From: Daniel Stern (stern@thisvi.jpl.nasa.gov)
Date: Fri Jan 26 2007 - 12:33:43 PST
i just searched for the word "dust" in alessandro's paper and found the
following relevant paragraph:
"We have also investigated the effect of dust extinction on the best-fit
photometric-stellar masses by including a fourth free parameter, 0.0<
E(B-V)< 0.4, following the Cardelli et al. (1989) prescription. By
performing the fit on 28 galaxies for which IRAC photometry is available
in all 4 bands, we find that in $ {\sim } $$ 40\%$ of the cases E(B-V)=0
gives the best fit. In the remaining cases, masses which are lower by $0.2
\pm 0.1$ dex are found, with corresponding $E(B-V) \le 0.2$. This test
supports the validity of the dust-free model assumption, as also widely
used in the literature for early-type galaxies."
--> so half the time he gets no dust and the other half of the time he
gets E(B-V)<0.2.
On Fri, 26 Jan 2007, Greg Aldering wrote:
>
> Hi Piero,
>
>
> I took a look at thne Rettura et al paper hoping to find
> the fitted E(B-V) values for each galaxy, but apparently
> they are not published. Would you, Peter, Dan or Adam happen
> to have them?
>
> Thanks,
>
> Greg
>
>
> On Fri, 26 Jan 2007, Piero Rosati wrote:
>
> > Hi everyone,
> > fantastic proposal!
> >
> > I have 2 comments, 1 correction and a question for Marc regarding Fig.
> > 3a:
> >
> > 1)
> > Regarding the evidence of no or little dust in ellipticals, we say:
> >
> > "Recent Spitzer data (Temi et al. 2005) confirms that most nearby
> > ellipticals have the SED’s expected for dust-free
> > systems."
> > This was also found in early-types at z~1, and I think it would be
> > worth mentioning it.
> > Rettura et al. 2006 (A&A 458, 717-726) used SED fitting with 10
> > bands, including the 4 IRAC bands, of 30 early-type galaxies at
> > 0.8<z<1.2 in the field (mostly GOODS) and showed evidence of *no or
> > very modest dust extinction*. This is the relevant paragraph in that
> > paper, just to save you the time:
> >
> > We have also investigated the effect of dust extinction on the best-
> > fit photometric-stellar masses by including a fourth free parameter,
> > 0.0 < E( B − V ) < 0.4, following the Cardelli et al. (1989)
> > prescription. By performing the fit on 28 galaxies for which IRAC
> > photometry is available in all 4 bands, we find that in ∼40% of the
> > cases E( B − V ) 0 gives the best fit. In the remaining cases,
> > masses which are lower by 0.2 ± 0.1 dex are found, with corresponding
> > E( B − V ) ≤ 0.2. This test supports the validity of the dust-free
> > model assumption, as also widely used in the literature for early-
> > type galaxies.
> >
> >
> > 2)
> > Mass-richness relation plot. It's nice, and the scatter/outliers not
> > surprising given the nature of any richness parameter. We don't want
> > to give the impression though this will be the kind of plots which
> > will provide the "mass calibration" of future Xray/SZ surveys. Best
> > mass indicators are currently physical quantities extracted from X-
> > ray and SZ observations: T, Mgas, Lx,Y, Yx (the so called Yx=Tx*Mgas
> > being the most fashionable these days). I doubt that anyone will use
> > n_gal in the era of precision cosmology. This is mentioned at the end
> > of the Cluster Science section (pag.6) but it should rather be here.
> > So I think we should add in this section something like:
> >
> > Chandra and XMM observations of these clusters already in hand and
> > upcoming SZ observations will allow us to probe for the first time at
> > 1<z<1.5 the relation between fiducial lensing masses and physical
> > parameters derived form X-ray and SZ measurements (Lx, Tx, Mgas, Y).
> > These relations provide the critical calibrations for precision
> > cosmology with next generation cluster surveys.
> >
> >
> > -Correction:
> > Pag.6: The GTO program has *four* clusters at z>1
> >
> > -Question for Marc: the caption of Fig.3a (VLT based CMR) reads
> > "CMR in this same cluster using data from the VLT FORS and ISAAC
> > (transformed to the ACS i,z passbands)"
> > FORS has already i&z bands, how did you use ISAAC (J&K bands) to
> > "transform" to ACS i&z ??
> >
> >
> > Piero
> >
> > On Jan 25, 2007, at 11:32 AM, Tony Spadafora wrote:
> >
> > > Cluster search group,
> > >
> > > The working draft of the cycle 16 proposal on
> > > http://supernova.lbl.gov/HSTclusterSN/proposals/HSTc16/clusters/text/
> > > (HSTclusterSN/HSTclusterSN)
> > >
> > > has Wednesday's reworking of various sections. Comments are
> > > welcome. There are still embedded internal questions and ?'s in
> > > various places. Sci Just will need to be cut a little (~11 lines).
> > > Some of the figures need work. All of the captions and references
> > > will need to be checked.
> > >
> > > -Tony
> > >
> >
> >
>
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