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How much Microwave Emission can we See from Interplanetary Dust?

How much Microwave Emission can we See from Interplanetary Dust?. Valeri Dikarev a t the Cosmic Structure and Evolution Workshop on September, 24, 2009 in Bielefeld. Why was interplanetary dust ignored?. IPD is not on the list of biases for WMAP. Why does IPD’s emissivity drops?.

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How much Microwave Emission can we See from Interplanetary Dust?

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  1. How much Microwave Emission can we See from Interplanetary Dust? ValeriDikarev at the Cosmic Structure and Evolution Workshop on September, 24, 2009 in Bielefeld

  2. Why was interplanetary dust ignored? • IPD is not on the list of biases for WMAP

  3. Why does IPD’s emissivity drops? • Standard emissivity law λ-2 for λ>> size • IPD sizes from 10 to 100 μm • Grün et al. (1985): the interplanetary meteoroid flux model

  4. How do we know dust size distribution? • In the size range above 100 μm: from Earth-bound measurements only!

  5. Is interplanetary dust really ignorable? • ‘Clouds’ are composed of macroscopic particles

  6. A proper estimate of microwave emission should answer two questions • How big should meteoroids be in order to stay hidden in the infrared light and mimic the CMB spectrum in the microwaves? • How many such meteoroids are in the Solar system?

  7. The optical constants • Homogeneous silicate spheres

  8. The optical constants • Homogeneous carbonaceous spheres

  9. The optical constants • Homogeneous iron spheres

  10. The absorption efficiencies • Homogeneous silicate spheres

  11. The absorption efficiencies • Homogeneous carbonaceous spheres

  12. The absorption efficiencies • Homogeneous iron spheres

  13. The excess temperature spectra • Homogeneous silicate spheres, τIR=10-7

  14. The excess temperature spectra • Homogeneous carbonaceous spheres

  15. How many big meteoroids are there? • The radial number density distribution of 135 short-period comets, time-averaged • The cumulative number of meteoroids from SP comets on the line of sight from the Earth in the anti-solar direction • The optical depth of big (>100μm) meteoroids can reach 10-7 and match that of the ‘visible’ dust (from 10 to 100μm in size)

  16. Summary • Thermal emission from dust in the microwaves estimated as ~10 μK • Intriguingly close to anomaly magnitude (~30 μK) • Alarmingly higher than the currently presumed systematic biases of WMAP data (5 μK) • Dust can be a low noise for the CMB studies • CMB (~100 μK) is a huge noise for the dust studies

  17. Results to appear in November’s ApJ

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