-
M. Ackermann,
M. Ajello,
A. Allafort,
E. Antolini,
L. Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri,
R. Bellazzini,
B. Berenji, [......],
V. Vitale,
A. P. Waite, E. Wallace,
P. Wang,
B. L. Winer,
M. T. Wolff,
D. L. Wood,
K. S. Wood,
Z. Yang,
and S. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: The Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of γ-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of source types known to emit γ rays, 630 of these sources are "unassociated" (i.e., have no obvious counterparts at other wavelengths). Here, we employ two statistical analyses of the primary γ-ray characteristics for these unassociated sources in an effort to correlate their γ-ray properties with the active galactic nucleus (AGN) and pulsar populations in 1FGL. Based on the correlation results, we classify 221 AGN-like and 134 pulsar-like sources in the 1FGL unassociated sources. The results of these source "classifications" appear to match the expected source distributions, especially at high Galactic latitudes. While useful for planning future multiwavelength follow-up observations, these analyses use limited inputs, and their predictions should not be considered equivalent to "probable source classes" for these sources. We discuss multiwavelength results and catalog cross-correlations to date, and provide new source associations for 229 Fermi-LAT sources that had no association listed in the 1FGL catalog. By validating the source classifications against these new associations, we find that the new association matches the predicted source class in ~80% of the sources.
The Astrophysical Journal 06/2012; 753(1):83. · 6.02 Impact Factor
-
The Fermi-LAT collaboration: M. Ackermann,
M. Ajello,
W. B. Atwood,
L. Baldini,
G. Barbiellini,
D. Bastieri,
K. Bechtol,
R. Bellazzini,
R. D. Blandford,
E. D. Bloom, [......],
V. Vasileiou,
G. Vianello,
V. Vitale,
A. P. Waite, E. Wallace,
K. S. Wood,
M. Wood,
Z. Yang,
G. Zaharijas,
S. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: We have performed an analysis of the diffuse gamma-ray emission with the
Fermi Large Area Telescope in the Milky Way Halo region searching for a signal
from dark matter annihilation or decay. In the absence of a robust dark matter
signal, constraints are presented. We consider both gamma rays produced
directly in the dark matter annihilation/decay and produced by inverse Compton
scattering of the e+e- produced in the annihilation/decay. Conservative limits
are derived requiring that the dark matter signal does not exceed the observed
diffuse gamma-ray emission. A second set of more stringent limits is derived
based on modeling the foreground astrophysical diffuse emission using the
GALPROP code. Uncertainties in the height of the diffusive cosmic-ray halo, the
distribution of the cosmic-ray sources in the Galaxy, the index of the
injection cosmic-ray electron spectrum and the column density of the
interstellar gas are taken into account using a profile likelihood formalism,
while the parameters governing the cosmic-ray propagation have been derived
from fits to local cosmic-ray data. The resulting limits impact the range of
particle masses over which dark matter thermal production in the early Universe
is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic
ray anomalies as annihilation of dark matter.
05/2012;
-
P. L. Nolan,
A. A. Abdo,
M. Ackermann,
M. Ajello,
A. Allafort,
E. Antolini,
W. B. Atwood,
M. Axelsson,
L. Baldini,
J. Ballet, [......],
A. P. Waite, E. Wallace,
P. Wang,
M. Werner,
B. L. Winer,
D. L. Wood,
K. S. Wood,
M. Wood,
Z. Yang,
and S. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: We present the second catalog of high-energy γ-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24 month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 MeV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely γ-ray-producing source classes.
The Astrophysical Journal Supplement Series 03/2012; 199(2):31. · 13.46 Impact Factor
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
E. Antolini,
L. Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri,
K. Bechtol,
R. Bellazzini, [......],
N. Vilchez,
V. Vitale,
A. P. Waite, E. Wallace,
P. Wang,
B. L. Winer,
K. S. Wood,
Z. Yang,
T. Ylinen,
and M. Ziegler
[show abstract]
[hide abstract]
ABSTRACT: This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4-2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis. For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares. More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range. Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects. Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks. Variable sources of the sample have weekly and 3-4 day bin light curves that can be described by 1/f α PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)—measured for a few blazars showing strong activity—complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism. The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 1.5 and 1.7, respectively. The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days. Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars.
The Astrophysical Journal 09/2010; 722(1):520. · 6.02 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
W B Atwood,
L Baldini,
J Ballet,
G Barbiellini,
D Bastieri,
K Bechtol,
R Bellazzini, [......],
M Sasada,
V I Shenavrin,
S N Shore,
G K Skinner,
J Sokoloski,
M Stroh,
A M Tatarnikov,
M Uemura,
G M Wahlgren,
M Yamanaka
[show abstract]
[hide abstract]
ABSTRACT: Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.
Science 08/2010; 329(5993):817-21. · 31.20 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
A Allafort,
E Antolini,
W B Atwood,
M Axelsson,
L Baldini,
J Ballet,
G Barbiellini, [......],
V Vitale,
A P Waite, E Wallace,
P Wang,
K Watters,
B L Winer,
K S Wood,
Z Yang,
T Ylinen,
M Ziegler
[show abstract]
[hide abstract]
ABSTRACT: We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission.
The Astrophysical Journal Supplement Series 06/2010; 188(2):405-436. · 13.46 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
W B Atwood,
L Baldini,
J Ballet,
G Barbiellini,
D Bastieri,
B M Baughman,
K Bechtol, [......],
V Vitale,
A P Waite, E Wallace,
P Wang,
B L Winer,
K S Wood,
T Ylinen,
M Ziegler,
M J Hardcastle,
D Kazanas
[show abstract]
[hide abstract]
ABSTRACT: The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating from the giant radio lobes of the radio galaxy Centaurus A. The resolved gamma-ray image shows the lobes clearly separated from the central active source. In contrast to all other active galaxies detected so far in high-energy gamma-rays, the lobe flux constitutes a considerable portion (greater than one-half) of the total source emission. The gamma-ray emission from the lobes is interpreted as inverse Compton-scattered relic radiation from the cosmic microwave background, with additional contribution at higher energies from the infrared-to-optical extragalactic background light. These measurements provide gamma-ray constraints on the magnetic field and particle energy content in radio galaxy lobes, as well as a promising method to probe the cosmic relic photon fields.
Science 04/2010; 328(5979):725-9. · 31.20 Impact Factor
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
A. Allafort,
L. Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri,
K. Bechtol,
R. Bellazzini, [......],
N. Vilchez,
V. Vitale,
A. P. Waite, E. Wallace,
P. Wang,
P. Weltevrede,
B. L. Winer,
K. S. Wood,
T. Ylinen,
and M. Ziegler
[show abstract]
[hide abstract]
ABSTRACT: Millisecond pulsars (MSPs) have been firmly established as a class of γ-ray emitters via the detection of pulsations above 0.1 GeV from eight MSPs by the Fermi Large Area Telescope (LAT). Using 13 months of LAT data, significant γ-ray pulsations at the radio period have been detected from the MSP PSR J0034–0534, making it the ninth clear MSP detection by the LAT. The γ-ray light curve shows two peaks separated by 0.274 ± 0.015 in phase which are very nearly aligned with the radio peaks, a phenomenon seen only in the Crab pulsar until now. The ≥0.1 GeV spectrum of this pulsar is well fit by an exponentially cutoff power law with a cutoff energy of 1.8 ± 0.6 ± 0.1 GeV and a photon index of 1.5 ± 0.2 ± 0.1, first errors are statistical and second are systematic. The near-alignment of the radio and γ-ray peaks strongly suggests that the radio and γ-ray emission regions are co-located and both are the result of caustic formation.
The Astrophysical Journal 03/2010; 712(2):957. · 6.02 Impact Factor
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
W. B. Atwood,
M. Axelsson,
L. Baldini,
J. Ballet,
G. Barbiellini,
M. G. Baring,
D. Bastieri, [......],
V. Vitale,
A. P. Waite, E. Wallace,
P. Wang,
K. Watters,
P. Weltevrede,
B. L. Winer,
K. S. Wood,
T. Ylinen,
and M. Ziegler
[show abstract]
[hide abstract]
ABSTRACT: We report on γ-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nançay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first γ-ray peak leads the radio main pulse by (281 ± 12 ± 21) μs, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to γ-ray statistics, and the second arises from the rotation parameters. The improved sensitivity and the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at Ec = (5.8 ± 0.5 ± 1.2) GeV, spectral index of Γ = (1.97 ± 0.02 ± 0.06) and integral photon flux above 100 MeV of (2.09 ± 0.03 ± 0.18) × 10–6 cm–2 s–1. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed γ-ray photons are observed up to ~ 20 GeV which precludes emission near the stellar surface, below altitudes of around 4-5 stellar radii in phase intervals encompassing the two main peaks. A detailed phase-resolved spectral analysis is also performed: the hardest emission from the Crab Pulsar comes from the bridge region between the two γ-ray peaks while the softest comes from the falling edge of the second peak. The spectrum of the nebula in the energy range 100 MeV-300 GeV is well described by the sum of two power laws of indices Γsync = (3.99 ± 0.12 ± 0.08) and ΓIC = (1.64 ± 0.05 ± 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism.
The Astrophysical Journal 12/2009; 708(2):1254. · 6.02 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
W B Atwood,
M Axelsson,
L Baldini,
J Ballet,
G Barbiellini,
M G Baring,
D Bastieri, [......],
A P Waite, E Wallace,
P Wang,
K Watters,
N Webb,
P Weltevrede,
B L Winer,
K S Wood,
T Ylinen,
M Ziegler
[show abstract]
[hide abstract]
ABSTRACT: Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.
Science 08/2009; 325(5942):848-52. · 31.20 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
W B Atwood,
M Axelsson,
L Baldini,
J Ballet,
G Barbiellini,
D Bastieri,
M Battelino, [......],
V Vasileiou,
N Vilchez,
V Vitale,
A P Waite, E Wallace,
P Wang,
B L Winer,
K S Wood,
T Ylinen,
M Ziegler
[show abstract]
[hide abstract]
ABSTRACT: Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m;{2} sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E-3.0 and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.
Physical Review Letters 06/2009; 102(18):181101. · 7.37 Impact Factor
-
A A Abdo,
M Ackermann,
M Ajello,
A Allafort,
E Antolini,
W B Atwood,
M Axelsson,
L Baldini,
J Ballet,
G Barbiellini, [......],
C Sg,
M S,
Shaw,
E J Siskind,
A P Waite, E Wallace,
P Wang,
K Watters,
B L Winer,
K S Wood
N. Gehrels N. Giglietto N. Kawai J. Knödlseder Llena Garde J. E. McEnery C. Monte T. Nakamori P. L. Nolan J. P. Norris E. Nuss T. Ohsugi N. Omodei J. F. Ormes J. H. Panetta J. Ripken J.-L. Starck T. E. Stephens D. J. Suson Z. Yang. 01/2002; 16191621231619303120312313923236142323393839474021501391910142339632232121212314583238396231644391039236319161226673119107010(69).
-
A ~A Abdo,
M Ackermann,
M Ajello,
A Allafort,
E Antolini,
W ~B Atwood,
M Axelsson,
L Baldini,
J Ballet,
G Barbiellini, [......],
M Villata,
V Vitale,
A ~P Waite, E Wallace,
P Wang,
B ~L Winer,
K ~S Wood,
Z Yang,
T Ylinen,
M Ziegler
apj. 715:429-457.
-
[show abstract]
[hide abstract]
ABSTRACT: A prosthesis constructed from an advanced textile reinforced composite is used as an example to demonstrate the potential of three-dimensional (3-D) woven reinforcements in composite components. Fabric micromechanical modelling and linear finite element analyses have been applied to determine the response of a 3-D woven composite with a step-wise variation of architecture. Comparisons of the proposed 3-D design with components of laminated construction are provided to show the benefits likely to be gained through the utilization of 3-D woven reinforced composites.
Composites Part A: Applied Science and Manufacturing.
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
W B Atwood,
M. Axelsson,
L Baldini,
J. Ballett,
G. Barbiellini,
D. Bastieri,
B. M. Baughman, [......],
C. Venter,
N. Vilchez,
V Vitale,
A P Waite, E. Wallace,
P Wang,
B. L. Winer,
K. S. Wood,
T. Ylinen,
M Ziegler
The Astrophysical Journal Letters, v.706, L56-L61 (2009).
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
W B Atwood,
M. Axelsson,
L Baldini,
J. Ballet,
G. Barbiellini,
M. G. Baring,
D. Bastieri, [......],
V Vitale,
A P Waite, E. Wallace,
P Wang,
K. Watters,
P. Weltevrede,
B. L. Winer,
K. S. Wood,
T. Ylinen,
M Ziegler
[show abstract]
[hide abstract]
ABSTRACT: We report on γ -ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nan¸cay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first γ -ray peak leads the radio main pulse by (281 ± 12 ± 21) μs, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to γ -ray statistics, and the second arises from the rotation parameters. The improved sensitivity and the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at Ec = (5.8 ± 0.5 ± 1.2) GeV, spectral index of Γ = (1.97 ± 0.02 ± 0.06) and integral photon flux above 100 MeV of (2.09 ± 0.03 ± 0.18) × 10−6 cm−2 s−1. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed γ -ray photons are observed up to ∼20 GeV which precludes emission near the stellar surface, below altitudes of around 4–5 stellar radii in phase intervals encompassing the two main peaks. A detailed phase-resolved spectral analysis is also performed: the hardest emission from the Crab Pulsar comes from the bridge region between the two γ -ray peaks while the softest comes from the falling edge of the second peak. The spectrum of the nebula in the energy range 100 MeV–300 GeV is well described by the sum of two power laws of indices Γsync = (3.99 ± 0.12 ± 0.08) and ΓIC = (1.64 ± 0.05 ± 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism.
Astrophysical Journal.
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
E. Antolini,
L Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri,
K. Bechtol,
R. Bellazzini, [......],
N. Vilchez,
V Vitale,
A P Waite, E. Wallace,
P Wang,
B. L. Winer,
K. S. Wood,
Z Yang,
T. Ylinen,
M Ziegler
[show abstract]
[hide abstract]
ABSTRACT: This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4–2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis. For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares. More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range. Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects. Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks. Variable sources of the sample have weekly and 3–4 day bin light curves that can be described by 1/f α PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)—measured for a few blazars showing strong activity—complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism. The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 1.5 and 1.7, respectively. The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days. Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars
Astrophysical Journal.
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
W B Atwood,
M. Axelsson,
L Baldini,
J. Ballet,
D. L. Band,
G. Barbiellini,
D. Bastieri, [......],
N. Vilchez,
V Vitale,
A P Waite, E. Wallace,
P Wang,
K. Watters,
B. L. Winer,
K. S. Wood,
T. Ylinen,
M Ziegler
Astrophysical Journal, Supplement Series, v.183, 46-66 (2009).
-
A. A. Abdo,
M. Ackermann,
M. Ajello,
W B Atwood,
M. Axelsson,
L Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri,
M. Battelino, [......],
V. Vasileiou,
N. Vilchez,
V Vitale,
A P Waite, E. Wallace,
P Wang,
B. L. Winer,
K. S. Wood,
T. Ylinen,
M Ziegler
Physical Review Letters, v.102 (2009).
