The on-orbit calibration of the Fermi Large Area Telescope

Abdo, A. A.; Ackermann, M.; Ajello, M.; Ampe, J.; Anderson, B.; Atwood, W. B.; Axelsson, M.; Bagagli, R.; Baldini, Luca; Ballet, J.; Barbiellini, G.; Bartelt, J.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bédérède, D.; Bellardi, F.; Bellazzini, R.; Belli, F.; Berenji, B.; Bisello, D.; Bissaldi, E.; Bloom, E. D.; Bogaert, G.; Bogart, J. R.; Bonamente, E.; Borgland, A. W.; Bourgeois, P.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T. H.; Busetto, G.; Caliandro, G. A.; Cameron, R. A.; Campell, M.; Caraveo, P. A.; Carius, Staffan; Carlson, P.; Casandjian, J. M.; Cavazzuti, E.; Ceccanti, M.; Cecchi, C.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chipaux, R.; Cillis, A.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Condamoor, Shantha; Conrad, J.; Corbet, R. H. D.; Cutini, S.; Davis, David; Deklotz, M.; Dermer, C. D.; Angelis, A. De; Palma, F. de; Digel, S. W.; Dizon, P.; Dormody, M.; Silva, E. do Couto e; Drell, P. S.; Dubois, R.; Dumora, D.; Edmonds, Y.; Fabiani, D.; Farnier, C.; Favuzzi, C.; Ferrara, E. C.; Ferreira, O.; Fewtrell, Z.; Flath, D.; Fleury, P.; Focke, W. B.; Fouts, K.; Frailis, M.; Freytag, D.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Goodman, J. A.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hakimi, M.; Haller, G.; Hanabata, Y.; Hart, Philip; Hascall, P.; Hays, E.; Huffer, M.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, R. P.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kavelaars, A.; Kelly, Heather; Kerr, M.; Klamra, W.; Knödlseder, J.; Kocian, M.; Kuehn, F.; Kuss, M.; Latronico, L.; Lavalley, C.; Leas, Byron E.; Lee, B.; Lee, S.-H.; Lemoine‐Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Lung, D.K.; Madejski, G.; Makeev, A.; Marangelli, B.; Marchetti, Marco; Massai, M.M.; May, D.; Mazzenga, G.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meurer, C.; Michelson, P. F.; Minuti, M.; Mirizzi, N.; Mitra, P.; Mitthumsiri, W.; Mizuno, T.; Моисеев, А. А.; Mongelli, M.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nelson, David J.; Nilsson, L.; Nishino, Seiji; Nolan, P. L.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, Masanori; Paccagnella, A.; Paneque, D.; Panetta, J.; Parent, D.; Pelassa, V.; Pepé, M.; Pesce-Rollins, M.; Picozza, P.; Pinchera, Michele; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Rapposelli, Emilio; Raynor, William; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Reyes, Luis; Ritz, S.; Robinson, S.; Rochester, Lynn; Rodriguez, A. Y.; Romani, Roger W.; Roth, M.; Ryde, F.; Sacchetti, A.; Sadrozinski, H. F-W.; Saggini, N.; Sánchez, David; Sander, A.; Sapozhnikov, L.; Saxton, O. H.; Parkinson, P. M. Saz; Sellerholm, A.; Sgrò, C.; Siskind, E. J.; Smith, David A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Starck, Jean-Luc; Stephens, T. E.; Strickman, M. S.; Strong, A. W.; Sugizaki, M.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, Takaaki; Tenze, A.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Tramacere, A.; Turri, M.; Usher, T.; Vilchez, N.; Virmani, N.; Vitale, V.; Wai, L.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, D. L.; Wood, K. S.; Yasuda, Hajimu; Ylinen, T.; Ziegler, M.

doi:10.1016/j.astropartphys.2009.08.002

Cited by 149 publications

(88 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the intense background of charged particles from cosmic rays and trapped radiation at the orbit of the Fermi satellite, the instruments are protected by a segmented anti-coincidence detector used to reject charged-particle background events. More information about the LAT is provided in Atwood et al (2009), the LAT in-flight calibration is described in Abdo et al (2009), Ackermann et al (2012a, and Ackermann et al (2012b).…”

Section: Fermi-lat Data Analysismentioning

confidence: 99%

Fermi acceleration along the orbit of η Carinae

Balbo¹,

Walter²

2017

A&A

View full text Add to dashboard Cite

Context. The η Carinae binary system hosts one of the most massive stars, which features the highest known mass-loss rate. This dense wind encounters the much faster wind expelled by the stellar companion, dissipating mechanical energy in the shock, where particles can be accelerated up to relativistic energies and subsequently produce very-high-energy γ-rays. Aims. We aim at comparing the variability of the γ-ray emission of η Carinae along the binary orbit with the predictions of simulations to establish the nature of the emission and of the seed particles. Methods. We have used data from the Fermi Large Area Telescope obtained during its first seven years of observations and spanning two passages of η Carinae at periastron. We performed the analysis using the new PASS8 pipeline and its improved instrument response function, extracting low and high-energy light curves as well as spectra in different orbital phase bins. We also introduced particle acceleration in hydrodynamic simulations of the system, assuming a dipolar magnetic field generated by the most massive star, and compared the γ-ray observations with the predictions of diffuse shock acceleration in a multi-cell geometry.Results. The main source of the γ-ray emission originates from a position compatible with η Carinae and located within the Homunculus Nebula. Two emission components can be distinguished. The low-energy component cuts off below 10 GeV and its flux, modulated by the orbital motion, varies by a factor less than 2. Short-term variability occurs at periastron. The flux of the high-energy component varies by a factor 3-4 but is different during the two periastrons. The variabilities observed at low energy, including some details of them, and those observed at high energy during the first half of the observations, match the prediction of the simulation, assuming a surface magnetic field of 500 G. The high-energy component and the thermal X-ray emission were weaker than expected around the second periastron suggesting a modification of the wind density in the inner wind collision zone. Conclusions. Diffuse shock acceleration in the complex geometry of the wind collision zone of η Carinae provides a convincing match to the observations and new diagnostic tools to probe the geometry and energetics of the system. This demonstrates that Fermi acceleration is at work in the wind collisions and that a few percent of the shock mechanical energy are converted into particle acceleration. Further observations are required to understand the periastron-to-periastron variability of the high-energy component and to associate it firmly with hadronic origin. We estimate that η Carinae is a pevatron at periastron and is bright enough to be detected by IceCube after many years of observations. Orbital modulations of the high-energy component can be distinguished from those of photo absorption by the four large size telescopes of the Cherenkov Telescope Array to be placed in the southern hemisphere.

show abstract

Section: Fermi-lat Data Analysismentioning

confidence: 99%

Fermi acceleration along the orbit of η Carinae

Balbo¹,

Walter²

2017

A&A

View full text Add to dashboard Cite

show abstract

“…Table 1 shows the expected number of high energy protons and heliums nuclei for a 10 years exposure of the GAMMA-400 experiment, assuming the Polygonato model [8], with an expected p/e rejection factor better than 10 5 [3], and with a realistic reconstruction efficiency of the order of 40%. We can observe that we expect to collect a statistic larger than 100 events both for protons and helium, allowing a detailed probe of the interesting knee region, that has never been directly investigated with an in orbit detector up to now.…”

Section: The Gamma-400 Gamma-ray Telescopementioning

confidence: 99%

“…These GAMMA-400 instrument characteristics are addressed in the paper. The comparison with the performance of currently operating space mission Fermi-LAT [2,3] is also presented.…”

Section: Introductionmentioning

confidence: 99%

The GAMMA-400 space mission for measuring high-energy gamma rays and cosmic rays

Topchiev¹,

Suchkov²,

Galper³

et al. 2017

The Fourteenth Marcel Grossmann Meeting

View full text Add to dashboard Cite

The scientific goals of the GAMMA-400 space mission and the design of the new spacebased gamma-ray telescope GAMMA-400 are presented. GAMMA-400 is a dual experiment dedicated to the study of gamma rays and electrons, protons and nuclei. It has aimed to a broad range of scientific topics, such as search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, especially Galactic Center, Galactic and extragalactic diffuse emission, as well as high-precision measurements of cosmic rays spectra. GAMMA-400 will have the best parameters when measuring gamma rays: the angular resolution ∼0.01 deg. (at 100 GeV), the energy resolution ∼1% (at 100 GeV), and the proton rejection factor ∼10 6 and will be able to measure gamma-ray and cosmic-ray electron + positron fluxes in the energy range from 100 MeV to 20 TeV, as well as protons and nuclei up to the knee (10 15 -10 16 eV).

show abstract

“…The details of the energy calibration, referred to as the "proton inter-range calibration", are given in [8]. To perform this calibration, we first correct the observed CAL signals for electronic nonlinearities (as measured by an electronic chargeinjection process) and for position-dependent scintillation response (as measured by a direct calibration with sea-level muons and on-orbit with protons).…”

Section: Lat Energy Calibrationmentioning

confidence: 99%

“…This calibrates the highest-gain, lowest-energy range of the CAL readout. The remaining gain ranges [1] of the CAL readout are calibrated by enforcing that adjacent gain ranges give the same measured energy in the regions of energy space in which they overlap [8].…”

Section: Lat Energy Calibrationmentioning

confidence: 99%

In-flight measurement of the absolute energy scale of the Fermi Large Area Telescope

Ackermann¹,

Ajello²,

Allafort³

et al. 2012

Astroparticle Physics

Self Cite

View full text Add to dashboard Cite

The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electronplus-positron (CRE) spectrum in low earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between ∼6 and ∼13 GeV with an estimated uncertainty of ∼2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

show abstract

The on-orbit calibration of the Fermi Large Area Telescope

Cited by 149 publications

References 23 publications

Fermi acceleration along the orbit of η Carinae

Fermi acceleration along the orbit of η Carinae

The GAMMA-400 space mission for measuring high-energy gamma rays and cosmic rays

In-flight measurement of the absolute energy scale of the Fermi Large Area Telescope

Contact Info

Product

Resources

About