Interstellar Absorption Coefficient

[Chalky]

I am trying to work out how the distance modulus given by Riess et al
as

mu(o) = m-M = 5 log LD + 25, on p 28 of astro-ph/0611572v2,

relates to the distance modulus given by Riess as

mu(mag) in http://braeburn.pha.jhu.edu/~ariess/R06./sn_sample.

Presumably they are related by the interstellar absorption
coefficient, but I don't know what that is, or how to calculate the
relationship.

Can anyone help?

C

chalky at bleachboys.co.uk

[Steve Willner]

In article <mt2.0-20552...@hercules.herts.ac.uk>,

Chalky <chalk...@bleachboys.co.uk> writes:
> I am trying to work out how the distance modulus given by Riess et al
> as
> mu(o) = m-M = 5 log LD + 25, on p 28 of astro-ph/0611572v2,
> relates to the distance modulus given by Riess as
> mu(mag) in http://braeburn.pha.jhu.edu/~ariess/R06./sn_sample.
>
> Presumably they are related by the interstellar absorption
> coefficient

You need to add the K-correction (given by Reiss et al. in Table 2)
and subtract the interstellar extinction correction. The authors
don't say where they got the latter -- at least I can't find it in a
quick scan -- but it must be in one of their references. Values for
at least some objects are in Table 6. Typically these would come
from Burstein & Heiles (1982) or Schlegel et al. (1998), but there's
always a chance the authors have done something different. I haven't
actually tested this calculation, so I may be missing something, but
maybe it will get you started.

Tabulated extinction corrections for specific galaxies are
conveniently found from NED: http://nedwww.ipac.caltech.edu/
Just do an "object by name" search, and look at "basic data."
You might want to see whether the Table 6 values agree with what NED
shows.

--
Steve Willner Phone 617-495-7123 swil...@cfa.harvard.edu
Cambridge, MA 02138 USA
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