2 includes a pair of low background Phoswich scientillation detectors of good sensitivity and provides a good opportunity to study faint solar hard X-ray flares during the solar minimum. We present the detection of Quasi-Periodic Pulsations in a solar flare and also provide
The cadmium zinc telluride (CZT) is a new generation X-ray detector. CZT detectors are of high in... more The cadmium zinc telluride (CZT) is a new generation X-ray detector. CZT detectors are of high interest because of the high spatial and energy resolutions in X-ray and gamma-ray energies at room temperature. We present the results of laboratory tests of electronics and the detector modules for imaging application in space astronomy. The test setup, edure and results of the tests are discussed in detail.
We have carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from t... more We have carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from the Indian navy transmitter (VTX) operating at 18.2 kHz. We have used more than a dozen of receivers scattered throughout the Indian sub-continent in each of these campaigns. To our knowledge, this is the largest campaign of its kind in this region. The propagation paths range from 500 km to almost 3,000 km covering an area of about 4 million sq km. We have presented the results of the amplitude variation of the diurnal signal at each of these receiving stations in winter and summer and compare them. We have clearly found the non-reciprocity of the east to west and west to east propagation. Our results generally agree with the signal shapes obtained using the long wave propagation capability code based on mode propagation through the Earth-ionosphere cavity.
We present the results of analysis of simultaneous observation of several Solar Flares (SF) by RT... more We present the results of analysis of simultaneous observation of several Solar Flares (SF) by RT‐2 Experiment onboard CORONAS‐PHOTON satellite and ICSP‐VLF receivers. The ionospheric response of the solar flare is clearly detected in the VLF signals. The hard X‐ray event ...
The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, tempo... more The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, temporal, and spatial details of solar hard X-ray flares in the 15–150 keV range. Above this energy (and upto 1000 keV), it also acts as an omni-directional gamma-ray detector with a capability to study gamma-ray bursts (GRB), bright solar flares, and X-ray pulsars. With an ensemble of
We present the results of an analysis of hard X-ray observations of the C2.7 solar flare detected... more We present the results of an analysis of hard X-ray observations of the C2.7 solar flare detected by the RT -2 Experiment onboard the Coronas − P hoton satellite. We detect hard X-ray pulsations at periods of ∼12 s and ∼15 s. We find a marginal evidence for a decrease in period with time. We have augmented these results using the publicly available data from the RHESSI satellite. We present a spectral analysis and measure the spectral parameters.
We present the results of an analysis of the prompt gamma-ray emission from GRB 090618 using the ... more We present the results of an analysis of the prompt gamma-ray emission from GRB 090618 using the RT -2 Experiment onboard the Coronas − P hoton satellite. GRB 090618 shows multiple peaks and a detailed study of the temporal structure as a function of energy is carried out. As the GRB was incident at an angle of 77 • to the detector axis, we have generated appropriate response functions of the detectors to derive the spectrum of this GRB. We have augmented these results using the publicly available data from the Swif t BAT detector and show that a combined spectral analysis can measure the spectral parameters quite accurately. We also attempt a spectral and timing analysis of individual peaks and find evidence for a systematic change in the pulse emission characteristics for the successive pulses. In particular, we find that the peak energy of the spectrum, E p , is found to monotonically decrease with time, for the successive pulses of this GRB.
The RT-2 detectors onboard the Coronas-Photon satellite are designed for solar flare obser-vation... more The RT-2 detectors onboard the Coronas-Photon satellite are designed for solar flare obser-vations and they provide omni-directional gamma-ray sensitivity above 100 keV. We present the results of the detection of several gamma-ray bursts from February to November 2009. In particular, we present the temporal and spectral results of the multi-peaked GRB 090618.
Imaging in hard X-rays of any astrophysical source with high angular resolution is a challenging ... more Imaging in hard X-rays of any astrophysical source with high angular resolution is a challenging job. Shadow-casting technique is one of the most viable options for imaging in hard X-rays. We have used two different types of shadow-casters, namely, Coded Aperture Mask (CAM) and Fresnel Zone Plate (FZP) pair and two types of pixellated solid-state detectors, namely, CZT and CMOS in RT-2/CZT payload, the hard X-ray imaging instrument onboard the CORONAS-PHOTON satellite. In this paper, we present the results of simulations with different combinations of coders (CAM This work was made possible in part from a grant from Indian Space Research Organization (ISRO). Upendra Desai initiated the Zone Plate work and his contribution in the form of suggestions and discussions has proved quite valuable for this work. The whole-hearted support from G. Madhavan Nair, Ex-Chairman, ISRO, who initiated the RT-2 project, is gratefully acknowledged.
RT-2 instruments will cover the energy range of 15 keV to 150 keV extendable up to ∼1 MeV. It con... more RT-2 instruments will cover the energy range of 15 keV to 150 keV extendable up to ∼1 MeV. It consists of three detectors (two Phoswich detectors, namely, RT-2/S, RT-2/G and one solidstate imaging detector RT-2/CZT) and one processing electronic device (RT-2/E). Both Phoswich detectors will have time resolved spectrum, whereas the solid-state imaging detector will have high resolved image of the solar flares in hard X-rays. We have used Co-57 (122 keV) radio-active source for onboard calibration of all three detectors. In this paper, we briefly discuss the in-flight performance of RT-2 instruments and present initial flight data from the instruments.
The RT-2 detectors onboard the Coronas-Photon satellite have detected several solar flares from F... more The RT-2 detectors onboard the Coronas-Photon satellite have detected several solar flares from February to November 2009. RT-2 includes a pair of low background Phoswich scientillation detectors of good sensitivity and provides a good opportunity to study faint solar hard X-ray flares during the solar minimum. We present the detection of Quasi-Periodic Pulsations in a solar flare and also provide
The cadmium zinc telluride (CZT) is a new generation X-ray detector. CZT detectors are of high in... more The cadmium zinc telluride (CZT) is a new generation X-ray detector. CZT detectors are of high interest because of the high spatial and energy resolutions in X-ray and gamma-ray energies at room temperature. We present the results of laboratory tests of electronics and the detector modules for imaging application in space astronomy. The test setup, edure and results of the tests are discussed in detail.
We have carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from t... more We have carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from the Indian navy transmitter (VTX) operating at 18.2 kHz. We have used more than a dozen of receivers scattered throughout the Indian sub-continent in each of these campaigns. To our knowledge, this is the largest campaign of its kind in this region. The propagation paths range from 500 km to almost 3,000 km covering an area of about 4 million sq km. We have presented the results of the amplitude variation of the diurnal signal at each of these receiving stations in winter and summer and compare them. We have clearly found the non-reciprocity of the east to west and west to east propagation. Our results generally agree with the signal shapes obtained using the long wave propagation capability code based on mode propagation through the Earth-ionosphere cavity.
We present the results of analysis of simultaneous observation of several Solar Flares (SF) by RT... more We present the results of analysis of simultaneous observation of several Solar Flares (SF) by RT‐2 Experiment onboard CORONAS‐PHOTON satellite and ICSP‐VLF receivers. The ionospheric response of the solar flare is clearly detected in the VLF signals. The hard X‐ray event ...
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Papers by Tilak Katoch