SPECTRA OF GALACTIC COMPONENTS OBSERVED BY WMAP

R.D.Davies, R.J.Davis Jodrell Bank ObservatoryC.Dickinson California Institute of Technology

A.J.Banday, T.R.Jaffe MPI fur AstrophysikK.M.Gorski Caltech and JPL

Five regions in each of the foregrounds (free-free, synchrotron and anomalous dust) were selected for study which were minimally contaminated by the others. The standard templates (H-alpha, 408 MHz and 100-micron dust) were used in both a T-T and a cross-correlation analysis.

The emissivity of each component in the WMAP frequency range was determined. The implications for determining the correction for CMB foreground emission, both in total power and polarization, are discussed.

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THE POSITIONS OF THE 15 REGIONS CHOSEN FOR STUDY

Fields 1-5 are free-free; fields 6-10 are dust; fields 11-15 are synchrotron.

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NOTES ON THE 15 FIELDS

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FIELD 4 – FREE-FREE DOMINATEDl = 250 to 260 b = -25 to -35

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FIELD 6 – DUST DOMINATEDl = 118 to 135 b = +20 to =37

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FIELD 11 – SYNCHROTRON DOMINATEDl = 33 to 45 b = +50 to +70

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T-T PLOTS FOR FIELD 6 (DUST DOMINATED)The dust correlation for the K, Ka and Q bands

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THE FREE-FREE EMISSION AT K AND Ka BANDSComparison for Te = 8000K

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DUST AND SYNCHROTRON EMISSION IN WMAP BANDS

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CROSS-CORRLATION RESULTS FOR THE THREE FOREGROUNDS

For each foreground the average value is given in each band.There is agreement with the T-T analysis.

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DUST EMISSIVITIES IN 10 INDIVIDUAL CLOUDS

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AVERAGE DUST EMISSIVITY (10 CLOUDS) SPARATED INTO VIBRATIONAL AND ANOMALOUS COMPONENTS

Index of +1.67 is assumed for vibrational component.

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CONCLUSIONS

The spectra of the free-free and synchrotron components were essentially as expected. For free-free the electron temperature is in the range 7000 – 8000K, with a spectral index of -2.13. The synchrotron spectral index at WMAP frequencies is -3.0 to -3.1.

However the anomalous dust emissivity varies by a factor of 2 from cloud to cloud.

The construction of an anomalous dust template for Planck will need to account for this varying emissivity. The predicted polarized emission from dust may be similarly affected.