  In the last few years the Fermi-LAT instrument has detected GeV gamma-ray
emission from several novae. Such GeV emission can be interpreted in terms of
inverse Compton emission from electrons accelerated in the shock or in terms of
emission from hadrons accelerated in the same conditions. The latter might
reach much higher energies and could produce a second component in the
gamma-ray spectrum at TeV energies. We perform follow-up observations of
selected novae and dwarf novae in search of the second component in TeV energy
gamma rays. This can shed light on the acceleration process of leptons and
hadrons in nova explosions. We have performed observations with the MAGIC
telescopes of 3 sources, a symbiotic nova YY Her, a dwarf nova ASASSN-13ax and
a classical nova V339 Del, shortly after their outbursts. We did not detect TeV
gamma-ray emission from any of the objects observed. The TeV upper limits from
MAGIC observations and the GeV detection by Fermi constrain the acceleration
parameters for electrons and hadrons.
