9 research outputs found
Gamma Hadron Separation using Pairwise Compactness Method with HAWC
The High-Altitude Water Cherenkov (HAWC) Observatory is a ground based
air-shower array deployed on the slopes of Volcan Sierra Negra in the state of
Puebla, Mexico. While HAWC is optimized for the detection of gamma-ray induced
air-showers, the background flux of hadronic cosmic-rays is four orders of
magnitude greater, making background rejection paramount for gamma-ray
observations. On average, gamma-ray and cosmic-ray showers are characterized by
different topologies at ground level. We will present a method to identify the
primary particle type in an air-shower that uses the spatial relationship of
triggered PMTs (or "hits") in the detector. For a given event hit-pattern on
the HAWC array, we calculate the mean separation distance of the hits for a
subset of hit pairs weighted by their charges. By comparing the mean charge and
mean separating distance for the selected hits, we infer the identity of the
event's primary. We will report on the efficiency for identifying gamma-rays
and the performance of the technique with simulation.Comment: Presented at the 34th International Cosmic Ray Conference (ICRC2015),
The Hague, The Netherlands. See arXiv:1508.03327 for all HAWC contribution
Local Background Estimation for Improved Gas Plume Identification in Hyperspectral Images
Deep learning identification models have shown promise for identifying gas
plumes in Longwave IR hyperspectral images of urban scenes, particularly when a
large library of gases are being considered. Because many gases have similar
spectral signatures, it is important to properly estimate the signal from a
detected plume. Typically, a scene's global mean spectrum and covariance matrix
are estimated to whiten the plume's signal, which removes the background's
signature from the gas signature. However, urban scenes can have many different
background materials that are spatially and spectrally heterogeneous. This can
lead to poor identification performance when the global background estimate is
not representative of a given local background material. We use image
segmentation, along with an iterative background estimation algorithm, to
create local estimates for the various background materials that reside
underneath a gas plume. Our method outperforms global background estimation on
a set of simulated and real gas plumes. This method shows promise in increasing
deep learning identification confidence, while being simple and easy to tune
when considering diverse plumes.Comment: Submitted to International Geoscience and Remote Sensing Symposium
(IGARSS), 2024. 5 pages, 2 figure
All-sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field
We present the first full-sky analysis of the cosmic ray arrival direction distribution with data collected by the High-Altitude Water Cherenkov and IceCube observatories in the northern and southern hemispheres at the same median primary particle energy of 10 TeV. The combined sky map and angular power spectrum largely eliminate biases that result from partial sky coverage and present a key to probe into the propagation properties of TeV cosmic rays through our local interstellar medium and the interaction between the interstellar and heliospheric magnetic fields. From the map, we determine the horizontal dipole components of the anisotropy δ 0h = 9.16 ×10 -4 and δ 6h = 7.25 ×10 -4 (±0.04 × 10 -4 ). In addition, we infer the direction (229.°2 ± 3.°5 R.A. 11.°4 ± 3.°0 decl.) of the interstellar magnetic field from the boundary between large-scale excess and deficit regions from which we estimate the missing corresponding vertical dipole component of the large-scale anisotropy to be δN ∼ -3.97 +1.0 -2.0 × 10 -4 .0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
All-sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field
We present the first full-sky analysis of the cosmic ray arrival direction distribution with data collected by the High-Altitude Water Cherenkov and IceCube observatories in the northern and southern hemispheres at the same median primary particle energy of 10 TeV. The combined sky map and angular power spectrum largely eliminate biases that result from partial sky coverage and present a key to probe into the propagation properties of TeV cosmic rays through our local interstellar medium and the interaction between the interstellar and heliospheric magnetic fields. From the map, we determine the horizontal dipole components of the anisotropy δ 0h = 9.16 ×10 -4 and δ 6h = 7.25 ×10 -4 (±0.04 × 10 -4 ). In addition, we infer the direction (229.°2 ± 3.°5 R.A. 11.°4 ± 3.°0 decl.) of the interstellar magnetic field from the boundary between large-scale excess and deficit regions from which we estimate the missing corresponding vertical dipole component of the large-scale anisotropy to be δN ∼ -3.97 +1.0 -2.0 × 10 -4 .SCOPUS: ar.jinfo:eu-repo/semantics/publishe