From: Ana M. Mourao (amourao@ist.utl.pt)
Date: Tue Feb 22 2005 - 16:37:50 PST
Hi,
please find bellow some comments on the 1999ac paper
Ana (in Lisbon)
_____________________________________________________________________________
pag 8, line 3-5
"This has no impact on the analysis presented, since we restrict focus to line
profiles, which cover wavelength scales smaller than those affected by
reddening."
Question: it is not clear the scales you have in mind: each line/one by one
or the total from the very blue to the very red (and in this case might be
wrong).
pag 11, 3rd paragraph, lines 4-5
" Still, approximate techniques are used to make the process fast and
interactive,
but the results are powerful"
-> the word "but" is probably not the best option.
Change "but" to "and", or just write: "with powerful results"?
pag 11, 3rd paragraph, lines 6-7
Not very easy to read. What if it's changed to:
... In the latter case, the results of direct analysis may help to rule out
or to select among
hydrodynamical models, before extensive simulation calculations are
performed. (...)
pag 11, last paragraph, lines 1-2
"based a simple" change to "based on a simple"
"during the" change to "for the" or "appropriate" change
to "applying"
pag 13, very last phrase, comment on Ni III:
Don't you find even stranger to get Fe III instead of Ni III at day -15?
I understand that, for instance, the composition of the outermost layers of
the SNe 91T was probably dominated by a time dependent mixture of 56Ni, 56Co
and 56Fe.
If this is the case for the 99ac, it is easier to have Ni III, rather than Fe
III at day -15.
Ejecta Geometry
paragraph 2
Discussion on the P-Cygni profile: I find it a bit confusing.
Following your explanation, it is not clear in which referential we are
supposed to be
to understand it:
- in the center of the star
- in the observer's (at the telescope)
- in the expanding layer
What is red shifted for one, can be blue shifted for the other. From the
text
it looks like you start by putting yourself in the center o the star but
after you "jump" to the "telescope" frame. According to the text
it's hard to understand if you consider that in both ref frames light is
blueshifted (and this is wrong, as you know).
Do you assume that material moving PERPENDICULAR to the direction of
observation will scatter light without Doppler effect?
These layers are moving with velocities of 15000 Km/s and the dilation of
time can be detected. I estimate this effect to be small, of order
of 1.25/1000, Probably hard to detect. But for sure these perpendicular, and
scattered in our direction, photons will not contribute to the blue part of
the spectrum.
The very last comment is that, even with the explanation in pag 24,
I am not so convinced that 1999ac deserves a title in a paper with "Unusual".
But that's ok. Too many "Unusual". Probably a note on a very peculiar spectral
feature will help (carbon velocities? as in last year version)
Ana M. Mourao, CENTRA e Dep. de Fisica
IST, Univ. Tecnica de Lisboa
phone: (351) 218417728
fax: (351) 218419118
This archive was generated by hypermail 2.1.4 : Tue Feb 22 2005 - 16:38:00 PST