Markus Ackermann
SLAC National Accelerator Laboratory
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Featured researches published by Markus Ackermann.
Physical Review Letters | 2010
A. A. Abdo; Markus Ackermann; M. Ajello; U Stanford; W. B. Atwood; Santa Cruz Uc; L. Baldini; Pisa Infn; J. Ballet; Saclay Dapnia; G. Barbiellini; Trieste Infn; U Trieste; D. Bastieri; Padua Infn; U Padua; K. Bechtol; R. Bellazzini; B. Berenji; E. D. Bloom; E. Bonamente; Perugia Infn; U Perugia; A. W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M. Brigida; U Bari; Bari Infn
Dark matter (DM) particle annihilation or decay can produce monochromatic gamma rays readily distinguishable from astrophysical sources. gamma-ray line limits from 30 to 200 GeV obtained from 11 months of Fermi Large Area Space Telescope data from 20-300 GeV are presented using a selection based on requirements for a gamma-ray line analysis, and integrated over most of the sky. We obtain gamma-ray line flux upper limits in the range 0.6-4.5x10{-9} cm{-2} s{-1}, and give corresponding DM annihilation cross-section and decay lifetime limits. Theoretical implications are briefly discussed.
The Astrophysical Journal | 2012
J. Lande; Markus Ackermann; A. Allafort; J. Ballet; K. Bechtol; T. H. Burnett; J. Cohen-Tanugi; Alex Drlica-Wagner; S. Funk; F. Giordano; Marie-Hélène Grondin; Matthew Kerr; M. Lemoine-Goumard
Spatial extension is an important characteristic for correctly associating γ-ray-emitting sources with their counterparts at other wavelengths and for obtaining an unbiased model of their spectra. We present a new method for quantifying the spatial extension of sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi). We perform a series of Monte Carlo simulations to validate this tool and calculate the LAT threshold for detecting the spatial extension of sources. We then test all sources in the second Fermi-LAT catalog for extension. We report the detection of seven new spatially extended sources.
Physical Review D | 2017
Rasmus Westphal Rasmussen; Walter Winter; Markus Ackermann; M. Kowalski; Lukas Lechner
We systematically study the allowed parameter space for the flavor composition of astrophysical neutrinos measured at Earth, including beyond the Standard Model theories at production, during propagation, and at detection. One motivation is to illustrate the discrimination power of the next-generation neutrino telescopes such as IceCube-Gen2. We identify several examples that lead to potential deviations from the standard neutrino mixing expectation such as significant sterile neutrino production at the source, effective operators modifying the neutrino propagation at high energies, dark matter interactions in neutrino propagation, or nonstandard interactions in Earth matter. IceCube-Gen2 can exclude about 90% of the allowed parameter space in these cases, and hence will allow us to efficiently test and discriminate between models. More detailed information can be obtained from additional observables such as the energy dependence of the effect, fraction of electron antineutrinos at the Glashow resonance, or number of tau neutrino events.
HIGH ENERGY GAMMA‐RAY ASTRONOMY: Proceedings of the 4th International Meeting on#N#High Energy Gamma‐Ray Astronomy | 2009
Markus Ackermann; Gudlaugur Johannesson; Seth W. Digel; I. V. Moskalenko; Troy A. Porter; O. Reimer; Andrew W. Strong
The Fermi Gamma-Ray Space Telescope with its main instrument the LAT is the most sensitive {gamma}-ray telescope in the energy region between 30 MeV and 100 GeV. One of the prime scientific goals of this mission is the measurement and interpretation of the diffuse Galactic and extragalactic {gamma}-ray emission. While not limited by photon statistics, this analysis presents several challenges: Instrumental response functions, residual background from cosmic rays as well as resolved and unresolved foreground {gamma}-ray sources have to be taken carefully into account in the interpretation of the data. Detailed modeling of the diffuse {gamma}-ray emission is being performed and will form the basis of the investigations. We present the analysis approach to be applied to the Fermi LAT data, namely the modeling of the diffuse emission components and the background contributions, followed by an all-sky maximum-likelihood fitting procedure. We also report on the performance of this method evaluated in tests on simulated Fermi LAT and real EGRET data.
arXiv: Astrophysics | 2007
Markus Ackermann; M. Hayashida; Robert Wagner; Martin Tluczykont; E. Bernardini; F. Goebel; N. Galante; Konstancja Satalecka
Archive | 2008
Konstancja Satalecka; E. Bernardini; Markus Ackermann; E. Al
Astronomische Nachrichten | 2007
Markus Ackermann; E. Bernardini; N. Galante; F. Gobel; M. Hayashida; Konstancja Satalecka; Martin Tluczykont; Robin Wagner
Archive | 2010
Aous A. Abdo; Markus Ackermann; M. Ajello; A. Allafort; Elisa Antolini; W. B. Atwood; Magnus Axelsson; L. Baldini; Jean Ballet; Guido Barbiellini; Denis Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; Fevzi Belli; B. Berenji; Dario Bisello; R. D. Blandford; Elliott D. Bloom; E. Bonamente; Jerry T. Bonnell; A. W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; G. Busetto; Silvio Buson
Archive | 2010
A. A. Abdo; Markus Ackermann; M. Ajello; A. Allafort; W. B. Atwood; L. Baldini; J. Ballet; Jonathan Granot; M. Ziegler
Prepared for | 2005
Markus Ackermann; Elisa Bernardini; T. Hauschildt