15 Result(s)
within
Ravi Subrahmanyan
Physics
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Article
Detecting global signal from cosmic dawn and epoch of reionization with SKA
A key science project for SKA-Low is the interferometer imaging of spatio-temporal fluctuations in the hydrogen ionization fraction and spin temperature as a diagnostic of cosmic dawn (CD) and epoch of reioniz...
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Article
On the detection of a cosmic dawn signal in the radio background
The astrophysics of the cosmic dawn, when star formation commenced in the first collapsed objects, is predicted to be revealed by spectral and spatial signatures in the cosmic radio background at long waveleng...
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Article
Open AccessPeering into the dark (ages) with low-frequency space interferometers
The Dark Ages and Cosmic Dawn are largely unexplored windows on the infant Universe (z ~ 200–10). Observations of the redshifted 21-cm line of neutral hydrogen can provide valuable new insight into fundamental...
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Article
SARAS 3 CD/EoR radiometer: design and performance of the receiver
SARAS is an ongoing experiment aiming to detect the redshifted global 21-cm signal expected from Cosmic Dawn (CD) and the Epoch of Reionization (EoR). Standard cosmological models predict the signal to be pres...
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Article
SARAS 2: a spectral radiometer for probing cosmic dawn and the epoch of reionization through detection of the global 21-cm signal
The global 21-cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts ...
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Article
A digital-receiver for the MurchisonWidefield Array
An FPGA-based digital-receiver has been developed for a low-frequency imaging radio interferometer, the Murchison Widefield Array (MWA). The MWA, located at the Murchison Radio-astronomy Observatory (MRO) in W...
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Article
SARAS: a precision system for measurement of the cosmic radio background and signatures from the epoch of reionization
SARAS is a correlation spectrometer purpose designed for precision measurements of the cosmic radio background and faint features in the sky spectrum at long wavelengths that arise from redshifted 21-cm from g...
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Article
18 GHz SZ Measurements of the Bullet Cluster
We present 18 GHz observations of the Bullet cluster using the Austalia Telescope Compact Array (ATCA), which show structure in the Sunyaev–Zeldovich effect; in particular, a deep, compact feature which does n...
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Article
The Australia telescope 20 GHz survey: hardware, observing strategy, and scanning survey catalog
The Australia Telescope 20 GHz (AT20G) survey is a large area (2π sr), sensitive (40 mJy), high frequency (20 GHz) survey of the southern sky. The survey was conducted in two parts: an initial fast scanning surve...
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Chapter and Conference Paper
Radio Monitoring of Supernova 2001ig: The First Year
Supernova 2001ig in NGC 7424 has been observed with the Australia Telescope Compact Array at ∼2 week intervals since its discovery, making this the best-studied Type IIb radio supernova since SN 1993J.We prese...
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Article
A measurement of the cosmic microwave background temperature 1280 MHz
The absolute temperature of the cosmic microwave background (CMB) has been measured at a frequency of 1280 MHz. The observation was made with a modified version of the L-band receiver used in the Giant Metre w...
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Article
Microwave background radiation related evidence in favour of the standard model
The discovery of the 3K microwave background radiation (MBR) and its interpretation as a relict of the hot big bang was probably the most important observation that led to the elevation of the hot big bang model ...
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Article
An observational constraint on the existence of proto-superclsuters atz=3.3
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Article
An observational constraint on the existence of proto-superclusters at z =3.3
Observations have been conducted using the Ooty Radio Telescope in order to place constraints on the evolutionary scenario leading to the formation of the present day superclusters. The experiment attempted to...
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Article
A search for protocliisters atz = 3.3
We have used the Very Large Array to image a single field in a set of adjacent frequency bands around 333.0 MHz in an attempt to detect 21 cm emission from large scale H I inhomogeneities at a redshift of z = ...
