Search

Your search keyword '"Mooney, B"' showing total 32 results
Start Over Author "Mooney, B" Database OAIster
32 results on '"Mooney, B"'

1. HBV-STOP study: Large hepatitis B virus flares off nucleot(s)ide analog therapy cause large innate immune response.

Author

Bowden S., Jackson K., Locarnini S., Visvanathan K., Thompson A., Hall S., Burns G., Anagnostou D., Morris R., Mooney B., Levy M., Sievert W., Lubel J., Nicoll A., Strasser S., Desmond P., Ngu M., Angus P., Meredith C., Revill P., Bowden S., Jackson K., Locarnini S., Visvanathan K., Thompson A., Hall S., Burns G., Anagnostou D., Morris R., Mooney B., Levy M., Sievert W., Lubel J., Nicoll A., Strasser S., Desmond P., Ngu M., Angus P., Meredith C., and Revill P.

Abstract

Background and Aim: Current guidelines recommend indefinite nucleot( s)ide analog (NA) therapy for patients with HBeAg-negative chronic hepatitis B virus (HBV). However, sustained virological response (SVR) has been described in patients after discontinuation of long-term NA therapy. The HBV-STOP study is a prospective multicenter study of NA discontinuation in patients who have achieved long-term virological suppression on treatment. In addition to previously describing clinical outcomes after treatment discontinuation, we also aim to detail the immunological response in this scenario, especially that of the innate immune system. Method(s): Stimulation study: To gauge the potential innate activation of the peripheral blood cells by the flare, we stimulated peripheral blood mononuclear cell (PBMC) samples of HBV-STOP study patients by toll-like receptor (TLR)-specific ligands (TLR-2, TLR-3, TLR-4, TLR-7/8, and TLR-9) ex vivo. These patients either had a large biochemical flare (alanine aminotransferase [ALT] level > 10 x ULN) or did not have a biochemical flare (ALT < ULN). PBMCs were tested at baseline and peak ALT level time points, and matched non-flare samples were used as controls. Cytokine levels (IL-6, IL-8, IL-10, TNF, CCL-2, and CXCL-10) were measured after PBMC stimulation. Flow cytometry study: Additionally, we performed flow cytometry on PBMC samples of HBV-STOP study patients who either had a large biochemical flare (ALT > 10 x ULN) or did not have a biochemical flare. We did these studies at baseline and peak ALT level time points. Non-flare samples were matched to the closest respective week. Flow cytometry was used to isolate specific natural killer (NK) cell and monocyte populations using CD 56, CD 3, CD 16, and CD 14 cell surface markers. Expression of various immune markers was assessed in each cell population, including NKP46, NKG2D, TLR2, TLR4, and TREM1. Result(s): The stimulation study cohort consisted of 13 patients with flares and 12 patient

Published
2021

2. HBV-STOP study: Large hepatitis B virus flares off nucleot(s)ide analog therapy cause large innate immune response.

Author

Bowden S., Jackson K., Locarnini S., Visvanathan K., Thompson A., Hall S., Burns G., Anagnostou D., Morris R., Mooney B., Levy M., Sievert W., Lubel J., Nicoll A., Strasser S., Desmond P., Ngu M., Angus P., Meredith C., Revill P., Bowden S., Jackson K., Locarnini S., Visvanathan K., Thompson A., Hall S., Burns G., Anagnostou D., Morris R., Mooney B., Levy M., Sievert W., Lubel J., Nicoll A., Strasser S., Desmond P., Ngu M., Angus P., Meredith C., and Revill P.

Abstract

Background and Aim: Current guidelines recommend indefinite nucleot( s)ide analog (NA) therapy for patients with HBeAg-negative chronic hepatitis B virus (HBV). However, sustained virological response (SVR) has been described in patients after discontinuation of long-term NA therapy. The HBV-STOP study is a prospective multicenter study of NA discontinuation in patients who have achieved long-term virological suppression on treatment. In addition to previously describing clinical outcomes after treatment discontinuation, we also aim to detail the immunological response in this scenario, especially that of the innate immune system. Method(s): Stimulation study: To gauge the potential innate activation of the peripheral blood cells by the flare, we stimulated peripheral blood mononuclear cell (PBMC) samples of HBV-STOP study patients by toll-like receptor (TLR)-specific ligands (TLR-2, TLR-3, TLR-4, TLR-7/8, and TLR-9) ex vivo. These patients either had a large biochemical flare (alanine aminotransferase [ALT] level > 10 x ULN) or did not have a biochemical flare (ALT < ULN). PBMCs were tested at baseline and peak ALT level time points, and matched non-flare samples were used as controls. Cytokine levels (IL-6, IL-8, IL-10, TNF, CCL-2, and CXCL-10) were measured after PBMC stimulation. Flow cytometry study: Additionally, we performed flow cytometry on PBMC samples of HBV-STOP study patients who either had a large biochemical flare (ALT > 10 x ULN) or did not have a biochemical flare. We did these studies at baseline and peak ALT level time points. Non-flare samples were matched to the closest respective week. Flow cytometry was used to isolate specific natural killer (NK) cell and monocyte populations using CD 56, CD 3, CD 16, and CD 14 cell surface markers. Expression of various immune markers was assessed in each cell population, including NKP46, NKG2D, TLR2, TLR4, and TREM1. Result(s): The stimulation study cohort consisted of 13 patients with flares and 12 patient

Published
2021

3. A survey of unidentified egret sources at very high energies

Author

Fegan, S. J., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Lessard, R. W., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, P., Mukherjee, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Fegan, S. J., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Lessard, R. W., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, P., Mukherjee, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Published
2005

4. A very high energy gamma-ray spectrum of 1ES 2344+514

Author

Schroedter, M., Badran, H. M., Buckley, J. H., Gordo, J. B., Carter-Lewis, D. A., Duke, C., Fegan, D. J., Fegan, S. F., Finley, J. P., Gillanders, G. H., Grube, J., Horan, D., Kenny, G. E., Kertzman, M., Kosack, K., Krennrich, F., Kieda, D. B., Kildea, J., Lang, M. J., Lee, K., Moriarty, P., Quinn, J., Quinn, M., Power-Mooney, B., Sembroski, G. H., Wakely, S. P., Vassiliev, V. V., Weekes, T. C., Zweerink, J., Schroedter, M., Badran, H. M., Buckley, J. H., Gordo, J. B., Carter-Lewis, D. A., Duke, C., Fegan, D. J., Fegan, S. F., Finley, J. P., Gillanders, G. H., Grube, J., Horan, D., Kenny, G. E., Kertzman, M., Kosack, K., Krennrich, F., Kieda, D. B., Kildea, J., Lang, M. J., Lee, K., Moriarty, P., Quinn, J., Quinn, M., Power-Mooney, B., Sembroski, G. H., Wakely, S. P., Vassiliev, V. V., Weekes, T. C., and Zweerink, J.

Abstract

The BL Lacertae (BL Lac) object 1ES 2344+514 (1ES 2344), at a redshift of 0.044, was discovered as a source of very high energy (VHE) gamma rays by the Whipple collaboration in 1995 (Catanese et al.). This detection was recently confirmed by the HEGRA collaboration (Tluczykont et al.). As is typical for high-frequency-peaked blazars, the VHE gamma-ray emission is highly variable. On the night of 1995 December 20, a gamma-ray flare of 5.3 sigma significance was detected, the brightest outburst from this object to date. The emission region is compatible with a point source. The spectrum between 0.8 and 12.6 TeV can be described by a power law, d(3)N/dEdAdt = (5.1 +/- 1.0(st) +/- 1.2(sy)) X 10(-7)(E/TeV)(-2.54 +/- 0.17st +/- 0.07sy) TeV-1 m(-2) s(-1). If we compare the spectral index with that of the other five confirmed TeV blazars, the spectrum of 1ES 2344 is similar to that of 1ES 1959+650, which is located at almost the same distance. The spectrum of 1ES 2344 is steeper than the brightest flare spectra of Markarian 421 (Mrk 421) and Markarian 501 ( Mrk 501), both of which are located at a distance about two-thirds that of 1ES 2344, and harder than the spectra of PKS 2155-304 and H1426+428, which are located almost 3 times as far away. This trend is consistent with attenuation caused by the infrared extragalactic background radiation.

Published
2005

5. A multiwavelength view of the TeV blazar markarian 421: Correlated variability, flaring, and spectral evolution

Author

Blazejowski, M. B., Blaylock, G., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cogan, P., Cui, W., Daniel, M., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gammell, S., Gibbs, K., Gillanders, G. G., Grube, J., Gutierrez, K., Hall, J., Hanna, D., Holder, J., Horan, D., Humensky, B., Kenny, G., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M., LeBohec, S., Linton, E., Evans, J. L., Maier, G., Mendoza, D., Milovanovic, A., Moriarty, P., Nagai, T. N., Ong, R. A., Mooney, B. P., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rebillot, P., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Valcarel, L., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., White, R., Zweerink, J., Mochejska, B., Smith, B., Aller, M., Aller, H., Terasranta, H., Boltwood, P., Sadun, A., Stanek, K., Adams, E., Foster, J., Hartman, J., Lai, K., Bottcher, M., Reimer, A., Jung, I., Blazejowski, M. B., Blaylock, G., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cogan, P., Cui, W., Daniel, M., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gammell, S., Gibbs, K., Gillanders, G. G., Grube, J., Gutierrez, K., Hall, J., Hanna, D., Holder, J., Horan, D., Humensky, B., Kenny, G., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M., LeBohec, S., Linton, E., Evans, J. L., Maier, G., Mendoza, D., Milovanovic, A., Moriarty, P., Nagai, T. N., Ong, R. A., Mooney, B. P., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rebillot, P., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Valcarel, L., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., White, R., Zweerink, J., Mochejska, B., Smith, B., Aller, M., Aller, H., Terasranta, H., Boltwood, P., Sadun, A., Stanek, K., Adams, E., Foster, J., Hartman, J., Lai, K., Bottcher, M., Reimer, A., and Jung, I.

Abstract

We report results from an intensive multiwavelength monitoring campaign on the TeV blazar Mrk 421 over the period of 2003 - 2004. The source was observed simultaneously at TeV energies with the Whipple 10 m telescope and at X-ray energies with the Rossi X-Ray Timing Explorer (RXTE) during each clear night within the Whipple observing windows. Supporting observations were also frequently carried out at optical and radio wavelengths to provide simultaneous or contemporaneous coverages. The large amount of simultaneous data has allowed us to examine the variability of Mrk 421 in detail, including cross-band correlation and broadband spectral variability, over a wide range of flux. The variabilities are generally correlated between the X-ray and gamma-ray bands, although the correlation appears to be fairly loose. The light curves show the presence of flares with varying amplitudes on a wide range of timescales at both X-ray and TeV energies. Of particular interest is the presence of TeV flares that have no coincident counterparts at longer wavelengths, because the phenomenon seems difficult to understand in the context of the proposed emission models for TeV blazars. We have also found that the TeV flux reached its peak days before the X-ray flux did during a giant flare (or outburst) in 2004 (with the peak flux reaching similar to 135mcrab in X-rays, as seen by the RXTE ASM, and similar to 3 crab in gamma rays). Such a difference in the development of the flare presents a further challenge to both the leptonic and hadronic emission models. Mrk 421 varied much less at optical and radio wavelengths. Surprisingly, the normalized variability amplitude in the optical seems to be comparable to that in the radio, perhaps suggesting the presence of different populations of emitting electrons in the jet. The spectral energy distribution of Mrk 421 is seen to vary with flux, with the two characteristic peaks moving toward higher energies at higher fluxes. We have failed to fit

Published
2005

6. Spectrum of very high energy gamma-rays from the blazar 1ES 1959+650 during flaring activity in 2002

Author

Daniel, M. K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cogan, P., Cui, W., D'Vali, M., Perez, I. D., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Humensky, T. B., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Daniel, M. K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cogan, P., Cui, W., D'Vali, M., Perez, I. D., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Humensky, T. B., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

The blazar 1ES 1959+650 was observed in a flaring state with the Whipple 10 m Imaging Atmospheric Cerenkov Telescope in 2002 May. A spectral analysis has been carried out on the data from that time period, and the resulting very high energy gamma-ray spectrum (E greater than or equal to 316 GeV) can be well fitted by a power law of differential spectral index alpha = 2.78 +/- 0.12(stat) +/- 0.21(sys). On 2002 June 4, the source flared dramatically in the gamma-ray range without any coincident increase in the X-ray emission, providing the first unambiguous example of an "orphan'' gamma-ray flare from a blazar. The gamma-ray spectrum for these data can also be described by a simple power-law fit with alpha = 2.82 +/- 0.15(stat) +/- 0.30(sys). There is no compelling evidence for spectral variability or for any cutoff to the spectrum.

Published
2005

7. Spectrum of very high energy gamma-rays from the blazar 1ES 1959+650 during flaring activity in 2002

Author

Daniel, M. K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cogan, P., Cui, W., D'Vali, M., Perez, I. D., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Humensky, T. B., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Daniel, M. K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cogan, P., Cui, W., D'Vali, M., Perez, I. D., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Humensky, T. B., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

The blazar 1ES 1959+650 was observed in a flaring state with the Whipple 10 m Imaging Atmospheric Cerenkov Telescope in 2002 May. A spectral analysis has been carried out on the data from that time period, and the resulting very high energy gamma-ray spectrum (E greater than or equal to 316 GeV) can be well fitted by a power law of differential spectral index alpha = 2.78 +/- 0.12(stat) +/- 0.21(sys). On 2002 June 4, the source flared dramatically in the gamma-ray range without any coincident increase in the X-ray emission, providing the first unambiguous example of an "orphan'' gamma-ray flare from a blazar. The gamma-ray spectrum for these data can also be described by a simple power-law fit with alpha = 2.82 +/- 0.15(stat) +/- 0.30(sys). There is no compelling evidence for spectral variability or for any cutoff to the spectrum.

Published
2005

8. A very high energy gamma-ray spectrum of 1ES 2344+514

Author

Schroedter, M., Badran, H. M., Buckley, J. H., Gordo, J. B., Carter-Lewis, D. A., Duke, C., Fegan, D. J., Fegan, S. F., Finley, J. P., Gillanders, G. H., Grube, J., Horan, D., Kenny, G. E., Kertzman, M., Kosack, K., Krennrich, F., Kieda, D. B., Kildea, J., Lang, M. J., Lee, K., Moriarty, P., Quinn, J., Quinn, M., Power-Mooney, B., Sembroski, G. H., Wakely, S. P., Vassiliev, V. V., Weekes, T. C., Zweerink, J., Schroedter, M., Badran, H. M., Buckley, J. H., Gordo, J. B., Carter-Lewis, D. A., Duke, C., Fegan, D. J., Fegan, S. F., Finley, J. P., Gillanders, G. H., Grube, J., Horan, D., Kenny, G. E., Kertzman, M., Kosack, K., Krennrich, F., Kieda, D. B., Kildea, J., Lang, M. J., Lee, K., Moriarty, P., Quinn, J., Quinn, M., Power-Mooney, B., Sembroski, G. H., Wakely, S. P., Vassiliev, V. V., Weekes, T. C., and Zweerink, J.

Abstract

The BL Lacertae (BL Lac) object 1ES 2344+514 (1ES 2344), at a redshift of 0.044, was discovered as a source of very high energy (VHE) gamma rays by the Whipple collaboration in 1995 (Catanese et al.). This detection was recently confirmed by the HEGRA collaboration (Tluczykont et al.). As is typical for high-frequency-peaked blazars, the VHE gamma-ray emission is highly variable. On the night of 1995 December 20, a gamma-ray flare of 5.3 sigma significance was detected, the brightest outburst from this object to date. The emission region is compatible with a point source. The spectrum between 0.8 and 12.6 TeV can be described by a power law, d(3)N/dEdAdt = (5.1 +/- 1.0(st) +/- 1.2(sy)) X 10(-7)(E/TeV)(-2.54 +/- 0.17st +/- 0.07sy) TeV-1 m(-2) s(-1). If we compare the spectral index with that of the other five confirmed TeV blazars, the spectrum of 1ES 2344 is similar to that of 1ES 1959+650, which is located at almost the same distance. The spectrum of 1ES 2344 is steeper than the brightest flare spectra of Markarian 421 (Mrk 421) and Markarian 501 ( Mrk 501), both of which are located at a distance about two-thirds that of 1ES 2344, and harder than the spectra of PKS 2155-304 and H1426+428, which are located almost 3 times as far away. This trend is consistent with attenuation caused by the infrared extragalactic background radiation.

Published
2005

9. A multiwavelength view of the TeV blazar markarian 421: Correlated variability, flaring, and spectral evolution

Author

Blazejowski, M. B., Blaylock, G., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cogan, P., Cui, W., Daniel, M., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gammell, S., Gibbs, K., Gillanders, G. G., Grube, J., Gutierrez, K., Hall, J., Hanna, D., Holder, J., Horan, D., Humensky, B., Kenny, G., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M., LeBohec, S., Linton, E., Evans, J. L., Maier, G., Mendoza, D., Milovanovic, A., Moriarty, P., Nagai, T. N., Ong, R. A., Mooney, B. P., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rebillot, P., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Valcarel, L., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., White, R., Zweerink, J., Mochejska, B., Smith, B., Aller, M., Aller, H., Terasranta, H., Boltwood, P., Sadun, A., Stanek, K., Adams, E., Foster, J., Hartman, J., Lai, K., Bottcher, M., Reimer, A., Jung, I., Blazejowski, M. B., Blaylock, G., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cogan, P., Cui, W., Daniel, M., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gammell, S., Gibbs, K., Gillanders, G. G., Grube, J., Gutierrez, K., Hall, J., Hanna, D., Holder, J., Horan, D., Humensky, B., Kenny, G., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M., LeBohec, S., Linton, E., Evans, J. L., Maier, G., Mendoza, D., Milovanovic, A., Moriarty, P., Nagai, T. N., Ong, R. A., Mooney, B. P., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rebillot, P., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Valcarel, L., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., White, R., Zweerink, J., Mochejska, B., Smith, B., Aller, M., Aller, H., Terasranta, H., Boltwood, P., Sadun, A., Stanek, K., Adams, E., Foster, J., Hartman, J., Lai, K., Bottcher, M., Reimer, A., and Jung, I.

Abstract

We report results from an intensive multiwavelength monitoring campaign on the TeV blazar Mrk 421 over the period of 2003 - 2004. The source was observed simultaneously at TeV energies with the Whipple 10 m telescope and at X-ray energies with the Rossi X-Ray Timing Explorer (RXTE) during each clear night within the Whipple observing windows. Supporting observations were also frequently carried out at optical and radio wavelengths to provide simultaneous or contemporaneous coverages. The large amount of simultaneous data has allowed us to examine the variability of Mrk 421 in detail, including cross-band correlation and broadband spectral variability, over a wide range of flux. The variabilities are generally correlated between the X-ray and gamma-ray bands, although the correlation appears to be fairly loose. The light curves show the presence of flares with varying amplitudes on a wide range of timescales at both X-ray and TeV energies. Of particular interest is the presence of TeV flares that have no coincident counterparts at longer wavelengths, because the phenomenon seems difficult to understand in the context of the proposed emission models for TeV blazars. We have also found that the TeV flux reached its peak days before the X-ray flux did during a giant flare (or outburst) in 2004 (with the peak flux reaching similar to 135mcrab in X-rays, as seen by the RXTE ASM, and similar to 3 crab in gamma rays). Such a difference in the development of the flare presents a further challenge to both the leptonic and hadronic emission models. Mrk 421 varied much less at optical and radio wavelengths. Surprisingly, the normalized variability amplitude in the optical seems to be comparable to that in the radio, perhaps suggesting the presence of different populations of emitting electrons in the jet. The spectral energy distribution of Mrk 421 is seen to vary with flux, with the two characteristic peaks moving toward higher energies at higher fluxes. We have failed to fit

Published
2005

10. Tev Gamma-ray observations of the galactic center

Author

Kosack, K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Connaughton, V., Cui, W., Daniel, M., D'Vall, M., Perez, I. D. L., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Gutierrez, K., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Kosack, K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Connaughton, V., Cui, W., Daniel, M., D'Vall, M., Perez, I. D. L., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Gutierrez, K., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

We report a possible detection of TeV gamma rays from the Galactic center by the Whipple 10 m gamma-ray telescope. Twenty-six hours of data were taken over an extended period from 1995 through 2003 resulting in a total significance of 3.7 sigma. The measured excess corresponds to an integral flux of 1.6 x 10(-8) +/- 0.5 x 10(-8) (stat) +/- 0.3 x 10(-8) (sys) photons m(-2) s(-1) above an energy of 2.8 TeV, roughly 40% of the flux from the Crab Nebula at this energy. The 95% confidence region has an angular extent of about 15' and includes the position of Sgr A*. The detection is consistent with a point source and shows no evidence of variability.

Published
2004

11. Constraints on the very high energy emission from BL Lacertae objects

Author

Horan, D., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Evans, J. L., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Horan, D., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Evans, J. L., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

We present results from observations of 29 BL Lacertae objects, taken with the Whipple Observatory 10 m gamma-ray telescope between 1995 and 2000. The observed objects are mostly at low redshift (z<0.2), but observations of objects of up to z=0.444 are also reported. Five of the objects are EGRET sources and two are unconfirmed TeV sources. Three of the confirmed sources of extragalactic TeV gamma rays were originally observed as part of this survey and have been reported elsewhere. No significant excesses are detected from any of the other objects observed, on timescales of days, months, or years. We report 99.9% confidence level flux upper limits for the objects for each observing season. The flux upper limits are typically 20% of the Crab flux, although for some sources, limits as sensitive as 6% of the Crab flux were derived. The results are consistent with the synchrotron self-Compton model predictions considered in this work.

Published
2004

12. A search for TeV gamma-ray emission from high-peaked flat-spectrum radio quasars using the Whipple air Cerenkov telescope

Author

Falcone, A. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D., Duke, C., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R., Pallassini, R., Petry, D., Pizlo, F., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Tyler, K., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Falcone, A. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D., Duke, C., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R., Pallassini, R., Petry, D., Pizlo, F., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Tyler, K., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

Blazars have traditionally been separated into two broad categories based on their optical emission characteristics. Blazars with faint or no emission lines are referred to as BL Lacertae objects ( BL Lacs), and blazars with prominent, broad emission lines are commonly referred to as flat-spectrum radio quasars (FSRQs). The spectral energy distribution of FSRQs has generally been thought of as being more akin to the low-peaked BL Lacs, which exhibit a peak in the infrared region of the spectrum, as opposed to high-peaked BL Lacs (HBLs), which exhibit a peak in UV/X-ray region of the spectrum. All blazars that are currently confirmed as sources of TeV emission fall into the HBL category. Recent surveys have found several FSRQs that exhibit spectral properties, particularly the synchrotron peak frequency, similar to HBLs. These objects are potential sources of TeV emission according to several models of blazar jet emission and the evolution of blazars. Measurements of TeV flux or flux upper limits could impact existing theories explaining the links between different blazar types and could have a significant impact on our understanding of the nature of objects that are capable of TeV emission. In particular, the presence ( or absence) of TeV emission from FSRQs could confirm ( or cast doubt on) recent evolutionary models that expect intermediate objects in a transitional state between FSRQ and BL Lac. The Whipple 10 m imaging air Cerenkov gamma-ray telescope is well suited for TeV gamma-ray observations. Using the Whipple telescope, we have taken data on a small selection of nearby (z < 0.1 in most cases) high-peaked FSRQs. Although one of the objects, B2 0321+33, showed marginal evidence of flaring, no significant emission was detected. The implications of this paucity of emission and the derived upper limits are discussed.

Published
2004

13. VERITAS: the Very Energetic Radiation Imaging Telescope Array System

Author

Krennrich, F., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Vassiliev, V. V., Walker, G., Wakely, S. P., Weekes, T. C., Zweerink, J., Krennrich, F., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Vassiliev, V. V., Walker, G., Wakely, S. P., Weekes, T. C., and Zweerink, J.

Abstract

The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is the major next generation imaging atmospheric Cherenkov gamma-ray telescope in the western hemisphere and will be located in southern Arizona nearby Kitt Peak National Observatory. The VERITAS observatory will provide unprecedented sensitivity to photon energies between 50 GeV and 50 TeV. The first stage is an array of four telescopes to be fully operational in early 2006, with an expansion to seven telescopes envisioned for 2008. The construction of a prototype telescope is underway, for which first light is expected in Fall 2003. The technical concept is outlined and a progress report is given. (C) 2004 Published by Elsevier B.V.

Published
2004

14. Constraints on the very high energy emission from BL Lacertae objects

Author

Horan, D., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Evans, J. L., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Horan, D., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Catanese, M., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Evans, J. L., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

We present results from observations of 29 BL Lacertae objects, taken with the Whipple Observatory 10 m gamma-ray telescope between 1995 and 2000. The observed objects are mostly at low redshift (z<0.2), but observations of objects of up to z=0.444 are also reported. Five of the objects are EGRET sources and two are unconfirmed TeV sources. Three of the confirmed sources of extragalactic TeV gamma rays were originally observed as part of this survey and have been reported elsewhere. No significant excesses are detected from any of the other objects observed, on timescales of days, months, or years. We report 99.9% confidence level flux upper limits for the objects for each observing season. The flux upper limits are typically 20% of the Crab flux, although for some sources, limits as sensitive as 6% of the Crab flux were derived. The results are consistent with the synchrotron self-Compton model predictions considered in this work.

Published
2004

15. A search for TeV gamma-ray emission from high-peaked flat-spectrum radio quasars using the Whipple air Cerenkov telescope

Author

Falcone, A. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D., Duke, C., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R., Pallassini, R., Petry, D., Pizlo, F., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Tyler, K., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Falcone, A. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D., Duke, C., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R., Pallassini, R., Petry, D., Pizlo, F., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Tyler, K., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

Blazars have traditionally been separated into two broad categories based on their optical emission characteristics. Blazars with faint or no emission lines are referred to as BL Lacertae objects ( BL Lacs), and blazars with prominent, broad emission lines are commonly referred to as flat-spectrum radio quasars (FSRQs). The spectral energy distribution of FSRQs has generally been thought of as being more akin to the low-peaked BL Lacs, which exhibit a peak in the infrared region of the spectrum, as opposed to high-peaked BL Lacs (HBLs), which exhibit a peak in UV/X-ray region of the spectrum. All blazars that are currently confirmed as sources of TeV emission fall into the HBL category. Recent surveys have found several FSRQs that exhibit spectral properties, particularly the synchrotron peak frequency, similar to HBLs. These objects are potential sources of TeV emission according to several models of blazar jet emission and the evolution of blazars. Measurements of TeV flux or flux upper limits could impact existing theories explaining the links between different blazar types and could have a significant impact on our understanding of the nature of objects that are capable of TeV emission. In particular, the presence ( or absence) of TeV emission from FSRQs could confirm ( or cast doubt on) recent evolutionary models that expect intermediate objects in a transitional state between FSRQ and BL Lac. The Whipple 10 m imaging air Cerenkov gamma-ray telescope is well suited for TeV gamma-ray observations. Using the Whipple telescope, we have taken data on a small selection of nearby (z < 0.1 in most cases) high-peaked FSRQs. Although one of the objects, B2 0321+33, showed marginal evidence of flaring, no significant emission was detected. The implications of this paucity of emission and the derived upper limits are discussed.

Published
2004

16. Tev Gamma-ray observations of the galactic center

Author

Kosack, K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Connaughton, V., Cui, W., Daniel, M., D'Vall, M., Perez, I. D. L., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Gutierrez, K., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Zweerink, J., Kosack, K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Connaughton, V., Cui, W., Daniel, M., D'Vall, M., Perez, I. D. L., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J. A., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Gutierrez, K., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., McEnery, J., Moriarty, R., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Syson, A., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., and Zweerink, J.

Abstract

We report a possible detection of TeV gamma rays from the Galactic center by the Whipple 10 m gamma-ray telescope. Twenty-six hours of data were taken over an extended period from 1995 through 2003 resulting in a total significance of 3.7 sigma. The measured excess corresponds to an integral flux of 1.6 x 10(-8) +/- 0.5 x 10(-8) (stat) +/- 0.3 x 10(-8) (sys) photons m(-2) s(-1) above an energy of 2.8 TeV, roughly 40% of the flux from the Crab Nebula at this energy. The 95% confidence region has an angular extent of about 15' and includes the position of Sgr A*. The detection is consistent with a point source and shows no evidence of variability.

Published
2004

17. VERITAS: the Very Energetic Radiation Imaging Telescope Array System

Author

Krennrich, F., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Vassiliev, V. V., Walker, G., Wakely, S. P., Weekes, T. C., Zweerink, J., Krennrich, F., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D., Celik, O., Cui, W., Daniel, M., D'Vali, M., Perez, I. D. C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L. F., Gaidos, J., Gammell, S., Gibbs, K., Gillanders, G. H., Grube, J., Hall, J., Hall, T. A., Hanna, D., Hillas, A. M., Holder, J., Horan, D., Jarvis, A., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Lang, M. J., LeBohec, S., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Quinn, M., Ragan, K., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G., Swordy, S. P., Syson, A., Vassiliev, V. V., Walker, G., Wakely, S. P., Weekes, T. C., and Zweerink, J.

Abstract

The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is the major next generation imaging atmospheric Cherenkov gamma-ray telescope in the western hemisphere and will be located in southern Arizona nearby Kitt Peak National Observatory. The VERITAS observatory will provide unprecedented sensitivity to photon energies between 50 GeV and 50 TeV. The first stage is an array of four telescopes to be fully operational in early 2006, with an expansion to seven telescopes envisioned for 2008. The construction of a prototype telescope is underway, for which first light is expected in Fall 2003. The technical concept is outlined and a progress report is given. (C) 2004 Published by Elsevier B.V.

Published
2004

18. Search for high-energy gamma rays from an X-ray-selected blazar sample

Author

Perez, I. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cui, W., Dowdall, C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R. A., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Perez, I. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cui, W., Dowdall, C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R. A., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

Our understanding of blazars has been greatly increased in recent years by extensive multiwavelength observations, particularly in the radio, X-ray, and gamma-ray regions. Over the past decade the Whipple 10 m telescope has contributed to this with the detection of five BL Lacertae objects at very high gamma-ray energies. The combination of multiwavelength data has shown that blazars follow a well-defined sequence in terms of their broadband spectral properties. Together with providing constraints on emission models, this information has yielded a means by which potential sources of TeV emission may be identified and predictions made as to their possible gamma-ray flux. We have used the Whipple telescope to search for TeV gamma-ray emission from eight objects selected from a list of such candidates. No evidence has been found for very high energy emission from the objects in our sample, and upper limits have been derived for the mean gamma-ray flux above 390 GeV. These flux upper limits are compared with the model predictions, and the implications of our results for future observations are discussed.

Published
2003

19. Detection of TeV gamma rays from the BL Lacertae object 1ES 1959+650 with the Whipple 10 meter telescope

Author

Holder, J., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Dowdall, C., Duke, C., Perez, I. D., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Holder, J., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Dowdall, C., Duke, C., Perez, I. D., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

We present the first strong detection of very high energy gamma-rays from the close (z=0.048) X-ray-selected BL Lacertae object 1ES 1959+650. Observations were made with the Whipple 10 m telescope on Mount Hopkins, Arizona, using the atmospheric Cerenkov imaging technique. The flux between 2002 May and July was highly variable, with a mean of 0.64+/-0.03 times the steady flux from the Crab Nebula and reaching a maximum of 5 crab, with variability on timescales as short as 7 hr.

Published
2003

20. Search for high-energy gamma rays from an X-ray-selected blazar sample

Author

Perez, I. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cui, W., Dowdall, C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R. A., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Perez, I. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Cui, W., Dowdall, C., Duke, C., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R. A., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

Our understanding of blazars has been greatly increased in recent years by extensive multiwavelength observations, particularly in the radio, X-ray, and gamma-ray regions. Over the past decade the Whipple 10 m telescope has contributed to this with the detection of five BL Lacertae objects at very high gamma-ray energies. The combination of multiwavelength data has shown that blazars follow a well-defined sequence in terms of their broadband spectral properties. Together with providing constraints on emission models, this information has yielded a means by which potential sources of TeV emission may be identified and predictions made as to their possible gamma-ray flux. We have used the Whipple telescope to search for TeV gamma-ray emission from eight objects selected from a list of such candidates. No evidence has been found for very high energy emission from the objects in our sample, and upper limits have been derived for the mean gamma-ray flux above 390 GeV. These flux upper limits are compared with the model predictions, and the implications of our results for future observations are discussed.

Published
2003

21. Detection of TeV gamma rays from the BL Lacertae object 1ES 1959+650 with the Whipple 10 meter telescope

Author

Holder, J., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Dowdall, C., Duke, C., Perez, I. D., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Holder, J., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Dowdall, C., Duke, C., Perez, I. D., Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortson, L., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., LeBohec, S., Linton, E. T., Lloyd-Evans, J., Moriarty, P., Muller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Petry, D., Power-Mooney, B., Quinn, J., Rebillot, P., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

We present the first strong detection of very high energy gamma-rays from the close (z=0.048) X-ray-selected BL Lacertae object 1ES 1959+650. Observations were made with the Whipple 10 m telescope on Mount Hopkins, Arizona, using the atmospheric Cerenkov imaging technique. The flux between 2002 May and July was highly variable, with a mean of 0.64+/-0.03 times the steady flux from the Crab Nebula and reaching a maximum of 5 crab, with variability on timescales as short as 7 hr.

Published
2003

22. The TeV spectrum of H1426+428

Author

Petry, D., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Duke, C., Perez, I. de la Calle, Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krennrich, F., LeBohec, S., Moriarty, P., Müller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Power-Mooney, B., Quinn, J., Reay, N. W., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sidwell, R., Stanton, N., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Petry, D., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Duke, C., Perez, I. de la Calle, Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krennrich, F., LeBohec, S., Moriarty, P., Müller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Power-Mooney, B., Quinn, J., Reay, N. W., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sidwell, R., Stanton, N., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

The BL Lac object H1426+428 was recently detected as a high energy gamma-ray source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape dF/dE = 10^(-7.31 +- 0.15(stat) +- 0.16(syst)) x E^(-3.50 +- 0.35(stat) +- 0.05(syst)) m^(-2)s^(-1)TeV^(-1) The statistical evidence from our data for emission above 2.5 TeV is 2.6 sigma. With 95% c.l., the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is consistent with the (non-contemporaneous) measurement by Aharonian et al. (2002) both in shape and in normalization. Below 800 GeV, the data clearly favours a spectrum steeper than that of any other TeV Blazar observed so far indicating a difference in the processes involved either at the source or in the intervening space., Comment: LaTeX, 8 pages, 4 figures, accepted for publication in ApJ

Published
2002
Full Text
View/download PDF

23. The TeV spectrum of H1426+428

Author

Petry, D., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Duke, C., Perez, I. de la Calle, Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krennrich, F., LeBohec, S., Moriarty, P., Müller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Power-Mooney, B., Quinn, J., Reay, N. W., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sidwell, R., Stanton, N., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., Weekes, T. C., Petry, D., Bond, I. H., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Cui, W., Duke, C., Perez, I. de la Calle, Falcone, A., Fegan, D. J., Fegan, S. J., Finley, J. P., Gaidos, J. A., Gibbs, K., Gammell, S., Hall, J., Hall, T. A., Hillas, A. M., Holder, J., Horan, D., Jordan, M., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krennrich, F., LeBohec, S., Moriarty, P., Müller, D., Nagai, T. N., Ong, R., Page, M., Pallassini, R., Power-Mooney, B., Quinn, J., Reay, N. W., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sidwell, R., Stanton, N., Swordy, S. P., Vassiliev, V. V., Wakely, S. P., Walker, G., and Weekes, T. C.

Abstract

The BL Lac object H1426+428 was recently detected as a high energy gamma-ray source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape dF/dE = 10^(-7.31 +- 0.15(stat) +- 0.16(syst)) x E^(-3.50 +- 0.35(stat) +- 0.05(syst)) m^(-2)s^(-1)TeV^(-1) The statistical evidence from our data for emission above 2.5 TeV is 2.6 sigma. With 95% c.l., the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is consistent with the (non-contemporaneous) measurement by Aharonian et al. (2002) both in shape and in normalization. Below 800 GeV, the data clearly favours a spectrum steeper than that of any other TeV Blazar observed so far indicating a difference in the processes involved either at the source or in the intervening space., Comment: LaTeX, 8 pages, 4 figures, accepted for publication in ApJ

Published
2002
Full Text
View/download PDF

24. Lipids and nutrition of the southern rock lobster, Jasus edwardsii, from hatch to puerulus

Author

Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Ritar, AJ, Smith, GG, Hart, PR, Jeffs, AG, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Ritar, AJ, Smith, GG, Hart, PR, and Jeffs, AG

Abstract

We examined the lipid class and fatty-acid composition of the southern rock lobster, Jasus edwardsii, phyllosomas larvae and puerulus stage to improve understanding of their nutrition in relation to aquaculture. Lipid is critical in the nutrition of larval crustaceans, including lobsters. Specimens were from Tasmanian waters, Australia, and North Island, New Zealand, waters. Analyses were by TLC-FID and capillary GC and GC-MS. Phyllosomas larvae and nektonic pueruli were low in storage lipid (triacylglycerol), and phospholipid was the major lipid class. Sterol, mainly cholesterol, was the next most abundant class. The ratio of the essential omega-3 fatty acid eicosapentaenoic acid (EPA) to the omega-6 fatty acid arachidonic acid (AA) was lower in newly hatched phyllosomas (1.2-1.3) than in other phyllosomas (stages III-XI; 2.8-6.7) and pueruli (3.8). Ratios of the omega-3 fatty acid DHA (docosahexaenoic acid) to EPA were also lower in newly hatched phyllosomas (0.5) than in later-stage phyllosomas (1.5-2.1) and pueruli (1.2). We have followed up these compositional data by successfully enriching the live diet (Artemia) of early phyllosomas with AA, EPA and DHA. This dietary manipulation has achieved ratios of these key polyunsaturated fatty acids similar to those of wild phyllosomas. These findings will be of significance to the future of rock-lobster aquaculture.

25. Changes in gut content and composition of juvenile Artemia after oil enrichment and during starvation

Author

Smith, GG, Ritar, AJ, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Hart, PR, Smith, GG, Ritar, AJ, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, and Hart, PR

Abstract

Some predators, such as spiny lobster phyllosoma larvae, tear Artemia to pieces before ingestion. This results in the loss of gut content, which may partly negate the benefits of enrichment with essential fatty acids (EFA). Therefore, the influence of gut content on the lipid composition of juvenile Artemia (5 day old) was examined by starvation alone or starvation with forced gut evacuation using 20-30 um plastic beads. Artemia gut content at 3 h and 6 h after the completion of feeding did not contribute significantly to the total lipid or fatty acid profiles of the Artemia. Artemia subjected to starvation alone (without beads) failed to evacuate their gut over the 6 h starvation period suggesting they require the intake of suitable sized particulate matter to undertake gut evacuation. To assess the uptake of EFA in nauplii (day 2) and juveniles, an enrichment diet containing high levels of arachidonic [AA, 20:4(n-6)] and eicosapentaenoic acid [EPA, 20:5(n-3)] was compared to a basal oat-based diet and a commercial oil emulsion high in docosahexaenoic acid [DHA (22:6(n-3)]. Both AA and EPA were increased in juvenile Artemia within a 24 h enrichment period at a rate proportional to their inclusion in the enrichment, while DHA was incorporated to a lesser degree. For all three EFA, the percentage loss during 6h starvation was small, but was greater for DHA than EPA or AA. Juvenile Artemia, a life stage seldom used in feeding regimes, have the ability to assume the AA and EPA profile of their dietary source. The ability to produce a larger food source with a non-traditional fatty acid profile may be valuable for a number of larval crustacean and fish species.

26. Lipid, fatty acid, and sterol composition of eight species of Kareniaceae (dinophyta): chemotaxonomy and putative lipid phycotoxins

Author

Mooney, B, Nichols, PD, de Salas, MF, Hallegraeff, GM, Mooney, B, Nichols, PD, de Salas, MF, and Hallegraeff, GM

Abstract

The lipid class, fatty acid, and sterol composition of eight species of ichthyotoxic marine gymnodinioid dinoflagellate (Karenia, Karlodinium, and Takayama) species was examined. The major lipid class in all species was phospholipid (78%–95%), with low levels of triacylglycerol (TAG; 0%–16%) and free fatty acid (FFA; 1%– 11%). The common dinoflagellate polyunsaturated fatty acids (PUFA), octadecapentaenoic acid (OPA 18:5x3), and docosahexaenoic acid (DHA 22:6x3), were present in all species in varying amounts (14%–35% and 8%–23%, respectively). The verylong-chain PUFA (VLC-PUFA) 28:7x6 and 28:8x3 were present at low levels (<1%), and the ratio of these fatty acids may be a useful chemotaxonomic marker at the species level. The typical dinoflagellate sterol dinosterol was absent from all species tested. A predominance of the 4-methyl and 4-desmethyl D8(14) sterols in all dinoflagellate species included 23-methyl-27-norergosta-8(14),22-dien-3b-ol (Karenia papilionacea A. J. Haywood et Steid, 59%–66%); 27-nor-(24R)-4a-methyl-5a-ergosta-8(14),22-dien-3b-ol, brevesterol, (Takayama tasmanica de Salas, Bolch et Hallegraeff 84%, Takayama helix de Salas, Bolch, Botes et Hallegraeff 71%, Karenia brevis (C. C. Davis) G. Hansen et Moestrup 45%, Karlodinium KDSB01 40%, Karenia mikimotoi (Miyake et Kominami ex Oda) G. Hansen et Moestrup 38%); and (24R)-4a-methyl-5a-ergosta- 8(14),22-dien-3b-ol, gymnodinosterol, (K. mikimotoi 48%, Karenia umbella de Salas, Bolch et Hallegraeff 59%, Karlodinium veneficum (D. L. Ballant.) J. Larsen 71%–83%). In Takayama species, five steroid ketones were identified, including for the first time the 3-keto form of brevesterol and gymnodinosterol. These results indicate a biochemical link between sterol and steroid ketone biosynthesis, suggesting that selected dinoflagellates can make a significant contribution to ketones in marine sediments. The presence of steroid ketones, specific sterols, and fatty acids, and the ratio of VLC-PUFA may prove to be

29. Lipids and nutrition of the southern rock lobster, Jasus edwardsii, from hatch to puerulus

Author

Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Ritar, AJ, Smith, GG, Hart, PR, Jeffs, AG, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Ritar, AJ, Smith, GG, Hart, PR, and Jeffs, AG

Abstract

We examined the lipid class and fatty-acid composition of the southern rock lobster, Jasus edwardsii, phyllosomas larvae and puerulus stage to improve understanding of their nutrition in relation to aquaculture. Lipid is critical in the nutrition of larval crustaceans, including lobsters. Specimens were from Tasmanian waters, Australia, and North Island, New Zealand, waters. Analyses were by TLC-FID and capillary GC and GC-MS. Phyllosomas larvae and nektonic pueruli were low in storage lipid (triacylglycerol), and phospholipid was the major lipid class. Sterol, mainly cholesterol, was the next most abundant class. The ratio of the essential omega-3 fatty acid eicosapentaenoic acid (EPA) to the omega-6 fatty acid arachidonic acid (AA) was lower in newly hatched phyllosomas (1.2-1.3) than in other phyllosomas (stages III-XI; 2.8-6.7) and pueruli (3.8). Ratios of the omega-3 fatty acid DHA (docosahexaenoic acid) to EPA were also lower in newly hatched phyllosomas (0.5) than in later-stage phyllosomas (1.5-2.1) and pueruli (1.2). We have followed up these compositional data by successfully enriching the live diet (Artemia) of early phyllosomas with AA, EPA and DHA. This dietary manipulation has achieved ratios of these key polyunsaturated fatty acids similar to those of wild phyllosomas. These findings will be of significance to the future of rock-lobster aquaculture.

30. Changes in gut content and composition of juvenile Artemia after oil enrichment and during starvation

Author

Smith, GG, Ritar, AJ, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, Hart, PR, Smith, GG, Ritar, AJ, Phleger, CF, Nelson, MM, Mooney, B, Nichols, PD, and Hart, PR

Abstract

Some predators, such as spiny lobster phyllosoma larvae, tear Artemia to pieces before ingestion. This results in the loss of gut content, which may partly negate the benefits of enrichment with essential fatty acids (EFA). Therefore, the influence of gut content on the lipid composition of juvenile Artemia (5 day old) was examined by starvation alone or starvation with forced gut evacuation using 20-30 um plastic beads. Artemia gut content at 3 h and 6 h after the completion of feeding did not contribute significantly to the total lipid or fatty acid profiles of the Artemia. Artemia subjected to starvation alone (without beads) failed to evacuate their gut over the 6 h starvation period suggesting they require the intake of suitable sized particulate matter to undertake gut evacuation. To assess the uptake of EFA in nauplii (day 2) and juveniles, an enrichment diet containing high levels of arachidonic [AA, 20:4(n-6)] and eicosapentaenoic acid [EPA, 20:5(n-3)] was compared to a basal oat-based diet and a commercial oil emulsion high in docosahexaenoic acid [DHA (22:6(n-3)]. Both AA and EPA were increased in juvenile Artemia within a 24 h enrichment period at a rate proportional to their inclusion in the enrichment, while DHA was incorporated to a lesser degree. For all three EFA, the percentage loss during 6h starvation was small, but was greater for DHA than EPA or AA. Juvenile Artemia, a life stage seldom used in feeding regimes, have the ability to assume the AA and EPA profile of their dietary source. The ability to produce a larger food source with a non-traditional fatty acid profile may be valuable for a number of larval crustacean and fish species.

31. Lipid, fatty acid, and sterol composition of eight species of Kareniaceae (dinophyta): chemotaxonomy and putative lipid phycotoxins

Author

Mooney, B, Nichols, PD, de Salas, MF, Hallegraeff, GM, Mooney, B, Nichols, PD, de Salas, MF, and Hallegraeff, GM

Abstract

The lipid class, fatty acid, and sterol composition of eight species of ichthyotoxic marine gymnodinioid dinoflagellate (Karenia, Karlodinium, and Takayama) species was examined. The major lipid class in all species was phospholipid (78%–95%), with low levels of triacylglycerol (TAG; 0%–16%) and free fatty acid (FFA; 1%– 11%). The common dinoflagellate polyunsaturated fatty acids (PUFA), octadecapentaenoic acid (OPA 18:5x3), and docosahexaenoic acid (DHA 22:6x3), were present in all species in varying amounts (14%–35% and 8%–23%, respectively). The verylong-chain PUFA (VLC-PUFA) 28:7x6 and 28:8x3 were present at low levels (<1%), and the ratio of these fatty acids may be a useful chemotaxonomic marker at the species level. The typical dinoflagellate sterol dinosterol was absent from all species tested. A predominance of the 4-methyl and 4-desmethyl D8(14) sterols in all dinoflagellate species included 23-methyl-27-norergosta-8(14),22-dien-3b-ol (Karenia papilionacea A. J. Haywood et Steid, 59%–66%); 27-nor-(24R)-4a-methyl-5a-ergosta-8(14),22-dien-3b-ol, brevesterol, (Takayama tasmanica de Salas, Bolch et Hallegraeff 84%, Takayama helix de Salas, Bolch, Botes et Hallegraeff 71%, Karenia brevis (C. C. Davis) G. Hansen et Moestrup 45%, Karlodinium KDSB01 40%, Karenia mikimotoi (Miyake et Kominami ex Oda) G. Hansen et Moestrup 38%); and (24R)-4a-methyl-5a-ergosta- 8(14),22-dien-3b-ol, gymnodinosterol, (K. mikimotoi 48%, Karenia umbella de Salas, Bolch et Hallegraeff 59%, Karlodinium veneficum (D. L. Ballant.) J. Larsen 71%–83%). In Takayama species, five steroid ketones were identified, including for the first time the 3-keto form of brevesterol and gymnodinosterol. These results indicate a biochemical link between sterol and steroid ketone biosynthesis, suggesting that selected dinoflagellates can make a significant contribution to ketones in marine sediments. The presence of steroid ketones, specific sterols, and fatty acids, and the ratio of VLC-PUFA may prove to be

Catalog

Books, media, physical & digital resources
See catalog results