Zobrazeno 1 - 10
of 231
pro vyhledávání: '"Shankar N. Udaya"'
Autor:
Singh, Saurabh, T., Jishnu Nambissan, Subrahmanyan, Ravi, Shankar, N. Udaya, Girish, B. S., Raghunathan, A., Somashekar, R., Srivani, K. S., Rao, Mayuri Sathyanarayana
The astrophysics of cosmic dawn, when star formation commenced in the first collapsed objects, is predicted to be revealed as spectral and spatial signatures in the cosmic radio background at long wavelengths. The sky-averaged redshifted 21-cm absorp
Externí odkaz:
http://arxiv.org/abs/2112.06778
Autor:
Raghunathan, Agaram, Subrahmanyan, Ravi, Shankar, N. Udaya, Singh, Saurabh, Nambissan, Jishnu, Kavitha, K., Mahesh, Nivedita, Somashekar, R., Sindhu, Gaddam, Girish, B. S., Srivani, K. S., Rao, Mayuri S.
The critical component of radio astronomy radiometers built to detect redshifted 21-cm signals from Cosmic Dawn is the antenna element. We describe the design and performance of an octave bandwidth cone disc antenna built to detect this signal in the
Externí odkaz:
http://arxiv.org/abs/2104.03522
Autor:
T., Jishnu Nambissan, Subrahmanyan, Ravi, Somashekar, R., Shankar, N. Udaya, Singh, Saurabh, Raghunathan, A., Girish, B. S., Srivani, K. S., Rao, Mayuri Sathyanarayana
Publikováno v:
Experimental Astronomy (2021)
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 present in the redshift range $z \sim $6--35,
Externí odkaz:
http://arxiv.org/abs/2104.01756
Autor:
Girish, B. S., Srivani, K. S., Subrahmanyan, Ravi, Shankar, N. Udaya, Singh, Saurabh, Nambissan, T. Jishnu, Rao, Mayuri Sathyanarayana, Somashekar, R., Raghunathan, A.
Publikováno v:
Journal of Astronomical Instrumentation Vol. 09, No. 02, 2050006 (2020)
In the currently accepted model for cosmic baryon evolution, Cosmic Dawn and the Epoch of Reionization are significant times when first light from the first luminous objects emerged, transformed and subsequently ionized the primordial gas. The 21 cm
Externí odkaz:
http://arxiv.org/abs/2104.00582
Autor:
Barry, N., Wilensky, M., Trott, C. M., Pindor, B., Beardsley, A. P., Hazelton, B. J., Sullivan, I. S., Morales, M. F., Pober, J. C., Line, J., Greig, B., Byrne, R., Lanman, A., Li, W., Jordan, C. H., Joseph, R. C., McKinley, B., Rahimi, M., Yoshiura, S., Bowman, J. D., Gaensler, B. M., Hewitt, J. N., Jacobs, D. C., Mitchell, D. A., Shankar, N. Udaya, Sethi, S. K., Subrahmanyan, R., Tingay, S. J., Webster, R. L., Wyithe, J. S. B.
Measurements of 21 cm Epoch of Reionization (EoR) structure are subject to systematics originating from both the analysis and the observation conditions. Using 2013 data from the Murchison Widefield Array (MWA), we show the importance of mitigating b
Externí odkaz:
http://arxiv.org/abs/1909.00561
Autor:
Bell, M. E., Murphy, Tara, Hancock, P. J., Callingham, J. R., Johnston, S., Kaplan, D. L., Hunstead, R. W., Sadler, E. M., Croft, S., White, S. V., Hurley-Walker, N., Chhetri, R., Morgan, J. S., Edwards, P. G., Rowlinson, A., Offringa, A. R., Bernardi, G., Bowman, J. D., Briggs, F., Cappallo, R. J., Deshpande, A. A., Gaensler, B. M., Greenhill, L. J., Hazelton, B. J., Johnston-Hollitt, M., Lonsdale, C. J., McWhirter, S. R., Mitchell, D. A., Morales, M. F., Morgan, E., Oberoi, D., Ord, S. M., Prabu, T., Shankar, N. Udaya, Srivani, K. S., Subrahmanyan, R., Tingay, S. J., Wayth, R. B., Webster, R. L., Williams, A., Williams, C. L.
We report on a search for low-frequency radio variability in 944 bright (> 4Jy at 154 MHz) unresolved, extragalactic radio sources monitored monthly for several years with the Murchison Widefield Array. In the majority of sources we find very low lev
Externí odkaz:
http://arxiv.org/abs/1810.10152
Autor:
Li, W., Pober, J. C., Hazelton, B. J., Barry, N., Morales, M. F., Sullivan, I., Parsons, A. R., Ali, Z. S., Dillon, J. S., Beardsley, A. P., Bowman, J. D., Briggs, F., Byrne, R., Carroll, P., Crosse, B., Emrich, D., Ewall-Wice, A., Feng, L., Franzen, T. M. O., Hewitt, J. N., Horsley, L., Jacobs, D. C., Johnston-Hollitt, M., Jordan, C., Joseph, R. C., Kaplan, D. L., Kenney, D., Kim, H., Kittiwisit, P., Lanman, A., Line, J., McKinley, B., Mitchell, D. A., Murray, S., Neben, A., Offringa, A. R., Pallot, D., Paul, S., Pindor, B., Procopio, P., Rahimi, M., Riding, J., Sethi, S. K., Shankar, N. Udaya, Steele, K., Subrahmanian, R., Tegmark, M., Thyagarajan, N., Tingay, S. J., Trott, C., Walker, M., Wayth, R. B., Webster, R. L., Williams, A., Wu, C., Wyithe, S.
Interferometric arrays seeking to measure the 21 cm signal from the Epoch of Reionization must contend with overwhelmingly bright emission from foreground sources. Accurate recovery of the 21 cm signal will require precise calibration of the array, a
Externí odkaz:
http://arxiv.org/abs/1807.05312
Autor:
Singh, Saurabh, Subrahmanyan, Ravi, Shankar, N. Udaya, Rao, Mayuri Sathyanarayana, Fialkov, Anastasia, Cohen, Aviad, Barkana, Rennan, Girish, B. S., Raghunathan, A., Somashekar, R., Srivani, K. S.
Spectral distortions in the cosmic microwave background over the 40--200~MHz band are imprinted by neutral hydrogen in the intergalactic medium prior to the end of reionization. This signal, produced in the redshift range $z = 6-34$ at the rest frame
Externí odkaz:
http://arxiv.org/abs/1711.11281
Autor:
Singh, Saurabh, Subrahmanyan, Ravi, Shankar, N. Udaya, Rao, Mayuri Sathyanarayana, Girish, B. S., Raghunathan, A., Somashekar, R., Srivani, K. S.
The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted t
Externí odkaz:
http://arxiv.org/abs/1710.01101
Autor:
Singh, Saurabh, Subrahmanyan, Ravi, Shankar, N. Udaya, Rao, Mayuri Sathyanarayana, Fialkov, Anastasia, Cohen, Aviad, Barkana, Rennan, Girish, B. S., Raghunathan, A., Somashekar, R., Srivani, K. S.
Long wavelength spectral distortions in the Cosmic Microwave Background arising from the 21-cm transition in neutral Hydrogen are a key probe of Cosmic Dawn and the Epoch of Reionization. These features may reveal the nature of the first stars and ul
Externí odkaz:
http://arxiv.org/abs/1703.06647