Search

Your search keyword '"Ryan, J. M."' showing total 113 results
Start Over Author "Ryan, J. M." Publication Type Electronic Resources
113 results on '"Ryan, J. M."'

1. Comparing Long-Duration Gamma-Ray Flares and High-Energy Solar Energetic Particles

Author

de Nolfo, G. A., Bruno, A., Ryan, J. M., Dalla, S., Giacalone, J., Richardson, I. G., Christian, E. R., Stochaj, S. J., Bazilevskaya, G. A., Boezio, M., Martucci, M., Mikhailov, V. V., Munini, R., de Nolfo, G. A., Bruno, A., Ryan, J. M., Dalla, S., Giacalone, J., Richardson, I. G., Christian, E. R., Stochaj, S. J., Bazilevskaya, G. A., Boezio, M., Martucci, M., Mikhailov, V. V., and Munini, R.

Abstract

Little is known about the origin of the high-energy and sustained emission from solar Long-Duration Gamma-Ray Flares (LDGRFs), identified with the Compton Gamma Ray Observatory (CGRO), the Solar Maximum Mission (SMM), and now Fermi. Though Fermi/Large Area Space Telescope (LAT) has identified dozens of flares with LDGRF signature, the nature of this phenomenon has been a challenge to explain both due to the extreme energies and long durations. The highest-energy emission has generally been attributed to pion production from the interaction of >300 MeV protons with the ambient matter. The extended duration suggests that particle acceleration occurs over large volumes extending high in the corona, either from stochastic acceleration within large coronal loops or from back precipitation from coronal mass ejection driven shocks. It is possible to test these models by making direct comparison between the properties of the accelerated ion population producing the gamma-ray emission derived from the Fermi/LAT observations, and the characteristics of solar energetic particles (SEPs) measured by the Payload for Matter-Antimatter Exploration and Light Nuclei Astrophysics (PAMELA) spacecraft in the energy range corresponding to the pion-related emission detected with Fermi. For fourteen of these events we compare the two populations -- SEPs in space and the interacting particles at the Sun -- and discuss the implications in terms of potential sources. Our analysis shows that the two proton numbers are poorly correlated, with their ratio spanning more than five orders of magnitude, suggesting that the back precipitation of shock-acceleration particles is unlikely the source of the LDGRF emission., Comment: Accepted for publication in ApJ

Published
2019
Full Text
View/download PDF

2. Comparing Long-Duration Gamma-Ray Flares and High-Energy Solar Energetic Particles

Author

de Nolfo, G. A., Bruno, A., Ryan, J. M., Dalla, S., Giacalone, J., Richardson, I. G., Christian, E. R., Stochaj, S. J., Bazilevskaya, G. A., Boezio, M., Martucci, M., Mikhailov, V. V., Munini, R., de Nolfo, G. A., Bruno, A., Ryan, J. M., Dalla, S., Giacalone, J., Richardson, I. G., Christian, E. R., Stochaj, S. J., Bazilevskaya, G. A., Boezio, M., Martucci, M., Mikhailov, V. V., and Munini, R.

Abstract

Little is known about the origin of the high-energy and sustained emission from solar Long-Duration Gamma-Ray Flares (LDGRFs), identified with the Compton Gamma Ray Observatory (CGRO), the Solar Maximum Mission (SMM), and now Fermi. Though Fermi/Large Area Space Telescope (LAT) has identified dozens of flares with LDGRF signature, the nature of this phenomenon has been a challenge to explain both due to the extreme energies and long durations. The highest-energy emission has generally been attributed to pion production from the interaction of >300 MeV protons with the ambient matter. The extended duration suggests that particle acceleration occurs over large volumes extending high in the corona, either from stochastic acceleration within large coronal loops or from back precipitation from coronal mass ejection driven shocks. It is possible to test these models by making direct comparison between the properties of the accelerated ion population producing the gamma-ray emission derived from the Fermi/LAT observations, and the characteristics of solar energetic particles (SEPs) measured by the Payload for Matter-Antimatter Exploration and Light Nuclei Astrophysics (PAMELA) spacecraft in the energy range corresponding to the pion-related emission detected with Fermi. For fourteen of these events we compare the two populations -- SEPs in space and the interacting particles at the Sun -- and discuss the implications in terms of potential sources. Our analysis shows that the two proton numbers are poorly correlated, with their ratio spanning more than five orders of magnitude, suggesting that the back precipitation of shock-acceleration particles is unlikely the source of the LDGRF emission., Comment: Accepted for publication in ApJ

Published
2019
Full Text
View/download PDF

3. Evidence of Energy and Charge Sign Dependence of the Recovery Time for the 2006 December Forbush Event Measured by the PAMELA Experiment

Author

Munini, R., Boezio, M., Bruno, A., Christian, E. C., Nolfo, G. A. D., Felice, V. D., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Santis, C. D., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Potgieter, M. S., Munini, R., Boezio, M., Bruno, A., Christian, E. C., Nolfo, G. A. D., Felice, V. D., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Santis, C. D., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Potgieter, M. S.

Abstract

New results on the short-term galactic cosmic-ray (GCR) intensity variation (Forbish decrease) in 2006 December measured by the PAMELA instrument are presented. Forbush decreases are sudden suppressions of the GCR intensities, which are associated with the passage of interplanetary transients such as shocks and interplanetary coronal mass ejections (ICMEs). Most of the past measurements of this phenomenon were carried out with groundbased detectors such as neutron monitors or muon telescopes. These techniques allow only the indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease, commencing on 2006 December 14 and following a CME at the Sun on 2006 December 13, was studied in a wide rigidity range (0.4-20 GV) and for different species of GCRs detected directly in space. The daily averaged GCR proton intensity was used to investigate the rigidity dependence of the amplitude and the recovery time of the Forbush decrease. Additionally, for the first time, the temporal variations in the helium and electron intensities during a Forbush decrease were studied. Interestingly, the temporal evolutions of the helium and proton intensities during the Forbush decrease were found to be in good agreement, while the low rigidity electrons (<2 GV) displayed a faster recovery. This difference in the electron recovery is interpreted as a charge sign dependence introduced by drift motions experienced by the GCRs during their propagation through the heliosphere., QC 20180206

Published
2018
Full Text
View/download PDF

4. Blog

Author

Ryan, J M, Turner, B S, Epstein, C F, Kivisto, P, Kyung-Sup, C, Outhwaite, W, Bruns, Axel, Ryan, J M, Turner, B S, Epstein, C F, Kivisto, P, Kyung-Sup, C, Outhwaite, W, and Bruns, Axel

Abstract

Weblogs, or blogs, are a particular form and format for publishing a series of what are usually relatively brief articles to a Website, where they are listed in reverse chronological order. Originally used mostly for publishing personal diaries, blogs were widely adopted across a range of personal and professional purposes, and arguably inspired the format of subsequent social media platforms; today, blog-style content is ubiquitous on the Web, without the term ‘blog’ necessarily being applied in all cases.

Published
2018

5. Solar energetic particle events observed by the PAMELA mission

Author

Bruno, A., Bazilevskaya, G. A., Boezio, M., Christian, E. R., de Nolfo, G. A., Martucci, M., Merge', M., Mikhailov, V. V., Munini, R., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Bruno, A., Bazilevskaya, G. A., Boezio, M., Christian, E. R., de Nolfo, G. A., Martucci, M., Merge', M., Mikhailov, V. V., Munini, R., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

Despite the significant progress achieved in recent years, the physical mechanisms underlying the origin of solar energetic particles (SEPs) are still a matter of debate. The complex nature of both particle acceleration and transport poses challenges to developing a universal picture of SEP events that encompasses both the low-energy (from tens of keV to a few hundreds of MeV) observations made by space-based instruments and the GeV particles detected by the worldwide network of neutron monitors in ground-level enhancements (GLEs). The high-precision data collected by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite experiment offer a unique opportunity to study the SEP fluxes between $\sim$80 MeV and a few GeV, significantly improving the characterization of the most energetic events. In particular, PAMELA can measure for the first time with good accuracy the spectral features at moderate and high energies, providing important constraints for current SEP models. In addition, the PAMELA observations allow the relationship between low and high-energy particles to be investigated, enabling a clearer view of the SEP origin. No qualitative distinction between the spectral shapes of GLE, sub-GLE and non-GLE events is observed, suggesting that GLEs are not a separate class, but are the subset of a continuous distribution of SEP events that are more intense at high energies. While the spectral forms found are to be consistent with diffusive shock acceleration theory, which predicts spectral rollovers at high energies that are attributed to particles escaping the shock region during acceleration, further work is required to explore the relative influences of acceleration and transport processes on SEP spectra., Comment: 26 pages, 13 figures, 2 tables

Published
2018
Full Text
View/download PDF

6. Evidence of energy and charge sign dependence of the recovery time for the December 2006 Forbush event measured by the PAMELA experiment

Author

Munini, R., Boezio, M., Bruno, A., Christian, E. C., de Nolfo, G. A., Di Felice, V., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Potgieter, M. S., Munini, R., Boezio, M., Bruno, A., Christian, E. C., de Nolfo, G. A., Di Felice, V., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Potgieter, M. S.

Abstract

New results on the short-term galactic cosmic ray (GCR) intensity variation (Forbush decrease) in December 2006 measured by the PAMELA instrument are presented. Forbush decreases are sudden suppressions of the GCR intensities which are associated with the passage of interplanetary transients such as shocks and interplanetary coronal mass ejections (ICMEs). Most of the past measurements of this phenomenon were carried out with ground-based detectors such as neutron monitors or muon telescopes. These techniques allow only the indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease commencing on 2006 December 14, following a CME at the Sun on 2006 December 13 was studied in a wide rigidity range (0.4 - 20 GV) and for different species of GCRs detected directly in space. The daily averaged GCR proton intensity was used to investigate the rigidity dependence of the amplitude and the recovery time of the Forbush decrease. Additionally, for the first time, the temporal variations in the helium and electron intensities during a Forbush decrease were studied. Interestingly, the temporal evolutions of the helium and proton intensities during the Forbush decrease were found in good agreement, while the low rigidity electrons (< 2 GV) displayed a faster recovery. This difference in the electron recovery is interpreted as a charge-sign dependence introduced by drift motions experienced by the GCRs during their propagation through the heliosphere.

Published
2018
Full Text
View/download PDF

7. Solar energetic particle events observed by the PAMELA mission

Author

Bruno, A., Bazilevskaya, G. A., Boezio, M., Christian, E. R., de Nolfo, G. A., Martucci, M., Merge', M., Mikhailov, V. V., Munini, R., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Bruno, A., Bazilevskaya, G. A., Boezio, M., Christian, E. R., de Nolfo, G. A., Martucci, M., Merge', M., Mikhailov, V. V., Munini, R., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

Despite the significant progress achieved in recent years, the physical mechanisms underlying the origin of solar energetic particles (SEPs) are still a matter of debate. The complex nature of both particle acceleration and transport poses challenges to developing a universal picture of SEP events that encompasses both the low-energy (from tens of keV to a few hundreds of MeV) observations made by space-based instruments and the GeV particles detected by the worldwide network of neutron monitors in ground-level enhancements (GLEs). The high-precision data collected by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite experiment offer a unique opportunity to study the SEP fluxes between $\sim$80 MeV and a few GeV, significantly improving the characterization of the most energetic events. In particular, PAMELA can measure for the first time with good accuracy the spectral features at moderate and high energies, providing important constraints for current SEP models. In addition, the PAMELA observations allow the relationship between low and high-energy particles to be investigated, enabling a clearer view of the SEP origin. No qualitative distinction between the spectral shapes of GLE, sub-GLE and non-GLE events is observed, suggesting that GLEs are not a separate class, but are the subset of a continuous distribution of SEP events that are more intense at high energies. While the spectral forms found are to be consistent with diffusive shock acceleration theory, which predicts spectral rollovers at high energies that are attributed to particles escaping the shock region during acceleration, further work is required to explore the relative influences of acceleration and transport processes on SEP spectra., Comment: 26 pages, 13 figures, 2 tables

Published
2018
Full Text
View/download PDF

8. Evidence of energy and charge sign dependence of the recovery time for the December 2006 Forbush event measured by the PAMELA experiment

Author

Munini, R., Boezio, M., Bruno, A., Christian, E. C., de Nolfo, G. A., Di Felice, V., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Potgieter, M. S., Munini, R., Boezio, M., Bruno, A., Christian, E. C., de Nolfo, G. A., Di Felice, V., Martucci, M., Merge, M., Richardson, I. G., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, P., Casolino, M., Castellini, G., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Potgieter, M. S.

Abstract

New results on the short-term galactic cosmic ray (GCR) intensity variation (Forbush decrease) in December 2006 measured by the PAMELA instrument are presented. Forbush decreases are sudden suppressions of the GCR intensities which are associated with the passage of interplanetary transients such as shocks and interplanetary coronal mass ejections (ICMEs). Most of the past measurements of this phenomenon were carried out with ground-based detectors such as neutron monitors or muon telescopes. These techniques allow only the indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease commencing on 2006 December 14, following a CME at the Sun on 2006 December 13 was studied in a wide rigidity range (0.4 - 20 GV) and for different species of GCRs detected directly in space. The daily averaged GCR proton intensity was used to investigate the rigidity dependence of the amplitude and the recovery time of the Forbush decrease. Additionally, for the first time, the temporal variations in the helium and electron intensities during a Forbush decrease were studied. Interestingly, the temporal evolutions of the helium and proton intensities during the Forbush decrease were found in good agreement, while the low rigidity electrons (< 2 GV) displayed a faster recovery. This difference in the electron recovery is interpreted as a charge-sign dependence introduced by drift motions experienced by the GCRs during their propagation through the heliosphere.

Published
2018
Full Text
View/download PDF

9. Short-term variation in the galactic cosmic ray intensity measured with the PAMELA experiment

Author

Munini, R., Di Felice, V., Boezio, M., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Potgieter, M. S., Christian, E. C., De Nolfo, G. A., Richardson, I., Ryan, J. M., Stochaj, S., Munini, R., Di Felice, V., Boezio, M., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Santis, C., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Potgieter, M. S., Christian, E. C., De Nolfo, G. A., Richardson, I., Ryan, J. M., and Stochaj, S.

Abstract

New results on the galactic cosmic ray (GCR) short-term intensity variation associated with Forbush decrease and co-rotating interaction regions (CIRs) measured by the PAMELA instrument between November 2006 and March 2007 are presented. Most of the past measurements on Forbush decrease events were carried out with neutron monitor detector. This tecnique allows only indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease associated with the December 13th coronal mass ejection (CME) was studied in a wide rigidity range (0.4 - 20 GV) and for different species of GCRs detected directly in space. Using GCR protons, the amplitude and the recovery time of the Forbush decrease were studied for ten rigidity interval with a temporal resolution of one day. For comparison the helium and the electron intensity over time were also studied. The temporal evolution of the helium and proton intensity was found in good agreement while the electrons show, on average, a faster recovery time. This was interpreted as a charge-sign dependence introduced by drift motion experienced by the low rigidity (< 5 GV) GCRs during their propagation through the heliosphere. Moreover a clear 13.5 days cyclical variation was observed in the GCR proton intensity after the Forbush decrease. This phenomena could be interpreted as an effect of prominent structures of compressed plasma in the solar wind, i.e. CIRs, or to the latitudinal gradient due to the crossing of the heliospheric current sheet (HCS)., QC 20181218

Published
2017

10. PAMELA measurements of solar energetic particle spectra

Author

Mergè, M., Bruno, A., Martucci, M., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Christian, E. R., De Santis, C., De Donato, C., De Nolfo, G. A., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Marcelli, N., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Richardson, I., Ryan, J. M., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Mergè, M., Bruno, A., Martucci, M., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Christian, E. R., De Santis, C., De Donato, C., De Nolfo, G. A., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Marcelli, N., Mayorov, A. G., Menn, W., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Richardson, I., Ryan, J. M., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The charged particle acceleration and transport during solar events have been widely studied in the past decades. The satellite-borne PAMELA experiment has been continuously collecting data since 2006. The apparatus is designed to study charged particles in the cosmic radiation. The combination of permanent magnet, silicon micro-strip spectrometer and silicon-tungsten imaging calorimeter, with the redundancy of instrumentation allows very precise studies on the physics of cosmic rays in a wide energy range and with high statistics. This makes PAMELA a well suited instrument for Solar Energetic Particles (SEP) observations. Not only it spans the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but also PAMELA carries out the first direct measurements of SEP energy spectra, composition and angular distribution. PAMELA has observed many SEP events in solar cycle 24, offering unique opportunity to address several questions on high-energy SEP origin. A preliminary analysis on proton spectra during several events of the 24th solar cycle is presented., QC 20181214

Published
2017

11. Geomagnetically trapped, albedo and solar energetic particles : Trajectory analysis and flux reconstruction with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The PAMELA satellite experiment is providing comprehensive observations of the interplanetary and magnetospheric radiation in the near-Earth environment. Thanks to its identification capabilities and the semi-polar orbit, PAMELA is able to precisely measure the energetic spectra and the angular distributions of the different cosmic-ray populations over a wide latitude region, including geomagnetically trapped and albedo particles. Its observations comprise the solar energetic particle events between solar cycles 23 and 24, and the geomagnetic cutoff variations during magnetospheric storms. PAMELA's measurements are supported by an accurate analysis of particle trajectories in the Earth's magnetosphere based on a realistic geomagnetic field modeling, which allows the classification of particle populations of different origin and the investigation of the asymptotic directions of arrival., QC 20170815

Published
2017
Full Text
View/download PDF

12. Balloon Flight Test of a Compton Telescope Based on Scintillators with Silicon Photomultiplier Readouts

Author

Bloser, P. F., Legere, J. S., Bancroft, C. M., Ryan, J. M., McConnell, M. L., Bloser, P. F., Legere, J. S., Bancroft, C. M., Ryan, J. M., and McConnell, M. L.

Abstract

We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4 - 10 MeV) detectors capable of making sensitive observations. A fast scintillator- based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits the rejection of background via time-of-flight (ToF) discrimination. The Solar Compton Telescope (SolCompT) prototype was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr3:Ce crystal for a calorimeter detector. Both scintillator detectors were read out by 2 x 2 arrays of Hamamatsu S11828-3344 MPPC devices. Custom front-end electronics provided optimum signal rise time and linearity, and custom power supplies automatically adjusted the SiPM bias voltage to compensate for temperature-induced gain variations. A tagged calibration source, consisting of ~240 nCi of Co-60 embedded in plastic scintillator, was placed in the field of view and provided a known source of gamma rays to measure in flight. The SolCompT balloon payload was launched on 24 August 2014 from Fort Sumner, NM, and spent ~3.75 hours at a float altitude of ~123,000 feet. The instrument performed well throughout the flight. After correcting for small (~10%) residual gain variations, we measured an in-flight ToF resolution of ~760 ps (FWHM). Advanced scintillators with SiPM readouts continue to show great promise for future gamma-ray instruments., Comment: 39 pages, 25 figures, to appear in NIM-A

Published
2016
Full Text
View/download PDF

13. Balloon Flight Test of a Compton Telescope Based on Scintillators with Silicon Photomultiplier Readouts

Author

Bloser, P. F., Legere, J. S., Bancroft, C. M., Ryan, J. M., McConnell, M. L., Bloser, P. F., Legere, J. S., Bancroft, C. M., Ryan, J. M., and McConnell, M. L.

Abstract

We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4 - 10 MeV) detectors capable of making sensitive observations. A fast scintillator- based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits the rejection of background via time-of-flight (ToF) discrimination. The Solar Compton Telescope (SolCompT) prototype was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr3:Ce crystal for a calorimeter detector. Both scintillator detectors were read out by 2 x 2 arrays of Hamamatsu S11828-3344 MPPC devices. Custom front-end electronics provided optimum signal rise time and linearity, and custom power supplies automatically adjusted the SiPM bias voltage to compensate for temperature-induced gain variations. A tagged calibration source, consisting of ~240 nCi of Co-60 embedded in plastic scintillator, was placed in the field of view and provided a known source of gamma rays to measure in flight. The SolCompT balloon payload was launched on 24 August 2014 from Fort Sumner, NM, and spent ~3.75 hours at a float altitude of ~123,000 feet. The instrument performed well throughout the flight. After correcting for small (~10%) residual gain variations, we measured an in-flight ToF resolution of ~760 ps (FWHM). Advanced scintillators with SiPM readouts continue to show great promise for future gamma-ray instruments., Comment: 39 pages, 25 figures, to appear in NIM-A

Published
2016
Full Text
View/download PDF

14. Pamela's measurements of magnetospheric effects on high-energy solar particles

Author

Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, Per, Casolino, M., Castellini, G., Christian, E. R., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, Per, Casolino, M., Castellini, G., Christian, E. R., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Merge, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The nature of particle acceleration at the Sun, whether through flare reconnection processes or through shocks driven by coronal mass ejections, is still under scrutiny despite decades of research. The measured properties of solar energetic particles (SEPs) have long been modeled in different particle-acceleration scenarios. The challenge has been to disentangle the effects of transport from those of acceleration. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument enables unique observations of SEPs including the composition and angular distribution of the particles about the magnetic field, i.e., pitch angle distribution, over a broad energy range (>80 MeV)-bridging a critical gap between space-based and ground-based measurements. We present high-energy SEP data from PAMELA acquired during the 2012 May 17 SEP event. These data exhibit differential anisotropies and thus transport features over the instrument rigidity range. SEP protons exhibit two distinct pitch angle distributions: a low-energy population that extends to 90 degrees and a population that is beamed at high energies (>1 GeV), consistent with neutron monitor measurements. To explain a low-energy SEP population that exhibits significant scattering or redistribution accompanied by a high-energy population that reaches the Earth relatively unaffected by dispersive transport effects, we postulate that the scattering or redistribution takes place locally. We believe that these are the first comprehensive measurements of the effects of solar energetic particle transport in the Earth's magnetosheath., QC 20150408

Published
2015
Full Text
View/download PDF

15. Solar energetic particle events : Trajectory analysis and flux reconstruction with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, Per, Casolino, M., Castellini, G., Christian, E. C., De Donato, C., De Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, Per, Casolino, M., Castellini, G., Christian, E. C., De Donato, C., De Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA satellite experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from about 80 MeV to several GeV in near-Earth space, bridging the low energy data by other space-based instruments and the Ground Level Enhancement (GLE) data by the worldwide network of neutron monitors. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies. This work reports the analysis methods developed to estimate the SEP energy spectra as a function of the particle pitch-angle with respect to the Interplanetary Magnetic Field (IMF) direction. The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results for the May 17, 2012 event are presented., QC 20161115

Published
2015

16. Magnetospheric effects on high-energy solar particles during the 2012 May 17th event measured with the PAMELA experiment

Author

Martucci, M., Bazilevskaya, G. A., Boezio, M., Bravar, U., Bruno, A., Christian, E. R., De Nolfo, G. A., Lee, M., Mergè, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Martucci, M., Bazilevskaya, G. A., Boezio, M., Bravar, U., Bruno, A., Christian, E. R., De Nolfo, G. A., Lee, M., Mergè, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, Mark, Picozza, P., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The great challenge in constraining scenarios for solar energetic particle (SEP) acceleration is due to the fact that the signatures of acceleration itself are heavily modified by transport within interplanetary space. During transport, SEPs are subject to pitch angle scattering by the turbulent magnetic field, adiabatic focusing, or reflecting magnetic structures. Ground Level Enhancements (GLEs) provide an ideal way to study acceleration with minimal transport. In this work, we present a unique high-energy SEP observation from PAMELA of the 2012 May 17 GLE and interpret the observed pitch angle distributions as a result of local scattering (1 AU) by the Earth's magnetosheath., QC 20161121

Published
2015

17. Solar energetic particle events: trajectory analysis and flux reconstruction with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA satellite experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from about 80 MeV to several GeV in near-Earth space, bridging the low energy data by other space-based instruments and the Ground Level Enhancement (GLE) data by the worldwide network of neutron monitors. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies. This work reports the analysis methods developed to estimate the SEP energy spectra as a function of the particle pitch-angle with respect to the Interplanetary Magnetic Field (IMF) direction. The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results for the May 17, 2012 event are presented., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)085

Published
2015

18. PAMELA's measurements of geomagnetically trapped and albedo protons

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

Data from the PAMELA satellite experiment were used to perform a detailed measurement of under-cutoff protons at low Earth orbits. On the basis of a trajectory tracing approach using a realistic description of the magnetosphere, protons were classified into geomagnetically trapped and re-entrant albedo. The former include stably-trapped protons in the South Atlantic Anomaly, which were analyzed in the framework of the adiabatic theory, investigating energy spectra, spatial and angular distributions; results were compared with the predictions of the AP8 and the PSB97 empirical trapped models. The albedo protons were classified into quasi-trapped, concentrating in the magnetic equatorial region, and un-trapped, spreading over all latitudes and including both short-lived (precipitating) and long-lived (pseudo-trapped) components. Features of the penumbra region around the geomagnetic cutoff were investigated as well. PAMELA observations significantly improve the characterization of the high energy proton populations in near Earth orbits., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)288

Published
2015

19. PAMELA's measurements of geomagnetic cutoff variations during solar energetic particle events

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

Data from the PAMELA satellite experiment were used to measure the geomagnetic cutoff for high-energy ($\gtrsim$ 80 MeV) protons during the solar particle events on 2006 December 13 and 14. The variations of the cutoff latitude as a function of rigidity were studied on relatively short timescales, corresponding to single spacecraft orbits (about 94 minutes). Estimated cutoff values were cross-checked with those obtained by means of a trajectory tracing approach based on dynamical empirical modeling of the Earth's magnetosphere. We find significant variations in the cutoff latitude, with a maximum suppression of about 6 deg for $\sim$80 MeV protons during the main phase of the storm. The observed reduction in the geomagnetic shielding and its temporal evolution were compared with the changes in the magnetosphere configuration, investigating the role of IMF, solar wind and geomagnetic (Kp, Dst and Sym-H indexes) variables and their correlation with PAMELA cutoff results., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)287

Published
2015

20. PAMELA's Measurements of Magnetospheric Effects on High Energy Solar Particles

Author

Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The nature of particle acceleration at the Sun, whether through flare reconnection processes or through shocks driven by coronal mass ejections (CMEs), is still under scrutiny despite decades of research. The measured properties of solar energetic particles (SEPs) have long been modeled in different particle-acceleration scenarios. The challenge has been to disentangle to the effects of transport from those of acceleration. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument, enables unique observations of SEPs including composition and the angular distribution of the particles about the magnetic field, i.e. pitch angle distribution, over a broad energy range (>80 MeV) -- bridging a critical gap between space-based measurements and ground-based. We present high-energy SEP data from PAMELA acquired during the 2012 May 17 SEP event. These data exhibit differential anisotropies and thus transport features over the instrument rigidity range. SEP protons exhibit two distinct pitch angle distributions; a low-energy population that extends to 90{\deg} and a population that is beamed at high energies (>1 GeV), consistent with neutron monitor measurements. To explain a low-energy SEP population that exhibits significant scattering or redistribution accompanied by a high-energy population that reaches the Earth relatively unaffected by dispersive transport effects, we postulate that the scattering or redistribution takes place locally. We believe these are the first comprehensive measurements of the effects of solar energetic particle transport in the Earth's magnetosheath., Comment: 21 pages, 4 figures. Accepted for publication in The Astrophysical Journal Letters

Published
2015
Full Text
View/download PDF

21. Education and Consumption

Author

Cook, Daniel, Ryan, J Michael, Cook, D ( Daniel ), Ryan, J M ( J Michael ), Rössel, Jörg, Cook, Daniel, Ryan, J Michael, Cook, D ( Daniel ), Ryan, J M ( J Michael ), and Rössel, Jörg

Published
2015

22. Solar energetic particle events: trajectory analysis and flux reconstruction with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA satellite experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from about 80 MeV to several GeV in near-Earth space, bridging the low energy data by other space-based instruments and the Ground Level Enhancement (GLE) data by the worldwide network of neutron monitors. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies. This work reports the analysis methods developed to estimate the SEP energy spectra as a function of the particle pitch-angle with respect to the Interplanetary Magnetic Field (IMF) direction. The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results for the May 17, 2012 event are presented., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)085

Published
2015

23. PAMELA's measurements of geomagnetic cutoff variations during solar energetic particle events

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

Data from the PAMELA satellite experiment were used to measure the geomagnetic cutoff for high-energy ($\gtrsim$ 80 MeV) protons during the solar particle events on 2006 December 13 and 14. The variations of the cutoff latitude as a function of rigidity were studied on relatively short timescales, corresponding to single spacecraft orbits (about 94 minutes). Estimated cutoff values were cross-checked with those obtained by means of a trajectory tracing approach based on dynamical empirical modeling of the Earth's magnetosphere. We find significant variations in the cutoff latitude, with a maximum suppression of about 6 deg for $\sim$80 MeV protons during the main phase of the storm. The observed reduction in the geomagnetic shielding and its temporal evolution were compared with the changes in the magnetosphere configuration, investigating the role of IMF, solar wind and geomagnetic (Kp, Dst and Sym-H indexes) variables and their correlation with PAMELA cutoff results., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)287

Published
2015

24. PAMELA's measurements of geomagnetically trapped and albedo protons

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergè, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

Data from the PAMELA satellite experiment were used to perform a detailed measurement of under-cutoff protons at low Earth orbits. On the basis of a trajectory tracing approach using a realistic description of the magnetosphere, protons were classified into geomagnetically trapped and re-entrant albedo. The former include stably-trapped protons in the South Atlantic Anomaly, which were analyzed in the framework of the adiabatic theory, investigating energy spectra, spatial and angular distributions; results were compared with the predictions of the AP8 and the PSB97 empirical trapped models. The albedo protons were classified into quasi-trapped, concentrating in the magnetic equatorial region, and un-trapped, spreading over all latitudes and including both short-lived (precipitating) and long-lived (pseudo-trapped) components. Features of the penumbra region around the geomagnetic cutoff were investigated as well. PAMELA observations significantly improve the characterization of the high energy proton populations in near Earth orbits., Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015), 30 July - 6 August, 2015, The Hague, The Netherlands, Volume: PoS(ICRC2015)288

Published
2015

25. PAMELA's Measurements of Magnetospheric Effects on High Energy Solar Particles

Author

Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Bruno, A., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Thakur, N., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., and Zampa, N.

Abstract

The nature of particle acceleration at the Sun, whether through flare reconnection processes or through shocks driven by coronal mass ejections (CMEs), is still under scrutiny despite decades of research. The measured properties of solar energetic particles (SEPs) have long been modeled in different particle-acceleration scenarios. The challenge has been to disentangle to the effects of transport from those of acceleration. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument, enables unique observations of SEPs including composition and the angular distribution of the particles about the magnetic field, i.e. pitch angle distribution, over a broad energy range (>80 MeV) -- bridging a critical gap between space-based measurements and ground-based. We present high-energy SEP data from PAMELA acquired during the 2012 May 17 SEP event. These data exhibit differential anisotropies and thus transport features over the instrument rigidity range. SEP protons exhibit two distinct pitch angle distributions; a low-energy population that extends to 90{\deg} and a population that is beamed at high energies (>1 GeV), consistent with neutron monitor measurements. To explain a low-energy SEP population that exhibits significant scattering or redistribution accompanied by a high-energy population that reaches the Earth relatively unaffected by dispersive transport effects, we postulate that the scattering or redistribution takes place locally. We believe these are the first comprehensive measurements of the effects of solar energetic particle transport in the Earth's magnetosheath., Comment: 21 pages, 4 figures. Accepted for publication in The Astrophysical Journal Letters

Published
2015
Full Text
View/download PDF

26. Analysis on H spectral shape during the early 2012 SEPs with the PAMELA experiment

Author

Martucci, M., Boezio, M., Bravar, U., Carbone, R., Christian, E. R., De Nolfo, G. A., Merge, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Sotgiu, A., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Pascale, M. P., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, Mark, Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Martucci, M., Boezio, M., Bravar, U., Carbone, R., Christian, E. R., De Nolfo, G. A., Merge, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Sotgiu, A., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., De Donato, C., De Pascale, M. P., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, Mark, Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The satellite-borne PAMELA experiment has been continuously collecting data since 2006. This apparatus is designed to study charged particles in the cosmic radiation. The combination of a permanent magnet, a silicon strip tracker and a silicon-tungsten imaging calorimeter, and the redundancy of instrumentation allow very precise studies on the physics of cosmic rays in a wide energy range and with high statistics. This makes PAMELA a very suitable instrument for Solar Energetic Particle (SEP) observations. Not only does it span the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but PAMELA also carries out the first direct measurements of the composition for the highest energy SEP events, including those causing Ground Level Enhancements (GLEs). In particular, PAMELA has registered many SEP events during solar cycle 24, offering unique opportunities to address the question of high-energy SEP origin. A preliminary analysis on proton spectra behaviour during this event is presented in this work., QC 20140508

Published
2014
Full Text
View/download PDF

27. POET : A SMEX mission for gamma ray burst polarimetry

Author

McConnell, M. L., Baring, M., Bloser, P., Dwyer, J. F., Emslie, A. G., Ertley, C. D., Greiner, J., Harding, A. K., Hartmann, D. H., Hill, J. E., Kaaret, P., Kippen, R. M., Mattingly, D., McBreen, S., Pearce, M., Produit, Nicolas, Ryan, J. M., Ryde, F., Sakamoto, T., Toma, K., Vestrand, W. T., Zhang, B., McConnell, M. L., Baring, M., Bloser, P., Dwyer, J. F., Emslie, A. G., Ertley, C. D., Greiner, J., Harding, A. K., Hartmann, D. H., Hill, J. E., Kaaret, P., Kippen, R. M., Mattingly, D., McBreen, S., Pearce, M., Produit, Nicolas, Ryan, J. M., Ryde, F., Sakamoto, T., Toma, K., Vestrand, W. T., and Zhang, B.

Abstract

Polarimeters for Energetic Transients (POET) is a mission concept designed to t within the envelope of a NASA Small Explorer (SMEX) mission. POET will use X-ray and gamma-ray polarimetry to uncover the energy release mechanism associated with the formation of stellar-mass black holes and investigate the physics of extreme magnetic ields in the vicinity of compact objects. Two wide-FoV, non-imaging polarimeters will provide polarization measurements over the broad energy range from about 2 keV up to about 500 keV. A Compton scatter polarimeter, using an array of independent scintillation detector elements, will be used to collect data from 50 keV up to 500 keV. At low energies (215 keV), data will be provided by a photoelectric polarimeter based on the use of a Time Projection Chamber for photoelectron tracking. During a two-year baseline mission, POET will be able to collect data that will allow us to distinguish between three basic models for the inner jet of gamma-ray bursts., QC 20150608

Published
2014
Full Text
View/download PDF

28. Back-Tracing and Flux Reconstruction for Solar Events with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA satellite-borne experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from $\sim$80 MeV to several GeV in near-Earth space. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies related to SEP events. This paper focuses on the analysis methods developed to estimate SEP energy spectra as a function of the particle pitch angle with respect to the Interplanetary Magnetic Field (IMF). The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results of the calculation for the May 17, 2012 event are reported., Comment: 25 pages, 9 figures

Published
2014

29. The Study of TeV Variability and Duty Cycle of Mrk 421 from 3 Years of Observations with the Milagro Observatory

Author

Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., Delay, R. S., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Fraija, N., González, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Hüntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., Marinelli, A., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Patricelli, B., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., Delay, R. S., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Fraija, N., González, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Hüntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., Marinelli, A., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Patricelli, B., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

TeV flaring activity with time scales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different time scales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypothesis of the baseline flux and for different flare selections and we compare our results with the X-ray duty cycle estimated by Resconi et al. 2009. The robustness of the results is discussed., Comment: 27 pages, 6 figures, ApJ accepted

Published
2014
Full Text
View/download PDF

30. Milagro Observations of Potential TeV Emitters

Author

Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

This paper reports the results from three targeted searches of Milagro TeV sky maps: two extragalactic point source lists and one pulsar source list. The first extragalactic candidate list consists of 709 candidates selected from the Fermi-LAT 2FGL catalog. The second extragalactic candidate list contains 31 candidates selected from the TeVCat source catalog that have been detected by imaging atmospheric Cherenkov telescopes (IACTs). In both extragalactic candidate lists Mkn 421 was the only source detected by Milagro. This paper presents the Milagro TeV flux for Mkn 421 and flux limits for the brighter Fermi-LAT extragalactic sources and for all TeVCat candidates. The pulsar list extends a previously published Milagro targeted search for Galactic sources. With the 32 new gamma-ray pulsars identified in 2FGL, the number of pulsars that are studied by both Fermi-LAT and Milagro is increased to 52. In this sample, we find that the probability of Milagro detecting a TeV emission coincident with a pulsar increases with the GeV flux observed by the Fermi-LAT in the energy range from 0.1 GeV to 100 GeV., Comment: 18 pages, 6 Figures and 4 tables

Published
2014
Full Text
View/download PDF

31. Back-Tracing and Flux Reconstruction for Solar Events with PAMELA

Author

Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Bruno, A., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Boezio, M., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bravar, U., Cafagna, F., Campana, D., Carbone, R., Carlson, P., Casolino, M., Castellini, G., Christian, E. C., De Donato, C., de Nolfo, G. A., De Santis, C., De Simone, N., Di Felice, V., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, S. Y., Kvashnin, A. N., Lee, M., Leonov, A., Malakhov, V., Marcelli, L., Martucci, M., Mayorov, A. G., Menn, W., Mergé, M., Mikhailov, V. V., Mocchiutti, E., Monaco, A., Mori, N., Munini, R., Osteria, G., Palma, F., Panico, B., Papini, P., Pearce, M., Picozza, P., Ricci, M., Ricciarini, S. B., Ryan, J. M., Sarkar, R., Scotti, V., Simon, M., Sparvoli, R., Spillantini, P., Stochaj, S., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G. I., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA satellite-borne experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from $\sim$80 MeV to several GeV in near-Earth space. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies related to SEP events. This paper focuses on the analysis methods developed to estimate SEP energy spectra as a function of the particle pitch angle with respect to the Interplanetary Magnetic Field (IMF). The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results of the calculation for the May 17, 2012 event are reported., Comment: 25 pages, 9 figures

Published
2014

32. Milagro Observations of Potential TeV Emitters

Author

Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

This paper reports the results from three targeted searches of Milagro TeV sky maps: two extragalactic point source lists and one pulsar source list. The first extragalactic candidate list consists of 709 candidates selected from the Fermi-LAT 2FGL catalog. The second extragalactic candidate list contains 31 candidates selected from the TeVCat source catalog that have been detected by imaging atmospheric Cherenkov telescopes (IACTs). In both extragalactic candidate lists Mkn 421 was the only source detected by Milagro. This paper presents the Milagro TeV flux for Mkn 421 and flux limits for the brighter Fermi-LAT extragalactic sources and for all TeVCat candidates. The pulsar list extends a previously published Milagro targeted search for Galactic sources. With the 32 new gamma-ray pulsars identified in 2FGL, the number of pulsars that are studied by both Fermi-LAT and Milagro is increased to 52. In this sample, we find that the probability of Milagro detecting a TeV emission coincident with a pulsar increases with the GeV flux observed by the Fermi-LAT in the energy range from 0.1 GeV to 100 GeV., Comment: 18 pages, 6 Figures and 4 tables

Published
2014
Full Text
View/download PDF

33. The Study of TeV Variability and Duty Cycle of Mrk 421 from 3 Years of Observations with the Milagro Observatory

Author

Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., Delay, R. S., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Fraija, N., González, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Hüntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., Marinelli, A., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Patricelli, B., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Abeysekara, A. U., Allen, B. T., Aune, T., Barber, A. S., Berley, D., Braun, J., Chen, C., Christopher, G. E., Delay, R. S., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Fraija, N., González, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Hüntemeyer, P. H., Imran, A., Kolterman, B. E., Linnemann, J. T., Marinelli, A., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Patricelli, B., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Schneider, M., Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

TeV flaring activity with time scales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. In this scenario, correlations between the X-ray and the TeV fluxes are expected, TeV orphan flares are hardly explained and the activity (measured as duty cycle) of the source at TeV energies is expected to be equal or less than that observed in X-rays if only SSC is considered. To estimate the TeV duty cycle of Mrk 421 and to establish limits on its variability at different time scales, we continuously observed Mrk 421 with the Milagro observatory. Mrk 421 was detected by Milagro with a statistical significance of 7.1 standard deviations between 2005 September 21 and 2008 March 15. The observed spectrum is consistent with previous observations by VERITAS. We estimate the duty cycle of Mrk 421 for energies above 1 TeV for different hypothesis of the baseline flux and for different flare selections and we compare our results with the X-ray duty cycle estimated by Resconi et al. 2009. The robustness of the results is discussed., Comment: 27 pages, 6 figures, ApJ accepted

Published
2014
Full Text
View/download PDF

34. Study on 2012 march 7 solar particle event and forbush decrease with the PAMELA experiment

Author

Ricci, M., de Nolfo, G. A., Martucci, M., Ryan, J. M., Boezio, M., Bravar, U., Carbone, R., Christian, E. R., Mergè, M., Mocchiutti, E., Munini, R., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Donato, C. D. E., de Pascale, M. P., Santis, C. D. E., Simone, N. D. E., Felice, V. D. I., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, M., Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sotgiu, A., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Ricci, M., de Nolfo, G. A., Martucci, M., Ryan, J. M., Boezio, M., Bravar, U., Carbone, R., Christian, E. R., Mergè, M., Mocchiutti, E., Munini, R., Stochaj, S., Thakur, N., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Donato, C. D. E., de Pascale, M. P., Santis, C. D. E., Simone, N. D. E., Felice, V. D. I., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, M., Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Scotti, V., Simon, M., Sotgiu, A., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astro-physics) space-borne experiment was launched on 15 June 2006 and has been continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 MeV to several hundreds of GeV. The on-board instrumentation is built around a permanent magnet with a silicon microstrip tracker, providing charge and track detection information. During solar maximum conditions of solar cycle 24, PAMELA has been providing key information about solar energetic particles (SEPs) and their influence at Earth. We discuss here the recent 2012 March 7 SEP event with a brief comment on the subsequent Forbush decrease, registered by PAMELA. This event was also observed by Fermi/LAT exhibiting unprecedented time-extended γ-ray emission (> 100 MeV) lasting nearly 20 hours. We compare the derived accelerated ion population at the Sun with the ion population measured in space by PAMELA and discuss the implications for particle acceleration., QC 20181113

Published
2013

35. Pamela observation of the 2012 may 17 gle event

Author

Carbone, R., Thakur, N., Martucci, M., Boezio, M., Bravar, U., Christian, E. R., de Nolfo, G. A., Mergè, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Donato, C. D. E., de Pascale, M. P., Santis, C. D. E., Simone, N. D. E., Felice, V. D. I., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, Mark, Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Simon, M., Scotti, V., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., Zverev, V. G., Carbone, R., Thakur, N., Martucci, M., Boezio, M., Bravar, U., Christian, E. R., de Nolfo, G. A., Mergè, M., Mocchiutti, E., Munini, R., Ricci, M., Ryan, J. M., Stochaj, S., Adriani, O., Barbarino, G. C., Bazilevskaya, G. A., Bellotti, R., Bogomolov, E. A., Bongi, M., Bonvicini, V., Bottai, S., Bruno, A., Cafagna, F., Campana, D., Carlson, Per, Casolino, M., Castellini, G., Donato, C. D. E., de Pascale, M. P., Santis, C. D. E., Simone, N. D. E., Felice, V. D. I., Formato, V., Galper, A. M., Karelin, A. V., Koldashov, S. V., Koldobskiy, S., Krutkov, Y., Kvashnin, A. N., Leonov, A., Malakhov, V., Marcelli, L., Mayorov, A. G., Menn, W., Mikhailov, V. V., Monaco, A., Mori, N., Osteria, G., Palma, F., Papini, P., Pearce, Mark, Picozza, P., Pizzolotto, C., Ricciarini, S. B., Sarkar, R., Simon, M., Scotti, V., Sparvoli, R., Spillantini, P., Stozhkov, Y. I., Vacchi, A., Vannuccini, E., Vasilyev, G., Voronov, S. A., Yurkin, Y. T., Zampa, G., Zampa, N., and Zverev, V. G.

Abstract

The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment has been collecting data in orbit since July 2006, providing accurate measurements of the energy spectra and composition of the cosmic radiation from a few hundred MeV/n up to hundred GeV/n. This wide interval of measured energies makes PAMELA a unique instrument for Solar Energetic Particle (SEP) observations. Not only does it span the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but also PAMELA carries out the first direct measurements of the composition for the highest energy SEP events, including those causing Ground Level Enhancements (GLEs). PAMELA has registered many SEP events in solar cycle 24 including the 2012 May 17 GLE event (GLE 71), offering unique opportunities to address the question of high-energy SEP origin. Experimental performances and preliminary results on the 2012 May 17 events will be presented. We will discuss the derived particle injection time and compare with other time scales at the Sun including the flare and CME onset times., QC 20181105

Published
2013

36. Spectrum and Morphology of the Two Brightest Milagro Sources in the Cygnus Region: MGRO J2019+37 and MGRO J2031+41

Author

Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Bonamente, E., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Galbraith-Frew, J. G., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Morgan, T., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Bonamente, E., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Galbraith-Frew, J. G., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Morgan, T., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1 to 200 TeV using the last 3 years of Milagro data (2005-2008), with the detector in its final configuration. MGRO J2019+37 is detected with a significance of 12.3 standard deviations ($\sigma$), and is better fit by a power law with an exponential cutoff than by a simple power law, with a probability $>98$% (F-test). The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of $7^{+5}_{-2}\times10^{-10}$ $\mathrm{s^{-1}\: m^{-2}\: TeV^{-1}}$, a spectral index of $2.0^{+0.5}_{-1.0}$ and a cutoff energy of $29^{+50}_{-16}$ TeV. MGRO J2031+41 is detected with a significance of 7.3$\sigma$, with no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of $2.4^{+0.6}_{-0.5}\times10^{-10}$ $\mathrm{s^{-1}\: m^{-2}\: TeV^{-1}}$ and a spectral index of $3.08^{+0.19}_{-0.17}$. The overall flux is subject to an $\sim$30% systematic uncertainty. The systematic uncertainty on the power law indices is $\sim$0.1. A comparison with previous results from TeV J2032+4130, MGRO J2031+41 and MGRO J2019+37 is also presented., Comment: 11 pages, 10 figures

Published
2012
Full Text
View/download PDF

37. Spectrum and Morphology of the Two Brightest Milagro Sources in the Cygnus Region: MGRO J2019+37 and MGRO J2031+41

Author

Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Bonamente, E., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Galbraith-Frew, J. G., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Morgan, T., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Bonamente, E., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Galbraith-Frew, J. G., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Morgan, T., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are analyzed using Milagro data with a new technique, and their emission is tested under two different spectral assumptions: a power law and a power law with an exponential cutoff. The new analysis technique is based on an energy estimator that uses the fraction of photomultiplier tubes in the observatory that detect the extensive air shower. The photon spectrum is measured in the range 1 to 200 TeV using the last 3 years of Milagro data (2005-2008), with the detector in its final configuration. MGRO J2019+37 is detected with a significance of 12.3 standard deviations ($\sigma$), and is better fit by a power law with an exponential cutoff than by a simple power law, with a probability $>98$% (F-test). The best-fitting parameters for the power law with exponential cutoff model are a normalization at 10 TeV of $7^{+5}_{-2}\times10^{-10}$ $\mathrm{s^{-1}\: m^{-2}\: TeV^{-1}}$, a spectral index of $2.0^{+0.5}_{-1.0}$ and a cutoff energy of $29^{+50}_{-16}$ TeV. MGRO J2031+41 is detected with a significance of 7.3$\sigma$, with no evidence of a cutoff. The best-fitting parameters for a power law are a normalization of $2.4^{+0.6}_{-0.5}\times10^{-10}$ $\mathrm{s^{-1}\: m^{-2}\: TeV^{-1}}$ and a spectral index of $3.08^{+0.19}_{-0.17}$. The overall flux is subject to an $\sim$30% systematic uncertainty. The systematic uncertainty on the power law indices is $\sim$0.1. A comparison with previous results from TeV J2032+4130, MGRO J2031+41 and MGRO J2019+37 is also presented., Comment: 11 pages, 10 figures

Published
2012
Full Text
View/download PDF

38. On the sensitivity of the HAWC observatory to gamma-ray bursts

Author

HAWC collaboration, Abeysekara, A. U., Aguilar, J. A., Aguilar, S., Alfaro, R., Almaraz, E., Álvarez, C., Álvarez-Romero, J. de D., Álvarez, M., Arceo, R., Arteaga-Velázquez, J. C., Badillo, C., Barber, A., Baughman, B. M., Bautista-Elivar, N., Belmont, E., Benítez, E., BenZvi, S. Y., Berley, D., Bernal, A., Bonamente, E., Braun, J., Caballero-Lopez, R., Cabrera, I., Carramiñana, A., Carrasco, L., Castillo, M., Chambers, L., Conde, R., Condreay, P., Cotti, U., Cotzomi, J., D'Olivo, J. C., de la Fuente, E., De León, C., Delay, S., Delepine, D., DeYoung, T., Diaz, L., Diaz-Cruz, L., Dingus, B. L., Duvernois, M. A., Edmunds, D., Ellsworth, R. W., Fick, B., Fiorino, D. W., Flandes, A., Fraija, N. I., Galindo, A., García-Luna, J. L., García-Torales, G., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Guzmán-Ceron, C., Hampel-Arias, Z., Harris, T., Hays, E., Hernandez-Cervantes, L., Hüntemeyer, P. H., Imran, A., Iriarte, A., Jimenez, J. J., Karn, P., Kelley-Hoskins, N., Kieda, D., Langarica, R., Lara, A., Lauer, R., Lee, W. H., Linares, E. C., Linnemann, J. T., Longo, M., Luna-García, R., Martínez, H., Martínez, J., Martínez, L. A., Martínez, O., Martínez-Castro, J., Martos, M., Matthews, J., McEnery, J. E., Medina-Tanco, G., Mendoza-Torres, J. E., Miranda-Romagnoli, P. A., Montaruli, T., Moreno, E., Mostafa, M., Napsuciale, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Tapia, A. Olmos, Orozco, V., Pérez, V., Pérez-Pérez, E. G., Perkins, J. S., Pretz, J., Ramirez, C., Ramírez, I., Rebello, D., Rentería, A., Reyes, J., Rosa-González, D., Rosado, A., Ryan, J. M., Sacahui, J. R., Salazar, H., Salesa, F., Sandoval, A., Santos, E., Schneider, M., Shoup, A., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, W., Suárez, F., Suarez, N., Taboada, I., Tellez, A. F., Tenorio-Tagle, G., Tepe, A., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Valdes-Galicia, J., Vanegas, P., Vasileiou, V., Vázquez, O., Vázquez, X., Villaseñor, L., Wall, W., Walters, J. S., Warner, D., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Zaborov, D., Zepeda, A., HAWC collaboration, Abeysekara, A. U., Aguilar, J. A., Aguilar, S., Alfaro, R., Almaraz, E., Álvarez, C., Álvarez-Romero, J. de D., Álvarez, M., Arceo, R., Arteaga-Velázquez, J. C., Badillo, C., Barber, A., Baughman, B. M., Bautista-Elivar, N., Belmont, E., Benítez, E., BenZvi, S. Y., Berley, D., Bernal, A., Bonamente, E., Braun, J., Caballero-Lopez, R., Cabrera, I., Carramiñana, A., Carrasco, L., Castillo, M., Chambers, L., Conde, R., Condreay, P., Cotti, U., Cotzomi, J., D'Olivo, J. C., de la Fuente, E., De León, C., Delay, S., Delepine, D., DeYoung, T., Diaz, L., Diaz-Cruz, L., Dingus, B. L., Duvernois, M. A., Edmunds, D., Ellsworth, R. W., Fick, B., Fiorino, D. W., Flandes, A., Fraija, N. I., Galindo, A., García-Luna, J. L., García-Torales, G., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Guzmán-Ceron, C., Hampel-Arias, Z., Harris, T., Hays, E., Hernandez-Cervantes, L., Hüntemeyer, P. H., Imran, A., Iriarte, A., Jimenez, J. J., Karn, P., Kelley-Hoskins, N., Kieda, D., Langarica, R., Lara, A., Lauer, R., Lee, W. H., Linares, E. C., Linnemann, J. T., Longo, M., Luna-García, R., Martínez, H., Martínez, J., Martínez, L. A., Martínez, O., Martínez-Castro, J., Martos, M., Matthews, J., McEnery, J. E., Medina-Tanco, G., Mendoza-Torres, J. E., Miranda-Romagnoli, P. A., Montaruli, T., Moreno, E., Mostafa, M., Napsuciale, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Tapia, A. Olmos, Orozco, V., Pérez, V., Pérez-Pérez, E. G., Perkins, J. S., Pretz, J., Ramirez, C., Ramírez, I., Rebello, D., Rentería, A., Reyes, J., Rosa-González, D., Rosado, A., Ryan, J. M., Sacahui, J. R., Salazar, H., Salesa, F., Sandoval, A., Santos, E., Schneider, M., Shoup, A., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, W., Suárez, F., Suarez, N., Taboada, I., Tellez, A. F., Tenorio-Tagle, G., Tepe, A., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Valdes-Galicia, J., Vanegas, P., Vasileiou, V., Vázquez, O., Vázquez, X., Villaseñor, L., Wall, W., Walters, J. S., Warner, D., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Zaborov, D., and Zepeda, A.

Abstract

We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles.

Published
2011
Full Text
View/download PDF

39. Observation and Spectral Measurements of the Crab Nebula with Milagro

Author

Abdo, A. A., Allen, B. T., Aune, T., Benbow, W., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Falcone, A., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Gordo, J. B., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, and G. B., Abdo, A. A., Allen, B. T., Aune, T., Benbow, W., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Falcone, A., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Gordo, J. B., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, and G. B.

Abstract

The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by observing the particle footprint reaching the ground. The fraction of detectors recording signals from photons at the ground is a suitable proxy for the energy of the primary particle and has been used to measure the photon energy spectrum of the Crab Nebula between ~1 and ~100 TeV. The TeV emission is believed to be caused by inverse-Compton up-scattering scattering of ambient photons by an energetic electron population. The location of a TeV steepening or cutoff in the energy spectrum reveals important details about the underlying electron population. We describe the experiment and the technique for distinguishing gamma-ray events from the much more-abundant hadronic events. We describe the calculation of the significance of the excess from the Crab and how the energy spectrum is fit. The fit is consistent with values measured by IACTs between 1 and 20 TeV. Fixing the spectral index to values that have been measured below 1 TeV by IACT experiments (2.4 to 2.6), the fit to the Milagro data suggests that Crab exhibits a spectral steepening or cutoff between about 20 to 40 TeV., Comment: Submitted to Astrophysical Journal

Published
2011
Full Text
View/download PDF

40. Observation and Spectral Measurements of the Crab Nebula with Milagro

Author

Abdo, A. A., Allen, B. T., Aune, T., Benbow, W., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Falcone, A., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Gordo, J. B., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, and G. B., Abdo, A. A., Allen, B. T., Aune, T., Benbow, W., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Falcone, A., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Gordo, J. B., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, and G. B.

Abstract

The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by observing the particle footprint reaching the ground. The fraction of detectors recording signals from photons at the ground is a suitable proxy for the energy of the primary particle and has been used to measure the photon energy spectrum of the Crab Nebula between ~1 and ~100 TeV. The TeV emission is believed to be caused by inverse-Compton up-scattering scattering of ambient photons by an energetic electron population. The location of a TeV steepening or cutoff in the energy spectrum reveals important details about the underlying electron population. We describe the experiment and the technique for distinguishing gamma-ray events from the much more-abundant hadronic events. We describe the calculation of the significance of the excess from the Crab and how the energy spectrum is fit. The fit is consistent with values measured by IACTs between 1 and 20 TeV. Fixing the spectral index to values that have been measured below 1 TeV by IACT experiments (2.4 to 2.6), the fit to the Milagro data suggests that Crab exhibits a spectral steepening or cutoff between about 20 to 40 TeV., Comment: Submitted to Astrophysical Journal

Published
2011
Full Text
View/download PDF

41. On the sensitivity of the HAWC observatory to gamma-ray bursts

Author

HAWC collaboration, Abeysekara, A. U., Aguilar, J. A., Aguilar, S., Alfaro, R., Almaraz, E., Álvarez, C., Álvarez-Romero, J. de D., Álvarez, M., Arceo, R., Arteaga-Velázquez, J. C., Badillo, C., Barber, A., Baughman, B. M., Bautista-Elivar, N., Belmont, E., Benítez, E., BenZvi, S. Y., Berley, D., Bernal, A., Bonamente, E., Braun, J., Caballero-Lopez, R., Cabrera, I., Carramiñana, A., Carrasco, L., Castillo, M., Chambers, L., Conde, R., Condreay, P., Cotti, U., Cotzomi, J., D'Olivo, J. C., de la Fuente, E., De León, C., Delay, S., Delepine, D., DeYoung, T., Diaz, L., Diaz-Cruz, L., Dingus, B. L., Duvernois, M. A., Edmunds, D., Ellsworth, R. W., Fick, B., Fiorino, D. W., Flandes, A., Fraija, N. I., Galindo, A., García-Luna, J. L., García-Torales, G., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Guzmán-Ceron, C., Hampel-Arias, Z., Harris, T., Hays, E., Hernandez-Cervantes, L., Hüntemeyer, P. H., Imran, A., Iriarte, A., Jimenez, J. J., Karn, P., Kelley-Hoskins, N., Kieda, D., Langarica, R., Lara, A., Lauer, R., Lee, W. H., Linares, E. C., Linnemann, J. T., Longo, M., Luna-García, R., Martínez, H., Martínez, J., Martínez, L. A., Martínez, O., Martínez-Castro, J., Martos, M., Matthews, J., McEnery, J. E., Medina-Tanco, G., Mendoza-Torres, J. E., Miranda-Romagnoli, P. A., Montaruli, T., Moreno, E., Mostafa, M., Napsuciale, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Tapia, A. Olmos, Orozco, V., Pérez, V., Pérez-Pérez, E. G., Perkins, J. S., Pretz, J., Ramirez, C., Ramírez, I., Rebello, D., Rentería, A., Reyes, J., Rosa-González, D., Rosado, A., Ryan, J. M., Sacahui, J. R., Salazar, H., Salesa, F., Sandoval, A., Santos, E., Schneider, M., Shoup, A., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, W., Suárez, F., Suarez, N., Taboada, I., Tellez, A. F., Tenorio-Tagle, G., Tepe, A., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Valdes-Galicia, J., Vanegas, P., Vasileiou, V., Vázquez, O., Vázquez, X., Villaseñor, L., Wall, W., Walters, J. S., Warner, D., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Zaborov, D., Zepeda, A., HAWC collaboration, Abeysekara, A. U., Aguilar, J. A., Aguilar, S., Alfaro, R., Almaraz, E., Álvarez, C., Álvarez-Romero, J. de D., Álvarez, M., Arceo, R., Arteaga-Velázquez, J. C., Badillo, C., Barber, A., Baughman, B. M., Bautista-Elivar, N., Belmont, E., Benítez, E., BenZvi, S. Y., Berley, D., Bernal, A., Bonamente, E., Braun, J., Caballero-Lopez, R., Cabrera, I., Carramiñana, A., Carrasco, L., Castillo, M., Chambers, L., Conde, R., Condreay, P., Cotti, U., Cotzomi, J., D'Olivo, J. C., de la Fuente, E., De León, C., Delay, S., Delepine, D., DeYoung, T., Diaz, L., Diaz-Cruz, L., Dingus, B. L., Duvernois, M. A., Edmunds, D., Ellsworth, R. W., Fick, B., Fiorino, D. W., Flandes, A., Fraija, N. I., Galindo, A., García-Luna, J. L., García-Torales, G., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Guzmán-Ceron, C., Hampel-Arias, Z., Harris, T., Hays, E., Hernandez-Cervantes, L., Hüntemeyer, P. H., Imran, A., Iriarte, A., Jimenez, J. J., Karn, P., Kelley-Hoskins, N., Kieda, D., Langarica, R., Lara, A., Lauer, R., Lee, W. H., Linares, E. C., Linnemann, J. T., Longo, M., Luna-García, R., Martínez, H., Martínez, J., Martínez, L. A., Martínez, O., Martínez-Castro, J., Martos, M., Matthews, J., McEnery, J. E., Medina-Tanco, G., Mendoza-Torres, J. E., Miranda-Romagnoli, P. A., Montaruli, T., Moreno, E., Mostafa, M., Napsuciale, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Tapia, A. Olmos, Orozco, V., Pérez, V., Pérez-Pérez, E. G., Perkins, J. S., Pretz, J., Ramirez, C., Ramírez, I., Rebello, D., Rentería, A., Reyes, J., Rosa-González, D., Rosado, A., Ryan, J. M., Sacahui, J. R., Salazar, H., Salesa, F., Sandoval, A., Santos, E., Schneider, M., Shoup, A., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, W., Suárez, F., Suarez, N., Taboada, I., Tellez, A. F., Tenorio-Tagle, G., Tepe, A., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Valdes-Galicia, J., Vanegas, P., Vasileiou, V., Vázquez, O., Vázquez, X., Villaseñor, L., Wall, W., Walters, J. S., Warner, D., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Zaborov, D., and Zepeda, A.

Abstract

We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles.

Published
2011
Full Text
View/download PDF

42. A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2

Author

Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoit, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, Marchi, Simone, Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoit, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, and Marchi, Simone

Abstract

The peculiar object P/2010 A2 was discovered(1) in January 2010 and given a cometary designation because of the presence of a trail of material, although there was no central condensation or coma. The appearance of this object, in an asteroidal orbit (small eccentricity and inclination) in the inner main asteroid belt attracted attention as a potential new member of the recently recognized(2) class of main-belt comets. If confirmed, this new object would expand the range in heliocentric distance over which main-belt comets are found. Here we report observations of P/2010 A2 by the Rosetta spacecraft. We conclude that the trail arose from a single event, rather than a period of cometary activity, in agreement with independent results(3). The trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid. The shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately. We determine that this was an asteroid collision that occurred around 10 February 2009.

Published
2010
Full Text
View/download PDF

43. A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2

Author

Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoît, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, Marchi, Simone, Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoît, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, and Marchi, Simone

Abstract

The peculiar object P/2010 A2 was discovered by the LINEAR near-Earth asteroid survey in January 2010 and given a cometary designation due to the presence of a trail of material, although there was no central condensation or coma. The appearance of this object, in an asteroidal orbit (small eccentricity and inclination) in the inner main asteroid belt attracted attention as a potential new member of the recently recognized class of 'Main Belt Comets' (MBCs). If confirmed, this new object would greatly expand the range in heliocentric distance over which MBCs are found. Here we present observations taken from the unique viewing geometry provided by ESA's Rosetta spacecraft, far from the Earth, that demonstrate that the trail is due to a single event rather than a period of cometary activity, in agreement with independent results from the Hubble Space Telescope (HST). The trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid. The shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately. We determine that this was an asteroid collision that occurred around February 10, 2009., Comment: Published in Nature on 14/10/2010. 25 pages, includes supplementary material

Published
2010
Full Text
View/download PDF

44. A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2

Author

Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoît, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, Marchi, Simone, Snodgrass, Colin, Tubiana, Cecilia, Vincent, Jean-Baptiste, Sierks, Holger, Hviid, Stubbe, Moissl, Richard, Boehnhardt, Hermann, Barbieri, Cesare, Koschny, Detlef, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, Carry, Benoît, Lowry, Stephen C., Laird, Ryan J. M., Weissman, Paul R., Fitzsimmons, Alan, and Marchi, Simone

Abstract

The peculiar object P/2010 A2 was discovered by the LINEAR near-Earth asteroid survey in January 2010 and given a cometary designation due to the presence of a trail of material, although there was no central condensation or coma. The appearance of this object, in an asteroidal orbit (small eccentricity and inclination) in the inner main asteroid belt attracted attention as a potential new member of the recently recognized class of 'Main Belt Comets' (MBCs). If confirmed, this new object would greatly expand the range in heliocentric distance over which MBCs are found. Here we present observations taken from the unique viewing geometry provided by ESA's Rosetta spacecraft, far from the Earth, that demonstrate that the trail is due to a single event rather than a period of cometary activity, in agreement with independent results from the Hubble Space Telescope (HST). The trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid. The shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately. We determine that this was an asteroid collision that occurred around February 10, 2009., Comment: Published in Nature on 14/10/2010. 25 pages, includes supplementary material

Published
2010
Full Text
View/download PDF

45. Milagro Observations of Multi-TeV Emission from Galactic Sources in the Fermi Bright Source List

Author

Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

We present the result of a search of the Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area Telescope. We select sources based on their categorization in the BSL, taking all confirmed or possible Galactic sources in the field of view of Milagro. Of the 34 Fermi sources selected, 14 are observed by Milagro at a significance of 3 standard deviations or more. We conduct this search with a new analysis which employs newly-optimized gamma-hadron separation and utilizes the full 8-year Milagro dataset. Milagro is sensitive to gamma rays with energy from 1 to 100 TeV with a peak sensitivity from 10-50 TeV depending on the source spectrum and declination. These results extend the observation of these sources far above the Fermi energy band. With the new analysis and additional data, multi-TeV emission is definitively observed associated with the Fermi pulsar, J2229.0+6114, in the Boomerang Pulsar Wind Nebula (PWN). Furthermore, an extended region of multi-TeV emission is associated with the Fermi pulsar, J0634.0+1745, the Geminga pulsar., Comment: Accepted for publication in Astrophysical Journal Letters June 30, 2009

Published
2009
Full Text
View/download PDF

46. Milagro Observations of Multi-TeV Emission from Galactic Sources in the Fermi Bright Source List

Author

Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Chen, C., Christopher, G. E., DeYoung, T., Dingus, B. L., Ellsworth, R. W., Gonzalez, M. M., Goodman, J. A., Hays, E., Hoffman, C. M., Huentemeyer, P. H., Kolterman, B. E., Linnemann, J. T., McEnery, J. E., Morgan, T., Mincer, A. I., Nemethy, P., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

We present the result of a search of the Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area Telescope. We select sources based on their categorization in the BSL, taking all confirmed or possible Galactic sources in the field of view of Milagro. Of the 34 Fermi sources selected, 14 are observed by Milagro at a significance of 3 standard deviations or more. We conduct this search with a new analysis which employs newly-optimized gamma-hadron separation and utilizes the full 8-year Milagro dataset. Milagro is sensitive to gamma rays with energy from 1 to 100 TeV with a peak sensitivity from 10-50 TeV depending on the source spectrum and declination. These results extend the observation of these sources far above the Fermi energy band. With the new analysis and additional data, multi-TeV emission is definitively observed associated with the Fermi pulsar, J2229.0+6114, in the Boomerang Pulsar Wind Nebula (PWN). Furthermore, an extended region of multi-TeV emission is associated with the Fermi pulsar, J0634.0+1745, the Geminga pulsar., Comment: Accepted for publication in Astrophysical Journal Letters June 30, 2009

Published
2009
Full Text
View/download PDF

47. Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a Polarized Hard X-Ray Beam

Author

Bloser, P. F., Legere, J. S., McConnell, M. L., Macri, J. R., Bancroft, C. M., Connor, T. P., Ryan, J. M., Bloser, P. F., Legere, J. S., McConnell, M. L., Macri, J. R., Bancroft, C. M., Connor, T. P., and Ryan, J. M.

Abstract

The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete "engineering model" of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46 +/- 0.06 and 0.48 +/- 0.03 at 69.5 keV and 129.5 keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept., Comment: 35 pages, 14 figures, accepted for publication in NIM-A

Published
2008
Full Text
View/download PDF

48. The Large Scale Cosmic-Ray Anisotropy as Observed with Milagro

Author

Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Hopper, B., Hüntemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Nemethy, P., Noyes, D., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B. T., Aune, T., Berley, D., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., Hopper, B., Hüntemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Nemethy, P., Noyes, D., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

Results are presented of a harmonic analysis of the large scale cosmic-ray anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy pro jections in right ascension generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los Alamos, New Mexico. With a high duty cycle and large field-of-view, Milagro is an excellent instrument for measuring this anisotropy with high sensitivity at TeV energies. The analysis is conducted using a seven year data sample consisting of more than 95 billion events, the largest such data set in existence. We observe an anisotropy with a magnitude around 0.1% for cosmic rays with a median energy of 6 TeV. The dominant feature is a deficit region of depth (2.49 +/- 0.02 stat. +/- 0.09 sys.)x10^(-3) in the direction of the Galactic North Pole centered at 189 degrees right ascension. We observe a steady increase in the magnitude of the signal over seven years., Comment: 36 pages, 16 figures, submitted to ApJ

Published
2008
Full Text
View/download PDF

49. A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with Milagro

Author

Abdo, A. A., Allen, B., Aune, T., Berley, D., Blaufuss, E., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., H"untemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Moskalenko, I. V., Nemethy, P., Noyes, D., Porter, T. A., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Strong, A. W., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B., Aune, T., Berley, D., Blaufuss, E., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzalez, M. M., Goodman, J. A., Hoffman, C. M., H"untemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Moskalenko, I. V., Nemethy, P., Noyes, D., Porter, T. A., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Strong, A. W., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

Diffuse $\gamma$-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse $\gamma$-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse $\gamma$-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30$^\circ$ and 110$^\circ$ and between 136$^\circ$ and 216$^\circ$ and for Galactic latitudes between -10$^\circ$ and 10$^\circ$ are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region ($l\in[65^\circ,85^\circ]$). For the Cygnus region, the flux is twice the predicted value. This excess can be explained by the presence of active cosmic ray sources accelerating hadrons which interact with the local dense interstellar medium and produce gamma rays through pion decay., Comment: 15 pages, 3 figures, accepted by ApJ

Published
2008
Full Text
View/download PDF

50. Discovery of Localized Regions of Excess 10-TeV Cosmic Rays

Author

Abdo, A. A., Allen, B., Aune, T., Berley, D., Blaufuss, E., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzales, M. M., Goodman, J. A., Hoffman, C. M., Hüntemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Nemethy, P., Noyes, D., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., Yodh, G. B., Abdo, A. A., Allen, B., Aune, T., Berley, D., Blaufuss, E., Casanova, S., Chen, C., Dingus, B. L., Ellsworth, R. W., Fleysher, L., Fleysher, R., Gonzales, M. M., Goodman, J. A., Hoffman, C. M., Hüntemeyer, P. H., Kolterman, B. E., Lansdell, C. P., Linnemann, J. T., McEnery, J. E., Mincer, A. I., Nemethy, P., Noyes, D., Pretz, J., Ryan, J. M., Parkinson, P. M. Saz, Shoup, A., Sinnis, G., Smith, A. J., Sullivan, G. W., Vasileiou, V., Walker, G. P., Williams, D. A., and Yodh, G. B.

Abstract

An analysis of 7 years of Milagro data performed on a 10-degree angular scale has found two localized regions of excess of unknown origin with greater than 12 sigma significance. Both regions are inconsistent with gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6 sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at ~10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found., Comment: Submitted to PhysRevLett

Published
2008
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results