Detection of new point sources in WMAP 7 year data using internal templates and needlets

TL;DR

This paper introduces a novel needlet-based method for detecting point sources in WMAP 7-year CMB data, successfully identifying over a thousand sources, including many new detections, by leveraging internal templates to eliminate the CMB component.

Contribution

The paper presents a new needlet-based approach utilizing internal templates for improved point source detection in CMB maps, effectively reducing CMB contamination and increasing detection sensitivity.

Findings

Detected 2102 point sources at 5σ significance.

Identified 603 new sources not previously reported in WMAP data.

Matched most sources with known 5GHz counterparts.

Abstract

We have developed a new needlet based method to detect point sources in cosmic microwave background (CMB) maps and have applied it to the WMAP 7 year data. We use both the individual frequency channels as well as internal templates, the difference between pairs of frequency channels, with the advantage that the CMB component is eliminated. Using the area of the sky outside the Kq85 galactic mask, we detect a total of 2102 point sources at the $5\sigma$ level in either the frequency maps or the internal templates. Of these, 1116 are detected either at $5\sigma$ directly in the frequency channels or at $5\sigma$ in the internal templates and $\geq3\sigma$ at the corresponding position in the frequency channels. Of the 1116 sources, 603 are detections which have not been reported so far in WMAP data. We have made a catalogue of these sources available with position and flux estimated in the WMAP channels where they are seen. In total, we identified 1029 of the 1116 sources with counterparts at 5GHz and 69 at other frequencies.