Search Results - "Vedantham, H K"

A fast radio burst localized to a massive galaxy by Ravi, V., Catha, M., D’Addario, L., Djorgovski, S. G., Hallinan, G., Hobbs, R., Kocz, J., Kulkarni, S. R., Shi, J., Vedantham, H. K., Weinreb, S., Woody, D. P.

“…Intense, millisecond-duration bursts of radio waves (named fast radio bursts) have been detected from beyond the Milky Way 1 . Their dispersion measures—which…”
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Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR by Mertens, F G, Mevius, M, Koopmans, L V E, Offringa, A R, Mellema, G, Zaroubi, S, Brentjens, M A, Gan, H, Gehlot, B K, Pandey, V N, Sardarabadi, A M, Vedantham, H K, Yatawatta, S, Asad, K M B, Ciardi, B, Chapman, E, Gazagnes, S, Ghara, R, Ghosh, A, Giri, S K, Iliev, I T, Jelić, V, Kooistra, R, Mondal, R, Schaye, J, Silva, M B

“…ABSTRACT A new upper limit on the 21 cm signal power spectrum at a redshift of z ≈ 9.1 is presented, based on 141 h of data obtained with the Low-Frequency…”
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The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst by Ravi, V., Shannon, R. M., Bailes, M., Bannister, K., Bhandari, S., Bhat, N. D. R., Burke-Spolaor, S., Caleb, M., Flynn, C., Jameson, A., Johnston, S., Keane, E. F., Kerr, M., Tiburzi, C., Tuntsov, A. V., Vedantham, H. K.

“…Fast radio bursts (FRBs) are millisecond-duration events thought to originate beyond the Milky Way galaxy. Uncertainty surrounding the burst sources, and their…”
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THE FLUENCE AND DISTANCE DISTRIBUTIONS OF FAST RADIO BURSTS by Vedantham, H. K., Ravi, V., Hallinan, G., Shannon, R. M.

“…ABSTRACT Fast radio bursts (FRB) are millisecond-duration radio pulses with apparent extragalactic origins. All but two of the FRBs have been discovered using…”
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The first power spectrum limit on the 21-cm signal of neutral hydrogen during the Cosmic Dawn at z = 20–25 from LOFAR by Gehlot, B K, Mertens, F G, Koopmans, L V E, Brentjens, M A, Zaroubi, S, Ciardi, B, Ghosh, A, Hatef, M, Iliev, I T, Jelić, V, Kooistra, R, Krause, F, Mellema, G, Mevius, M, Mitra, M, Offringa, A R, Pandey, V N, Sardarabadi, A M, Schaye, J, Silva, M B, Vedantham, H K, Yatawatta, S

“…ABSTRACT Observations of the redshifted 21-cm hyperfine line of neutral hydrogen from early phases of the Universe such as Cosmic Dawn and the Epoch of…”
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The AARTFAAC Cosmic Explorer: observations of the 21-cm power spectrum in the EDGES absorption trough by Gehlot, B K, Mertens, F G, Koopmans, L V E, Offringa, A R, Shulevski, A, Mevius, M, Brentjens, M A, Kuiack, M, Pandey, V N, Rowlinson, A, Sardarabadi, A M, Vedantham, H K, Wijers, R A M J, Yatawatta, S, Zaroubi, S

“…ABSTRACT The 21-cm absorption feature reported by the EDGES collaboration is several times stronger than that predicted by traditional astrophysical models. If…”
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Coherent radio emission from a quiescent red dwarf indicative of star–planet interaction by Vedantham, H. K., Callingham, J. R., Shimwell, T. W., Tasse, C., Pope, B. J. S., Bedell, M., Snellen, I., Best, P., Hardcastle, M. J., Haverkorn, M., Mechev, A., O’Sullivan, S. P., Röttgering, H. J. A., White, G. J.

“…Low-frequency ( ν  ≲ 150 MHz) stellar radio emission is expected to originate in the outer corona at heights comparable to and larger than the stellar radius…”
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The population of M dwarfs observed at low radio frequencies by Callingham, J. R., Vedantham, H. K., Shimwell, T. W., Pope, B. J. S., Davis, I. E., Best, P. N., Hardcastle, M. J., Röttgering, H. J. A., Sabater, J., Tasse, C., van Weeren, R. J., Williams, W. L., Zarka, P., de Gasperin, F., Drabent, A.

“…Coherent low-frequency (≲200 MHz) radio emission from stars encodes the conditions of the outer corona, mass-ejection events and space weather 1 – 5 . Previous…”
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Probing ionospheric structures using the LOFAR radio telescope by Mevius, M., Tol, S., Pandey, V. N., Vedantham, H. K., Brentjens, M. A., Bruyn, A. G., Abdalla, F. B., Asad, K. M. B., Bregman, J. D., Brouw, W. N., Bus, S., Chapman, E., Ciardi, B., Fernandez, E. R., Ghosh, A., Harker, G., Iliev, I. T., Jelić, V., Kazemi, S., Koopmans, L. V. E., Noordam, J. E., Offringa, A. R., Patil, A. H., Weeren, R. J., Wijnholds, S., Yatawatta, S., Zaroubi, S.

“…LOFAR is the LOw‐Frequency Radio interferometer ARray located at midlatitude (52°53′N). Here we present results on ionospheric structures derived from 29 LOFAR…”
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Polarization leakage in epoch of reionization windows – I. Low Frequency Array observations of the 3C196 field by Asad, K. M. B., Koopmans, L. V. E., Jelić, V., Pandey, V. N., Ghosh, A., Abdalla, F. B., Bernardi, G., Brentjens, M. A., de Bruyn, A. G., Bus, S., Ciardi, B., Chapman, E., Daiboo, S., Fernandez, E. R., Harker, G., Iliev, I. T., Jensen, H., Martinez-Rubi, O., Mellema, G., Mevius, M., Offringa, A. R., Patil, A. H., Schaye, J., Thomas, R. M., van der Tol, S., Vedantham, H. K., Yatawatta, S., Zaroubi, S.

“…Detection of the 21-cm signal coming from the epoch of reionization (EoR) is challenging especially because, even after removing the foregrounds, the residual…”
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Symmetric Achromatic Variability in Active Galaxies: A Powerful New Gravitational Lensing Probe? by Vedantham, H. K., Readhead, A. C. S., Hovatta, T., Pearson, T. J., Blandford, R. D., Gurwell, M. A., Lähteenmäki, A., Max-Moerbeck, W., Pavlidou, V., Ravi, V., Reeves, R. A., Richards, J. L., Tornikoski, M., Zensus, J. A.

“…We report the discovery of a rare new form of long-term radio variability in the light curves of active galaxies (AG)-symmetric achromatic variability (SAV)-a…”
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On the mechanism of polarized metre-wave stellar emission by Vedantham, H K

“…ABSTRACT Two coherent radio emission mechanisms operate in stellar coronae: plasma emission and cyclotron emission. They directly probe the electron density…”
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Faraday conversion and magneto-ionic variations in fast radio bursts by Vedantham, H K, Ravi, V

“…ABSTRACT The extreme, time-variable Faraday rotation observed in the repeating fast radio burst (FRB) 121102 and its associated persistent synchrotron source…”
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Radio wave scattering by circumgalactic cool gas clumps by Vedantham, H K, Phinney, E S

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Scintillation noise power spectrum and its impact on high-redshift 21-cm observations by Vedantham, H. K., Koopmans, L. V. E.

“…Visibility scintillation resulting from wave propagation through the turbulent ionosphere can be an important source of noise at low radio frequencies (ν ≲…”
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FRB 121102: Drastic changes in the burst polarization contrasts with the stability of the persistent emission by Plavin, A, Paragi, Z, Marcote, B, Keimpema, A, Hessels, J W T, Nimmo, K, Vedantham, H K, Spitler, L G

“…ABSTRACT We study milliarcsecond-scale properties of the persistent radio counterpart to FRB 121102 and investigate the spectro-polarimetric properties of a…”
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Scintillation noise in widefield radio interferometry by Vedantham, H. K., Koopmans, L. V. E.

“…In this paper, we consider random phase fluctuations imposed during wave propagation through a turbulent plasma (e.g. ionosphere) as a source of additional…”
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SMILE: Search for MIlli-LEnses by Casadio, C, Blinov, D, Readhead, A C S, Browne, I W A, Wilkinson, P N, Hovatta, T, Mandarakas, N, Pavlidou, V, Tassis, K, Vedantham, H K, Zensus, J A, Diamantopoulos, V, Dolapsaki, K E, Gkimisi, K, Kalaitzidakis, G, Mastorakis, M, Nikolaou, K, Ntormousi, E, Pelgrims, V, Psarras, K

“…ABSTRACT Dark matter (DM) haloes with masses below ∼108 M⊙, which would help to discriminate between DM models, may be detected through their gravitational…”
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Chromatic effects in the 21 cm global signal from the cosmic dawn by Vedantham, H. K., Koopmans, L. V. E., de Bruyn, A. G., Wijnholds, S. J., Ciardi, B., Brentjens, M. A.

“…The redshifted 21 cm brightness distribution from neutral hydrogen is a promising probe into the cosmic dark ages, cosmic dawn and re-ionization. Low Frequency…”
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The Relativistic Jet Orientation and Host Galaxy of the Peculiar Blazar PKS 1413+135 by Readhead, A. C. S., Ravi, V., Liodakis, I., Lister, M. L., Singh, V., Aller, M. F., Blandford, R. D., Browne, I. W. A., Gorjian, V., Grainge, K. J. B., Gurwell, M. A., Hodges, M. W., Hovatta, T., Kiehlmann, S., Lähteenmäki, A., Mcaloone, T., Max-Moerbeck, W., Pavlidou, V., Pearson, T. J., Peirson, A. L., Perlman, E. S., Reeves, R. A., Soifer, B. T., Taylor, G. B., Tornikoski, M., Vedantham, H. K., Werner, M., Wilkinson, P. N., Zensus, J. A.

“…PKS 1413+135 is one of the most peculiar blazars known. Its strange properties led to the hypothesis almost four decades ago that it is gravitationally lensed…”
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