This paper presents the results of a detailed theoretical investigation
of the impact which internal rotation has on the astroseismic properties
of sdB stars. The evolutionary properties of HB stars are the crossroad
of several theoretical and empirical investigations, but several
long-standing
problems still await a plain physical explanation. In this investigation,
the Authors address the problem of the rotation rates among HB stars and
construct a new evolutionary and pulsation scenario for variable sdB stars.
In particular, they suggest using the rich spectra of these nonradially
pulsating stars to constrain their internal rotation. The physical
assumptions adopted throughout the paper are very convincing and
supply robust predictions on the pulsation frequencies of these objects.

This is an important investigation in order to understand the uncertainties
which are currently affecting evolutionary and pulsational properties of sdB
stars. I recommend that this paper be published in the Astronophysical
Journal, as soon as a few revisions are made. There are a few minor points,
and a main concern, that should be addressed by the authors in the revision
of the manuscript.


I have the following substantial concern about the contents of the paper:

1) Section 1.1, pg. 2:
a) The authors discuss current measurements of rotation rates of field and
cluster HB stars. However, the empirical scenario is even more puzzling.
Rotation rates for RR Lyrae stars (Peterson et al. 1996, ApJ, 465, L47;
Carney et al.  2003, AJ, 125, 293) suggest that these objects show low
rotation velocities (< 10 km/s). This finding supports the evidence
that rotation velocity is low in hot HB stars (T> 11,000 K); it becomes
higher for cooler HB stars (7,500 <= T < 11,000), and finally is once
again lower for RR Lyrae stars (6,000 <= T < 7,500 K). It is interesting
to note that - in this temperature range - the change of the total mass
in cluster HB stars is at most of the order of 0.2-0.25Mo. This might
indicate that the difference in the progenitors mass should not be too
different. I would suggest that the authors discuss this point and comment
whether the mass-loss along the RGB may play any role to explain empirical
facts.

b) Recent spectroscopic surveys and theoretical investigations suggest
that a substantial fraction of field sdB stars might be members of binary
systems (Han et al. 2003, MNRAS, 341, 669).  I would also suggest that
the Authors comment this hypothesis.

c) I agree with the Authors that the classification of field sdB stars is
really a thorny problem. However, I only partially agree with the
classification                          
of these objects as Pop. I stars. There are no doubts that in the Galactic
field                          
a fraction of sdB stars have more massive progenitors. However, the chemical
composition can hardly be adopted, since - during these evolutionary phases -
they experience both gravitational settling and radiative levitation.
Therefore,                          
the present chemical composition might be significantly different from the
composition of their parent population. Moreover, Sweigart and collaborators
(Moehler et al. 2004, A&A, 415, 313; Brown et al. 2000, ApJ, 532, 308)
suggested                          
a new evolutionary scenario to produce sdB stars. The RGB stars affected by
strong mass loss along the RGB experience during the subsequent phases a
Hot-Helium flash (see also Momany et al. 2004, A&A, 420, 605).
I would suggest that the Authors comment this point and mention that their
analysis might require an extension to lower stellar masses.


Two minor points:
1) section 2.1, pg. 6:
I would suggest that the Authors include a Table, which summarizes
the input parameters adopted to construct evolutionary models.
Moreover, I would also suggest that the Authors compare the He-core
masses at the He-flash with similar values available in the literature
(amont the many others Bono et al. 1997, ApJ, 479, 279).

2) section 3, pg. 9:
Theoretical preditions plotted in figures 1 and 2 are very interesting.
I was wondering whether current predictions affects the luminosity of
the RGB-Bump. Several investigations have been devoted to this evolutionary
feature, but current understanding is far from being complete (Riello et al.
2003, A&A, 410, 553; Cassisi et al. 2002, ApJ, 565, 1231). If this is the
case,
the comparison between theory and observations might supply useful
constraints
upon the physical assumptions adopted to mimic the rotation rate both in
convective and in radiative regions. In particular, it would be interesting
to check whether angular momentum conservation affects the shape of the
discontinuity in the chemical profile, left behind by the receding convective
region. Obviously, this is only a suggestion, probably biased by my own
interests.


A few typos:
1) Abstract, 12 lines from top:
The word "momention" should be changed into "momentum".

2) Section 1.2, pg. 4, 2nd paragraph, 2 lines from top:
The word "corse" should be changed into "cores".

3) Section 3.1, pg. 10, 1st line:
The word "remant" should be changed into "remnant".

4) Section 3.1, pg. 10, 6 lines from top:
The acronym "i.e." should be changed into "e.g.".

5) Section 4, pg. 12, 6 lines from top:
The word "stars" is repeated twice.

6) Section 4, pg. 12, 9 lines from top:
The word "mingling" is not clear to me.

7) Section 4.2, pg. 14, 2 lines from top:
The spurious dots should be removed.

8) Section 5, pg. 16, last paragraph, 3 lines from top:
The spurious dots should be removed.

9) Section 5, pg. 17, 4 lines from top:
The word "differental" should be changed into "differential".


Again, this is a good paper and the results will improve our understanding
of the pulsation and evolutionary properties of sdB stars, and in turn to
shed new light upon HB stars and their progeny.