QUIJOTE scientific results - V. The microwave intensity and polarization spectra of the Galactic regions W49, W51 and IC443

We present new intensity and polarization maps obtained with the QUIJOTE experiment towards the Galactic regions W49, W51 and IC443, co v ering the frequenc y range from 10 to 20 GHz at similar to 1 deg angular resolution, with a sensitivity in the range 35-79 mu K beam(-1) for total intensity and 13-23 mu K beam(-1) for polarization. For each region, we combine QUIJOTE maps with ancillary data at frequencies ranging from 0.4 to 3000 GHz, reconstruct the spectral energy distribution and model it with a combination of known foregrounds. We detect anomalous microwave emission (AME) in total intensity towards W49 at 4.7 sigma and W51 at 4.0 sigma with peak frequencies vAME = (20 . 0 +/- 1 . 4) GHz and vAME = (17 . 7 +/- 3 . 6) GHz , respectively; this is the first detection of AME towards W51. The contamination from ultracompact H II regions to the residual AME flux density is estimated at 10 per cent in W49 and 5 per cent in W51, and does not rule out the AME detection. The polarized SEDs reveal a synchrotron contribution with spectral indices alpha s = -0.67 +/- 0.10 in W49 and alpha s = -0.51 +/- 0.07 in W51, ascribed to the diffuse Galactic emission and to the local supernov a remnant, respecti vely. To wards IC443 in total intensity we measure a broken power-law synchrotron spectrum with cut-off frequency v0 , s = (114 +/- 73) GHz , in agreement with previous studies; our analysis, however, rules out any AME contribution which had been previously claimed towards IC443. No evidence of polarized AME emission is detected in this study.

Automated summary

We present new intensity and polarization maps obtained with the QUIJOTE experiment towards the Galactic regions W49, W51 and IC443. We detect anomalous microwave emission (AME) in total intensity towards W49 and W51, and measure a broken power-law synchrotron spectrum towards IC443. The polarized SEDs reveal a synchrotron contribution without evidence of polarized AME emission in this study.