Introduction to general relativity this energy loss would be too small to be detectable, but this energy loss was observed in 1974 in a binary pulsar called PSR1913+16. In such a system, one of the orbiting stars is a pulsar. This has two consequences: a pulsar is an extremely dense object known as a neutron star, for which gravitational wave emission is much stronger than for ordinary stars. Also, a pulsar emits a narrow beam of electromagnetic radiation from its magnetic poles. As the pulsar rotates, its beam sweeps over the Earth, where it is seen as a regular series of radio pulses, just
POlarization Emission of Millimeter Activity at the Sun of observing at 45 and 90 GHz comes from the necessity to determine the "upturn" frequency in the so-called "THz events": if the main radiation mechanism is synchrotron radiation from accelerated electrons emitting at chromospheric or coronal heights, it is expected a spectrum with a long and descending logarithmic tail towards millimeter wavelengths. In some cases this classical ("textbook") shape is broken and an "upturn" or "spectral reversion" is observed. Since the reversion or "upturn" frequency has been estimated around 50 to 100 GHz for the observed cases, the importance of POEMAS is justified. POlarization Emission of Millimeter Activity at