Celestial Atlas
PGC 28000 - 28499 ←     PGC Objects: PGC 28500 - 28999 Link for sharing this page on Facebook     → PGC 29000 - 29499
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Page last updated July 27, 2015

PGC 28630 (=
NGC 3031 = M81)
A magnitude 6.9 spiral galaxy (type SA(s)ab?) in Ursa Major (RA 09 55 33.2, Dec +69 03 55)
For anything else see NGC 3031

PGC 28636 (=
NGC 3027)
A magnitude 11.8 spiral galaxy (type SB(s)bc? pec?) in Ursa Major (RA 09 55 40.6, Dec +72 12 13)
For anything else see NGC 3027

PGC 28757 (= Holmberg IX, a companion of
M81)
A magnitude 14.3 irregular galaxy (type Im?) in Ursa Major (RA 09 57 32.0, Dec +69 02 46)
Physical Information: The recessional velocity of PGC 28757 is only 45 km/sec, far too small in comparison to peculiar (non-Hubble expansion) velocities to be of any use in determining its distance. Redshift-independent distance estimates range from 8.5 to 32.5 million light years, with the most commonly accepted value being 11 to 12 million light years, as it is believed to be a satellite of approximately 12 million light year distant NGC 3031 (= M81). Given that and its apparent size of ? arcmin, the galaxy is about ? thousand light years across. It is believed that most of the stars in the dwarf galaxy (and the galaxy itself) were created as a result of a close encounter between M81, M82 and NGC 3077 between 200 and 300 million years ago. That interaction tore some one of the older stars from one or more of the galaxies and triggered a wave of intense star formation that resulted in most of the stars now visible in PGC 28757, and is still continuing in the region between it and M81 at a slower rate, as evidenced by a "bluish fuzz" in the region near the two galaxies, which consists of newly formed stars, but too few of them to be easily imaged.
SDSS image of region near PGC 28757, also showing part of NGC 3031 (also known as M81)
Above, a 12 arcmin wide SDSS image centered on PGC 28757, also showing part of M81
Below, a 4 arcmin wide image of the galaxy (Image Credit NASA, ESA, Hubble Heritage Team (STScI/AURA) Acknowledgment: D. de Mello (Catholic University of America and GSFC), superimposed on a DSS image to fill in missing areas)
HST image of irregular galaxy PGC 28757

PGC 28960 (=
NGC 3100 = NGC 3103)
A magnitude 11.1 lenticular galaxy (type SAB0(s)a? pec) in Antlia (RA 10 00 40.8, Dec -31 39 52)
For anything else see NGC 3100
Celestial Atlas
PGC 28000 - 28499 ←     PGC Objects: PGC 28500 - 28999     → PGC 29000 - 29499