Willman 1

RA:

10 : 49.4

Dec:

+ 51 : 03

Type:

dSph ? Globular Cluster ?

RV:

Distance:

147 kly

Apparent Dimension:

1.75 arc min

Diameter:

Brightness:

15.3 mag vis

Abs. Mag:

Mass:

This dwarf galaxy was discovered in 2004 as an overdensity of red, resolved stars in the Sloan Digital Sky Survey, by a team of astronomers led by Beth Willman (Willman et.al. 2005). At the time of its discovery, it was the intrinsically faintest and lowest surface brightness dwarf galaxy known, more than five times less luminous than the faintest previously known dSph dwarfs, i.e. And IX, the Draco Dwarf and the Ursae Minor Dwarf. This has given rise to speculations if this was a new sort of objects between dwarf galaxies and globular clusters, or a new candidate for "Cold Dark Matter" in the universe (e.g. Kleyna et.al. 2005).

.. more to come soon ..

References

• Jan T. Kleyna, Mark I. Wilkinson, N. Wye Evans, and Gerard Gilmore, 2005. Ursa Major: A Missing Low-Mass CDM Halo? Astrophysical Journal, Vol. 630, Issue 2, pp. L141-L144 (September 2005) [ADS: 2005ApJ...630L.141K] - [Preprint: astro-ph/0507154]
• Beth Willman, Julianne J. Dalcanton, David Martinez-Delgado, Andrew A. West, Michael B. Blanton, David W. Hogg, J.C. Barentine, Howard J. Brewington, Michael Harvaner, S.J. Kleinman, Jurek Krzesinski, Dan Long, Eric H. Nelson, Jr., Atsuko Nitta, and Stefanie A. Snedden, 2005. A New Milky Way Dwarf Galaxy in Ursa Major. Astrophysical Journal, Vol. 626, Issue. 2, pp. L85-L86 (June 2005) [ADS: 2005ApJ...626L..85W] - [Preprint: astro-ph/0503552]

Last Modification: February 14, 2005