Removing point sources from CMB maps

For high-precision cosmic microwave background (CMB) experiments, contamination from extragalactic point sources is a major concern. It is therefore useful to be able to detect and discard point source contaminated pixels using the map itself. We show that the sensitivity with which this can be done can often be greatly improved (by factors between 2.5 and 18 for the upcoming Planck mission) by a customized hi-pass filtering that suppresses fluctuations due to CMB and diffuse galactic foregrounds. This means that point source contamination will not severely degrade the cleanest Planck channels unless current source count estimates are off by more than an order of magnitude. A catalog of around 40,000 far infra-red sources at 857 GHz may be a useful by-product of Planck.Comment: 4 pages, with 2 figures included. Minor revisions to match accepted version. Color figure and links at http://www.sns.ias.edu/~max/cleaning.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/cleaning.html (faster from Europe) or from [email protected], and Angelica's foreground links at http://www.sns.ias.edu/~angelica/foreground.htm

Galactic emission at 19 GHz

We cross-correlate a 19 GHz full sky Cosmic Microwave Background (CMB) survey with other maps to quantify the foreground contribution. Correlations are detected with the Diffuse Infrared Background Experiment (DIRBE) 240, 140 and 100 micron maps at high latitudes (|b|>30degrees), and marginal correlations are detected with the Haslam 408 MHz and the Reich & Reich 1420 MHz synchrotron maps. The former agree well with extrapolations from higher frequencies probed by the COBE DMR and Saskatoon experiments and are consistent with both free-free and rotating dust grain emission.Comment: 4 pages, with 4 figures included. Accepted for publication in ApJL. Color figure and links at http://www.sns.ias.edu/~angelica/foreground.html#19 or from [email protected]

ENTRE O PASSADO E O PRESENTE: CORPOS QUE DIVERGEM

ENTRE O PASSADO E O PRESENTE: CORPOS QUE DIVERGE

ENTRE O PASSADO E O PRESENTE: CORPOS QUE DIVERGEM

ENTRE O PASSADO E O PRESENTE: CORPOS QUE DIVERGE

The Large-Scale Polarization of the Microwave Foreground

Most of the useful information about inflationary gravitational waves and reionization is on large angular scales where Galactic foreground contamination is the worst, so a key challenge is to model, quantify and remove polarized foregrounds. We use the Leiden radio surveys to quantify the polarized synchrotron radiation at large angular scales, which is likely to be the most challenging polarized contaminant for the WMAP satellite. We find that the synchrotron E- and B-contributions are equal to within 10% from 408-820MHz with a hint of E-domination at higher frequencies. We quantify Faraday Rotation & Depolarization effects and show that they cause the synchrotron polarization percentage to drop both towards lower frequencies and towards lower multipoles.Comment: To be published in the proceedings of "The Cosmic Microwave Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and K.A. Olive). 4 pages. More foreground information at http://www.hep.upenn.edu/~angelica/foreground.html#polar or from [email protected]