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1. Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope

Author

Horan, D., Atkins, R. W., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Byrum, K. L., Celik, O., Chow, Y. C. K., Cogan, P., Cui, W., Daniel, M. K., Perez, I. de la Calle, Dowdall, C., Falcone, A. D., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gillanders, G. H., Grube, J., Gutierrez, K. J., Hall, J., Hanna, D., Holder, J., Hughes, S. B., Humensky, T. B., Kenny, G. E., Kertzman, M., Kieda, D. B., Kildea, J., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Moriarty, P., Nagai, T., Ong, R. A., Perkins, J. S., Petry, D., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, D., Swordy, S. P., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Weekes, T. C., White, R. J., and Williams, D. A.

Subjects
Astrophysics
Abstract

Gamma-ray burst (GRB) observations at very high energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10m Gamma-ray Telescope and GRBs will continue to be high priority targets as the next generation observatory, VERITAS, comes on-line. Upper limits on the VHE emission, at late times (>~4 hours), from seven GRBs observed with the Whipple Telescope are reported here., Comment: Accepted for publication in the January 20, 2007 volume of the Astrophysical Journal, 655, 396

Published
2007
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2. The First VERITAS Telescope

Author

Holder, J., Atkins, R. W., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Byrum, K. L., Carter-Lewis, D. A., Celik, O., Chow, Y. C. K., Cogan, P., Cui, W., Daniel, M. K., Perez, I. de la Calle, Dowdall, C., Dowkontt, P., Duke, C., Falcone, A. D., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gibbs, K., Gillanders, G., Glidewell, O. J., Grube, J., Gutierrez, K. J., Gyuk, G., Hall, J., Hanna, D., Hays, E., Horan, D., Hughes, S. B., Humensky, T. B., Imran, A., Jung, I., Kaaret, P., Kenny, G. E., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Little, E. K., Maier, G., Manseri, H., Milovanovic, A., Moriarty, P., Mukherjee, R., Ogden, P. A., Ong, R. A., Perkins, J. S., Pizlo, F., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sleege, G., Steele, D., Swordy, S. P., Syson, A., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., White, R. J., Williams, D. A., and Wagner, R.

Subjects
Astrophysics
Abstract

The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications., Comment: Accepted by Astroparticle Physics

Published
2006
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3. Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002

Author

Gutierrez, K., Badran, H. M., Bradbury, S. M., Buckley, J. H., Celik, O., Chow, Y. C., Cogan, P., Cui, W., Daniel, M., Falcone, A., Fegan, S. J., Finley, J. P., Gillanders, G. H., Grube, J., Holder, J., Horan, D., Hughes, S. B., Jung, I., Kieda, D., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Bohec, S. Le, Maier, G., Moriarty, P., Perkins, J., Pohl, M., Quinn, J., Rebillot, P. F., Rose, H. J., Schroedter, M., Sembroski, G. H., Wakely, S. P., Weekes, T. C., and White, R. J.

Subjects
Astrophysics
Abstract

In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray activity. This prompted a multiwavelength observation campaign with the Whipple 10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical Observatory, and the University of Michigan Radio Astrophysical Observatory. We present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and compare the source characteristics with those measured during observations taken during the years 2000 and 2002. The X-ray observations gave a data set with high signal-to-noise light curves and energy spectra; however, the gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore, we find that the radio and optical fluxes do not show statistically significant deviations from those measured during the 2002 flaring periods. While the X-ray flux and X-ray photon index appear correlated during subsequent observations, the apparent correlation evolved significantly between the years 2000, 2002, and 2003. We discuss the implications of this finding for the mechanism that causes the flaring activity., Comment: 17 pages, 6 figures, 2 tables

Published
2006
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4. TeV Gamma-Ray Observations of the Perseus and Abell 2029 Galaxy Clusters

Author

Perkins, J. S., Badran, H. M., Blaylock, G., Bradbury, S. M., Cogan, P., Chow, Y. C. K., Cui, W., Daniel, M. K., Falcone, A. D., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gillanders, G. H., Gutierrez, K. J., Grube, J., Hall, J., Hanna, D., Holder, J., Horan, D., Hughes, S. B., Kenny, G. E., Kertzman, M., Kieda, D. B., Kildea, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Moriarty, P., Ong, R. A., Pohl, M., Ragan, K., Rebillot, P. F., Sembroski, G. H., Steele, D., Swordy, S. P., Valcarcel, L., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., and Williams, D. A.

Subjects
Astrophysics
Abstract

Galaxy clusters might be sources of TeV gamma rays emitted by high-energy protons and electrons accelerated by large scale structure formation shocks, galactic winds, or active galactic nuclei. Furthermore, gamma rays may be produced in dark matter particle annihilation processes at the cluster cores. We report on observations of the galaxy clusters Perseus and Abell 2029 using the 10 m Whipple Cherenkov telescope during the 2003-2004 and 2004-2005 observing seasons. We apply a two-dimensional analysis technique to scrutinize the clusters for TeV emission. In this paper we first determine flux upper limits on TeV gamma-ray emission from point sources within the clusters. Second, we derive upper limits on the extended cluster emission. We subsequently compare the flux upper limits with EGRET upper limits at 100 MeV and theoretical models. Assuming that the gamma-ray surface brightness profile mimics that of the thermal X-ray emission and that the spectrum of cluster cosmic rays extends all the way from thermal energies to multi-TeV energies with a differential spectral index of -2.1, our results imply that the cosmic ray proton energy density is less than 7.9% of the thermal energy density for the Perseus cluster., Comment: Accepted for publication in the Astrophysical Journal

Published
2006
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5. A Very High Energy Gamma-Ray Spectrum of 1ES 2344+514

Author

Schroedter, M., Badran, H. M., Buckley, J. H., Gordo, J. Bussons, 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, Kuen, Moriarty, P., Quinn, J., Quinn, M., Power-Mooney, G. B., Sembroski, H., Wakely, S. P., Vassiliev, V. V., Weekes, T. C., and Zweerink, J.

Subjects
Astrophysics
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 \citep{2344Catanese98}. This detection was recently confirmed by the HEGRA Collaboration \citep{2344Hegra03}. As is typical for high-frequency peaked blazars, the VHE gamma-ray emission is highly variable. On the night of 20 December, 1995, 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 TeV and 12.6 TeV can be described by a power law $\frac{\ud^3 N}{\ud E \ud A \ud t}=(5.1\pm1.0_{st}\pm1.2_{sy})\times10^{-7} (E/ \mathrm{TeV})^{-2.54 \pm0.17_{st}\pm0.07_{sy}} \mathrm{\frac{1}{TeV m^2 s}}$. Comparing the spectral index with that of the other five confirmed TeV blazars, the spectrum of 1ES 2344 is similar to 1ES 1959+650, 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 located at a distance about 2/3 that of 1ES 2344, and harder than the spectra of PKS 2155-304 and H~1426+428, which are located almost three times as far. This trend is consistent with attenuation caused by the infrared extragalactic background radiation., Comment: 27 pages, 11 figures, accepted by ApJ

Published
2005
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6. Cutoff in the TeV Energy Spectrum of Markarian 421 During Strong Flares in 2001

Author

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

Subjects
Astrophysics
Abstract

Exceptionally strong and long lasting flaring activity of the blazar Markarian 421 (Mrk 421) occurred between January and March 2001. Based on the excellent signal-to-noise ratio of the data we derive the energy spectrum between 260 GeV - 17 TeV with unprecedented statistical precision. The spectrum is not well described by a simple power law even with a curvature term. Instead the data can be described by a power law with exponential cutoff: $\rm {{dN}\over{dE}} \propto \rm E^{-2.14 \pm 0.03_{stat}} \times e^{-E/E_{0}} m^{-2} s^{-1} TeV^{-1}$ with $\rm E_{0} = 4.3 \pm 0.3_{stat} TeV$. Mrk 421 is the second $\gamma$-ray blazar that unambiguously exhibits an absorption-like feature in its spectral energy distribution at 3-6 TeV suggesting that this may be a universal phenomenon, possibly due to the extragalactic infra-red background radiation., Comment: 14 pages, 3 figures, submitted to ApJL

Published
2001
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7. Discovery of >350 GeV Gamma Rays from the BL Lacertae Object 1ES 2344+514

Author

Catanese, M., Akerlof, C. W., Badran, H. M., Biller, S. D., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., Burdett, A. M., Gordo, J. Bussons, Carter-Lewis, D. A., Cawley, M. F., Connaughton, V., Fegan, D. J., Finley, J. P., Gaidos, J. A., Hall, T., Hillas, A. M., Krennrich, F., Lamb, R. C., Lessard, R. W., Masterson, C., McEnery, J. E., Mohanty, G., Quinn, J., Rodgers, A. J., Rose, H. J., Samuelson, F. W., Schubnell, M. S., Sembroski, G. H., Srinivasan, R., Weekes, T. C., Wilson, C. W., and Zweerink, J.

Subjects
Astrophysics
Abstract

We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at gamma-ray energies above 300 Gev, the other two being Markarian 421 (Mrk 421) and Mrk501. These three active galactic nuclei are all X-ray selected and have the lowest known redshifts of any BL Lac objects currently identified. The evidence for emission derives primarily from an apparent flare on December 20, 1995 when a 6 sigma excess was detected with a flux approximately 63% of the very high energy gamma-ray emission from the Crab Nebula, the standard candle for TeV gamma-ray sources. Excluding the flare, observations between October 1995 and January 1996 yield a 4 sigma detection corresponding to 11% of the VHE Crab Nebula flux. Observations spanning September 1996 to January 1997 failed to yield a significant detection of a steady flux or any flaring. For this period, the 99.9% confidence level upper limit is <8% of the Crab Nebula. The low baseline emission level and variations in nightly and yearly flux of 1ES 22344+514 are the same as the VHE emission characteristics of Mrk 421 and Mrk 501, Comment: 19 pages, 6 Postscript figures

Published
1997
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11. Mg 12 O 12 and Be 12 O 12 Nanocages as Sorbents and Sensors for H 2 S and SO 2 Gases: A Theoretical Approach.

Author

Badran, H. M., Eid, Kh. M., Baskoutas, Sotirios, and Ammar, H. Y.

Subjects
*SORBENTS, *DENSITY functional theory, *GASES, *DETECTORS, *MAGNESIUM hydride
Abstract

Theoretical calculations based on the Density Functional Theory (DFT) have been performed to investigate the interaction of H2S as well SO2 gaseous molecules at the surfaces of Be12O12 and Mg12O12 nano-cages. The results show that a Mg12O12 nano-cage is a better sorbent than a Be12O12 nano-cage for the considered gases. Moreover, the ability of SO2 gas to be adsorbed is higher than that of H2S gas. The HOMO–LUMO gap (Eg) of Be12O12 nano-cage is more sensitive to SO2 than H2S adsorption, while the Eg value of Mg12O12 nano-cage reveals higher sensitivity to H2S than SO2 adsorption. The molecular dynamic calculations show that the H2S molecule cannot be retained at the surface of a Be12O12 nano-cage within 300–700 K and cannot be retained on a Mg12O12 nano-cage at 700 K, while the SO2 molecule can be retained at the surfaces of Be12O12 and Mg12O12 nano-cages up to 700 K. Moreover, the thermodynamic calculations indicate that the reactions between H2S as well SO2 with Be12O12 and Mg12O12 nano-cages are exothermic. Our results suggest that we can use Be12O12 and Mg12O12 nano-cages as sorbents as well as sensors for H2S and SO2 gases. [ABSTRACT FROM AUTHOR]

Published
2022
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18. Multiwavelength Observations of 1ES 1959+650, 1 Year after the Strong Outburst of 2002

Author

Gutierrez, K., Badran, H. M., Bradbury, S. M., Buckley, J. H., Celik, O., Chow, Y. C., Cogan, P., Cui, W., Daniel, M., Falcone, A., Fegan, S. J., Finley, J. P., Gillanders, G. H., Grube, J., Holder, J., Horan, D., Hughes, S. B., Jung, I., Kieda, D., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Maier, G., Moriarty, P., Perkins, J., Pohl, M., Quinn, J., Rebillot, P. F., Rose, H. J., Schroedter, M., Sembroski, G. H., Wakely, S. P., Weekes, T. C., White, R. J., Aller, M., Aller, H., Charlot, P., and Le Campion, J. F.

Subjects
tev gamma-rays, Astrophysics, telescope, 01 natural sciences, 4.85 ghz, spectrum, law.invention, blazar 1es-1959+650, Telescope, Observatory, law, evolution, 0103 physical sciences, strong flares, 010306 general physics, Blazar, mkn 501, variability, radiation, 010303 astronomy & astrophysics, Physics, Astronomy and Astrophysics, Light curve, 13. Climate action, Space and Planetary Science, Flare
Abstract

In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray activity. This prompted a multiwavelength observation campaign with the Whipple 10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical Observatory, and the University of Michigan Radio Astrophysical Observatory. We present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and compare the source characteristics with those measured during observations taken during the years 2000 and 2002. The X-ray observations gave a data set with high signal-to-noise light curves and energy spectra; however, the gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore, we find that the radio and optical fluxes do not show statistically significant deviations from those measured during the 2002 flaring periods. While the X-ray flux and X-ray photon index appear correlated during subsequent observations, the apparent correlation evolved significantly between the years 2000, 2002, and 2003. We discuss the implications of this finding for the mechanism that causes the flaring activity.

Published
2006

19. Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope

Author

Lang, Mark, Gillanders, Gary, Horan, D., Atkins, R. W., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Byrum, K. L., Celik, O., Chow, Y. C. K., Cogan, P., Cui, W., Daniel, M. K., Perez, I. de la Calle, Dowdall, C., Falcone, A. D., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gillanders, G. H., Grube, J., Gutierrez, K. J., Hall, J., Hanna, D., Holder, J., Hughes, S. B., Humensky, T. B., Kenny, G. E., Kertzman, M., Kieda, D. B., Kildea, J., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Moriarty, P., Nagai, T., Ong, R. A., Perkins, J. S., Petry, D., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, D., Swordy, S. P., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Weekes, T. C., White, R. J., and Williams, D. A.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics
Abstract

Gamma-ray burst (GRB) observations at very high energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10m Gamma-ray Telescope and GRBs will continue to be high priority targets as the next generation observatory, VERITAS, comes on-line. Upper limits on the VHE emission, at late times (>~4 hours), from seven GRBs observed with the Whipple Telescope are reported here. peer-reviewed

Published
2007

20. Multiwavelength observations of the blazar Markarian 421 in 2002 December and 2003 January

Author

Rebillot, P. F., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Carter-Lewis, D. A., Celik, O., Chow, Y. C., Cogan, P., Cui, W., Daniel, M., Duke, C., Falcone, A., Fegan, S. J., Finley, J. P., Fortson, L. F., Gillanders, G. H., Grube, J., Gutierrez, K., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hughes, S. B., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Linton, E., Maier, G., Moriarty, P., Perkins, J., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, G., Swordy, S. P., Valcarcel, L., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., Zweerink, J., Aller, M., Aller, H., Boltwood, P., Jung, I., Kranich, D., Nilsson, K., Pasanen, M., Sadun, A., and Sillanpaa, A.

Subjects
bl lacertae objects : individual (mrk 421), galaxies : jets, gamma rays : observations radiation, mechanisms : nonthermal, x-rays : individual (mrk 421), tev gamma-rays, active galactic nuclei, bl-lacertae objects, self-compton model, x-ray, spectral evolution, lac objects, strong flares, crab-nebula, mkn 501, Astrophysics::High Energy Astrophysical Phenomena
Abstract

We report on a multiwavelength campaign on the TeV gamma-ray blazar Mrk 421 performed during 2002 December and 2003 January. These target of opportunity observations were initiated by the detection of X-ray and TeV gamma-ray flares with the All Sky Monitor (ASM) on board the Rossi X-Ray Timing Explorer (RXTE) and the 10 m Whipple gamma-ray telescope. The campaign included observational coverage in the radio (University of Michigan Radio Astronomy Observatory), optical (Boltwood, La Palma KVA 0.6 m; WIYN 0.9 m), X-ray (RXTE pointed telescopes), and TeV gamma-ray (Whipple and HEGRA) bands. At TeV energies, the observations revealed several flares at intermediate flux levels, peaking between 1 and 1.5 times the flux from the Crab Nebula. While the time-averaged spectrum can be fitted with a single power law of photon index Gamma = 2.8 from dN gamma/dE proportional to E-Gamma, we find some evidence for spectral variability. Confirming earlier results, the campaign reveals a rather loose correlation between the X-ray and TeV gamma-ray fluxes. In one case, a very strong X-ray flare is not accompanied by a comparable TeV gamma-ray flare. Although the source flux was variable in the optical and radio bands, the sparse sampling of the optical and radio light curves does not allow us to study the correlation properties in detail. We present a simple analysis of the data with a synchrotron self-Compton model, emphasizing that models with very high Doppler factors and low magnetic fields can describe the data.

Published
2006

21. Observation of M87 at 400 GeV with the Whipple 10 meter telescope

Author

Le Bohec, S., 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., 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., Jarvis, A., Jordan, M., Kenny, G. E., Kertzman, M., Kieda, D., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Linton, E., Lloyd-Evans, J., Milovanovic, A., Moriarty, P., Muller, D., Nagai, T., Nolan, S., Ong, R. A., Pallassini, R., Petry, D., 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.

Subjects
galaxies : active, galaxies : individual (m87), gamma rays : observations, tev gamma-rays, bl-lacertae object, high-resolution, galaxy m-87, lac object, jet, emission, spectrum, radio, polarization, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

We present results from observations taken with the Whipple 10 m very high energy gamma-ray telescope with maximal sensitivity at 400 GeV during 39 hr between 2000 and 2003 in the direction of the giant radio galaxy M87. Using the entire data set, we derive a 99% confidence level upper limit on the flux of gamma-ray emission above 400 GeV from M87 to be less than or equal to 6: 9; 10(-1)2 cm(-2) s(-1). This suggests variability at the 90% confidence level when compared to the flux measured by the HEGRA collaboration in 1999 if the differential spectrum is steeper than a power law of index 3.75. Our search for a correlation between the Rossi X-Ray Timing Explorer all-sky monitor observation and a potential gamma-ray signal is inconclusive.

Published
2004

23. Very High Energy Observations of Gamma‐Ray Burst Locations with the Whipple Telescope

Author

Horan, D., primary, Atkins, R. W., additional, Badran, H. M., additional, Blaylock, G., additional, Bradbury, S. M., additional, Buckley, J. H., additional, Byrum, K. L., additional, Celik, O., additional, Chow, Y. C. K., additional, Cogan, P., additional, Cui, W., additional, Daniel, M. K., additional, de la Calle Perez, I., additional, Dowdall, C., additional, Falcone, A. D., additional, Fegan, D. J., additional, Fegan, S. J., additional, Finley, J. P., additional, Fortin, P., additional, Fortson, L. F., additional, Gillanders, G. H., additional, Grube, J., additional, Gutierrez, K. J., additional, Hall, J., additional, Hanna, D., additional, Holder, J., additional, Hughes, S. B., additional, Humensky, T. B., additional, Kenny, G. E., additional, Kertzman, M., additional, Kieda, D. B., additional, Kildea, J., additional, Krawczynski, H., additional, Krennrich, F., additional, Lang, M. J., additional, LeBohec, S., additional, Maier, G., additional, Moriarty, P., additional, Nagai, T., additional, Ong, R. A., additional, Perkins, J. S., additional, Petry, D., additional, Quinn, J., additional, Quinn, M., additional, Ragan, K., additional, Reynolds, P. T., additional, Rose, H. J., additional, Schroedter, M., additional, Sembroski, G. H., additional, Steele, D., additional, Swordy, S. P., additional, Toner, J. A., additional, Valcarcel, L., additional, Vassiliev, V. V., additional, Wagner, R. G., additional, Wakely, S. P., additional, Weekes, T. C., additional, White, R. J., additional, and Williams, D. A., additional

Published
2007
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24. Multiwavelength Observations of the Blazar Markarian 421 in 2002 December and 2003 January

Author

Rebillot, P. F., primary, Badran, H. M., additional, Blaylock, G., additional, Bradbury, S. M., additional, Buckley, J. H., additional, Carter‐Lewis, D. A., additional, Celik, O., additional, Chow, Y. C., additional, Cogan, P., additional, Cui, W., additional, Daniel, M., additional, Duke, C., additional, Falcone, A., additional, Fegan, S. J., additional, Finley, J. P., additional, Fortson, L. F., additional, Gillanders, G. H., additional, Grube, J., additional, Gutierrez, K., additional, Gyuk, G., additional, Hanna, D., additional, Holder, J., additional, Horan, D., additional, Hughes, S. B., additional, Kenny, G. E., additional, Kertzman, M., additional, Kieda, D., additional, Kildea, J., additional, Kosack, K., additional, Krawczynski, H., additional, Krennrich, F., additional, Lang, M. J., additional, Le Bohec, S., additional, Linton, E., additional, Maier, G., additional, Moriarty, P., additional, Perkins, J., additional, Pohl, M., additional, Quinn, J., additional, Ragan, K., additional, Reynolds, P. T., additional, Rose, H. J., additional, Schroedter, M., additional, Sembroski, G. H., additional, Steele, G., additional, Swordy, S. P., additional, Valcarcel, L., additional, Vassiliev, V. V., additional, Wakely, S. P., additional, Weekes, T. C., additional, Zweerink, J., additional, VERITAS Collaboration), (The, additional, Aller, M., additional, Aller, H., additional, Boltwood, P., additional, Jung, I., additional, Kranich, D., additional, Nilsson, K., additional, Pasanen, M., additional, Sadun, A., additional, and Sillanpaa, A., additional

Published
2006
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25. A Very High Energy Gamma‐Ray Spectrum of 1ES 2344+514

Author

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

Published
2005
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26. A Survey of Unidentified EGRET Sources at Very High Energies

Author

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

Published
2005
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27. Spectrum of Very High Energy Gamma‐Rays from the blazar 1ES 1959+650 during Flaring Activity in 2002

Author

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

Published
2005
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28. Observation of M87 at 400 GeV with the Whipple 10 Meter Telescope

Author

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

Published
2004
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29. TeV Gamma-Ray Observations of the Galactic Center

Author

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

Published
2004
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30. Constraints on the Very High Energy Emission from BL Lacertae Objects

Author

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

Published
2004
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31. Detection of the BL Lacertae Object H1426+428 at TeV Gamma‐Ray Energies

Author

Horan, D., primary, Badran, H. M., additional, Bond, I. H., additional, Bradbury, S. M., additional, Buckley, J. H., additional, Carson, M. J., additional, Carter‐Lewis, D. A., additional, Catanese, M., additional, Cui, W., additional, Dunlea, S., additional, Das, D., additional, de la Calle Perez, I., additional, D’Vali, M., additional, Fegan, D. J., additional, Fegan, S. J., additional, Finley, J. P., additional, Gaidos, J. A., additional, Gibbs, K., additional, Gillanders, G. H., additional, Hall, T. A., additional, Hillas, A. M., additional, Holder, J., additional, Jordan, M., additional, Kertzman, M., additional, Kieda, D., additional, Kildea, J., additional, Knapp, J., additional, Kosack, K., additional, Krennrich, F., additional, Lang, M. J., additional, LeBohec, S., additional, Lessard, R., additional, Lloyd‐Evans, J., additional, McKernan, B., additional, Moriarty, P., additional, Muller, D., additional, Ong, R., additional, Pallassini, R., additional, Petry, D., additional, Quinn, J., additional, Reay, N. W., additional, Reynolds, P. T., additional, Rose, H. J., additional, Sembroski, G. H., additional, Sidwell, R., additional, Stanton, N., additional, Swordy, S. P., additional, Vassiliev, V. V., additional, Wakely, S. P., additional, and Weekes, T. C., additional

Published
2002
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32. Cutoff in the T[CLC]e[/CLC]V Energy Spectrum of Markarian 421 during Strong Flares in 2001

Author

Krennrich, F., primary, Badran, H. M., additional, Bond, I. H., additional, Bradbury, S. M., additional, Buckley, J. H., additional, Carter-Lewis, D. A., additional, Catanese, M., additional, Cui, W., additional, Dunlea, S., additional, Das, D., additional, de la Calle Perez, I., additional, Fegan, D. J., additional, Fegan, S. J., additional, Finley, J. P., additional, Gaidos, J. A., additional, Gibbs, K., additional, Gillanders, G. H., additional, Hall, T. A., additional, Hillas, A. M., additional, Holder, J., additional, Horan, D., additional, Jordan, M., additional, Kertzman, M., additional, Kieda, D., additional, Kildea, J., additional, Knapp, J., additional, Kosack, K., additional, Lang, M. J., additional, LeBohec, S., additional, McKernan, B., additional, Moriarty, P., additional, Müller, D., additional, Ong, R., additional, Pallassini, R., additional, Petry, D., additional, Quinn, J., additional, Reay, N. W., additional, Reynolds, P. T., additional, Rose, H. J., additional, Sembroski, G. H., additional, Sidwell, R., additional, Stanton, N., additional, Swordy, S. P., additional, Vassiliev, V. V., additional, Wakely, S. P., additional, and Weekes, T. C., additional

Published
2001
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33. Discovery of Gamma‐Ray Emission above 350 GeV from the BL Lacertae Object 1ES 2344+514

Author

Catanese, M., primary, Akerlof, C. W., additional, Badran, H. M., additional, Biller, S. D., additional, Bond, I. H., additional, Boyle, P. J., additional, Bradbury, S. M., additional, Buckley, J. H., additional, Burdett, A. M., additional, Gordo, J. Bussons, additional, Carter‐Lewis, D. A., additional, Cawley, M. F., additional, Connaughton, V., additional, Fegan, D. J., additional, Finley, J. P., additional, Gaidos, J. A., additional, Hall, T., additional, Hillas, A. M., additional, Krennrich, F., additional, Lamb, R. C., additional, Lessard, R. W., additional, Masterson, C., additional, McEnery, J. E., additional, Mohanty, G., additional, Quinn, J., additional, Rodgers, A. J., additional, Rose, H. J., additional, Samuelson, F. W., additional, Schubnell, M. S., additional, Sembroski, G. H., additional, Srinivasan, R., additional, Weekes, T. C., additional, Wilson, C. W., additional, and Zweerink, J., additional

Published
1998
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34. Deployment of the VERITAS observatory.

Author

LeBohec, S, Atkins, R W, Badran, H M, Blaylock, G, Bond, I H, Boyle, P J, Bradbury, Sm, Buckley, J H, Carter-Lewis, Da, Celik, O, Chow, Y C K, Cogan, P, CuP, W, Daniel, M K, Perez, I de la Calle, Dowdall, Dowkontt, P, Duke, C, Ergin, T, and Falcone, A D

Published
2006
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35. Effect of CO adsorption on properties of transition metal doped porphyrin: A DFT and TD-DFT study.

Author

Ammar HY and Badran HM

Abstract

The structural, electronic and optical properties of transition metal doped porphyrin (TM@P; TM = Mn, Co, Fe, Cu, Ni, Zn) as well as the effect of CO adsorption on TM@P properties have been investigated using the density functional theory (DFT). The presented results include adsorption energies, bond lengths, electronic configurations, magnetic moments, density of states, frontier molecular orbitals, and UV-Vis. spectra. Our calculation results show that, the CO molecule favors to be adsorbed on TM-doped Porphyrin with its carbon head. The most energetically stable adsorption of CO is reported for Fe doped Porphyrin. The interaction between CO molecules with TM@P is attributed to donation-back donation as well as charge transfer mechanisms. Mn, Co and Fe-doped porphyrins have visible active nature which may be affected by CO adsorption, whereas, Ni, Cu and Zn-doped porphyrins have UV active nature which not affected by CO adsorption. These results may be meaningful for CO removal and detection., (© 2019 Published by Elsevier Ltd.)

Published
2019
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36. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

Author

El-Reefy HI, Badran HM, Sharshar T, Hilal MA, and Elnimr T

Subjects
Cesium Radioisotopes analysis, Lakes chemistry, Potassium Radioisotopes analysis, Radiation Monitoring, Radium analysis, Soil Pollutants, Radioactive analysis, Spectrometry, Gamma, Thorium analysis, Uranium analysis, Radioisotopes analysis
Abstract

In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Published
2014
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37. Environmental assessment of gamma-radiation levels in stream sediments around Sharm El-Sheikh, South Sinai, Egypt.

Author

Al-Sharkawy A, Hiekal MT, Sherif MI, and Badran HM

Subjects
Egypt, Indian Ocean, Potassium Radioisotopes analysis, Radiation Monitoring, Radioisotopes analysis, Rivers chemistry, Spectrometry, Gamma, Geologic Sediments chemistry, Metals, Heavy analysis, Potassium analysis, Soil Pollutants, Radioactive analysis, Water Pollutants, Radioactive analysis
Abstract

A total surface area of ∼170 km(2) including 28 localities around Sharm El-Sheikh, South Sinai, were investigated by γ-ray spectroscopy. The concentrations of NORM were found to be five to seven-fold that in dune sands in different regions in Sinai. While relatively higher levels of (238)U, (234)Th, (226)Ra, and (232)Th are associated with the existing monzo-syenogranite, the concentration of (40)K is more uniformly distributed in the studied area. Locations with higher concentrations of (137)Cs are mainly located in the northern part. The (238)U, (234)Th and (226)Ra isotopes in the (238)U-series are in secular equilibrium. The absorbed dose rates and gamma-radiation hazard indices in all locations were higher than the world average value and unity, respectively. Properly regulated land use is recommended for a buffer zone in the northern part of the study area., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Published
2012
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38. Distribution of gamma-ray emitting radionuclides in the environment of Burullus Lake: I. Soils and vegetations.

Author

El-Reefy HI, Sharshar T, Zaghloul R, and Badran HM

Subjects
Cesium Radioisotopes analysis, Environmental Monitoring, Fresh Water chemistry, Geography, Nonlinear Dynamics, Potassium Radioisotopes analysis, Radium analysis, Thorium analysis, Fresh Water analysis, Gamma Rays, Plants, Edible chemistry, Radioisotopes analysis, Soil Pollutants, Radioactive analysis
Abstract

The concentrations and distribution of gamma-ray emitting isotopes in Burullus Lake were investigated with the aim of evaluating the environmental radioactivity. Particularly in wetlands, natural properties of the environment can cause the actual inventory to be different from the activity originally deposited. The mean concentrations of (226)Ra, (232)Th and (40)K were 14.3, 15.5 and 224 Bq/kg, respectively, in the coastal soils. On the other hand, soil samples from the islands had mean concentrations of 13.5, 17.4 and 341 Bq/kg for (226)Ra, (232)Th and (40)K, respectively. Samples from coast and islands show evidence of possible transfer and accumulation of the (137)Cs radionuclide. The mean (137)Cs activity concentrations in the soil samples were 1.2 and 15.1 Bq/kg in the coast and islands, respectively. The vertical migration of (137)Cs was studied based on its content in the consequently located three soil layers down to 30 cm depth. The radium equivalent, dose rate in air and annual dose equivalent from the terrestrial natural gamma-radiation were evaluated. The mean activity concentrations of the gamma-ray emitting radionuclides in vegetation were relatively low.

Published
2006
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39. Characteristics, spatial distribution and vertical profile of gamma-ray emitting radionuclides in the coastal environment of North Sinai.

Author

Seddeek MK, Badran HM, Sharshar T, and Elnimr T

Subjects
Egypt, Radiometry, Spectrometry, Gamma, Environmental Exposure statistics & numerical data, Gamma Rays, Radium analysis, Silicon Dioxide chemistry, Thorium analysis
Abstract

Radionuclide concentrations of beach and dune sand from various sites in Al-Arish city and surrounding area, North Sinai, Egypt, were measured. The sampling sites included locations in the local harbor, Al-Arish valley and Zaranik protected area. The results indicate that the activities of the products of (232)Th and (226)Ra series in samples from the harbor and along the beach were higher than those from non-coastal sites. The activity concentrations of (232)Th for beach sand ranged from 2.3 to 506.5 Bq/kg with an average of 83.4 Bq/kg, while that for dune sand ranged from 2.2 to 15.1 Bq/kg with an average of 6.4 Bq/kg. The average activity concentration of (226)Ra for beach sand was 56.0 Bq/kg (2.9-261.5 Bq/kg), while that for dune sand was 6.5 Bq/kg (3.0-14.7 Bq/kg). The average activity concentrations of (40)K for beach and dune sand were 88.1 Bq/kg and 178.4 Bq/kg, respectively. Six depth profiles in the harbor area were measured up to a depth of 1m within more than two years. These sets of measurements allowed the determination of the migration rate of black sand to be 0.094 cm/day. Samples with the smallest grain size (<0.2 mm) were found to have the highest level of activities, which were attributed to their high content of black sand. No risk exists for public health based on the calculated effective dose equivalent and the recommended limit of 5 mSv/y. On the other hand, local children and adults may receive doses higher than this recommended limit in two locations in the Zaranik protected area according to a model developed in this study.

Published
2005
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40. Levels of 137Cs and 40K in edible parts of some vegetables consumed in Egypt.

Author

Badran HM, Sharshar T, and Elnimer T

Subjects
Egypt, Humans, Risk Assessment, Cesium Radioisotopes analysis, Food Contamination, Potassium Radioisotopes analysis, Vegetables
Abstract

The concentrations of (137)Cs and (40)K in some Egyptian foodstuffs have been measured. The results of this study can be considered as a first step towards calculating the baseline levels of radioactivity in foodstuffs in Egypt. Furthermore, the data presented herein can be used as a reference level for future food radioactivity monitoring after the possible operation of the planned nuclear power plants, as well as to screen imported foodstuffs that are suspected of being contaminated. The overall intake of (137)Cs is quite low and no significant radionuclide contamination was found. The highest contents of (137)Cs and (40)K among the tested foodstuffs were in Jew's mallow and roquette. Calculations were also made to determine the potential dose to an individual consuming vegetables.

Published
2003
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