The Interstellar Boundary Explorer Science Operations Center

Schwadron, N. A.; Crew, G. B.; Vanderspek, R.; Allegrini, F.; Bzowski, M.; DeMagistre, R.; Dunn, G.; Funsten, H. O.; Fuselier, S. A.; Goodrich, K.; Gruntman, M.; Hanley, J.; Heerikuisen, Jacob; Heirtlzer, D.; Janzen, P. H.; Kucharek, H.; Loeffler, C.; Mashburn, K.; Maynard, K.; McComas, D. J.; Möbius, E.; Prested, C.; Randol, B. M.; Reisenfeld, D. B.; Reno, M.; Roelof, E. C.; Wu, Puxun

doi:10.1007/s11214-009-9513-x

Cited by 29 publications

(27 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the location of the IBEX-Lo instrument, the model performs a series of numerical integrations to account for the instrument response (Möbius et al 2009;Schwadron et al 2009Schwadron et al , 2013. These integrations are performed for the observational geometry specific to a given moment in time and include integration over 6°spin-sectors (there are 60 total spin-sectors covering each 360°rotation), integration over the viewing angles of the collimator, and integration over the energy (see Schwadron et al 2013).…”

Section: Integrated Instrument Response Model Using Analytic Trajectomentioning

confidence: 99%

“…These integrations are performed for the observational geometry specific to a given moment in time and include integration over 6°spin-sectors (there are 60 total spin-sectors covering each 360°rotation), integration over the viewing angles of the collimator, and integration over the energy (see Schwadron et al 2013). The integration over the collimator takes into account the detailed point-spread function of IBEX-Lo (Schwadron et al 2009). We summarize the integrations as follows.…”

Section: Integrated Instrument Response Model Using Analytic Trajectomentioning

confidence: 99%

“…We extend the analytic framework initially developed by Lee et al (2012) for solving trajectories of neutral atoms. Instead of adopting approximations to yield closed-form solutions in Earth's frame of reference (see also Lee et al 2015), we integrate over the complete IBEX-Lo response function (Schwadron et al 2009) in the frame of reference of the spacecraft to simulate neutral atom rates. We then utilize a larger amount of IBEX data (five years from 2009 through 2013) together with the improved model of interstellar He atoms to reduce uncertainties in the determination of the ISN flow vector and temperature.…”

mentioning

confidence: 99%

See 2 more Smart Citations

DETERMINATION OF INTERSTELLAR He PARAMETERS USING FIVE YEARS OF DATA FROM THE IBEX : BEYOND CLOSED FORM APPROXIMATIONS

Schwadron

Möbius

Leonard

et al. 2015

ApJS

Self Cite

View full text Add to dashboard Cite

Interstellar He represents a key sample of interstellar matter that, due to its high first ionization potential, survives the journey from beyond our solar system's heliospheric boundaries to Earth. Ongoing analysis of interstellar neutral (ISN) He atoms by the Interstellar Boundary Explorer (IBEX) has resulted in a growing sophistication in our understanding of the local interstellar flow. A key feature of the IBEX observations near perihelion of the ISN trajectories is a narrow "tube" of approximately degenerate interstellar parameters. These degenerate solutions provide a tightly coupled relationship between the interstellar flow longitude and latitude, speed, and temperature. However, the IBEX analysis resulting in a specific solution for the inflow longitude, inflow speed, temperature, and inflow latitude was accompanied by a sizeable uncertainty along the parameter tube. Here, we use the three-step method to find the interstellar parameters: (1) the ISN He peak rate in ecliptic longitude uniquely determines a relation (as part of the tube in parameter space) between the longitude ISN l ¥ and the speed V ISN¥ of the He ISN flow at infinity; (2) the ISN He peak latitude (on the great circle swept out in each spin) is compared to simulations to derive unique values for ISN l ¥ and V ISN¥ along the parameter tube; and (3) the angular width of the He flow distributions as a function of latitude is used to derive the interstellar He temperature. For simulated peak latitudes, we use a relatively new analytical tool that traces He atoms from beyond the termination shock into the position of IBEX and incorporates the detailed response function of IBEX-Lo. By varying the interstellar parameters along the IBEX parameter tube, we find the specific parameters that minimize the chi-square difference between observations and simulations. The new computational tool for simulating neutral atoms through the integrated IBEX-Lo response function makes no assumptions or expansions with respect to the spin-axis pointing or frame of reference. Thus, we are able to move beyond closed-form approximations and utilize observations of interstellar He during the complete five year period from 2009 to 2013 when the primary component of interstellar He is most prominent. Chi-square minimization of simulations compared to observations results in a He ISN flow longitude of 75 6 ± 1 4, latitude of −5 12 ± 0 27, speed of 25.4 ± 1.1 km s −1 , and temperature of 8000 ± 1300 K, where the uncertainties are related and apply along the IBEX parameter tube. This paper also provides documentation for a new release of ISN data and associated model runs.

show abstract

Section: Integrated Instrument Response Model Using Analytic Trajectomentioning

confidence: 99%

Section: Integrated Instrument Response Model Using Analytic Trajectomentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

DETERMINATION OF INTERSTELLAR He PARAMETERS USING FIVE YEARS OF DATA FROM THE IBEX : BEYOND CLOSED FORM APPROXIMATIONS

Schwadron

Möbius

Leonard

et al. 2015

ApJS

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, if the line-of-sight view from 1 au does not intersect the partial shell distribution of PUIs (Heerikhuisen et al 2010b;Zirnstein et al 2012), then ENAs produced from those PUIs cannot be observed by IBEX and are not counted in the flux seen at 1 au. As was done in our previous work (Zirnstein et al 2013(Zirnstein et al , 2015bHeerikhuisen et al 2014), we simulate the IBEX ribbon flux at all IBEX-Hi energies, integrating over a discrete set of energies in each IBEX-Hi energy passband, and weight the contribution of flux at each discrete energy using the IBEX-Hi energy response functions (Funsten et al 2009a;Schwadron et al 2009b). Each pixel in the simulated all-sky map is filtered using a simplified model of the IBEX-Hi hexagonal collimator response function (Funsten et al 2009a;Zirnstein et al 2013), where we assume a full width at half maximum (FWHM) of 7…”

Section: Simulating the Ibex Ribbonmentioning

confidence: 99%

Effects of solar wind speed on the secondary energetic neutral source of the Interstellar Boundary Explorer ribbon

Zirnstein

Funsten

Heerikhuisen

et al. 2016

A&A

Self Cite

View full text Add to dashboard Cite

The Interstellar Boundary EXplorer (IBEX) ribbon is an intense energetic neutral atom (ENA) emission feature encircling the sky, spanning energies ≤0.5-6 keV. The ribbon may be produced by the "secondary ENA" mechanism, where ENAs emitted from a source plasma population inside the heliosphere propagate outside the heliopause, undergo two charge-exchange events, and become secondary ENAs that may be directed back toward Earth and detected by IBEX. In this scenario, the source plasma population is governed by the interaction of the solar wind (SW) with the interstellar medium and is thus sensitive to the global SW properties. Moreover, this scenario predicts that the distance to the source of secondary ENAs depends on the ENA energy and SW speed, which in turn may affect the shape of the ribbon. In this paper, we use a computational model of the heliosphere with simplified SW boundary conditions to analyze the influence of ENA energy and SW speed, independent of time and latitude, on the global spatial and geometric properties of the ribbon. We find a strong dependence of the simulated ribbon energy spectrum and spatial symmetry on SW speed and ENA energy, and only a slight dependence on ribbon geometry. Our results suggest a significant number of primary ENAs from the inner heliosheath may contribute to the pickup ion source population outside the heliopause, depending on the ENA energy and SW speed. The lack of variation in the simulated ribbon center as a function of ENA energy and SW speed, in contrast to the observations, implies that the asymmetry of the SW plays an important role in determining the position of the ribbon. Comparisons to the IBEX data also signify the ribbon's dependence on the properties of the local interstellar medium, particularly the interstellar magnetic field.

show abstract

“…The efficiencies and transparencies are explained in detail in the IBEX science operation paper (Schwadron et al 2009). Those values are based on various calibration runs with neutral beams of four species during final calibration before flight.…”

mentioning

confidence: 99%

Ibex Observations of Secondary Interstellar Helium and Oxygen Distributions

Park

Kucharek

Möbius

et al. 2016

ApJ

View full text Add to dashboard Cite

In this study, we investigate the directional distributions of the secondary interstellar neutral (ISN) He and O populations at Earthʼs orbit. The secondary populations are created by charge exchange between ISN atoms and interstellar ions in the outer heliosheath. Using the IBEX-Lo He and O observations during the winter-spring seasons (early December to early June) in 2009-2011, we produced all-sky maps for He and O atoms with sputtering corrections. These sky maps include the directional distributions of the primary ISN gas and secondary populations. Our investigations reveal that the secondary He and O populations are observed in the ecliptic longitude range 160°-210°. The peak longitudes of the secondary He and O appear to be 14°-34°and 38°-43°a way from the peak longitude of the primary interstellar gas flow, respectively. These results indicate that the secondary populations have lower bulk speeds relative to the Sun and their flow directions deviate from the primary gas flow. These results may indicate that one side of the outer heliosheath is thicker than the other side relative to the flow direction of the primary interstellar gas flow.

show abstract

The Interstellar Boundary Explorer Science Operations Center

Cited by 29 publications

References 9 publications

DETERMINATION OF INTERSTELLAR He PARAMETERS USING FIVE YEARS OF DATA FROM THE IBEX : BEYOND CLOSED FORM APPROXIMATIONS

DETERMINATION OF INTERSTELLAR He PARAMETERS USING FIVE YEARS OF DATA FROM THE IBEX : BEYOND CLOSED FORM APPROXIMATIONS

Effects of solar wind speed on the secondary energetic neutral source of the Interstellar Boundary Explorer ribbon

Ibex Observations of Secondary Interstellar Helium and Oxygen Distributions

Contact Info

Product

Resources

About