Hi Chia Min,
Thanks for sending the draft around. There's some nice work in the paper.
Below are comments up to section 4. I'll try to get my comments on the
rest of the paper by the end of the week.
Regards,
Cees
Title:
* The title is perhaps a bit long. Since the title of Daniele's paper
was: "LOTAAS: Characterization of 20 pulsars", you could use
"LOTAAS: Timing of 21 pulsars", though I agree that having the
binary MSP in the title is a plus.
SECTION 1:
* I think the introduction needs a bit more work. Right now, the
information motivating this paper (pulsar properties from timing,
spectral indices from multi-frequency follow-up, pulse profile
evolution) is available, but it is not in a logical order. My
suggestion would be that you start with a general overview of pulsar
science, which has sofar been predominantly done at higher
frequencies and the importance of observing at lower
frequencies. You can then provide some information of low-frequency
studies of known pulsars (Pilia profiles, LOFAR Census, MSP Census,
Sobey RM study). This naturally leads into LOTAAS as the first real
low frequency pulsar search, and that this paper presents some of
the first timing and multi-frequency results of pulsars discovered
at these low frequencies.
SECTION 2:
* In the first paragraph it would be good to compare the setup of the
timing observations to that of the search observations in terms of
number of stations, bandwidth and integration time.
* Mention psrchive (with Hotan ref) after dspsr.
* Did you not use any ROACH data from Jodrell? Certainly for the
334MHz observations the coherent dedispersion will be important.
* I would also restructure section 2 somewhat, as right now the
information is spread about. Perhaps a subsection for timing
observations, timing of the binary, and follow up observations for
profile evolution and spectral properties. Another approach would be
to split it in LOFAR core, Jodrell and GLOW observations.
* The paragraphs about J1658 are also confusing, and I think all this
information can be distilled into a table. You also need to clarify
the timing procedure a bit, in that we start off with binary
parameters determined from variations in the spin period (an
incoherent timing solution), to a coherent timing solution where you
account for all rotations of the pulsar. You might also clarify the
'accounting for all rotations' at the start of section 2 when
discussing the timing of normal pulsars.
* Table 1: miutes -> minutes
* Table 1: Somewhere in the paper we need to provide the JXXXX+YY
names from the LOTAAS overview paper to these timing names. This
naturally fits in table 1.
SECTION 3:
* For determining the template, you need to specify to which profile
you fitted the von Mises profiles. Was it the single observation
with the highest S/N or some average of profiles?
* Add how many von Mises functions you had to use (just give the
minimum and maximum).
* "are split into 2 frequency channels" -> "are averaged into two
frequency channels".
* I'm a bit worried by only using two frequency channels to measure
DM, as you are using two measurements to obtain two parameters (TOA
and DM).
* How were the templates at different frequencies referenced to
absolute phase? If scattering or intrinsic profile evolution is
present then you could impart a DM offset by this approach.
* You need to clarify what is meant by a jump. That is not
nomenclature that non-pulsar astronomers know. Also change "Any
offsets" to "Any time offsets", and perhaps specify what causes
these (cable length differences etc).
* In paragraph 2 "In order to...", you may want to make it clear that
the dense campaigns were meant to remove ambiguities in the number
of pulse rotations between consecutive observations, and that
getting phase connection on short timescales allowed extrapolating
the timing solution to longer timescales without introducting
ambiguities.
* I mentioned this for section 2 as well, but for the timing solution
of J1658; explain that you got initial orbital parameters by
modelling the spin period variations, and used those to obtain a
phase coherent timing solution.
* I am not sure a reference exists for FITORBIT, in which case you may
have to explain in a bit more detail what the software does.
* "... is a low S/N pulsar" is an incorrect statement. low S/N is a
property of the telescope, not really the pulsar. Maybe rewrite to
"In the initial timing observations of PSR J1643+1338 it was
detected at low S/N."
* Section 3 is mixing observations and their analysis with
results. This may be a large change, but I think the first 4
paragraphs could be joined with section 2 to make a "Observations
and timing analysis" section. This resolves some of the duplicity of
the statements between section 2 and 3. The rest of section 3 could
be called "Timing properties".
Sections 4 and 5 also mix analysis and results. I think it would be
more logical to include the first paragraph of section 4 in section
2, and similarly the first few paragraphs of section 5 also fit
better in section 2.