A Blast To Chase: VLT Image of SN 2006X in Spiral Galaxy M100 (Forwarded)

ESO Education and Public Relations Dept.

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http://www.eso.org/outreach/press-re.../pr-08-06.html
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For immediate release: 23 February 2006

ESO Press Photo 08/06

A Blast To Chase

VLT Image of SN 2006X in Spiral Galaxy Messier 100

Possibly similar to what our own Milky Way looks like,
Messier 100 [1] is a grand design spiral galaxy that presents
an intricate structure, with a bright core and two prominent
arms, showing numerous young and hot massive stars as well as
extremely hot knots (HII regions). Two smaller arms are also
seen starting from the inner part and reaching towards the
larger spiral arms.

The galaxy, located 60 million light-years away, is slightly
larger than the Milky Way, with a diameter of about 120 000
light-years.

The galaxy was the target of the FORS1 multi-mode instrument
on ESO's Very Large Telescope, following the request of ESO
astronomers Dietrich Baade and Ferdinando Patat, who, with
their colleagues Lifan Wang (Lawrence Berkeley National
Laboratory, US) and Craig Wheeler (University of Texas,
Austin, US), performed detailed observations of the newly
found supernova SN 2006X [2].

SN 2006X was independently discovered early February by
Japanese amateur astronomer Shoji Suzuki and Italian
astronomer Marco Migliardi. Found on 4 February as the 24th
supernova of the year, it had a magnitude 17, meaning it was
1000 times fainter than the galaxy. It was soon established
that this was another example of a Type-Ia supernova [3],
observed before it reached its maximum brightness. The
supernova indeed brightened up by a factor 25 in about two
weeks.

Since SN 2006X became so bright and since it is located inside
the very much studied Messier 100 galaxy, there is no doubt
that a great wealth of information will be collected on this
supernova and, possibly, on the system that exploded. As such,
SN 2006X may prove an important milestone in the study of
Type Ia supernovae. This is particularly important as these
objects are used to measure the expansion of the universe
because they all have about the same intrinsic luminosity.

This is not the first supernova ever found in Messier 100.
Indeed, this is one of the most prolific galaxies as far as
supernovae are concerned. Since 1900, four others have been
discovered in it: SN 1901B, SN 1914A, SN 1959E, and SN 1979C.
Recent observations with ESA's XMM-Newton space observatory
have shown quite surprisingly that SN 1979C is still as bright
in X-ray light as it was 25 years ago. In visible light,
however, SN 1979C has since then faded by a factor 250.
SN 1979C belongs to the class of Type II supernovae and is
the result of the explosion of a star that was 18 times more
massive than our Sun.

High resolution images and their captions are available at
http://www.eso.org/outreach/press-re...hot-08-06.html

Notes

[1]: Messier 100, the 100th entry in Charles Messier catalogue,
was discovered in 1781 by French astronomer Pierre Méchain.
Located in the Coma Berenices (Berenice's Hair) constellation,
slightly north of the celestial equator, it is one of the
brightest members of the Virgo-Coma cluster of galaxies, about
60 million light-years away. Its visual magnitude is about 9,
meaning it is about 15 times fainter than what the unaided eye
can see. Messier 100 is one of the more distant galaxies where
accurate measurements of Cepheid variables have been made, as
can be seen in the ESO/ESA astronomy exercises (see ESO PR
29/01).

[2]: Other Type Ia supernovae studied by Dietrich Baade and
his colleagues can be found in ESO PR Photo 26/05 and ESO PR
23/03.

[3]: Such a supernova is thought to be the result of the
explosion of a small and dense star -- a white dwarf -- inside
a binary system. As its companion was continuously spilling
matter onto the white dwarf, the white dwarf reached a
critical mass, leading to a fatal instability and the
supernova.

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