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Astrophsyics

PCOS Science Goals

Explore the behavior of matter and energy in its most extreme environments

Cosmic rays—high-energy charged particles traveling at velocities that can approach the speed of light—are the only direct probe of chemical composition and nuclearsynthesis in the Universe. The majority of cosmic rays are atomic nuclei from hydrogen to the heaviest elements with energies spanning more than twelve orders of magnitude. Cosmic rays with energies below and just above the so-called "knee" in the middle of this energy range are most likely accelerated in supernova remnants. Their elemental and isotopic composition probes nucleosynthesis, nuclear interactions in the interstellar medium, the distribution of freshly synthesized elements, global Galactic properties, the mechanisms of supernova explosions, and particle acceleration in supernova shocks. At energies above roughly 1017 eV a different source dominates. The acceleration engines responsible for such extreme energies are not well understood, but at the highest energies, above 6 x 1019 eV, the rapid energy loss resulting from interactions with the cosmic microwave background limits sources to within about 100 Mpc. Other cosmic ray components include electrons, positrons, and antiprotons. Electrons are quite abundant and can be accelerated in many different types of sources, while positrons and antiprotons are largely the result of interactions of nuclear cosmic rays with the ISM but may also have other origins. Positrons as well as electrons can be produced directly in astrophysical objects such as pulsars and deviations in their spectra can provide important insights into nearby sources. Cosmic ray particles may also be produced directly in the annihilation of dark matter candidate particles such as, e.g., WIMPs, neutralinos, and Kaluza-Klein particles. Details of the spectra and composition of the resulting particles therefore provide important insights into the physics of particle accelerators and properties of the interstellar and/or intergalactic medium, and provide important constraints on the nature of the dark matter.


The European Space Agency LISA observatory


PCOS News

Program News and Announcements

21 October 2020
Revised submission date: Applications Sought for PhysPAG Executive Committee. Submissions now due November 6. »  Details.
14 October 2020
Astrophysics Advisory Committee meeting on 19–21 October 2020 »  Details.
14 October 2020
Astrophysics Explorers Announcement of Opportunity Community Announcement »  Details.
17 September 2020
NASA announces major revisions in Astrophysics Research and Analysis opportunity. Due dates remain unchanged. »  Details.
17 September 2020
NASA releases Citizen Science Seed Funding Program opportunity. Notices of Intent requested by 13 October 2020, with proposals due 11 December 2020. »  Details.
17 September 2020
NASA extends due date for Astrophysics Pioneers opportunity. Proposals are now due 8 October 2020. »  Details.
15 September 2020
Applications Sought for PhysPAG Executive Committee »  Details.
9 September 2020
Swift Cycle 17 Guest Investigator proposals due on 25 September 2020 »  Details.
4 September 2020
SMD Community Town Hall on Thurs 10 September »  Details.
4 September 2020
NuSTAR requests self-nominations for Users' Committee »  Details.
18 August 2020
XMM-Newton Guest Observer Announcement of Opportunity. »  Details.
17 August 2020
New Phase-1 Proposal Due Date for NICER Guest Observer Cycle 3. »  Details.
29 July 2020
Community Announcement: Intention to Amend ROSES-20 via a Future Appendix for Payloads and Research Investigations on the Surface of the Moon (PRISM). »  Details.
27 July 2020
Snowmass 21 planning underway, with several topical groups on PCOS-related science. »  Details.
23 July 2020
New deadline set for JWST Cycle 1 General Observer proposals. Proposals will be due by 08:00 pm Eastern Time (ET) on Tuesday November 24, 2020. »  Details.
2 July 2020
NASA releases final text for Astrophysics Pioneers opportunity. Notices of Intent due 13 August 2020; proposals due 1 October 2020. »  Details.

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  • NASA Official: Phil Newman
  • Web Curator: Pat Tyler
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