  GRB 090709A is a long gamma-ray burst (GRB) discovered by Swift, featuring a
bright X-ray afterglow as well as a faint infrared transient with very red and
peculiar colors. The burst attracted a large interest because of a possible
quasi-periodicity at P=8.1 s in the prompt emission, suggesting that it could
have a different origin with respect to standard, long GRBs. In order to
understand the nature of this burst, we obtained a target of opportunity
observation with XMM-Newton. X-ray spectroscopy, based on XMM-Newton and Swift
data, allowed us to model the significant excess in photoelectric absorption
with respect to the Galactic value as due to a large column density (about
6.5E+22 cm^-2) in the GRB host, located at z=4.2. Such a picture is also
consistent with the infrared transient's properties. Re-analysis of the prompt
emission, based on INTEGRAL and on Swift data, excludes any significant
modulation at P=8.1 s. Thus, we conclude that GRB 090709A is a distant,
standard, long GRB.
