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Your search keyword '"Krichbaum, T. P."' showing total 15 results
Start Over Author "Krichbaum, T. P." Journal monthly notices of the royal astronomical society
15 results on '"Krichbaum, T. P."'

1. MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity

Author

Komossa, S, primary, Grupe, D, additional, Kraus, A, additional, Gonzalez, A, additional, Gallo, L C, additional, Valtonen, M J, additional, Laine, S, additional, Krichbaum, T P, additional, Gurwell, M A, additional, Gómez, J L, additional, Ciprini, S, additional, Myserlis, I, additional, and Bach, U, additional

Published
2022
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2. Radio and γ -ray follow-up of the exceptionally high activity state of PKS 1510-089 in 2011

Author

Orienti, M., Koyama, S., D’Ammando, F., Giroletti, M., Kino, M., Nagai, H., Venturi, T., Dallacasa, D., Giovannini, G., Angelakis, E., Fuhrmann, L., Hovatta, T., Max-Moerbeck, W., Schinzel, F. K., Akiyama, K., Hada, K., Honma, M., Gasparrini, D., Krichbaum, T. P., Nestoras, I., Readhead, A. C. S., Richards, J. L., Riquelme, D., Sievers, A., Ungerechts, H., and Zensus, J. A.

Subjects
galaxies quasars: individual (PKS 1510−089), radio continuum: general, gamma-rays: observations, radiation mechanisms: non-thermal
Published
2013

3. Radio and optical intra-day variability observations of five blazars

Author

Liu, X., primary, Yang, P. P., additional, Liu, J., additional, Liu, B. R., additional, Hu, S. M., additional, Kurtanidze, O. M., additional, Zola, S., additional, Kraus, A., additional, Krichbaum, T. P., additional, Su, R. Z., additional, Gazeas, K., additional, Sadakane, K., additional, Nilson, K., additional, Reichart, D. E., additional, Kidger, M., additional, Matsumoto, K., additional, Okano, S., additional, Siwak, M., additional, Webb, J. R., additional, Pursimo, T., additional, Garcia, F., additional, Naves Nogues, R., additional, Erdem, A., additional, Alicavus, F., additional, Balonek, T., additional, and Jorstad, S. G., additional

Published
2017
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6. Probing the gamma-ray variability in 3C 279 using broad-band observations.

Author

Rani, B., Krichbaum, T. P., Lee, S.-S., Sokolovsky, K., Kang, S., Byun, D.-Y., Mosunova, D., and Zensus, J. A.

Subjects
*GAMMA ray astronomy, *ASTRONOMICAL observations, *POLARIZATION (Nuclear physics), *GALAXIES, *ENERGY density, *COMPTON scattering
Abstract

We present the results of a broad-band radio-to-GeV observing campaign organized to get a better understanding of the radiation processes responsible for the γ-ray flares observed in 3C 279. The total intensity and polarization observations of the source were carried out between 2013 December 28 and 2014 January 03 using the Fermi-Large Area Telescope, Swift-XRT, Swift-UVOT, and Korean VLBI Network telescopes. A prominent flare observed in the optical/near-UV passbands was found to be correlated with a concurrent γ-ray flare at a confidence level > 95 per cent, which suggests a co-spatial origin of the two. Moreover, the flaring activity in the two regimes was accompanied by no significant spectral variations. A peak in the X-ray light curve coincides with the peaks of the fractional polarization curves at 43 and 86 GHz radio bands. No prominent variation was noticed for the total intensity and the electric vector position angle observations at radio bands during this period. We noticed a possible hint of steepening of the radio spectrum with an increase in percentage polarization, which suggests that the radio polarization variations could be simply due to a spectral change. In a simple scenario, the correlated optical/γ-ray flares could be caused by the same population of emitting particles. The coincidence of the increase in radio polarization with the X-ray flux supports the picture that X-rays are produced via inverse-Compton scattering of radio photons. The observed fractional variability for the γ-ray flare ~0.23 does not exceed that in the optical regime, which is inconsistent with what we usually observe for 3C 279; it could be due to different dependencies of the magnetic field and the external radiation field energy density profiles along the jet. [ABSTRACT FROM AUTHOR]

Published
2017
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7. Detection of significant cm to sub-mm band radio and -ray correlated variability in Fermi bright blazars

Author

Fuhrmann, L., primary, Larsson, S., additional, Chiang, J., additional, Angelakis, E., additional, Zensus, J. A., additional, Nestoras, I., additional, Krichbaum, T. P., additional, Ungerechts, H., additional, Sievers, A., additional, Pavlidou, V., additional, Readhead, A. C. S., additional, Max-Moerbeck, W., additional, and Pearson, T. J., additional

Published
2014
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9. Radio and γ-ray follow-up of the exceptionally high-activity state of PKS 1510−089 in 2011

Author

Orienti, M., primary, Koyama, S., additional, D'Ammando, F., additional, Giroletti, M., additional, Kino, M., additional, Nagai, H., additional, Venturi, T., additional, Dallacasa, D., additional, Giovannini, G., additional, Angelakis, E., additional, Fuhrmann, L., additional, Hovatta, T., additional, Max-Moerbeck, W., additional, Schinzel, F. K., additional, Akiyama, K., additional, Hada, K., additional, Honma, M., additional, Niinuma, K., additional, Gasparrini, D., additional, Krichbaum, T. P., additional, Nestoras, I., additional, Readhead, A. C. S., additional, Richards, J. L., additional, Riquelme, D., additional, Sievers, A., additional, Ungerechts, H., additional, and Zensus, J. A., additional

Published
2012
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11. Multiwavelength intraday variability of the BL Lacertae S5 0716+714

Author

Gupta, Alok C., primary, Krichbaum, T. P., additional, Wiita, P. J., additional, Rani, B., additional, Sokolovsky, K. V., additional, Mohan, P., additional, Mangalam, A., additional, Marchili, N., additional, Fuhrmann, L., additional, Agudo, I., additional, Bach, U., additional, Bachev, R., additional, Böttcher, M., additional, Gabanyi, K. E., additional, Gaur, H., additional, Hawkins, K., additional, Kimeridze, G. N., additional, Kurtanidze, O. M., additional, Kurtanidze, S. O., additional, Lee, C.-U., additional, Liu, X., additional, McBreen, B., additional, Nesci, R., additional, Nestoras, G., additional, Nikolashvili, M. G., additional, Ohlert, J. M., additional, Palma, N., additional, Peneva, S., additional, Pursimo, T., additional, Semkov, E., additional, Strigachev, A., additional, Webb, J. R., additional, Wiesemeyer, H., additional, and Zensus, J. A., additional

Published
2012
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14. The radio structure of S5 1803+784

Author

Britzen, S., primary, Witzel, A., additional, Krichbaum, T. P., additional, Beckert, T., additional, Campbell, R. M., additional, Schalinski, C., additional, and Campbell, J., additional

Published
2005
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15. Detection of significant cm to sub-mm band radio and γ-ray correlated variability in Fermi bright blazars.

Author

Fuhrmann, L., Larsson, S., Chiang, J., Angelakis, E., Zensus, J. A., Nestoras, I., Krichbaum, T. P., Ungerechts, H., Sievers, A., Pavlidou, V., Readhead, A. C. S., Max-Moerbeck, W., and Pearson, T. J.

Subjects
BL Lacertae objects, RADIAL velocity of galaxies, GALAXY spectra, GAMMA ray bursts, STELLAR photospheres
Abstract

The exact location of the γ-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis between radio (11 cm to 0.8 mm wavelength, F-GAMMA programme) and γ-ray (0.1–300 GeV) ∼3.5 yr light curves of 54 Fermi-bright blazars. We perform a source stacking analysis and estimate significances and chance correlations using mixed source correlations. Our results reveal: (i) the first highly significant multiband radio and γ-ray correlations (radio lagging γ rays) when averaging over the whole sample, (ii) average time delays (source frame: 76 ± 23 to 7 ± 9 d), systematically decreasing from cm to mm/sub-mm bands with a frequency dependence τr, γ(ν) ∝ ν−1, in good agreement with jet opacity dominated by synchrotron self-absorption, (iii) a bulk γ-ray production region typically located within/upstream of the 3 mm core region (τ3mm, γ = 12 ± 8 d), (iv) mean distances between the region of γ-ray peak emission and the radio ‘τ = 1 photosphere’ decreasing from 9.8 ± 3.0 pc (11 cm) to 0.9 ± 1.1 pc (2 mm) and 1.4 ± 0.8 pc (0.8 mm), (v) 3 mm/γ-ray correlations in nine individual sources at a significance level where one is expected by chance (probability: 4 × 10−6), (vi) opacity and ‘time lag core shift’ estimates for quasar 3C 454.3 providing a lower limit for the distance of the bulk γ-ray production region from the supermassive black hole (SMBH) of ∼0.8–1.6 pc, i.e. at the outer edge of the broad-line region (BLR) or beyond. A 3 mm τ = 1 surface at ∼2–3 pc from the jet base (i.e. well outside the ‘canonical BLR’) finally suggests that BLR material extends to several parsec distances from the SMBH. [ABSTRACT FROM AUTHOR]

Published
2014
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