Pulsar birthrate set by cosmic-ray positron observations
Istituto di Fisica dell'Università di Urbino, via S. Chiara, Urbino, 06129, Italy
Corresponding author: cgrimani@fis.uniurb.it
Received:
23
September
2002
Accepted:
15
January
2004
The pulsar birthrate (PB) in our galaxy is a parameter known with a
large uncertainty. Different estimates indicate that 1/PB ranges between 30
and 250 years. Assuming
a polar-cap model
for gamma-ray production in gamma-ray pulsars,
positron fraction measurements in cosmic rays above a few GeV make it possible
to set a limit on PB.
Recent measurements of the 
) ratio indicate a PB
of one pulsar born every 
years when the uncertainty on
the secondary positron
calculations is taken into account. A PB compatible with this
result is found even in the case of a relevant production of positrons in the pulsar outer gaps.
Key words: stars: pulsar: general / ISM: cosmic-rays
© ESO, 2004