-------------------------- reply to the referee ----------------------


***

???
     In response to the referee's comments, we have made some 
revisions, especially in the interpretation of the observations.
We also shortened the length of the text for the 4 page
limitation of ApJ Letters.  
???

(Koji, I think since we are resubmitting to ApJL, that it
goes without saying that we think the paper is clear.)

     We reply to the referee's comments below.
***


Major concern 1

     We should first say our proposal of a jet is
very speculative and we do say this in our abstract.
The purpose of the jet is to explain a component of
the polarization of the supernova data for Feburary
that we identify from the data.
This component measured as polarized flux appears
to be a polarized, redshifted reflection of the flux spectrum:
the redshift being that caused by a velocity of order 0.23c.
The identification cannot be certain because there is not
exact agreement between the flux spectrum redshifted and
scaled to the observed polarized flux.
And in fact we would not expect exact agreement.
If a jet or jets are thrown out of a supernova during
the explosion phase, the supernova is likely to exhibit
other asymmetries that contribute to polarization.

    We note that Leonard et al. (2002, astro-ph/0206368)
agrees with us that the flux spectrum redshifted and
appropriately scaled does provide a partial match to
the observed polarized flux spectrum.

    In Section 4.3 ***of the previous version***,
we suggested some jet parameters (i.e.,
0.05 M_sun at of order 0.23c, etc.) that can yield the
right order of polarization component we have identified
and account for its disappearance by our later observations.
The parameters we ***suggested*** are not a unique choice, and
***this point was emphasized also*** in the ???previous version???.
The particular choice we made was partially made
because one of us (Jeffery) had the results in hand from
a calculation that preceded the discovery of SN 2002ap.

    According to the referee and the paper
by Berger et al. (2002, astro-ph/0206183), that reports
the radio observations and modeling of SN 2002ap, our
suggested jet parameters and the radio observations
and modeling are inconsistent.
The referee asks us to address this inconsistency.
We note that we are not experts in radio observations
and modeling ourselves, and so here we will not
challenge the conclusions of Berger et al.

    Consistency can perhaps be achieved by reducing
the speed of the jet model.
The redshift of 0.23c is what our data suggests, but
this can be obtained without having the characteristic
scattering location of the jet moving a 0.23c.
If the jet is not at 90 degrees to the line of sight
but at a smaller angle $\theta$ and behind the supernova, then
there are in effect two redshifts:  one from going into
the jet frame and one from coming out of it in the
somewhat opposite direction:   the redshift of
the scattered polarized flux would then be given by
    \lambda'=\lambda[ 1 + (1+\cos\theta)(v/c) ]
If theta is smallish, then our requirement on (v/c) can
be made smaller: ???
the lower limit of v is  0.23c / 2 = 0.115c***.
Of course, the polarization by Thomson scattering decreases
as \theta is made smaller.
It is left to later work ??? to see ??? if we can get 
the required polarization
with v significantly smaller than 0.23c.
In this regard it would be useful to find out how large a
(v/c) the Berger et al. observations and modeling can tolerate.

     We have decided to drop from the paper all mention of
parameters for the jet, except the essential velocity 0.23c
causing the redshift that we use to explain the polarization
component we have speculatively identified.
Our original set of parameters are inconsistent
with the Berger et al. observations and modeling as noted above.
Proposing another, more consistent set would take more modeling
which is not appropriate for letter of which our jet
speculation is only part.
Also it seems that any set we propose may be taken as
a claim to have established a reliable set no matter what we say
to the contrary.
For example, Berger et al. imply that we made a claim for
reliability for our original set when we explicitly did not.


Major Concern 2

    If there is a jet ??? thrown out of the core of
the exploding supernova, then it is plausible that
it carries some radioactive Ni-56.
The gamma-rays from decay would keep the jet ionized
to some degree just as they later keep the nebular
phase bulk ejecta ionized.
We now mention this possibility briefly.

    We could also say here that the jet is illuminated from
below by the ??? supernova ??? and this may provide some ionization.
X-rays from the circumstellar interaction might also contribute.
However, the modeling of the ionization state of a jet is beyond
the scope of our letter.


Major Concern 3

    We disagree that it is really critical to
present more details of the jet model that we are
thinking terms of.
Since we are dropping the mention of possible parameters,
the details of the model would become rather superfluous.
Our paper is a letter of which the jet hypothesis is
only a part.
Also the basic picture is clear enough.
A fraction of the supernova flux is redshifted, polarized,
and reflected into the line of sight by a jet (or a clump)
that breaks the symmetry of the supernova.
The polarized flux is diluted by the flux from the bulk
of the supernova (which is itself somewhat polarized).
The net polarization level turns out to be smallish:
of order 0.4 % or less in the continuum.
However, even such small polarization requires significant
asymmetry of some sort.
As we remark in the paper, the ellipsoidal ejecta polarization
model would require an axis ratio on the plane of the sky
that differed from 1 by of order 10 %.

    For the referee's interest, the polarization
jet model (Jeffery 2002, in preparation) is a very simple, semi-analytic,
non-relativistic model.  The purpose of the model is to
allow a semi-quantitative understanding of the polarization
a jet would cause including it's time dependence and to
allow a 1st order analyis of the observed data.
The model has a number of free parameters which unfortunately
are hard to set independently.
Because it is a very simple and semi-analytic model, it cannot span
the set of all possible jet models.
The model was in fact invented in 2001 and the paper on
it has not been finished merely because of time constraints
on the author.

Relativistic effects were not included in the model
because they are a complication and because Jeffery does
not believe highly relativistic jets could contribute to
the optical polarization.
The referee is correct that moderate relativistic effects
would make it harder (although not overwhelmingly so)
to obtain simultaneously the redshift and polarization
of the scattered flux that we require from the jet model for
SN 2002ap.
If we do decrease jet velocity below 0.23c, the relativistic
problem is decreased.

(Koji, the lessening of the redshift for a given polarization
would only be second order in beta from a back of the envelope
estimate.  But I don't think I need go on to a detailed explanation
and don't want to until I think it out more carefully.)

Major Concern 4

       The referee has not understood the effect of
redshift in the model.  Say that the bulk of the
supernova ejecta emits a flux F(lambda) toward the
observer.  A fraction f of this flux is redshifted,
scattered and polarized by the jet emitted in the
direction of the observer.
Assuming f is rather small and the non-relativistic
approximation can be made and the bulk supernova
flux is unpolarized, then the polarization
of the net flux at wavelength lambda is

P(lambda) = f P(theta) F( lambda(1+(1+cos\theta)(v/c) )
             / F(lambda)  ,

where theta is the angle of the jet from the line of sight
and P(theta) is the polarization of the scattered flux
(100 % for 90 degree scattering).
The ??? polarized ??? flux at lambda comes from a bluer part of
the spectrum.
If v/c=0, then the polarization would be constant:  such
a jet is not tenable:  the jet must be well outside of
the photosphere for the approximation to be made that
jet and photosphere are point-like.
For v/c of significant size, the polarization
will vary with wavelength because of the variation
of F(lambda) with wavelength.
The variation would be particularly strong about line
profiles.

    We have added a clarifying remark in the text.

(David, I add the equation of the polarization level
due to the scattered, redshifted light spectrum, which
will be helpful for the readers.)

(Koji, I modified the equation (I hope correctly) and its
location in the text.  I agree having the equation makes
the effect clearer than words would do.)


Minor Concern 1


    We do not reference the papers of Cropper et al (1988) and
Barrett et al (1988) because the former does not correct
the data for interstellar polarization (ISP) and the latter uses
an outdated ISP value.
Our references to the SN 1987A polarization data are to
support effects that are only reliably seen after a good
ISP correction.
We use a reference that uses the best ISP correction we
know of for SN 1987A data:  i.e., Jeffery, 1991, ApJS, 77, 405.

    The Wang et al. (1996) reference is an important one
and we *** ??? now ??? include*** it.


Minor Concern 2

    We agree with the referee that it would be interesting
to see if the data from the February and March epochs can
be analyzed on a day by day basis.  However, for a 1st
order analysis in a letter, using February and March averages
seemed reasonable since the day to day changes in those
epochs are not striking.  We do, in fact, present all the day to day
data in Figure 1.   A day by day analysis would be particularly
enhanced if our data were combined with that from other
groups (Leonard et al. 2002, astro-ph/0206368;  Wang et al
2002, astro-ph/0206386).


***
About other revisions

1. We deleted many sentences over the whole text in order to
  shorten the text length within the 4 page limitation of the
  Letter.

2. We shorten the subtitle from
     "Evidence for a high velocity asymmetric explosion of a hypernova"
  to
     "A high velocity asymmetric explosion"
  because some words in the previous subtitle are not appropriate.

3. Additionally we ??? present ??? the observation on June 9, ??? made ???
  two weeks after the submission of this paper. 
  ??? It is ??? presented primarily ???
  for the confirmation of the previously estimated ISP parameters.
  We do not consider it further in our 1st order analysis of
  the SN 2002ap polarimetry.  ???

4. The panels for the averaged values in the Figure 1 (d,e) are
  deleted for the shortening of the text length.
***

??????

     We thank the referee for his/her comments.

(Koji, it doesn't do any harm to thank the referee and I guess
we should be thankful.)

?????????