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Full-Text Articles in Physical Sciences and Mathematics

Exploring The Possibility Of O And Ne Contamination In Ulysses Observations Of Interstellar Helium, Brian E. Wood, Hans-Reinhard Müller, Maciej Bzowski, Justyna M. Sokół Oct 2015

Exploring The Possibility Of O And Ne Contamination In Ulysses Observations Of Interstellar Helium, Brian E. Wood, Hans-Reinhard Müller, Maciej Bzowski, Justyna M. Sokół

Dartmouth Scholarship

We explore the possibility that interstellar O and Ne may be contributing to the particle signal from the GAS instrument on Ulysses, which is generally assumed to be entirely He. Motivating this study is the recognition that an interstellar temperature higher than any previously estimated from Ulysses data could potentially resolve a discrepancy between Ulysses He measurements and those from the Interstellar Boundary Explorer (IBEX). Contamination by O and Ne could lead to Ulysses temperature measurements that are too low. We estimate the degree of O and Ne contamination necessary to increase the inferred Ulysses temperature to …


Revisiting Ulysses Observations Of Interstellar Helium, Brian E. Wood, Hans-Reinhard Müller, Manfred Witte Mar 2015

Revisiting Ulysses Observations Of Interstellar Helium, Brian E. Wood, Hans-Reinhard Müller, Manfred Witte

Dartmouth Scholarship

We report the results of a comprehensive reanalysis of Ulysses observations of interstellar He atoms flowing through the solar system, the goal being to reassess the interstellar He flow vector and to search for evidence of variability in this vector. We find no evidence that the He beam seen by Ulysses changes at all from 1994-2007. The direction of flow changes by no more than ~03 and the speed by no more than ~0.3 km s–1. A global fit to all acceptable He beam maps from 1994-2007 yields the following He flow parameters: V ISM = 26.08 ± …


The Broad-Lined Type Ic Sn 2012ap And The Nature Of Relativistic Supernovae Lacking A Gamma-Ray Burst Detection, D. Milisavljevic, R. Margutti, J. T. Parrent, A. M. Soderberg, R. A. Fesen Jan 2015

The Broad-Lined Type Ic Sn 2012ap And The Nature Of Relativistic Supernovae Lacking A Gamma-Ray Burst Detection, D. Milisavljevic, R. Margutti, J. T. Parrent, A. M. Soderberg, R. A. Fesen

Dartmouth Scholarship

We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from –13 to +272 days past the B-band maximum of –17.4 ± 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v ≈ 20,000 km s–1 that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also …