Cosmic ray isotope and charge resolution using large area scintillation-cherenkov-total energy telescopes

We are reporting here on the results obtained from a balloon exposure of a cosmic ray detector flown in 1977. This detector, described elsewhere, Gilman and Waddington (1975), Young (1979), measures elemental charge from scintillation and Cherenkov signals and mass from Cherenkov and total energy determined from a measure of residual range in nuclear emulsion. The charge resolution obtained ranged from 0.19 to 0.21 charge units between neon and nickel. This resolution was sufficient to ensure that all but a few percent of the nuclei were correctly identified, even for those elements of low abundance that have neighbors with high abundances, such as Cl or Al. The mass resolution obtained for those nuclei that stopped in the emulsions ranged from 0.40 to 0.70 amu for A between 20 and 60 amu. This was not adequate to uniquely resolve neighboring mass peaks in many cases, but was adequate to draw a number of conclusions regarding many of the more abundant elements.

Download Full-text

A large area, high charge resolution, scintillation counter telescope for cosmic ray studies

Nuclear Instruments and Methods ◽

10.1016/0029-554x(68)90068-2 ◽

1968 ◽

Vol 66 (1) ◽

pp. 119-124 ◽

Cited By ~ 8

Author(s):

T.T. Von Rosenvinge ◽

W.R. Webber

Keyword(s):

Scintillation Counter ◽

Cosmic Ray ◽

Large Area ◽

High Charge ◽

Charge Resolution ◽

Counter Telescope

Download Full-text

Diffuse γ-ray emission toward the massive star-forming region, W40

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037580 ◽

2020 ◽

Vol 639 ◽

pp. A80

Author(s):

Xiao-Na Sun ◽

Rui-Zhi Yang ◽

Yun-Feng Liang ◽

Fang-Kun Peng ◽

Hai-Ming Zhang ◽

...

Keyword(s):

Cosmic Ray ◽

High Energy ◽

Young Star ◽

Gas Content ◽

Large Area ◽

Stellar Cluster ◽

Production Region ◽

Star Forming ◽

Photon Index ◽

Young Star Clusters

We report the detection of high-energy γ-ray signal towards the young star-forming region, W40. Using 10-yr Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended γ-ray excess region with a significance of ~18σ. The radiation has a spectrum with a photon index of 2.49 ± 0.01. The spatial correlation with the ionized gas content favors the hadronic origin of the γ-ray emission. The total cosmic-ray (CR) proton energy in the γ-ray production region is estimated to be the order of 1047 erg. However, this could be a small fraction of the total energy released in cosmic rays (CRs) by local accelerators, presumably by massive stars, over the lifetime of the system. If so, W40, together with earlier detections of γ-rays from Cygnus cocoon, Westerlund 1, Westerlund 2, NGC 3603, and 30 Dor C, supports the hypothesis that young star clusters are effective CR factories. The unique aspect of this result is that the γ-ray emission is detected, for the first time, from a stellar cluster itself, rather than from the surrounding “cocoons”.

Download Full-text

A possible radio signal of annihilating dark matter in the Abell 4038 cluster

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slz185 ◽

2019 ◽

Vol 495 (1) ◽

pp. L124-L128 ◽

Cited By ~ 2

Author(s):

Man Ho Chan ◽

Chak Man Lee

Keyword(s):

Dark Matter ◽

Cross Section ◽

Radio Signal ◽

Dark Matter Particle ◽

Cosmic Ray ◽

Annihilation Cross Section ◽

Radio Continuum ◽

Test Statistic ◽

Large Area ◽

Dark Matter Annihilation

ABSTRACT In the past decade, some telescopes [e.g. Fermi-Large Area Telescope (LAT), Alpha Magnetic Spectrometer(AMS), and Dark Matter Particle Explorer(DAMPE)] were launched to detect the signals of annihilating dark matter in our Galaxy. Although some excess of gamma-rays, antiprotons, and electrons/positrons have been reported and claimed as dark matter signals, the uncertainties of Galactic pulsars’ contributions are still too large to confirm the claims. In this Letter, we report a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming the thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we get very large test statistic values >45 for four popular annihilation channels, which correspond to more than 6.5σ statistical preference. This provides a very strong evidence for the existence of annihilating dark matter. In particular, our results also support the recent claims of dark matter mass m ≈ 30–50 GeV annihilating via the bb̄ quark channel with the thermal annihilation cross-section.

Download Full-text