Coded Aperture Imaging in High-energy Astrophysics

Braga, J.

doi:10.1088/1538-3873/ab450a

Cited by 15 publications

(9 citation statements)

References 57 publications

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“…The WFM for eXTP is a coded mask instrument 8 . This is a concept already in wide use in past and current instruments for X-ray and gamma-ray astronomy, such as the past instruments GRANAT/SIGMA and BeppoSAX/WFC, and the current ones AGILE/SuperAGILE, INTEGRAL/SPI, IBIS, JEM-X, Neil Gehrels Swift/BAT.…”

Section: Wfm General Description and Accommodation On The Extp Spacec...mentioning

confidence: 99%

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The wide field monitor onboard the Chinese-European x-ray mission eXTP

Hernanz¹,

Brandt

Zand³

et al. 2022

Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray

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The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS), with a large involvement of Europe. The scientific payload of eXTP includes four instruments: the SFA (Spectroscopy Focusing Array) and the PFA (Polarimetry Focusing Array) -led by China -the LAD (Large Area Detector) and the WFM (Wide Field Monitor) -led by Europe (Italy and Spain). They offer a unique simultaneous wide-band X-ray timing and polarimetry sensitivity. The WFM is a wide field X-ray monitor instrument in the 2-50 keV energy range, consisting of an array of six coded mask cameras with a field of view of 180ºx90º at an angular resolution of 5 arcmin and 4 silicon drift detectors in each camera. Its unprecedented combination of large field of view and imaging down to 2 keV will allow eXTP to make important discoveries of the variable and transient X-ray sky and is essential in detecting transient black holes, that are part of the primary science goals of eXTP, so that they can be promptly followed up with other instruments on eXTP and elsewhere.

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Section: Wfm General Description and Accommodation On The Extp Spacec...mentioning

confidence: 99%

“…These detectors work in the (0.5-10) keV energy range, with an energy resolution better than 180 eV at 6 keV. Each one of the 4 PFA focal planes include a Gas Pixel Detector, designed in Italy, working in the (2)(3)(4)(5)(6)(7)(8) keV energy range, with an energy resolution better than 25% at 6 keV and polarimetric capability.…”

Section: Introductionmentioning

confidence: 99%

The wide field monitor onboard the Chinese-European x-ray mission eXTP

Hernanz¹,

Brandt

Zand³

et al. 2022

Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray

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“…In principle, a background-subtracted image of the sky can be reconstructed using this DPI (shadowgram) cast onto the detector, and the known mask shape. There are many methods that can be used to reconstruct the sky image, but in practice, this is typically performed with a balanced cross-correlation of the shadowgram and the mask pattern (the deconvolution array) via a fast Fourier transform to speed up the reconstruction process (Braga 2020). This technique is used for BAT, and is operationalized in the ftool batfftimage.…”

Section: Coded Aperture Imagingmentioning

confidence: 99%

Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction and Temporal Search): Detecting and Localizing the Faintest Gamma-Ray Bursts with a Likelihood Framework

DeLaunay

Tohuvavohu

2022

ApJ

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The detection of the gravitational wave (GW) counterpart GRB 170817A, underluminous compared to the cosmological gamma-ray burst (GRB) population by a factor of 10,000, motivates significant effort in detecting and localizing a dim, nearby, and slightly off-axis population of short GRBs. Swift’s Burst Alert Telescope (BAT) is one of the most sensitive GRB detectors in operation, and the only one that regularly localizes GRBs to arcminute precision, critical to rapid follow-up studies. However, the utility of BAT in targeted subthreshold searches had been historically curtailed by the unavailability of the necessary raw data for analysis. The new availability of time-tagged event data from the GUANO system motivates a renewed focus on developing sensitive targeted search analysis techniques to maximally exploit these data. While computationally cheap, we show that the typical coded-mask deconvolution imaging is limited in its sensitivity due to several factors. We formalize a maximum likelihood framework for the analysis of BAT data wherein signals are forward modeled through the full instrument response, and—coupled with the development of new response models—demonstrate its superior sensitivity to typical imaging via archival comparisons, injection campaigns, and a large number of low-latency GRB discoveries and confirmed arcminute localizations to date. We also demonstrate independent localization of some out-of-field-of-view GRBs for the first time. NITRATES’s increased sensitivity boosts the discovery rate of GRB 170817A–like events in BAT by a factor of at least 3−4×, along with enabling joint analyses and searches with other GRB, GW, neutrino, and FRB instruments. We provide public access to the response functions and search pipeline code.

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“…Multidimensional imaging technique can acquire plenty of optical information of scenes as much as nine dimensions (x, y, z, θ, ϕ, ψ, χ, λ, t), including three -dimensional (3D) spatial intensity distribution (x, y, z), propagation polar angles (θ, ϕ), propagations (ψ, χ), wavelength (λ) for spectral intensity and time (t) [1]. The multidimensional imaging has a variety of applications in astrophysics, remote sensing, security, and biochemistry et al [2][3][4][5]. Especially, 3D spatial distribution and one -dimensional (1D) spectral intensity is significant in target detection, recognition, tracking, scene classification and other computer vision fields et al [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Snapshot depth - spectral imaging based on image mapping and light field

Ding

Zhou

et al. 2022

Preprint

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In recent years, the snapshot multi - dimensional imaging technology is emerging and becomes an increasing research focus. Especially, the spatial, spectral and depth information of scenes is particularly useful in target detection, recognition, tracking, scene classification et al. This paper proposes a snapshot depth - spectral imaging architecture based on image mapping and light field to realize the capture of depth - spectral information in a single snapshot. Specifically, we modulate the depth - spectral information of targets onto a two - dimensional sensor in three steps. Firstly, an image mapper is utilized to slice and reflect the first image to different directions and make void space between two adjacent strip images. This is a spatial modulation processing. Then, a direct vision prism is used to disperse the mapped and collimated light. Finally, the light field sensor with a micro - lens array captures the dispersed light field. Complimentary, we also proposed the reconstruction method under the remapping and digital refocus framework. Through simulations, we demonstrate that the proposed snapshot depth – spectral imaging system is effective to measure the depth - spectral information of scenes in a single snapshot time.

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Coded Aperture Imaging in High-energy Astrophysics

Cited by 15 publications

References 57 publications

The wide field monitor onboard the Chinese-European x-ray mission eXTP

The wide field monitor onboard the Chinese-European x-ray mission eXTP

Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction and Temporal Search): Detecting and Localizing the Faintest Gamma-Ray Bursts with a Likelihood Framework

Snapshot depth - spectral imaging based on image mapping and light field

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