numerical galaxy morphology classification scheme

Question

For an assignment, I've been told to divide up the galaxies with a Virgo Cluster Catalog number into early and late-type galaxies using the GOLDMine database, http://goldmine.mib.infn.it:8080/

Accessing the data required for analysis is not a problem,

(Search by Parameters -> (Tick VIRGO cluster) QueryGOLDMine -> (Tick Type) Get output)

but I do not understand what the numbers listed for the galaxy type mean.

I originally thought they represented a galaxy's Numerical Hubble stage, but then realized the data contains numbers outside of the Hubble stage. (E.g 20 for VCC0003.)

What morphological classification scheme is the database using?

Answer 1

In the search by parameters screen you'll notice you can set limits on the morphological type. The types are given names, but the limits are input as though they are ordered. A little experimenting confirms the numbers you see reported as "type" correspond to the limits options, in the order of the drop-down menu. That is, we have:

-3: dS0           5: Sb           13: Pec
-2: dE/dS0        6: Sbc          14: S/BCD
-1: dE            7: Sc           15: Sm/BCD
 0: E-E/S0        8: Scd          16: Im/BCD
 1: S0            9: Sd           17: BCD
 2: S0a-S0/Sa    10: Sdm-Sd/Sm    18: S(dS)
 3: Sa           11: Sm           19: dIm/dE
 4: Sab          12: Im           20: ?

No these are not standard numbers, and no it doesn't really make sense to limit queries with these as though they form a strict, well-ordered sequence (perhaps you want S0 and Pec but nothing in between).