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Hubble
Laboratory
In
this
online
laboratory
you
will
examine
real
spectra
from
various
galaxies.
You
will
determine
the
red
shift
of
certain
spectral
lines
from
the
galaxy
to
calculate
its
recessional
velocity.
The
distance
of
the
galaxy
will
be
found
in
data
linked
to
the
galaxy
in
question.
The
galaxy
spectra
were
obtained
by
Robert
C.
Kennicutt
Jr.
of
the
University
of
Arizona,
and
are
published
in
The
Astrophysical
Journal
Supplement
Series,
volume
79,
pages
255-284,
1992,
and
are
also
available
on
the
WWW.
Thanks.
An
example
of
the
spectra
The
graph
on
the
left
shows
the
absorption
lines
from
the
galaxy
named
NGC1357.
The
two
lines
Ca
K
and
Ca
H
are
the
absorption
lines
measured
in
the
lab.
The
red
arrows
point
to
the
same
lines
that
have
been
detected
from
the
galaxy.
Note
they
have
been
moved
to
the
longer
wavelengths
of
the
spectrum,
ie,
redshifted.
Calculate
the
redshift
for
both
lines
and
find
the
average
redshift
value.
Click
the
television
to
see
an
example
of
how
to
calculate
the
red
shift
and
click
the
galaxy
image
to
go
to
the
lab