Conveners
Analysis techniques: Methods
- J. Michael Burgess (Max-Planck-Institut für extraterrestrische Physik)
Imaging, the process of converting data into images, is in general an ill-posed problem that requires regularization by additional information. Information field theory (IFT) provides a consistent framework to fuse measurement data and abstract knowledge on signal fields into an optimal image by using field theoretical methods in Bayesian inference. Here, the IFT based D$^3$PO algorithm will...
We report on the Fermi High-Latitude Extended Source Catalog (FHES), a systematic search for spatial extension of gamma-ray sources reported in the Fermi Large Area Telescope (LAT) 3FGL and 3FHL catalogs at Galactic latitudes |b| > 5 degrees. While the majority of high-latitude LAT sources are extragalactic blazars that appear point-like within the LAT angular resolution, there are several...
With the detection of gravitational wave emissions from from merging compact objects, it is now more important than ever to effectively mine the data-set of gamma-satellites for non-triggered, short-duration transients. Hence we developed a new method called the Automatized Detector Weight Optimization (ADWO), applicable for space-borne detectors such as Fermi' GBM and RHESSI' ACS. Provided...
As the Multi-Messenger era begins with detections of gravitational waves with LIGO and neutrinos with IceCube,Fermi GBM provides context observations of gamma-ray transients between 8 keV and 40 MeV. GBM has a wide field of view, high uptime, and both in-orbit triggering and high time resolution continuous data enabling offline searches for weaker transients. GBM detects numerous GRBs, SGRs,...
The Fermi Gamma-ray Space Telescope’s Gamma-ray Burst Monitor (GBM) is currently the most prolific detector of Gamma-ray Bursts (GRBs), including short-duration GRBs (sGRBs). Recently the detection rate of sGRBs has been increased dramatically through the use of ground-based searches to analyze untriggered GBM continuous time tagged event (CTTE) data. Motivated by the possibility that sGRBs...
With fast growing data collected by the Fermi Large Area Telescope as a big data problem, manual classification has become an impossible task for astronomers. In this paper, we propose a novel framework using machine learning techniques with automatic feature selection algorithms for gamma-ray object classification. We automate parameter tuning rather than manual tuning used in some previous...
The double-Compton telescope COMPTEL flew on the NASA Compton Gamma Ray Observatory (CGRO) satellite from 1991 to 2000, and is still the basis of most knowledge of the 1-30 MeV sky. Pending new missions like eAstrogam, for the next decade COMPTEL will still be a major resource for MeV gamma rays. A long-term effort to exploit heritage COMPTEL data is underway at MPE and MPA Garching. The full...
The all-sky monitoring capability of Fermi GBM makes it ideal for finding transients. Fermi GBM triggers on events such as gamma-ray bursts, soft gamma-ray repeaters, X-ray bursters, solar flares, and terrestrial gamma-ray flashes. A previous systematic search in offline data for X-ray bursts has uncovered untriggered gamma-ray bursts, and currently there is a dedicated offline search...
Advanced gamma-ray telescopes such as COSI, AMEGO, and eAstroGam measure many more parameters of the observed gamma rays than before, especially in the Compton regime. The measured energies and scatter directions (gamma ray and recoil electron), the detector geometry, the distance between interactions, and multiple Compton interactions all influence the response. For example, a matrix which...
The Fermi Large Area Telescope has been successfully operating in low Earth orbit almost continuously since its initial turn-on on 24 June 2008, for over 9 years. We present details of the current performance of the LAT detector and data acquisition sub-systems, together with long-term trends of key performance measures, and assess the expected performance in continued future operation. We...
Current pair-conversion event generators, e.g. in geant4, don't sample the five-dimensional differential crosssection (5D DCS), but a product of 1D DCSs. Most of them use high-energy and/or small angle approximations. Also the e+ and e- polar angles are generated independently so energy-momentum is not conserved.
None of them can simulate the conversion of polarized photons correctly...
The age of multi-wavelength and multi-messenger astronomy has arrived and with it, new tools are needed to analyze data from multiple instruments properly and with ease. The Multi-Mission Maximum Likelihood framework (3ML) provides this functionality via the novel use of instrument plugins which allow for every instrument’s unique data to be treated independently with an appropriate...
