CMB Spectral Distortions: Status and Prospects

Departures of the energy spectrum of the cosmic microwave background (CMB) from a perfect blackbody probe a fundamental property of the universe -- its thermal history. Current upper limits, dating back some 25 years, limit such spectral distortions to 50 parts per million and provide a foundation for the Hot Big Bang model of the early universe. Modern upgrades to the 1980's-era technology behind these limits enable three orders of magnitude or greater improvement in sensitivity. The standard cosmological model provides compelling targets at this sensitivity, spanning cosmic history from the decay of primordial density perturbations to the role of baryonic feedback in structure formation. Fully utilizing this sensitivity requires concurrent improvements in our understanding of competing astrophysical foregrounds. We outline a program using proven technologies capable of detecting the minimal predicted distortions even for worst-case foreground scenarios

За кадры. 1939. № 1 (231)

С Новым годом, товарищи!Изучаю сталинский учебник / Н. ЗоревГод грандиозного строительства / И. РуновГод плодотворной работы / И. РольникНаш вклад в науку и техникуО переписном листке / Д.. БозинНавстречу новому году / БакановУсилить партийное руководство работой Осоавиахима / ЗыряновНа геолого-разведочном факультете неблагополучно / АсовУспехи наших гимнастов / ЛанкинО трудовой книжке / П. ОдинцевХозяйственные "мелочи", мешающие работе / А. С. НестеренкоБеззаботный комендант / Д. МорозовИтоги вузовского смотра самодеятельности / Н. Аргун

BISOU: a balloon project to measure the CMB spectral distortions

International audienceThe BISOU (Balloon Interferometer for Spectral Observations of the Universe) project aims to study the viability and prospects of a balloon-borne spectrometer, pathfinder of a future space mission dedicated to the measurements of the CMB spectral distortions. We present here a preliminary concept based on previous space mission proposals, together with some sensitivity calculation results for the observation goals, showing that a 5-sigma measurement of the y-distortions is achievable

New horizons in cosmology with spectral distortions of the cosmic microwave background

International audienceThis Voyage 2050 paper highlights the unique science opportunities using spectral distortions of the cosmic microwave background (CMB). CMB spectral distortions probe many processes throughout the history of the Universe, delivering novel information that complements past, present and future efforts with CMB anisotropy and large-scale structure studies. Precision spectroscopy, possible with existing technology, would not only provide key tests for processes expected within the cosmological standard model but also open an enormous discovery space to new physics. This offers unique scientific opportunities for furthering our understanding of inflation, recombination, reionization and structure formation as well as dark matter and particle physics. A dedicated experimental approach could open this new window to the early Universe in the decades to come, allowing us to turn the long-standing upper distortion limits obtained with COBE/FIRAS some 25 years ago into clear detections of the expected standard distortion signals and also challenge our current understanding of the laws of nature