CAN IBEX DETECT INTERSTELLAR NEUTRAL HELIUM OR OXYGEN FROM ANTI-RAM DIRECTIONS?

Journal Article · Thu Oct 15 00:00:00 EDT 2015 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/220/2/30· OSTI ID:22520104

Galli, A.; Wurz, P. ^[1]; Park, J.; Kucharek, H.; Möbius, E.; Schwadron, N. A. ^[2]; Sokół, J. M.; Bzowski, M.; Kubiak, M. A.; Swaczyna, P. ^[3]; Fuselier, S. A.

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1. Physics Institute, University of Bern, Bern, 3012 (Switzerland)
2. University of New Hampshire, Durham, NH 03824 (United States)
3. Space Research Centre, Polish Academy of Sciences, Warsaw, 00-716 (Poland)

To better constrain the parameters of the interstellar neutral flow, we searched the Interstellar Boundary EXplorer (IBEX)-Lo database for helium and oxygen from the interstellar medium in the anti-ram direction in the three years (2009–2011) with the lowest background rates. We found that IBEX-Lo cannot observe interstellar helium from the anti-ram direction because the helium energy is too low for indirect detection by sputtering off the IBEX-Lo conversion surface. Our results show that this sputtering process has a low energy threshold between 25 and 30 eV, whereas the energy of the incident helium is only 10 eV for these observations. Interstellar oxygen, on the other hand, could in principle be detected in the anti-ram hemisphere, but the expected magnitude of the signal is close to the detection limit imposed by counting statistics and by the magnetospheric foreground.

• OSTI ID: 22520104
• Journal Information: Astrophysical Journal, Supplement Series, Vol. 220, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ATOMS
DATA ANALYSIS
DETECTION
EV RANGE
HELIOSPHERE
HELIUM
INTERSTELLAR SPACE
OXYGEN
SENSITIVITY
SPUTTERING
STATISTICS
STELLAR MAGNETOSPHERES
SUN