On December 9-10, 2004, the ESO Paranal Observatory was honoured with
an overnight visit by His Excellency the President of the Republic of
Chile, Ricardo Lagos and his wife, Mrs. Luisa Duran de Lagos. The high
guests were welcomed by the ESO Director General, Dr. Catherine
Cesarsky, ESO’s representative in Chile, Mr. Daniel Hofstadt, and
Prof. Maria Teresa Ruiz, Head of the Astronomy Department at the
Universidad de Chile, as well as numerous ESO staff members working at
the VLT site. The visit was characterised as private, and the
President spent a considerable time in pleasant company with the
Paranal staff, talking with and getting explanations from everybody.

The distinguished visitors were shown the various high-tech
installations at the observatory, including the Interferometric Tunnel
with the VLTI delay lines and the first Auxiliary Telescope.
Explanations were given by ESO astronomers and engineers and the
President, a keen amateur astronomer, gained a good impression of the
wide range of exciting research programmes that are carried out with
the VLT. President Lagos showed a deep interest and impressed everyone
present with many, highly relevant questions.

Having enjoyed the spectacular sunset over the Pacific Ocean from the
Residence terrace, the President met informally with the Paranal
employees who had gathered for this unique occasion. Later, President
Lagos visited the VLT Control Room from where the four 8.2-m Unit
Telescopes and the VLT Interferometer (VLTI) are operated. Here, the
President took part in an observing sequence of the spiral galaxy NGC
1097 (see PR Photo 35d/04) from the console of the MELIPAL telescope.

After one more visit to the telescope platform at the top of Paranal,
the President and his wife left the Observatory in the morning of
December 10, 2004, flying back to Santiago.

VLT obtains a splendid photo of a unique galaxy, NGC 1097

A unique and very beautiful image was obtained with the VIMOS
instrument with President Lagos at the control desk.

Located at a distance of about 45 million light-years in the southern
constellation Fornax (the Furnace), NGC 1097 is a relatively bright,
barred spiral galaxy of type SBb, seen face-on. At magnitude 9.5, and
thus just 25 times fainter than the faintest object that can be seen
with the unaided eye, it appears in small telescopes as a bright,
circular disc.

ESO PR Photo 35d/04, taken on the night of December 9 to 10, 2004 with
the VIsible Multi-Object Spectrograph (VIMOS), a four-channel
multiobject spectrograph and imager attached to the 8.2-m VLT Melipal
telescope, shows that the real structure is much more complicated. NGC
1097 is indeed a most interesting object in many respects.

As this striking image reveals, NGC 1097 presents a centre that
consists of a broken ring of bright knots surrounding the galaxy’s
nucleus. The sizes of these knots – presumably gigantic bubbles of
hydrogen atoms having lost one electron (HII regions) through the
intense radiation from luminous massive stars – range from roughly 750
to 2000 light-years. The presence of these knots suggests that an
energetic burst of star formation has recently occurred.

NGC 1097 is also known as an example of the so-called LINER
(Low-Ionization Nuclear Emission Region Galaxies) class. Objects of
this type are believed to be low-luminosity examples of Active
Galactic Nuclei (AGN), whose emission is thought to arise from matter
(gas and stars) falling into oblivion in a central black hole.

There is indeed much evidence that a supermassive black hole is
located at the very centre of NGC 1097, with a mass of several tens of
million times the mass of the Sun. This is at least ten times more
massive than the central black hole in our own Milky Way.

However, NGC 1097 possesses a comparatively faint nucleus only, and
the black hole in its centre must be on a very strict “diet”: only a
small amount of gas and stars is apparently being swallowed by the
black hole at any given moment.

A turbulent past

As can be clearly seen in the upper part of PR Photo 35d/04, NGC 1097
also has a small galaxy companion; it is designated NGC 1097A and is
located about 42,000 light-years away from the centre of NGC
1097. This peculiar elliptical galaxy is 25 times fainter than its big
brother and has a “box-like” shape, not unlike NGC 6771, the smallest
of the three galaxies that make up the famous Devil’s Mask, cf. ESO PR
Photo 12/04.

There is evidence that NGC 1097 and NGC 1097A have been interacting in
the recent past.

Another piece of evidence for this galaxy’s tumultuous past is the
presence of four jets – not visible on this image – discovered in the
1970’s on photographic plates. These jets are now believed to be the
captured remains of a disrupted dwarf galaxy that passed through the
inner part of the disc of NGC 1097.

Moreover, another interesting feature of this active galaxy is the
fact that no less than two supernovae were detected inside it within a
time span of only four years. SN 1999eu was discovered by Japanese
amateur Masakatsu Aoki (Toyama, Japan) on November 5, 1999. This
17th-magnitude supernova was a peculiar Type II supernova, the end
result of the core collapse of a very massive star. And in the night
of January 5 to 6, 2003, Reverend Robert Evans (Australia) discovered
another Type II supernova of 15th magnitude.

Also visible in this very nice image which was taken during very good
sky conditions – the seeing was well below 1 arcsec – are a multitude
of background galaxies of different colours and shapes. Given the fact
that the total exposure time for this three-colour image was just 11
min, it is a remarkable feat, demonstrating once again the very high
efficiency of the VLT.