H$\alpha$ Emitting Galaxies in the Deep And Wide Narrow-band Survey

H$\alpha$ is an spectral line of hydrogen that occurs when an electron transitions from its third to its second lowest energy level. H$\alpha$ emission ($\lambda$=6563 \AA) comes mainly from early-type stars, so its presence is the best tracer of recent star formation. Studying the H$\alpha$ luminosity of galaxies permits then the calculation of their star formation rates. The Deep And Wide Narrow-band Survey (DAWN) is an ongoing and uniquely deep survey that stands out for its sensitivity and area coverage. It is being done using a custom-made narrow-band filter, centered at 10660 {\AA} and 35 {\AA} wide. DAWN is an NOAO survey project that uses the 4-meter Mayall telescope at Kitt Peak National Observatory (Arizona) equipped with the NEWFIRM instrument,an infrared camera with a 28x28 arcmin field of view. This filter is suitable for the detection of H$\alpha$ emission at z $\sim$ 0.6, a redshift that corresponds to a time when the Universe was roughly half of its current age. From this survey we have $\sim$120 H$\alpha$ candidates in the COSMOS field with available photometric or spectroscopic redshifts. A fraction of these candidates are fainter than those in other similar surveys, which leads us to extend the H$\alpha$ luminosity function to fainter luminosities.