Novel Techniques for Decomposing Diffuse Backgrounds
Abstract
The total anisotropy of a diffuse background composed of two or more sources, such as the Fermi-Large Area Telescope (LAT)-measured gamma-ray background, is set by the anisotropy of each source population and the contribution of each population to the total intensity. The total anisotropy as a function of energy (the anisotropy energy spectrum) will modulate as the relative contributions of the sources change, implying that the anisotropy energy spectrum also encodes the intensity spectrum of each source class. We develop techniques, applicable to any such diffuse background, for unraveling the intensity spectrum of each component source population given a measurement of the total intensity spectrum and the total anisotropy energy spectrum, without introducing a priori assumptions about the spectra of the source classes. We demonstrate the potential of these methods by applying them to example scenarios for the composition of the Fermi-LAT gamma-ray background consistent with current data and feasible within 10 yr of observation.
Additional Information
© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 April 29. Received 2013 April 8; in original form 2012 November 7. First published online: May 29, 2013. BH acknowledges the Caltech Summer Undergraduate Research Fellowship (SURF) programme, the Alain Porter Memorial SURF Fellowship, Barbara and Stanley Rawn, Jr, and the National Science Foundation Graduate Research Fellowship under grant no. DGE- 0646086 for their generous support. BH also acknowledges CCAPP for its hospitality while this work was completed. VP acknowledges support for this work provided by NASA through Einstein Postdoctoral Fellowship grant number PF8-90060 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. JSG acknowledges support from NASA through Einstein Postdoctoral Fellowship grant PF1-120089 awarded by the Chandra X-ray Center, as well as from NSF CAREER grant no. PHY-0547102 (to John Beacom). This work was partially supported by NASA through the Fermi GI Programme grant number NNX09AT74G. We are grateful to Shin'ichiro Ando and Tonia Venters for helpful discussions, and to Anthony Readhead and the anonymous referee for valuable feedback.Attached Files
Published - MNRAS-2013-Hensley-591-602.pdf
Submitted - 1210.7239.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:ba3a1a2fc55e40485b636a4382df2e65
|
376.9 kB | Preview Download |
|
md5:f5d07f4c3de7e93a04b44a53f013ddf8
|
433.7 kB | Preview Download |
Additional details
- Eprint ID
- 36452
- Resolver ID
- CaltechAUTHORS:20130117-105415216
- Caltech Summer Undergraduate Research Fellowship (SURF)
- Alain Porter Memorial SURF Fellowship
- Barbara and Stanley Rawn, Jr.
- DGE-0646086
- NSF Graduate Research Fellowship
- PF8-90060
- NASA Einstein Fellowship
- NAS8-03060
- NASA
- PF1-120089
- NASA Einstein Fellowship
- PHY-0547102
- NSF
- NNX09AT74G
- NASA
- Created
-
2013-02-08Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field
- Caltech groups
- TAPIR