Zobrazeno 1 - 10
of 591
pro vyhledávání: '"SUBRAHMANYAN, R."'
Astrophysical Constraints from the SARAS3 non-detection of the Cosmic Dawn Sky-Averaged 21-cm Signal
Autor:
Bevins, H. T. J., Fialkov, A., Acedo, E. de Lera, Handley, W. J., Singh, S., Subrahmanyan, R., Barkana, R.
Observations of the redshifted 21-cm line of atomic hydrogen have resulted in several upper limits on the 21-cm power spectrum and a tentative detection of the sky-averaged signal at $z\sim17$. Made with the EDGES Low-Band antenna, this claim was rec
Externí odkaz:
http://arxiv.org/abs/2212.00464
Autor:
Bevins, H. T. J., Acedo, E. de Lera, Fialkov, A., Handley, W. J., Singh, S., Subrahmanyan, R., Barkana, R.
We present a Bayesian re-analysis of the sky-averaged 21-cm experimental data from SARAS2 using nested sampling implemented with polychord, spectrally smooth foreground modelling implemented with maxsmooth, detailed systematic modelling and rapid sig
Externí odkaz:
http://arxiv.org/abs/2201.11531
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:
Chluba, J., Kogut, A., Patil, S. P., Abitbol, M. H., Aghanim, N., Ali-Haimoud, Y., Amin, M. A., Aumont, J., Bartolo, N., Basu, K., Battistelli, E. S., Battye, R., Baumann, D., Ben-Dayan, I., Bolliet, B., Bond, J. R., Bouchet, F. R., Burgess, C. P., Burigana, C., Byrnes, C. T., Cabass, G., Chuss, D. T., Clesse, S., Cole, P. S., Dai, L., de Bernardis, P., Delabrouille, J., Desjacques, V., de Zotti, G., Diacoumis, J. A. D., Dimastrogiovanni, E., Di Valentino, E., Dunkley, J., Durrer, R., Dvorkin, C., Ellis, J., Eriksen, H. K., Fasiello, M., Fixsen, D., Finelli, F., Flauger, R., Galli, S., Garcia-Bellido, J., Gervasi, M., Gluscevic, V., Grin, D., Hart, L., Hernandez-Monteagudo, C., Hill, J. C., Jeong, D., Johnson, B. R., Lagache, G., Lee, E., Lewis, A., Liguori, M., Kamionkowski, M., Khatri, R., Kohri, K., Komatsu, E., Kunze, K. E., Mangilli, A., Masi, S., Mather, J., Matarrese, S., Miville-Deschenes, M. A., Montaruli, T., Munchmeyer, M., Mukherjee, S., Nakama, T., Nati, F., Ota, A., Page, L. A., Pajer, E., Poulin, V., Ravenni, A., Reichardt, C., Remazeilles, M., Rotti, A., Rubino-Martin, J. A., Sarkar, A., Sarkar, S., Savini, G., Scott, D., Serpico, P. D., Silk, J., Souradeep, T., Spergel, D. N., Starobinsky, A. A., Subrahmanyan, R., Sunyaev, R. A., Switzer, E., Tartari, A., Tashiro, H., Thakur, R. Basu, Trombetti, T., Wallisch, B., Wandelt, B. D., Wehus, I. K., Wollack, E. J., Zaldarriaga, M., Zannoni, M.
Following the pioneering observations with COBE in the early 1990s, studies of the cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures of the CMB energy spectrum from
Externí odkaz:
http://arxiv.org/abs/1903.04218
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:
Trott, Cathryn M., Jordan, C. H., Murray, S. G., Pindor, B., Mitchell, D. A., Wayth, R. B., Line, J., McKinley, B., Beardsley, A., Bowman, J., Briggs, F., Hazelton, B. J., Hewitt, J., Jacobs, D., Morales, M. F., Pober, J. C., Sethi, S., Shankar, U., Subrahmanyan, R., Tegmark, M., Tingay, S. J., Webster, R. L., Wyithe, J. S. B.
Structure imprinted in foreground extragalactic point sources by ionospheric refraction has the potential to contaminate Epoch of Reionisation (EoR) power spectra of the 21~cm emission line of neutral hydrogen. The alteration of the spatial and spect
Externí odkaz:
http://arxiv.org/abs/1809.06851
Autor:
Kapinska, A. D., Staveley-Smith, L., Crocker, R., Meurer, G. R., Bhandari, S., Hurley-Walker, N., Offringa, A. R., Hanish, D. J., Seymour, N., Ekers, R. D., Bell, M. E., Callingham, J. R., Dwarakanath, K. S., For, B. -Q., Gaensler, B. M., Hancock, P. J., Hindson, L., Johnston-Hollitt, M., Lenc, E., McKinley, B., Morgan, J., Procopio, P., Wayth, R. B., Wu, C., Zheng, Q., Barry, N., Beardsley, A. P., Bowman, J. D., Briggs, F., Carroll, P., Dillon, J. S., Ewall-Wice, A., Feng, L., Greenhill, L. J., Hazelton, B. J., Hewitt, J. N., Jacobs, D. J., Kim, H. -S., Kittiwisit, P., Line, J., Loeb, A., Mitchell, D. A., Morales, M. F., Neben, A. R., Paul, S., Pindor, B., Pober, J. C., Riding, J., Sethi, S. K., Shankar, N. Udaya, Subrahmanyan, R., Sullivan, I. S., Tegmark, M., Thyagarajan, N., Tingay, S. J., Trott, C. M., Webster, R. L., Wyithe, S. B., Cappallo, R. J., Deshpande, A. A., Kaplan, D. L., Lonsdale, C. J., McWhirter, S. R., Morgan, E., Oberoi, D., Ord, S. M., Prabu, T., Srivani, K. S., Williams, A., Williams, C. L.
We present new radio continuum observations of NGC253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC253 between 76 MHz and 11 GHz.
Externí odkaz:
http://arxiv.org/abs/1702.02434
Autor:
Feng, L., Vaulin, R., Hewitt, J. N., Remillard, R., Kaplan, D. L., Murphy, Tara, Kudryavtseva, N., Hancock, P., 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.
Many astronomical sources produce transient phenomena at radio frequencies, but the transient sky at low frequencies (<300 MHz) remains relatively unexplored. Blind surveys with new widefield radio instruments are setting increasingly stringent limit
Externí odkaz:
http://arxiv.org/abs/1701.03557
Autor:
Beardsley, A. P., Hazelton, B. J., Sullivan, I. S., Carroll, P., Barry, N., Rahimi, M., Pindor, B., Trott, C. M., Line, J., Jacobs, Daniel C., Morales, M. F., Pober, J. C., Bernardi, G., Bowman, Judd D., Busch, M. P., Briggs, F., Cappallo, R. J., Corey, B. E., de Oliveira-Costa, A., Dillon, Joshua S., Emrich, D., Ewall-Wice, A., Feng, L., Gaensler, B. M., Goeke, R., Greenhill, L. J., Hewitt, J. N., Hurley-Walker, N., Johnston-Hollitt, M., Kaplan, D. L., Kasper, J. C., Kim, H. S., Kratzenberg, E., Lenc, E., Loeb, A., Lonsdale, C. J., Lynch, M. J., McKinley, B., McWhirter, S. R., Mitchell, D. A., Morgan, E., Neben, A. R., Thyagarajan, Nithyanandan, Oberoi, D., Offringa, A. R., Ord, S. M., Paul, S., Prabu, T., Procopio, P., Riding, J., Rogers, A. E. E., Roshi, A., Shankar, N. Udaya, Sethi, Shiv K., Srivani, K. S., Subrahmanyan, R., Tegmark, M., Tingay, S. J., Waterson, M., Wayth, R. B., Webster, R. L., Whitney, A. R., Williams, A., Williams, C. L., Wu, C., Wyithe, J. S. B.
The Murchison Widefield Array (MWA) has collected hundreds of hours of Epoch of Reionization (EoR) data and now faces the challenge of overcoming foreground and systematic contamination to reduce the data to a cosmological measurement. We introduce s
Externí odkaz:
http://arxiv.org/abs/1608.06281
Autor:
Lenc, Emil, Gaensler, B. M., Sun, X. H., Sadler, E. M., Willis, A. G., Barry, N., Beardsley, A. P., Bell, M. E., Bernardi, G., Bowman, J. D., Briggs, F., Callingham, J. R., Cappallo, R. J., Carroll, P., Corey, B. E., de Oliveira-Costa, A., Deshpande, A. A., Dillon, J. S., Dwarkanath, K. S., Emrich, D., Ewall-Wice, A., Feng, L., For, B. -Q., Goeke, R., Greenhill, L. J., Hancock, P., Hazelton, B. J., Hewitt, J. N., Hindson, L., Hurley-Walker, N., Johnston-Hollitt, M., Jacobs, D. C., Kapinska, A. D., Kaplan, D. L., Kasper, J. C., Kim, H. -S., Kratzenberg, E., Line, J., Loeb, A., Lonsdale, C. J., Lynch, M. J., McKinley, B., McWhirter, S. R., Mitchell, D. A., Morales, M. F., Morgan, E., Morgan, J., Murphy, T., Neben, A. R., Oberoi, D., Offringa, A. R., Ord, S. M., Paul, S., Pindor, B., Pober, J. C., Prabu, T., Procopio, P., Riding, J., Rogers, A. E. E., Roshi, A., Shankar, N. Udaya, Sethi, S. K., Srivani, K. S., Staveley-Smith, L., Subrahmanyan, R., Sullivan, I. S., Tegmark, M., Thyagarajan, Nithyanandan, Tingay, S. J., Trott, C., Waterson, M., Wayth, R. B., Webster, R. L., Whitney, A. R., Williams, A., Williams, C. L., Wu, C., Wyithe, J. S. B., Zheng, Q.
We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg^2 centered on RA=0 h, Dec=-27 deg. The sensitivity available in our deep observations allows an in-band, frequency-dependent analysis of p
Externí odkaz:
http://arxiv.org/abs/1607.05779