T0: UCDs for "em"

From: Miguel Cerviño <mcs-at-iaa.es>
Date: Mon, 6 Jun 2005 19:22:29 +0200

Dear all,

I just revised the "em" UDCs and I post here some suggestions. I had just rewriten the whole "Q" list and added some entries, taken from
the 27-Feb 2005 Working Draft on IVOA SED Data Model (marked with *).

For clarity I has put together "Q" UCDs and "S" UCDs, the latter writen in increasing energy order.

First I center in "Q" UCDs, and I propose to keep:

Q|em.energy        |Energy value in the em frame
Q|em.freq         |Frequency value in the em frame
Q|em.wavenumber        |Wavenumber value in the em frame
Q|em.wl         |Wavelength value in the em frame

• Include:

Q|em.wl.air* |Wavelength value in the em frame in air frame

      somewhere it should be established default is vacuum?
      In most optical observation default is air and
      in UV vacuum as example, but SLOAN data release
      gives optical wl en vacuum...

• Other suggestions in IVOA SED DM WD:

Q|em.veloc*        |Apparent radial velocity
Q|em.veloc.radio*    |radio velocity
Q|em.veloc.optical*    |optical velocity
Q|em.veloc.beta*        |velocity/cr

• Changue from Q to E?

Q|em.wl.central     |Central wavelength
Q|em.wl.effective     |Effective wavelength

   I think that this UDCs does not corresponds to the EM but more    important for photometric characterizations. I do not know

About the characterization of the em spectrum by their energy ranges as proposed at:

http://www.ivoa.net/internal/IVOA/IvoaUCD/NoteEMSpectrum-20040520.html

I completely agree :) however, for clarity purpose and hogenity the UDCs I would suggest the following changues:

em.IR.K -->  em.IR.2-3um
em.IR.H -->  em.IR1500-2000nm
em.IR.J -->  em.IR1000-1500nm

em.opt.I -->  em.opt.750-1000nm
em.opt.R -->  em.opt.600-750nm
em.opt.V -->  em.opt.500-600nm

em.opt.B --> em.opt.400-500nm
em.opt.U --> em.opt.300-400nm

so there no will be confusion with fotometry bands (and machines always will found

      em.string.(number - number unit)
that, I do not know, but may be is more easier)

Analogously, for high energy:

em.X-ray.soft --> em.X.120-2000eV
em.X-ray.medium --> em.X.2-12keV
em.X-ray.hard --> em.X.12-120keV

em.gamma.soft --> em.gamma.120-500keV
em.gamma.hard --> em.gamma.500-1000keV

                   em.gamma.1-20MeV
                   em.VHgamma  (Very-high gamma: 20Mev-10GeV)
                   em.VHgamma.20-100MeV
                   em.VHgamma.100-1000MeV
                   em.VHgamma.1-10GeV
                   em.UHgamma  (Ultra high gamma rays, cosmic ray- 
domain)
                   em.UHgama.10-30GeV
                   em.UHgama.30+GeV

Here, the definitions for gamma-ray is a bit lossy, and I have not found a clear consensus between very-high and ultra-high gamma in the literature.... :(

Finally, I think that the inclusion of em.line would be useful, but only for a very sort list of lines (like there is irregular verbs in any language that, by the way, corresponds to the most commonly used verbs)
so (with a strong background of visual astronomy) I would agree with Hydrogen lines, but I do think that em.line.OIII should be depreciated (there is several OIII lines!, and if OIII is here, by not, O I, or
H+K Ca II etc...? so I propose depreciate em.line.OIII ...

so the list would be:

S    |em.line.HI     |21cm hydrogen line
S    |em.line.Brgamma     |Bracket gamma line
S    |em.line.Halpha     |H-alpha line
S    |em.line.Hbeta     |H-beta line
S    |em.line.Hgamma     |H-gamma line

Depreciated:

S |em.line.OIII |[OIII] line

Cheers

     Miguel Received on 2005-06-06Z19:22:30