UGC 2048, CGCG 505-014,
MCG +05-07-013,
PGC 9795[1]
NGC 973 is a giant[3]spiral galaxy located in the constellation
Triangulum. It is located at a distance of circa 200 million
light-years from Earth, which, given its apparent dimensions, means that NGC 973 is about 230,000 light years across. It was discovered by
Lewis Swift on October 30, 1885.[4]
Characteristics
NGC 973 is seen edge-on, with an inclination of nearly 90°.[5] Its
bulge is shaped like a box or peanut. The subtraction of axisymmetric components from the profile of the galaxy showed that its bulge has an X-like morphology, which indicates the presence of a
bar.[6] A prominent dust lane runs across the galaxy.[7]
The galaxy kinematics revealed that the northeast side is the approaching one and the southwest is receding. The disk appears flat, without warps. The total
hydrogen mass of the galaxy is estimated to be about 9×109M☉,[8] and the total
dust mass is estimated to be 1.4×108M☉, with clumpy distribution.[5] Faint emission from gas lying outside the plane of the galaxy was detected in
H-alpha, correlated with the galactic disk and halo.[9]
The nucleus of NGC 973 appears to be
active based on its emission. It is categorised as a type 2
Seyfert galaxy.[10][11] The most accepted theory for the energy source of active galactic nuclei is the presence of an
accretion disk around a
supermassive black hole.
NGC 973 forms a pair with IC 1815, which lies 4.6 arcminutes to the south.[15] A small
satellite was discovered in HI imaging near the northeast edge of the disk of NGC 973, with no optical counterpart.[8]
^
abXilouris, E. M.; Kylafis, N. D.; Papamastorakis, J.; Paleologou, E. V.; Haerendel, G. (1 September 1997). "The distribution of stars and dust in spiral galaxies: the edge-on spiral UGC 2048". Astronomy and Astrophysics. 325: 135–143.
Bibcode:
1997A&A...325..135X.
ISSN0004-6361.
^Guthrie, B. N. G. (1 May 1992). "Axial ratios of edge-on spirals". Astronomy and Astrophysics Supplement Series. 93: 255–270.
Bibcode:
1992A&AS...93..255G.
ISSN0365-0138.