Zobrazeno 1 - 10
of 825
pro vyhledávání: '"Greenhill L"'
Autor:
Spinelli, M., Kyriakou, G., Bernardi, G., Bolli, P., Greenhill, L. J., Fialkov, A., Garsden, H.
Cosmic Dawn, the onset of star formation in the early universe, can in principle be studied via the 21cm transition of neutral hydrogen, for which a sky-averaged absorption signal, redshifted to MHz frequencies, is predicted to be {\it O}(10-100)\,mK
Externí odkaz:
http://arxiv.org/abs/2206.12158
Autor:
Bevins, H. T. J., Handley, W. J., Fialkov, A., Acedo, E. de Lera, Greenhill, L. J., Price, D. C.
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 502, Issue 3, April 2021, Pages 4405-4425
Maximally Smooth Functions (MSFs) are a form of constrained functions in which there are no inflection points or zero crossings in high order derivatives. Consequently, they have applications to signal recovery in experiments where signals of interes
Externí odkaz:
http://arxiv.org/abs/2007.14970
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:
Price, D. C., Greenhill, L. J., Fialkov, A., Bernardi, G., Garsden, H., Barsdell, B. R., Kocz, J., Anderson, M. M., Bourke, S. A., Craig, J., Dexter, M. R., Dowell, J., Eastwood, M. W., Eftekhari, T., Ellingson, S. W., Hallinan, G., Hartman, J. M., Kimberk, R., Lazio, T. J. W., Leiker, S., MacMahon, D., Monroe, R., Schinzel, F., Taylor, G. B., Tong, E., Werthimer, D., Woody, D. P.
The Large-Aperture Experiment to Detect the Dark Age (LEDA) was designed to detect the predicted O(100)mK sky-averaged absorption of the Cosmic Microwave Background by Hydrogen in the neutral pre- and intergalactic medium just after the cosmological
Externí odkaz:
http://arxiv.org/abs/1709.09313
Autor:
Issaoun, S., Goddi, C., Matthews, L. D., Greenhill, L. J., Gray, M. D., Humphreys, E. M. L., Chandler, C. J., Krumholz, M., Falcke, H.
Publikováno v:
A&A 606, A126 (2017)
We present the first images of the 28SiO v=1, J=2-1 maser emission around the closest known massive young stellar object Orion Source I observed at 86 GHz (3mm) with the VLBA. These images have high spatial (~0.3 mas) and spectral (~0.054 km/s) resol
Externí odkaz:
http://arxiv.org/abs/1707.07455
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:
Paul, Sourabh, Sethi, Shiv K., Morales, Miguel F., Dwarkanath, K. S., Shankar, N. Udaya, Subrahmanyan, Ravi, Barry, N., Beardsley, A. P., Bowman, Judd D., Briggs, F., Carroll, P., de Oliveira-Costa, A., Dillon, Joshua S., Ewall-Wice, A., Feng, L., Greenhill, L. J., Gaensler, B. M., Hazelton, B. J., Hewitt, J. N., Hurley-Walker, N., Jacobs, D. J., Kim, Han-Seek, Kittiwisit, P., Lenc, E., Line, J., Loeb, A., McKinley, B., Mitchell, D. A., Neben, A. R., Offringa, A. R., Pindor, B., Pober, J. C., Procopio, P., Riding, J., Sullivan, I. S., Tegmark, M., Thyagarajan, Nithyanandan, Tingay, S. J., Trott, C. M., Wayth, R. B., Webster, R. L., Wyithe, J. S. B., Cappallo, Roger, Johnston-Hollitt, M., 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.
Publikováno v:
ApJ, 2016, 833, 2, 213
The Detection of redshifted 21 cm emission from the epoch of reionization (EoR) is a challenging task owing to strong foregrounds that dominate the signal. In this paper, we propose a general method, based on the delay spectrum approach, to extract H
Externí odkaz:
http://arxiv.org/abs/1610.07003
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