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1. Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope

Author

Ackermann, M, Ajello, M, Albert, A, Atwood, WB, Baldini, L, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bonino, R, Bottacini, E, Bregeon, J, Bruel, P, Buehler, R, Caliandro, GA, Cameron, RA, Caragiulo, M, Caraveo, PA, Cavazzuti, E, Cecchi, C, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Costanza, F, Cuoco, A, Cutini, S, D’Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Favuzzi, C, Fegan, SJ, Focke, WB, Franckowiak, A, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grove, JE, Guiriec, S, Harding, AK, Hewitt, JW, Horan, D, Hou, X, Iafrate, G, Jóhannesson, G, Kamae, T, Kuss, M, Larsson, S, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Magill, J, Maldera, S, Manfreda, A, Mayer, M, Mazziotta, MN, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monzani, ME, Morselli, A, Murgia, S, Nuss, E, Omodei, N, Orlando, E, Ormes, JF, Paneque, D, Perkins, JS, Pesce-Rollins, M, Petrosian, V, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reposeur, T, Sgrò, C, Siskind, EJ, Spada, F, and Spandre, G

Subjects
Fermi LAT Collaboration, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract

We have measured the gamma-ray emission spectrum of the Moon using the data collected by the Large Area Telescope onboard the Fermi satellite during its first seven years of operation, in the energy range from 30 MeV up to a few GeV. We have also studied the time evolution of the flux, finding a correlation with the solar activity. We have developed a full Monte Carlo simulation describing the interactions of cosmic rays with the lunar surface. The results of the present analysis can be explained in the framework of this model, where the production of gamma rays is due to the interactions of cosmic-ray proton and helium nuclei with the surface of the Moon. Finally, we have used our simulation to derive the cosmic-ray proton and helium spectra near Earth from the Moon gamma-ray data.

Published
2016

2. Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope.

Author

Ackermann, M, Ajello, M, Albert, A, Atwood, WB, Baldini, L, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bonino, R, Bottacini, E, Bregeon, J, Bruel, P, Buehler, R, Caliandro, GA, Cameron, RA, Caragiulo, M, Caraveo, PA, Cavazzuti, E, Cecchi, C, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Costanza, F, Cuoco, A, Cutini, S, D'Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Favuzzi, C, Fegan, SJ, Focke, WB, Franckowiak, A, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grove, JE, Guiriec, S, Harding, AK, Hewitt, JW, Horan, D, Hou, X, Iafrate, G, Jóhannesson, G, Kamae, T, Kuss, M, Larsson, S, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Magill, J, Maldera, S, Manfreda, A, Mayer, M, Mazziotta, MN, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monzani, ME, Morselli, A, Murgia, S, Nuss, E, Omodei, N, Orlando, E, Ormes, JF, Paneque, D, Perkins, JS, Pesce-Rollins, M, Petrosian, V, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reposeur, T, Sgrò, C, Siskind, EJ, Spada, F, and Spandre, G

Subjects
Fermi LAT Collaboration
Abstract

We have measured the gamma-ray emission spectrum of the Moon using the data collected by the Large Area Telescope onboard the Fermi satellite during its first seven years of operation, in the energy range from 30 MeV up to a few GeV. We have also studied the time evolution of the flux, finding a correlation with the solar activity. We have developed a full Monte Carlo simulation describing the interactions of cosmic rays with the lunar surface. The results of the present analysis can be explained in the framework of this model, where the production of gamma rays is due to the interactions of cosmic-ray proton and helium nuclei with the surface of the Moon. Finally, we have used our simulation to derive the cosmic-ray proton and helium spectra near Earth from the Moon gamma-ray data.

Published
2016

3. SEARCH FOR EXTENDED GAMMA-RAY EMISSION FROM THE VIRGO GALAXY CLUSTER WITH FERMI-LAT

Author

Ackermann, M, Ajello, M, Albert, A, Atwood, WB, Baldini, L, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Bissaldi, E, Bloom, ED, Bonino, R, Bottacini, E, Brandt, TJ, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caputo, R, Caragiulo, M, Caraveo, PA, Casandjian, JM, Cavazzuti, E, Cecchi, C, Charles, E, Chekhtman, A, Chiaro, G, Ciprini, S, Cohen-Tanugi, J, Conrad, J, Cutini, S, D’Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Favuzzi, C, Fegan, SJ, Focke, WB, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Guiriec, S, Gustafsson, M, Hewitt, JW, Hill, AB, Horan, D, Jeltema, TE, Jogler, T, Johnson, AS, Kuss, M, Larsson, S, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Maldera, S, Malyshev, D, Manfreda, A, Mayer, M, Mazziotta, MN, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Perkins, JS, Pesce-Rollins, M, Petrosian, V, Piron, F, Pivato, G, Porter, TA, Rainó, S, Rando, R, Razzano, M, and Reimer, A

Subjects
galaxies: clusters: individual, gamma-rays: galaxies: clusters, gamma-rays: general, astro-ph.HE, hep-ph, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be detectable by the latest generation of γ-ray telescopes. Here we use three years of Fermi-Large Area Telescope data, which are the most suitable for searching for very extended emission in the vicinity of the nearby Virgo galaxy cluster. Our analysis reveals statistically significant extended emission which can be well characterized by a uniformly emitting disk profile with a radius of 3 that moreover is offset from the cluster center. We demonstrate that the significance of this extended emission strongly depends on the adopted interstellar emission model (IEM) and is most likely an artifact of our incomplete description of the IEM in this region. We also search for and find new point source candidates in the region. We then derive conservative upper limits on the velocity-averaged DM pair annihilation cross section from Virgo. We take into account the potential γ-ray flux enhancement due to DM sub-halos and its complex morphology as a merging cluster. For DM annihilating into assuming a conservative sub-halo model setup, we find limits that are between 1 and 1.5 orders of magnitude above the expectation from the thermal cross section for mDM ≲ 100 GeV. In a more optimistic scenario, we exclude for mDM ≲ 40 GeV for the same channel. Finally, we derive upper limits on the γ-ray-flux produced by hadronic cosmic-ray interactions in the inter cluster medium. We find that the volume-averaged cosmic-ray-to-thermal pressure ratio is less than ∼6%.

Published
2015

4. SEARCH FOR EARLY GAMMA-RAY PRODUCTION IN SUPERNOVAE LOCATED IN A DENSE CIRCUMSTELLAR MEDIUM WITH THE FERMI LAT

Author

Ackermann, M, Arcavi, I, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bonino, R, Bottacini, E, Brandt, TJ, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caragiulo, M, Caraveo, PA, Cavazzuti, E, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cutini, S, D’Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Di Venere, L, Drell, PS, Favuzzi, C, Fegan, SJ, Franckowiak, A, Funk, S, Fusco, P, Gal-Yam, A, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grove, JE, Guiriec, S, Harding, AK, Hayashi, K, Hewitt, JW, Hill, AB, Horan, D, Jogler, T, Jóhannesson, G, Kocevski, D, Kuss, M, Larsson, S, Lashner, J, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Malyshev, D, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Murase, K, Nugent, P, Nuss, E, Ofek, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Schulz, A, Sgrò, C, Siskind, EJ, Spada, F, and Spandre, G

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, cosmic rays, gamma rays: general, methods: data analysis, supernovae: general, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics, Space sciences
Abstract

Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV γ-rays and TeV neutrinos on a timescale of several months. We perform the first systematic search for γ-ray emission in Fermi Large Area Telescope data in the energy range from to from the ensemble of 147 SNe Type IIn exploding in a dense CSM. We search for a γ-ray excess at each SNe location in a one-year time window. In order to enhance a possible weak signal, we simultaneously study the closest and optically brightest sources of our sample in a joint-likelihood analysis in three different time windows (1 year, 6 months, and 3 months). For the most promising source of the sample, SN 2010jl (PTF 10aaxf), we repeat the analysis with an extended time window lasting 4.5 years. We do not find a significant excess in γ-rays for any individual source nor for the combined sources and provide model-independent flux upper limits for both cases. In addition, we derive limits on the γ-ray luminosity and the ratio of γ-ray-to-optical luminosity ratio as a function of the index of the proton injection spectrum assuming a generic γ-ray production model. Furthermore, we present detailed flux predictions based on multi-wavelength observations and the corresponding flux upper limit at a 95% confidence level (CL) for the source SN 2010jl (PTF 10aaxf).

Published
2015

5. SEARCH for EARLY GAMMA-RAY PRODUCTION in SUPERNOVAE LOCATED in A DENSE CIRCUMSTELLAR MEDIUM with the FERMI LAT

Author

Ackermann, M, Arcavi, I, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bonino, R, Bottacini, E, Brandt, TJ, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caragiulo, M, Caraveo, PA, Cavazzuti, E, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cutini, S, D'Ammando, F, De Angelis, A, De Palma, F, Desiante, R, Di Venere, L, Drell, PS, Favuzzi, C, Fegan, SJ, Franckowiak, A, Funk, S, Fusco, P, Gal-Yam, A, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grove, JE, Guiriec, S, Harding, AK, Hayashi, K, Hewitt, JW, Hill, AB, Horan, D, Jogler, T, Jóhannesson, G, Kocevski, D, Kuss, M, Larsson, S, Lashner, J, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Malyshev, D, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Murase, K, Nugent, P, Nuss, E, Ofek, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Schulz, A, Sgrò, C, Siskind, EJ, Spada, F, and Spandre, G

Subjects
cosmic rays, gamma rays: general, methods: data analysis, supernovae: general, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV γ-rays and TeV neutrinos on a timescale of several months. We perform the first systematic search for γ-ray emission in Fermi Large Area Telescope data in the energy range from to from the ensemble of 147 SNe Type IIn exploding in a dense CSM. We search for a γ-ray excess at each SNe location in a one-year time window. In order to enhance a possible weak signal, we simultaneously study the closest and optically brightest sources of our sample in a joint-likelihood analysis in three different time windows (1 year, 6 months, and 3 months). For the most promising source of the sample, SN 2010jl (PTF 10aaxf), we repeat the analysis with an extended time window lasting 4.5 years. We do not find a significant excess in γ-rays for any individual source nor for the combined sources and provide model-independent flux upper limits for both cases. In addition, we derive limits on the γ-ray luminosity and the ratio of γ-ray-to-optical luminosity ratio as a function of the index of the proton injection spectrum assuming a generic γ-ray production model. Furthermore, we present detailed flux predictions based on multi-wavelength observations and the corresponding flux upper limit at a 95% confidence level (CL) for the source SN 2010jl (PTF 10aaxf).

Published
2015

6. FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG

Author

Acero, F, Ackermann, M, Ajello, M, Albert, A, Atwood, WB, Axelsson, M, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Belfiore, A, Bellazzini, R, Bissaldi, E, Blandford, RD, Bloom, ED, Bogart, JR, Bonino, R, Bottacini, E, Bregeon, J, Britto, RJ, Bruel, P, Buehler, R, Burnett, TH, Buson, S, Caliandro, GA, Cameron, RA, Caputo, R, Caragiulo, M, Caraveo, PA, Casandjian, JM, Cavazzuti, E, Charles, E, Chaves, RCG, Chekhtman, A, Cheung, CC, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Tanugi, J Cohen-, Cominsky, LR, Conrad, J, Cutini, S, D’Ammando, F, de Angelis, A, DeKlotz, M, de Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Dubois, R, Dumora, D, Favuzzi, C, Fegan, SJ, Ferrara, EC, Finke, J, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giebels, B, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grondin, M-H, Grove, JE, Guillemot, L, Guiriec, S, Hadasch, D, Harding, AK, Hays, E, Hewitt, JW, Hill, AB, Horan, D, Iafrate, G, Jogler, T, Jóhannesson, G, Johnson, RP, Johnson, AS, Johnson, TJ, Johnson, WN, Kamae, T, Kataoka, J, Katsuta, J, Kuss, M, La Mura, G, Landriu, D, Larsson, S, Latronico, L, Goumard, M Lemoine-, Li, J, Li, L, and Longo, F

Subjects
catalogs, gamma-rays: general, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in the 100 MeV-300 GeV range. Based on the first 4 yr of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the Second Fermi LAT catalog, the 3FGL catalog incorporates twice as much data, as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse γ-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources above significance, with source location regions, spectral properties, and monthly light curves for each. Of these, 78 are flagged as potentially being due to imperfections in the model for Galactic diffuse emission. Twenty-five sources are modeled explicitly as spatially extended, and overall 238 sources are considered as identified based on angular extent or correlated variability (periodic or otherwise) observed at other wavelengths. For 1010 sources we have not found plausible counterparts at other wavelengths. More than 1100 of the identified or associated sources are active galaxies of the blazar class; several other classes of non-blazar active galaxies are also represented in the 3FGL. Pulsars represent the largest Galactic source class. From source counts of Galactic sources we estimate that the contribution of unresolved sources to the Galactic diffuse emission is ∼3% at 1 GeV.

Published
2015

7. Updated search for spectral lines from Galactic dark matter interactions with pass 8 data from the Fermi Large Area Telescope

Author

Ackermann, M, Ajello, M, Albert, A, Anderson, B, Atwood, WB, Baldini, L, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bloom, ED, Bonino, R, Bottacini, E, Brandt, TJ, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caputo, R, Caragiulo, M, Caraveo, PA, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cuoco, A, Cutini, S, D'Ammando, F, De Angelis, A, De Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Fegan, SJ, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Grove, JE, Guiriec, S, Gustafsson, M, Hewitt, JW, Hill, AB, Horan, D, Jóhannesson, G, Johnson, RP, Kuss, M, Larsson, S, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Malyshev, D, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Moiseev, AA, Monzani, ME, Morselli, A, Murgia, S, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reposeur, T, Ritz, S, and Sánchez-Conde, M

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

Dark matter in the Milky Way may annihilate directly into γ rays, producing a monoenergetic spectral line. Therefore, detecting such a signature would be strong evidence for dark matter annihilation or decay. We search for spectral lines in the Fermi Large Area Telescope observations of the Milky Way halo in the energy range 200 MeV-500 GeV using analysis methods from our most recent line searches. The main improvements relative to previous works are our use of 5.8 years of data reprocessed with the Pass 8 event-level analysis and the additional data resulting from the modified observing strategy designed to increase exposure of the Galactic center region. We search in five sky regions selected to optimize sensitivity to different theoretically motivated dark matter scenarios and find no significant detections. In addition to presenting the results from our search for lines, we also investigate the previously reported tentative detection of a line at 133 GeV using the new Pass 8 data.

Published
2015

8. Updated search for spectral lines from Galactic dark matter interactions with pass 8 data from the Fermi Large Area Telescope

Author

Ackermann, M, Ajello, M, Albert, A, Anderson, B, Atwood, WB, Baldini, L, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Blandford, RD, Bloom, ED, Bonino, R, Bottacini, E, Brandt, TJ, Bregeon, J, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caputo, R, Caragiulo, M, Caraveo, PA, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cuoco, A, Cutini, S, D’Ammando, F, de Angelis, A, de Palma, F, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Fegan, SJ, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Grove, JE, Guiriec, S, Gustafsson, M, Hewitt, JW, Hill, AB, Horan, D, Jóhannesson, G, Johnson, RP, Kuss, M, Larsson, S, Latronico, L, Li, J, Li, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Malyshev, D, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Moiseev, AA, Monzani, ME, Morselli, A, Murgia, S, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reposeur, T, Ritz, S, and Sánchez-Conde, M

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract

Dark matter in the Milky Way may annihilate directly into γ rays, producing a monoenergetic spectral line. Therefore, detecting such a signature would be strong evidence for dark matter annihilation or decay. We search for spectral lines in the Fermi Large Area Telescope observations of the Milky Way halo in the energy range 200 MeV-500 GeV using analysis methods from our most recent line searches. The main improvements relative to previous works are our use of 5.8 years of data reprocessed with the Pass 8 event-level analysis and the additional data resulting from the modified observing strategy designed to increase exposure of the Galactic center region. We search in five sky regions selected to optimize sensitivity to different theoretically motivated dark matter scenarios and find no significant detections. In addition to presenting the results from our search for lines, we also investigate the previously reported tentative detection of a line at 133 GeV using the new Pass 8 data.

Published
2015

9. SEARCH FOR COSMIC-RAY-INDUCED GAMMA-RAY EMISSION IN GALAXY CLUSTERS

Author

Ackermann, M, Ajello, M, Albert, A, Allafort, A, Atwood, WB, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Chaves, RCG, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, D'Ammando, F, de Angelis, A, de Palma, F, Dermer, CD, Digel, SW, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Franckowiak, A, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Guiriec, S, Gustafsson, M, Hadasch, D, Hayashida, M, Hewitt, J, Hughes, RE, Jeltema, TE, Jóhannesson, G, Johnson, AS, Kamae, T, Kataoka, J, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Garde, M Llena, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nemmen, R, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Ruan, J, and Sánchez-Conde, M

Subjects
galaxies: clusters: intracluster medium, gamma rays: galaxies: clusters, astro-ph.HE, astro-ph.CO, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into γ rays that are potentially observable with the Large Area Telescope (LAT) on board the Fermi space telescope. We present a joint likelihood analysis searching for spatially extended γ-ray emission at the locations of 50 galaxy clusters in four years of Fermi-LAT data under the assumption of the universal cosmic-ray (CR) model proposed by Pinzke & Pfrommer. We find an excess at a significance of 2.7σ, which upon closer inspection, however, is correlated to individual excess emission toward three galaxy clusters: A400, A1367, and A3112. We discuss these cases in detail and conservatively attribute the emission to unmodeled background systems (for example, radio galaxies within the clusters).Through the combined analysis of 50 clusters, we exclude hadronic injection efficiencies in simple hadronic models above 21% and establish limits on the CR to thermal pressure ratio within the virial radius, R 200, to be below 1.25%-1.4% depending on the morphological classification. In addition, we derive new limits on the γ-ray flux from individual clusters in our sample. © 2014. The American Astronomical Society. All rights reserved.

Published
2014

10. Search for cosmic-ray-induced gamma-ray emission in galaxy clusters

Author

Ackermann, M, Ajello, M, Albert, A, Allafort, A, Atwood, WB, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Chaves, RCG, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, D'Ammando, F, De Angelis, A, De Palma, F, Dermer, CD, Digel, SW, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Franckowiak, A, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Guiriec, S, Gustafsson, M, Hadasch, D, Hayashida, M, Hewitt, J, Hughes, RE, Jeltema, TE, Jóhannesson, G, Johnson, AS, Kamae, T, Kataoka, J, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Garde, ML, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nemmen, R, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Ormes, JF, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Ruan, J, and Sánchez-Conde, M

Subjects
galaxies: clusters: intracluster medium, gamma rays: galaxies: clusters, astro-ph.HE, astro-ph.CO, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into γ rays that are potentially observable with the Large Area Telescope (LAT) on board the Fermi space telescope. We present a joint likelihood analysis searching for spatially extended γ-ray emission at the locations of 50 galaxy clusters in four years of Fermi-LAT data under the assumption of the universal cosmic-ray (CR) model proposed by Pinzke & Pfrommer. We find an excess at a significance of 2.7σ, which upon closer inspection, however, is correlated to individual excess emission toward three galaxy clusters: A400, A1367, and A3112. We discuss these cases in detail and conservatively attribute the emission to unmodeled background systems (for example, radio galaxies within the clusters).Through the combined analysis of 50 clusters, we exclude hadronic injection efficiencies in simple hadronic models above 21% and establish limits on the CR to thermal pressure ratio within the virial radius, R 200, to be below 1.25%-1.4% depending on the morphological classification. In addition, we derive new limits on the γ-ray flux from individual clusters in our sample. © 2014. The American Astronomical Society. All rights reserved.

Published
2014

11. MULTIFREQUENCY STUDIES OF THE PECULIAR QUASAR 4C +21.35 DURING THE 2010 FLARING ACTIVITY

Author

Ackermann, M, Ajello, M, Allafort, A, Antolini, E, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Bonamente, E, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Cecchi, C, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, D'Ammando, F, de Palma, F, Dermer, CD, do Couto e Silva, E, Donato, D, Drell, PS, Favuzzi, C, Finke, J, Focke, WB, Franckowiak, A, Fukazawa, Y, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Grenier, IA, Guiriec, S, Hayashida, M, Hewitt, JW, Horan, D, Hughes, RE, Iafrate, G, Johnson, AS, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nemmen, R, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Porter, TA, Rainò, S, Razzano, M, Reimer, A, Reimer, O, Sanchez, DA, Schulz, A, Sgrò, C, Siskind, EJ, Spandre, G, Spinelli, P, Stawarz, Ł, Takahashi, H, Takahashi, T, Thayer, JG, Thayer, JB, Thompson, DJ, and Tinivella, M

Subjects
galaxies: active, gamma rays: general, quasars: general, quasars: individual, radiation mechanisms: non-thermal, astro-ph.HE, astro-ph.CO, astro-ph.GA, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) γ -ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE;E >100 MeV) γ -rays, poses intriguing questions on the location of the γ -ray emitting region in this flat spectrum radio quasar. We present multifrequency data of 4C +21.35 collected from centimeter to VHE during 2010 to investigate the properties of this source and discuss a possible emission model. The first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon after a γ -ray flare detected by Fermi-LAT that peaked on April 29. The same emission mechanism may therefore be responsible for both the HE and VHE emission during the 2010 flaring episodes. Two optical peaks were detected on 2010 April 20 and June 30, close in time but not simultaneous with the two γ -ray peaks, while no clear connection was observed between the X-ray and γ -ray emission. An increasing flux density was observed in radio and mm bands from the beginning of 2009, in accordance with the increasing γ -ray activity observed by Fermi-LAT, and peaking on 2011 January 27 in the mm regime (230 GHz). We model the spectral energy distributions (SEDs) of 4C +21.35 for the two periods of the VHE detection and a quiescent state, using a one-zone model with the emission coming from a very compact region outside the broad line region. The three SEDs can be fit with a combination of synchrotron self-Compton and external Compton emission of seed photons from a dust torus, changing only the electron distribution parameters between the epochs. The fit of the optical/UV part of the spectrum for 2010 April 29 seems to favor an inner disk radius of

Published
2014

12. Multifrequency studies of the peculiar QUASAR 4C +21.35 during the 2010 flaring activity

Author

Ackermann, M, Ajello, M, Allafort, A, Antolini, E, Barbiellini, G, Bastieri, D, Bellazzini, R, Bissaldi, E, Bonamente, E, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Cecchi, C, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, D'Ammando, F, De Palma, F, Dermer, CD, Do Couto E Silva, E, Donato, D, Drell, PS, Favuzzi, C, Finke, J, Focke, WB, Franckowiak, A, Fukazawa, Y, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Grenier, IA, Guiriec, S, Hayashida, M, Hewitt, JW, Horan, D, Hughes, RE, Iafrate, G, Johnson, AS, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nemmen, R, Nuss, E, Ohsugi, T, Orienti, M, Orlando, E, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Porter, TA, Rainò, S, Razzano, M, Reimer, A, Reimer, O, Sanchez, DA, Schulz, A, Sgrò, C, Siskind, EJ, Spandre, G, Spinelli, P, Stawarz, Takahashi, H, Takahashi, T, Thayer, JG, Thayer, JB, Thompson, DJ, and Tinivella, M

Subjects
galaxies: active, gamma rays: general, quasars: general, quasars: individual, radiation mechanisms: non-thermal, astro-ph.HE, astro-ph.CO, astro-ph.GA, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) γ -ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE;E >100 MeV) γ -rays, poses intriguing questions on the location of the γ -ray emitting region in this flat spectrum radio quasar. We present multifrequency data of 4C +21.35 collected from centimeter to VHE during 2010 to investigate the properties of this source and discuss a possible emission model. The first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon after a γ -ray flare detected by Fermi-LAT that peaked on April 29. The same emission mechanism may therefore be responsible for both the HE and VHE emission during the 2010 flaring episodes. Two optical peaks were detected on 2010 April 20 and June 30, close in time but not simultaneous with the two γ -ray peaks, while no clear connection was observed between the X-ray and γ -ray emission. An increasing flux density was observed in radio and mm bands from the beginning of 2009, in accordance with the increasing γ -ray activity observed by Fermi-LAT, and peaking on 2011 January 27 in the mm regime (230 GHz). We model the spectral energy distributions (SEDs) of 4C +21.35 for the two periods of the VHE detection and a quiescent state, using a one-zone model with the emission coming from a very compact region outside the broad line region. The three SEDs can be fit with a combination of synchrotron self-Compton and external Compton emission of seed photons from a dust torus, changing only the electron distribution parameters between the epochs. The fit of the optical/UV part of the spectrum for 2010 April 29 seems to favor an inner disk radius of

Published
2014

13. Inferred Cosmic-Ray Spectrum from Fermi Large Area Telescope γ-Ray Observations of Earth’s Limb

Author

Ackermann, M, Ajello, M, Albert, A, Allafort, A, Baldini, L, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Bottacini, E, Bouvier, A, Brandt, TJ, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, Dalton, M, D'Ammando, F, de Angelis, A, de Palma, F, Dermer, CD, Digel, SW, Di Venere, L, do Couto e Silva, E, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Grove, JE, Guiriec, S, Gustafsson, M, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hayashi, K, Hewitt, JW, Horan, D, Hou, X, Hughes, RE, Inoue, Y, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Kamae, T, Kawano, T, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, and Morselli, A

Subjects
Fermi LAT Collaboration, astro-ph.HE, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the γ-ray emission from Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range ∼90  GeV-6  TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68±0.04 and 2.61±0.08 above ∼200  GeV, respectively.

Published
2014

14. Inferred cosmic-ray spectrum from Fermi large area telescope γ-ray observations of Earth's limb.

Author

Ackermann, M, Ajello, M, Albert, A, Allafort, A, Baldini, L, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Bottacini, E, Bouvier, A, Brandt, TJ, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, Dalton, M, D'Ammando, F, de Angelis, A, de Palma, F, Dermer, CD, Digel, SW, Di Venere, L, do Couto e Silva, E, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Gomez-Vargas, GA, Grenier, IA, Grove, JE, Guiriec, S, Gustafsson, M, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hayashi, K, Hewitt, JW, Horan, D, Hou, X, Hughes, RE, Inoue, Y, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Kamae, T, Kawano, T, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mayer, M, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, and Morselli, A

Subjects
Fermi LAT Collaboration, astro-ph.HE, General Physics, Physical Sciences
Abstract

Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the γ-ray emission from Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range ∼90  GeV-6  TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68±0.04 and 2.61±0.08 above ∼200  GeV, respectively.

Published
2014

15. The First Pulse of the Extremely Bright GRB 130427A: A Test Lab for Synchrotron Shocks

Author

Preece, R, Burgess, J Michael, von Kienlin, A, Bhat, PN, Briggs, MS, Byrne, D, Chaplin, V, Cleveland, W, Collazzi, AC, Connaughton, V, Diekmann, A, Fitzpatrick, G, Foley, S, Gibby, M, Giles, M, Goldstein, A, Greiner, J, Gruber, D, Jenke, P, Kippen, RM, Kouveliotou, C, McBreen, S, Meegan, C, Paciesas, WS, Pelassa, V, Tierney, D, van der Horst, AJ, Wilson-Hodge, C, Xiong, S, Younes, G, Yu, H-F, Ackermann, M, Ajello, M, Axelsson, M, Baldini, L, Barbiellini, G, Baring, MG, Bastieri, D, Bellazzini, R, Bissaldi, E, Bonamente, E, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, D'Ammando, F, de Angelis, A, de Palma, F, Dermer, CD, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Franckowiak, A, Fukazawa, Y, Fusco, P, Gargano, F, Gehrels, N, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Granot, J, Grenier, IA, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Iyyani, S, Jogler, T, Jóhannesson, G, Kawano, T, Knödlseder, J, Kocevski, D, Kuss, M, Lande, J, Larsson, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, and Lovellette, MN

Subjects
astro-ph.HE, General Science & Technology
Abstract

Gamma-ray burst (GRB) 130427A is one of the most energetic GRBs ever observed. The initial pulse up to 2.5 seconds is possibly the brightest well-isolated pulse observed to date. A fine time resolution spectral analysis shows power-law decays of the peak energy from the onset of the pulse, consistent with models of internal synchrotron shock pulses. However, a strongly correlated power-law behavior is observed between the luminosity and the spectral peak energy that is inconsistent with curvature effects arising in the relativistic outflow. It is difficult for any of the existing models to account for all of the observed spectral and temporal behaviors simultaneously.

Published
2014

16. The first pulse of the extremely bright GRB 130427A: a test lab for synchrotron shocks.

Author

Preece, R, Burgess, J Michael, von Kienlin, A, Bhat, PN, Briggs, MS, Byrne, D, Chaplin, V, Cleveland, W, Collazzi, AC, Connaughton, V, Diekmann, A, Fitzpatrick, G, Foley, S, Gibby, M, Giles, M, Goldstein, A, Greiner, J, Gruber, D, Jenke, P, Kippen, RM, Kouveliotou, C, McBreen, S, Meegan, C, Paciesas, WS, Pelassa, V, Tierney, D, van der Horst, AJ, Wilson-Hodge, C, Xiong, S, Younes, G, Yu, H-F, Ackermann, M, Ajello, M, Axelsson, M, Baldini, L, Barbiellini, G, Baring, MG, Bastieri, D, Bellazzini, R, Bissaldi, E, Bonamente, E, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, D'Ammando, F, de Angelis, A, de Palma, F, Dermer, CD, Desiante, R, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Franckowiak, A, Fukazawa, Y, Fusco, P, Gargano, F, Gehrels, N, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Godfrey, G, Granot, J, Grenier, IA, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Iyyani, S, Jogler, T, Jóhannesson, G, Kawano, T, Knödlseder, J, Kocevski, D, Kuss, M, Lande, J, Larsson, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, and Lovellette, MN

Subjects
astro-ph.HE, General Science & Technology
Abstract

Gamma-ray burst (GRB) 130427A is one of the most energetic GRBs ever observed. The initial pulse up to 2.5 seconds is possibly the brightest well-isolated pulse observed to date. A fine time resolution spectral analysis shows power-law decays of the peak energy from the onset of the pulse, consistent with models of internal synchrotron shock pulses. However, a strongly correlated power-law behavior is observed between the luminosity and the spectral peak energy that is inconsistent with curvature effects arising in the relativistic outflow. It is difficult for any of the existing models to account for all of the observed spectral and temporal behaviors simultaneously.

Published
2014

17. THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS

Author

Abdo, AA, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Belfiore, A, Bellazzini, R, Bhattacharyya, B, Bissaldi, E, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Burgay, M, Burnett, TH, Busetto, G, Buson, S, Caliandro, GA, Cameron, RA, Camilo, F, Caraveo, PA, Casandjian, JM, Cecchi, C, Çelik, Ö, Charles, E, Chaty, S, Chaves, RCG, Chekhtman, A, Chen, AW, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cognard, I, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, Cutini, S, D'Ammando, F, de Angelis, A, DeCesar, ME, De Luca, A, Hartog, PR den, de Palma, F, Dermer, CD, Desvignes, G, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Dubois, R, Dumora, D, Espinoza, CM, Falletti, L, Favuzzi, C, Ferrara, EC, Focke, WB, Franckowiak, A, Freire, PCC, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Gotthelf, EV, Grenier, IA, Grondin, M-H, Grove, JE, Guillemot, L, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hays, E, Hessels, J, Hewitt, J, Hill, AB, Horan, D, Hou, X, Hughes, RE, Jackson, MS, Janssen, GH, Jogler, T, Jóhannesson, G, Johnson, RP, and Johnson, AS

Subjects
catalogs, pulsars: general, stars: neutron, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions. © 2013. The American Astronomical Society. All rights reserved..

Published
2013

18. The second Fermi large area telescope catalog of gamma-ray pulsars

Author

Abdo, AA, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Belfiore, A, Bellazzini, R, Bhattacharyya, B, Bissaldi, E, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Burgay, M, Burnett, TH, Busetto, G, Buson, S, Caliandro, GA, Cameron, RA, Camilo, F, Caraveo, PA, Casandjian, JM, Cecchi, C, Çelik, O, Charles, E, Chaty, S, Chaves, RCG, Chekhtman, A, Chen, AW, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cognard, I, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, Cutini, S, D'Ammando, F, De Angelis, A, Decesar, ME, De Luca, A, Den Hartog, PR, De Palma, F, Dermer, CD, Desvignes, G, Digel, SW, Di Venere, L, Drell, PS, Drlica-Wagner, A, Dubois, R, Dumora, D, Espinoza, CM, Falletti, L, Favuzzi, C, Ferrara, EC, Focke, WB, Franckowiak, A, Freire, PCC, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Gotthelf, EV, Grenier, IA, Grondin, MH, Grove, JE, Guillemot, L, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hays, E, Hessels, J, Hewitt, J, Hill, AB, Horan, D, Hou, X, Hughes, RE, Jackson, MS, Janssen, GH, Jogler, T, Jóhannesson, G, Johnson, RP, and Johnson, AS

Subjects
catalogs, pulsars: general, stars: neutron, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions. © 2013. The American Astronomical Society. All rights reserved..

Published
2013

19. CONSTRAINTS ON THE GALACTIC POPULATION OF TeV PULSAR WIND NEBULAE USING FERMI LARGE AREA TELESCOPE OBSERVATIONS

Author

Acero, F, Ackermann, M, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, Dalton, M, D'Ammando, F, de Palma, F, Dermer, CD, Di Venere, L, do Couto e Silva, E, Drell, PS, Drlica-Wagner, A, Falletti, L, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grégoire, T, Grenier, IA, Grondin, M-H, Grove, JE, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hayashi, K, Hays, E, Hewitt, J, Hill, AB, Horan, D, Hou, X, Hughes, RE, Inoue, Y, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Kamae, T, Kawano, T, Kerr, M, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Lemoine-Goumard, M, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Marelli, M, Massaro, F, Mayer, M, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, and Mitthumsiri, W

Subjects
gamma rays: general, astro-ph.HE, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

Pulsar wind nebulae (PWNe) have been established as the most populous class of TeV γ-ray emitters. Since launch, the Fermi Large Area Telescope (LAT) has identified five high-energy (100 MeV < E < 100 GeV) γ-ray sources as PWNe and detected a large number of PWN candidates, all powered by young and energetic pulsars. The wealth of multi-wavelength data available and the new results provided by Fermi-LAT give us an opportunity to find new PWNe and to explore the radiative processes taking place in known ones. The TeV γ-ray unidentified (UNID) sources are the best candidates for finding new PWNe. Using 45 months of Fermi-LAT data for energies above 10 GeV, an analysis was performed near the position of 58 TeV PWNe and UNIDs within 5° of the Galactic plane to establish new constraints on PWN properties and find new clues on the nature of UNIDs. Of the 58 sources, 30 were detected, and this work provides their γ-ray fluxes for energies above 10 GeV. The spectral energy distributions and upper limits, in the multi-wavelength context, also provide new information on the source nature and can help distinguish between emission scenarios, i.e., between classification as a pulsar candidate or as a PWN candidate. Six new GeV PWN candidates are described in detail and compared with existing models. A population study of GeV PWN candidates as a function of the pulsar/PWN system characteristics is presented. © 2013. The American Astronomical Society. All rights reserved.

Published
2013

20. Constraints on the galactic population of TeV pulsar wind nebulae using fermi large area telescope observations

Author

Acero, F, Ackermann, M, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chaves, RCG, Chekhtman, A, Chiang, J, Chiaro, G, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, Dalton, M, D'Ammando, F, De Palma, F, Dermer, CD, Venere, LD, Silva, EDCE, Drell, PS, Drlica-Wagner, A, Falletti, L, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grégoire, T, Grenier, IA, Grondin, MH, Grove, JE, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hayashi, K, Hays, E, Hewitt, J, Hill, AB, Horan, D, Hou, X, Hughes, RE, Inoue, Y, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Kamae, T, Kawano, T, Kerr, M, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Lemoine-Goumard, M, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Marelli, M, Massaro, F, Mayer, M, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, and Mitthumsiri, W

Subjects
gamma rays: general, astro-ph.HE, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

Pulsar wind nebulae (PWNe) have been established as the most populous class of TeV γ-ray emitters. Since launch, the Fermi Large Area Telescope (LAT) has identified five high-energy (100 MeV < E < 100 GeV) γ-ray sources as PWNe and detected a large number of PWN candidates, all powered by young and energetic pulsars. The wealth of multi-wavelength data available and the new results provided by Fermi-LAT give us an opportunity to find new PWNe and to explore the radiative processes taking place in known ones. The TeV γ-ray unidentified (UNID) sources are the best candidates for finding new PWNe. Using 45 months of Fermi-LAT data for energies above 10 GeV, an analysis was performed near the position of 58 TeV PWNe and UNIDs within 5° of the Galactic plane to establish new constraints on PWN properties and find new clues on the nature of UNIDs. Of the 58 sources, 30 were detected, and this work provides their γ-ray fluxes for energies above 10 GeV. The spectral energy distributions and upper limits, in the multi-wavelength context, also provide new information on the source nature and can help distinguish between emission scenarios, i.e., between classification as a pulsar candidate or as a PWN candidate. Six new GeV PWN candidates are described in detail and compared with existing models. A population study of GeV PWN candidates as a function of the pulsar/PWN system characteristics is presented. © 2013. The American Astronomical Society. All rights reserved.

Published
2013

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