Kashlinsky, AlexanderArendt, RichardAshby, MAtrio-Barandela, F.et al2022-02-012022-02-012019-05-31Kashlinsky, A., Arendt, R. G., Ashby, M., Atrio-Barandela, F., Bromm, V., Cappelluti, N., … Yue, B. (2019). Populations behind the source-subtracted cosmic infrared background anisotropies. Bulletin of the AAS, 51(3). Retrieved from https://baas.aas.org/pub/2020n3i037http://hdl.handle.net/11603/24102Alexander Kashlinsky, R. G. Arendt, M. Ashby, F. Atrio-Barandela, V. Bromm, N. Cappelluti, S. Clesse, A. Comastri, G. Fazio, S. Driver, A. Ferrara, A. Finoguenov, J. Garcia-Bellido, D. Fixsen, G. Hasinger, K. Helgason, R. J. Hill, R. Jansen, J. Kruk, J. Mather, P. Natarajan, N. Odegard, M. Ricotti, M. Sahlen, E. Switzer, R. Windhorst, E. Wollack, and Bin YueAlthough the advent of ever-larger and more sensitive telescopes in the coming decade will reveal correspondingly fainter, more distant galaxies, a question will persist: what more is there that these telescopes cannot see? One answer is the source-subtracted Cosmic Infrared Background (CIB). The CIB is comprised of the collective light from all sources remaining after known, resolved sources are accounted for. A crucial point: unlike the cosmic microwave background, the CIB arises from discrete sources. Ever-more-sensitive surveys will identify the brightest of these, allowing them to be removed, and – like peeling layers off an onion – reveal deeper layers of the CIB. In this way it is possible to measure the contributions from populations not accessible to direct telescopic observation. Measurement of fluctuations in the source-subtracted CIB, i.e., the spatial power spectrum of the CIB after subtracting resolved sources, provides a robust means of characterizing its faint, and potentially new, populations. Studies over the past 15 years have revealed source-subtracted CIB fluctuations on scales out to ∼ 100′ which cannot be explained by extrapolating from known galaxy populations. Moreover, they appear highly coherent with the unresolved Cosmic X-ray Background, hinting at a significant population of accreting black holes among the CIB sources. Characterizing the source-subtracted CIB with high accuracy, and thereby con- straining the nature of the new populations, is feasible with upcoming instruments and would produce critically important cosmological information in the next decade. New coextensive 1 deep and wide-area near-infrared, X-ray, and microwave surveys will bring decisive opportunities to examine, with high fidelity, the spatial spectrum and origin of the CIB fluctuations and their cross-correlations with cosmic microwave and X-ray backgrounds, and determine the formation epochs and the nature of the new sources (stellar nucleosynthetic or accreting black holes).14 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domain Mark 1.0Text