[Lofarpwg] LOTAAS binary pulsar + 20 timing paper
Patrick Weltevrede
Patrick.Weltevrede at manchester.ac.uk
Tue Oct 8 10:36:58 UTC 2019
Hi Chia Min,
Related to J1749+5952: I think the from the statement "The increase in
width of the main peak at higher frequency could be due to a larger
fraction of the emission region coming into view as the height of the
emission region decreases" it isn't particularly clear what you have in
mind. Note that an increasing W50 does not automatically imply there is
more emission from the wings of the profile, it could equally well mean
that there is less emission from the region where the profile peaks.
Maybe instead:
"The increase in width of the main peak at higher frequency could be
affected by the exact beam pattern of the pulsar, and pulse longitude
dependent spectral index effects."
I admit the new sentence is not particularly revolutionary either, but I
think it is at least a bit more explicit in terms of what it means.
Cheers,
Patrick
On 08/10/2019 10:35, Chia Min Tan wrote:
> Hi everyone
>
> Thanks to everyone who sent me another round of comments. I've made
> changes based on the feedback and it should be almost ready for
> submission. I hope to submit by this Friday before I move to Canada.
>
> I have quite a few comments about the multi-frequency pulse profile
> studies and here are my thoughts about them:
>
> -On the measurement of scattering, I've only done them for J1745+1252
> and J0210+5845 and not J1810+0705 as Marisa's script currently only
> supports profiles that can be modelled as single Gaussian + scattering
> exponent.
>
> -I expanded on the definition of w50 and w10 of the pulse profiles
> saying that it measures between the outermost components that have
> height above 10% and 50% of the maximum of the profiles. I've also
> added a scale on the plots of the pulse profile to show the widths in
> milliseconds.
>
> -On J1643+1338, I believe it is clear that the profiles at all
> frequency consists of two separate components, and I can model them to
> show the w50 and the separation between the two components increases
> at higher frequencies, which are against RFM model.
>
> -On J1749+5952, the separation between the two major components
> follows RFM, but the individual components seems to be narrower at
> lower frequencies. I said it could be a larger portion of the emission
> regions came into view at higher frequencies, which makes the
> components wider.
>
> I don't expect any more major comments but if you have any feedback
> can you let me know by tomorrow?
>
> Thanks
> Chia Min
> ------------------------------------------------------------------------
> *From:* lofarpwg <lofarpwg-bounces at astron.nl> on behalf of Chia Min
> Tan <chiamin.tan at postgrad.manchester.ac.uk>
> *Sent:* Friday, September 6, 2019 3:13 PM
> *To:* lofarpwg at astron.nl <lofarpwg at astron.nl>
> *Subject:* Re: [Lofarpwg] LOTAAS binary pulsar + 20 timing paper
>
> Hi everyone
>
>
> I have received quite a few constructive comments about the paper and
> have been working on them over the past few weeks. Thanks to those
> that have sent me their feedback.
>
>
> I have actually made quite a few significant changes to the structure
> of the paper. I have rewritten the introduction of the paper to focus
> more on observing pulsars at low frequencies instead of a general
> introduction to pulsar observations. I have also reorganise the paper,
> where I place the observation and data analysis descriptions in
> Section 2 and focus on the various results in other sections. I have
> also made changes and additions on various result sections based on
> the questions and comments I have received. I've also added some
> discussion about the long-term flux density variation of PSR
> J1657+3304 and how it is unlikely to be scintillation.
>
>
> I have also received question about whether to present the binary
> pulsar PSR J1658+3630 in a separate paper. My plan now is to present
> the timing solution of the pulsar (including coarse modelling of DM
> variation to reduce the timing residual) and the average profile and
> spectrum. There are many more interesting work that can be done with
> the pulsar including modelling the scintillation properties, study of
> long term DM and profile variation, and also possibly to look at the
> optical properties of the binary companion. Cees previously kept some
> of the raw CV data from the pulsar with the thought of reprocess them
> with finer channels for scintillation studies. I'm not sure if he
> still have those data lying around.
>
>
> If anyone has any comments about the updated draft please send it to
> me within two weeks. Also for those who have sent me feedback, can you
> confirm if you want to be on the paper as a co-author and send me your
> affiliation?
>
>
> Cheers
>
> Chia Min
>
> ------------------------------------------------------------------------
> *From:* Michael Kramer <mkramer at mpifr-bonn.mpg.de>
> *Sent:* Tuesday, August 20, 2019 1:21:51 PM
> *To:* Cees Bassa <cbassa at gmail.com>
> *Cc:* Chia Min Tan <chiamin.tan at postgrad.manchester.ac.uk>;
> lofarpwg at astron.nl <lofarpwg at astron.nl>
> *Subject:* Re: [Lofarpwg] LOTAAS binary pulsar + 20 timing paper
> Dear Chia Min,
>
> I read the paper and have some comments which are hopefully useful.
> Please, let me know if
> my handwriting is difficult.
>
> Please, note my comments about the reference to spectra paper - which
> is also relevant for
> the census papers (I’ll read those shortly). The problem with the
> cited Bates et al. and
> Jankowski et al references is, that the spectra in both papers were
> derived for a relatively
> small frequency range, which is well above the the LOFAR frequencies.
> When you make
> comparisons it is probably more appropriate to refer to samples which
> are drawn from
> data covering the whole frequency range. Here the best reference is
> probably still Maron et al.
>
> Anyway, I hope the comments are useful.
>
> Cheers, Michael
>
>
>
> > On 6 Aug 2019, at 15:17, Cees Bassa <cbassa at gmail.com> wrote:
> >
> > 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.
> > _______________________________________________
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>
> ----------------------------------------------------------------------------------------------------------
> Prof. Dr. Michael Kramer
> Director - Max-Planck-Institut für Radioastronomie, Bonn, Germany
> Professor for Astrophysics - University of Manchester, UK
> Professor (Hon-Prof.) - University of Bonn, Germany
>
> Address: MPI fuer Radioastronomie
> Auf dem Huegel 69
> 53121 Bonn, Germany
>
> Phone: +49-228-525-278 (direct)
> +49-228-525-299 (secretary)
>
> EMAIL: mkramer at mpifr-bonn.mpg.de / michael.kramer at manchester.ac.uk
> ----------------------------------------------------------------------------------------------------------
>
>
>
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--
Dr. Patrick Weltevrede, senior lecturer in pulsar astrophysics
Jodrell Bank Centre for Astrophysics,
Department of Physics and Astronomy, University of Manchester
Office 3.210 Alan Turing Building
Tel: +44 (0) 16127 54162
Website: http://www.jodrellbank.manchester.ac.uk/
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