NGC1365

VLT Photos of NGC 1365

Fine Details in a Barred Galaxy

NGC 1365 is one of the most prominent "barred" galaxies in the sky. It
is a supergiant galaxy with a diameter of about 200,000 lightyears,
seen in the direction of the southern constellation Fornax (The
Furnace). It is a major member of the Fornax Cluster of Galaxies. The
distance is about 60 million light-years and the recession velocity
has been measured as 1632 km/sec.

A massive straight bar runs through this galaxy and contains the
nucleus at the centre. It consists mostly of older stars that give a
reddish colour to the bar.

The gravitational perturbation from the bar causes interstellar gas
and dust clouds to form a pair of spiral arms that extend from the
ends of the bar. Young luminous hot stars, born out of the
interstellar clouds, give these arms a prominent appearance and a blue
colour.

The bar and spiral pattern rotates clockwise, as seen from us. One
full turn takes about 350 million years.

Various images of NGC 1365 have recently been obtained with the three
instruments, FORS1, the Test Camera (TC), and ISAAC, now installed at
the VLT UT1. They show the intricate structure of this magnificent
galaxy, also in the innermost region, close to the centre. Some of
these images are included here.

PR Photo 08a/99 is a true-colour image of the major part of NGC 1365,
 combined from three exposures with the FORS1 multi-mode instrument at
 VLT UT1, in the B (blue), V (green) and R (red) optical bands. The
 exposure times were 360, 180 and 140 seconds, respectively. The image
 quality is about 0.8 arcsec. The field measures about 7 x 7
 arcmin2. North is up and East is left.