Seven Years of Imaging the Global Heliosphere with IBEX
IBEX Data Release 10
Dave McComas (Princeton University)
The Interstellar Boundary Explorer (IBEX) has now operated in space for seven years and returned nearly continuous observations that have led to scientific discoveries and reshaped our entire understanding of the outer heliosphere and its interaction with the local interstellar medium. This data release extends prior work by adding the 2014-2015 data for the first time and improving prior correction methods. The data, maps, and documentation provided here represent the tenth major release of IBEX data, providing a complete seven year set of Energetic Neutral Atom (ENA) observations from ~0.1 to 6 keV.
To download the entire data release as a zip file or to go to a table of plot directories and data selections for either IBEX-Lo or IBEX-Hi, click on one of the links below. To learn more about the structure and content of the files contained within the release, a detailed description follows. For questions about this or any other release, please email ibex_datareleases@lists.sr.unh.edu.
A detailed description and initial analysis of these maps is presented in McComas et al. 2017 (ApJS, In Press).
Data Directory Structure and Naming Conventions
The data in this release are separated into six-month and one-year segments, which represent the following IBEX orbits and dates:
The 6-month and annual allsky maps are representative of the following IBEX orbits and dates:
| Year | Skymap # | Start-End of Orbits or Arcs | Dates |
|---|---|---|---|
| 1 | Map1 | 11-34 | 12/25/2008 – 06/25/2009 |
| 1 | Map2 | 35-58 | 06/25/2009 – 12/25/2009 |
| 2 | Map3 | 59-82 | 12/25/2009 – 06/26/2010 |
| 2 | Map4 | 83-106 | 06/26/2010 – 12/26/2010 |
| 3 | Map5 | 107-130a | 12/26/2010 – 06/25/2011 |
| 3 | Map6 | 130b-150a | 06/25/2011 – 12/24/2011 |
| 4 | Map7 | 150b-170a | 12/24/2011 – 06/22/2012 |
| 4 | Map8 | 170b-190b | 06/22/2012 – 12/26/2012 |
| 5 | Map9 | 191a-210b | 12/26/2012 – 06/26/2013 |
| 5 | Map10 | 211a-230b | 06/26/2013 – 12/26/2013 |
| 6 | Map11 | 231a-250b | 12/26/2013 – 06/26/2014 |
| 6 | Map12 | 251a-270b | 06/26/2014 – 12/24/2014 |
| 7 | Map13 | 271a-290b | 12/24/2014 – 06/24/2015 |
| 7 | Map14 | 291a-310b | 06/24/2015 – 12/23/2015 |
Along with each set of individual maps, we provide the 7-year combined map for that category, as well as a combined set of ENA maps in equatorial and galactic coordinate systems for the broader astrophysical community.
Map directories are named using keywords that indicate the type of data they contain:
- cg - Compton-Getting corrections have been applied to the data to account for the speed of the spacecraft relative to the direction of arrival of the ENAs.
- tabular - survival probability corrections have been applied to the data to account for the loss of ENAs due to radiation pressure, photoionization and ionization via charge exchange with solar wind protons as they stream through the heliosphere. This correction scales the data out from IBEX at 1 AU to ~100 AU.
- noSP - no survival probability corrections have been applied to the data.
- ram - data was collected when the spacecraft was ramming into the incoming ENAs.
- antiram - data was collected when the spacecraft was moving away from the incoming ENAs.
- mapx - x identifies a particular set of orbits spanning 6 months.
- yearx - x identifies a particular set of orbits spanning one year.
- single - data was collected over the course of the entire seven-year span.
Filename Description
Data and map files are named using additional keywords that indicate the type of data they contain:
- hide - IBEX-Hi direct events
- lode - IBEX-Lo direct events
- hi-n - data from the nth energy bin of IBEX-Hi
- lo-n - data from the nth energy bin of IBEX-Lo
- trp - triple coincidence
- mono - Compton-Getting corrected data
- flux - flux data
- fsnr - signal/noise data
- ener - energies data
- numb - samples per pixel
- fexp - total time exposure data
- cnts - total counts data
- fraw- raw orbit data
- fvar- flux variances
File Headers
The first number in the first line of each data file gives the number of lines taken up by the header followed by the number of rows times the number of columns in the data (i.e. 30X60 indicates 30 rows of declination by 60 columns of right ascension values). The keyword “h_title” gives the description of the data and the units used.
IBEX Hi Observing Energetic Neutral Atoms In a Higher Range of Energies
Plots and Data Directories
6-month Compton-Getting Corrected Maps Compton-Getting maps adjust values after correcting for the speed of the spacecraft in relation to the direction of arrival of the ENAs. The data directories: |
6-month Maps These maps represent the data before any corrections are made for speed of spacecraft or survival probability. The data directories: |
Yearly Maps, Ram Direction These maps include data recorded from times when the aperture was pointed towards the hemisphere of the spacecraft’s motion. The maps do not include survival probability corrections. The data directories: Without Compton-Getting With Compton-Getting |
Yearly Maps, AntiRam These maps include data recorded at times when the aperture was pointed away from the hemisphere of the spacecraft’s motion. The maps do not include survival probability corrections. The data directories: Without Compton-Getting With Compton-Getting |
6-months, Compton-Getting and Compton-Getting Tabular Maps adjust values after correcting for the speed of the spacecraft in relation to the direction of arrival of the ENAs and include adjustments taking into account ENA survival probability as they move from the outer heliosphere to 1 AU (location of IBEX). The data directories: Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
Survival Probability Lookup Maps Survival Probability Maps account for the loss (extinction) of ENAs due to radiation pressure, photoionization and ionization via charge exchange with solar wind protons. The data directories: Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
Yearly Maps, Survival Probability Corrected, Ram Direction These maps include survival probability corrected data recorded from times when the aperture was pointed towards the hemisphere of the spacecraft’s motion. The data directories: With Compton-Getting Without Compton-Getting Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
Yearly Maps, Survival Probability Corrected, Antiram Direction These maps include survival probability corrected data recorded from times when the aperture was pointed away from the hemisphere of the spacecraft’s motion. The data directories: With Compton-Getting hvset_tabular_antiram_cg_single hvset_tabular_antiram_cg_year1 hvset_tabular_antiram_cg_year2 hvset_tabular_antiram_cg_year3 hvset_tabular_antiram_cg_year4 hvset_tabular_antiram_cg_year5 hvset_tabular_antiram_cg_year6 hvset_tabular_antiram_cg_year7 Without Compton-Getting Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
ENA Maps in Equatorial and Galactic Coordinates These maps in equatorial and galactic coordinate systems are for the use of the broader astrophysical community: hvset_tabular_ram_equatorial_single hvset_tabular_antiram_cg_single Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
All Hi Data Directories
| All IBEX Hi Data Directories |
IBEX Lo Observing Energetic Neutral Atoms In a Lower Range of Energies
Plots and Data Directories
6-month Maps These maps represent the data before any corrections are made for speed of spacecraft or survival probability. The data directories: |
Survival Probability Lookup Maps Survival Probability Maps account for the loss (extinction) of ENAs due to radiation pressure, photoionization and ionization via charge exchange with solar wind protons. The data directories: Note: Survival probability correction procedures are documented in Appendix B in McComas et al. 2017. |
All Lo Data Directories
| All IBEX Lo Data Directories |
Calculation Notes for Users to Combine Multiple Maps:
Combining different maps is done by accounting for the statistical uncertainties and time exposure weighting. Below is an example of combining three different maps.
ENA Exposure times for the three ENA maps: tau1, tau2, tau3;
ENA fluxes for the three ENA maps: flux1, flux2, flux3;
ENA flux variances for the three ENA maps: var1, var2, var3;
We now calculate the weights from the exposure times as,
wt1=tau1/(tau1+tau2+tau3)
wt2=tau2/(tau1+tau2+tau3)
wt3=tau3/(tau1+tau2+tau3)
Combined fluxes and propagated variances are then determined using:
combined_flux=flux1*wt1 + flux2*wt2 + flux3*wt3
combined_var=var1*(wt1)^2 + var2*(wt2)^2 + var3*(wt3)^2