The Cosmic Microwave Background Spectrum from the Full<i>COBE</i>FIRAS Data Set

Fixsen, D. J.; Cheng, E. S.; Gales, Joel; Mather, John C.; Shafer, R. A.; Wright, E. L.

doi:10.1086/178173

Cited by 1,603 publications

(1,960 citation statements)

References 8 publications

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“…The intensity spectrum of the CMB was precisely measured by COBE/FIRAS over two decades ago (Mather et al 1990;Fixsen et al 1996) and is consistent with a blackbody at temperature T 0 = 2.72548 ± 0.00057 K from ν 3 GHz to 3,000 GHz (Fixsen 2009). This agrees with a variety of other CMB observations including COBRA, TRIS, and ARCADE (Gush et al 1990;Gervasi et al 2008;Kogut et al 2006;Seiffert et al 2011).…”

Section: Introductionsupporting

confidence: 52%

“…1 Our analysis solely considers the spectral energy distribution (SED) of the sky monopole, relying on the spectral behavior of different components in order to separate them. In contrast, we note that the COBE/FIRAS analysis relied on spatial information in order to separate the extragalactic monopole from Galactic foregrounds [and the CMB dipole] (Fixsen et al 1996). An optimal analysis would combine spectral and spatial information, with the latter primarily helping to isolate Galactic foregrounds.…”

Section: Introductionmentioning

confidence: 95%

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Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

146

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Measurements of cosmic microwave background spectral distortions have profound implications for our understanding of physical processes taking place over a vast window in cosmological history. Foreground contamination is unavoidable in such measurements and detailed signal-foreground separation will be necessary to extract cosmological science. In this paper, we present MCMC-based spectral distortion detection forecasts in the presence of Galactic and extragalactic foregrounds for a range of possible experimental configurations, focusing on the Primordial Inflation Explorer (PIXIE) as a fiducial concept. We consider modifications to the baseline PIXIE mission (operating 12 months in distortion mode), searching for optimal configurations using a Fisher approach. Using only spectral information, we forecast an extended PIXIE mission to detect the expected average non-relativistic and relativistic thermal Sunyaev-Zeldovich distortions at high significance (194σ and 11σ, respectively), even in the presence of foregrounds. The ΛCDM Silk damping µ-type distortion is not detected without additional modifications of the instrument or external data. Galactic synchrotron radiation is the most problematic source of contamination in this respect, an issue that could be mitigated by combining PIXIE data with future ground-based observations at low frequencies (ν 15 − 30 GHz). Assuming moderate external information on the synchrotron spectrum, we project an upper limit of |µ| < 3.6 × 10 −7 (95% c.l.), slightly more than one order of magnitude above the fiducial ΛCDM signal from the damping of small-scale primordial fluctuations, but a factor of 250 improvement over the current upper limit from COBE/FIRAS. This limit could be further reduced to |µ| < 9.4 × 10 −8 (95% c.l.) with more optimistic assumptions about extra low-frequency information and would rule out many alternative inflation models as well as provide new constraints on decaying particle scenarios.

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Section: Introductionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 95%

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

146

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“…(21) numerically from z ¼ 10 7 to z ¼ 10 4 , using our previous results for the evolution of the DM and baryon temperatures, and then integrate over the range z ¼ 10 4 -2 × 10 6 to obtain Δ. The Far-Infrared Absolute Spectrophotometer (FIRAS) has excluded Δ ≳ 5 × 10 −5 [57], whereas a future PIXIE-like experiment [58] could have sensitivity to Δ ∼ 10 −8 . The constraint from FIRAS and sensitivity estimate for a next-generation PIXIE-like experiment are shown in Fig.…”

Section: Spectral Distortionmentioning

confidence: 99%

Early-Universe constraints on dark matter-baryon scattering and their implications for a global 21 cm signal

2018

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We present and compare several cosmological constraints on the cross section for elastic scattering between dark matter (DM) and baryons, for cross sections with a range of power-law dependences on the DM-baryon relative velocity v, especially focusing on the case of σ ∝ v −4 . We study constraints spanning a wide range of epochs in cosmological history, from prerecombination distortions to the blackbody spectrum and anisotropies of the cosmic microwave background (CMB), to modifications to the intergalactic medium temperature and the resulting 21 cm signal, and discuss the allowed signals in the latter channels given the constraints from the former. We improve previous constraints on DM-baryon scattering from the CMB anisotropies, demonstrate via principal component analysis that the effect on the CMB can be written as a simple function of DM mass for v −4 scattering, and map out the redshifts dominating this signal. We show that given high-redshift constraints on DM-baryon scattering, a v −4 scaling of the cross section for light DM would be sufficient to explain the deep 21 cm absorption trough recently claimed by the Experiment to Detect the Reionization Step, if 100% of the DM scatters with baryons; we estimate the minimal necessary velocity scaling and find that it is close to v −4 . For millicharged DM models proposed to explain the observation, where only a small fraction of the DM interacts, we estimate that a PIXIE-like future experiment measuring CMB spectral distortion could test the relevant parameter space.

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“…This data set was the first to put constraints on the spectral index and the amplitude of the initial power spectrum (Fixsen et al 1996). Further analyses of the CMB anisotropies should also give hints on the dominant mechanism which generates the initial density perturbation.…”

Section: Introductionmentioning

confidence: 97%

Using the COBE/DMR data as a test-bed for normality assessments

Aghanim¹,

Forni²,

Bouchet³

2001

A&A

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Abstract.A very important property of a statistical distribution is to know whether it obeys Gaussian statistics or not. On the one hand, it is of paramount importance in the context of CMB anisotropy studies, since deviations from a Gaussian distribution could indicate the presence of uncorrected measurement systematics, of remaining fluctuations contributed by foregrounds, of deviations from the simplest models of inflation or of topological defects. On the other hand, looking for a non-Gaussian signal is a very ill-defined task and performances of various assessment methods may differ widely when applied in different contexts. In previous studies, we introduced a sensitive wavelet-based method which we apply here to the COBE/DMR data set, already extensively studied, using different approaches. This provides an objective way to compare methods. It turns out that our multi-scale wavelet decomposition is a sensitive method. Yet, we show that the results are rather sensitive to the choice of both the decomposition scheme and the wavelet basis. We find that the detection of the non-Gaussian signature is "marginal" with a probability of at most 99%.

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The Cosmic Microwave Background Spectrum from the FullCOBEFIRAS Data Set

Cited by 1,603 publications

References 8 publications

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Early-Universe constraints on dark matter-baryon scattering and their implications for a global 21 cm signal

Using the COBE/DMR data as a test-bed for normality assessments

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