A detailed spectral study of GRB 041219A and its host galaxy
  GRB 041219A is one of the longest and brightest gamma-ray bursts (GRBs) ever
observed. It was discovered by the INTEGRAL satellite, and thanks to a
precursor happening about 300 s before the bulk of the burst, ground based
telescopes were able to catch the rarely-observed prompt emission in the
optical and in the near infrared bands. Here we present the detailed analysis
of its prompt gamma-ray emission, as observed with IBIS on board INTEGRAL, and
of the available X-ray afterglow data collected by XRT on board Swift. We then
present the late-time multi-band near infrared imaging data, collected at the
TNG, and the CFHT, that allowed us to identify the host galaxy of the GRB as an
under-luminous, irregular galaxy of about 5x10^9 M_Sun at best fit redshift of
z=0.31 -0.26 +0.54. We model the broad-band prompt optical to gamma-ray
emission of GRB 041219A within the internal shock model. We were able to
reproduce the spectra and light curve invoking the synchrotron emission of
relativistic electrons accelerated by a series of propagating shock waves
inside a relativistic outflow. On the other hand, it is less easy to
simultaneously reproduce the temporal and spectral properties of the infrared
data.
