Barred Spiral Galaxy NGC 3504 & Supernova 2001ac

Barred Spiral Galaxy NGC 3504

A 10 minute exposure with an ST-6 CCD camera thru Kopernik's 20-inch F/8.1 Ritchey Chretien Cassegrain telescope. The field of view is about 5x7 arc minutes, with North at the top.
Time: 3:49 UT, March 19th, 2001.

Supernova 2001ac:

Discovered March 12th, 2001, at Lick Observatory by the LOTOSS group.

This supernova has a strange spectrum and a report in IAU Circular 7597 says "....this may be a super-outburst of a luminous blue variable (star) rather than a true supernova". This object may well be an Eta Carinae type star at peak brightness.

Follow this Link to a NASA Web site on supernovas. It has a very nice animation and a description of what these objects are.

Spiral Galaxy NGC 3504:

(Click Here for a Hubble Space Telescope picture of the Nucleus of NGC 3504)

Quote from Dreyer's New General Catalog (NGC):

"Bright, large, extended, much brighter middle nucleus, partially resolved, westward of 2 (galaxies)."

Quote from the Deep Sky Field Guide to Uranometria 2000:

"Extremely bright nucleus in bright lens 1.4x0.8 arc minutes, with dark lanes."

NGC 3504 is a rather unusual barred spiral galaxy in the constellation Leo Minor. The spiral arms wrap nearly completely around the galaxy forming a faint outer ring. The galaxy's nucleus shows characteristics of both massive star formation and a LINER-type Active Galactic Nucleus. The presence of HII regions along the bar suggests that some gas is still falling toward the nucleus. The galaxy is a member of a small group but shows no obvious sign of interaction. This galaxy and supernova 2001ac are roughly at a distance of 81 million light years. The diameter of NGC 3504 is 63,400 light years.

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George Normandin, KAS

March 24th, 2001