Spiral
Galaxy NGC 300
NGC
1232 is located 20º south of the celestial equator, in the constellation
Eridanus (The River). The distance is about 100 million light-years, but the
excellent optical quality of the VLT and FORS allows us to see an incredible
wealth of details. At the indicated distance, the edge of the field shown
corresponds to about 200,000 light-years, or about twice the size of the Milky
Way galaxy.
The
image is a composite of three images taken behind three different filters: U
(360 nm; 10 min), B (420 nm; 6 min) and R (600 nm; 2:30 min) during a period of
0.7 arcsec seeing. The field shown measures 6.8 x 6.8 arcmin. North is up; East
is to the left.
Antennae Galaxies composite
The
Hubble image is the sharpest view of this object ever taken and serves as the
ultimate benchmark in terms of resolution. ALMA observes at much longer
wavelengths which makes it much harder to obtain comparably sharp images.
However, when the full ALMA array is completed its vision will be up to ten
times sharper than Hubble.
Most
of the ALMA test observations used to create this image were made using only
twelve antennas working together — far fewer than will be used for the first
science observations — and much closer together as well. Both
of these factors make the new image just a taster of what is to come. As the
observatory grows, the sharpness, speed, and quality of its observations will
increase dramatically as more antennas become available and the array grows in
size. This is nevertheless the best submillimetre-wavelength image ever taken
of the Antennae Galaxies and opens a new window on the submillimetre Universe.
While
visible light — shown here mainly in blue — reveals the newborn stars in the
galaxies, ALMA’s view shows us something that cannot be seen at those
wavelengths: the clouds of dense cold gas from which new stars form. The ALMA
observations — shown here in red, pink and yellow — were made at specific
wavelengths of millimetre and submillimetre light (ALMA bands 3 and 7), tuned
to detect carbon monoxide molecules in the otherwise invisible hydrogen clouds,
where new stars are forming.
Massive
concentrations of gas are found not only in the hearts of the two galaxies but
also in the chaotic region where they are colliding. Here, the total amount of
gas is billions of times the mass of the Sun — a rich reservoir of material for
future generations of stars. Observations like these will be vital in helping
us understand how galaxy collisions can trigger the birth of new stars. This is
just one example of how ALMA reveals parts of the Universe that cannot be seen
with visible-light and infrared telescopes.
Spiral Galaxy NGC 4565
Because
it is relatively close (it is only 12 times farther away than Messier 31, the
Andromeda galaxy, which is the major galaxy closest to us) and relatively large
(roughly one third larger than the Milky Way), it does not fit entirely into
the field of view of the FORS instrument (about 7 x 7 arcmin2).
Many
background galaxies are also visible in this FORS image, giving full meaning to
their nickname of "island universes"
Spiral galaxy NGC 1232
NGC
1232 is located 20º south of the celestial equator, in the constellation
Eridanus (The River). The distance is about 100 million light-years, but the
excellent optical quality of the VLT and FORS allows us to see an incredible wealth
of details. At the indicated distance, the edge of the field shown corresponds
to about 200,000 light-years, or about twice the size of the Milky Way galaxy.
The
image is a composite of three images taken behind three different filters: U
(360 nm; 10 min), B (420 nm; 6 min) and R (600 nm; 2:30 min) during a period of
0.7 arcsec seeing. The field shown measures 6.8 x 6.8 arcmin. North is up; East
is to the left.
The Spiral Galaxy NGC 5584 and SN 2007af
Sumber : ESO
0 komentar:
Posting Komentar