[Lofarpwg] LOFAR LBA census draft -- ready for commenting
Patrick Weltevrede
patrick.weltevrede at manchester.ac.uk
Fri Aug 23 15:34:57 UTC 2019
Hi Anya,
Regarding Fig. 2 - How much data is removed is also evident from the top
panels. So I don't think that is a particular strong reason for having
the dynamic spectra there.
Cheers,
Patrick
On 23/08/19 16:20, Anna Bilous wrote:
> Hi Patrick,
>
>
>
> Figure 2: I don't think having the dynamic spectra adds a lot, so
> I would remove them. In addition I had a question about the
> cleaned freq vs phase plots: why are there white rows which do not
> appear in the uncleaned version? Rows with empty samples appear as
> orange for other rows.
>
> I'm not sure for now about removing dynamic spectra, I think they make
> a good illustration of how much band was deleted. I'll take a look at
> the color issue.
>
>
> Figure 3: I don't really see the point in showing for each pulsar
> & beam what fraction of the data was deleted. I think that if this
> information should be available to the reader, then it should be
> in a table in the appendix. At the moment the figures in the paper
> itself (excluding the appendix) is dominated by plots which show
> that the data is non-ideal (two large figures about dropped
> packets & RFI, two small figures about interesting stuff related
> to the sample). If you want to show something related to the
> zapped fraction, I would make a histogram of the fraction of
> useful data, which is much smaller. I also don't think there is a
> reason to keep the inset. As you already do, you can simply state
> in the text that there is no correlation with date. Making the
> plot was a useful diagnostic for us, but the information in the
> inset will not be particularly useful for the reader.
>
>
> I agree with that, that plot remained from the days when we were
> trying to assess the amount of damage. I'll move the information to
> the summary table in Appendix and add a short description to the text.
>
> Cheers,
> Anya
>
>
>
>
> Section 4: I think this is part of "Observations and data
> reduction", so I would make it a subsection of section 3.
>
> It would be great to have this published!
>
> Cheers,
> Patrick
>
>
> Abstract - remove "Despite some telescope malfunction". I think it
> only puts off readers from reading the paper, and it is not
> particularly useful for the reader to read at this point.
>
> Section 2: 2nd paragraph - Add a sentence at the end like "The
> consequence is that only 88 out of the 194 pulsars which are in
> the HBA census were observed and discussed here." At the moment
> the text doesn't quite explicitly states if only HBA pulsars were
> observed, or all pulsars HBA pointings are available for (without
> the pulsar necessarily being detected).
>
> 3rd paragraph:
>
> with AN incoherent dedispersion scheme.
>
> only compensated FOR between channels
>
> The proposed source sample therefore ONLY? included pulsars with
> sufficiently (if only is not missing from the sentence, then I
> don't get the point of the paragraph)
>
> without ephemerides updateS.
>
> hoping to DETECT strong single pulses.
>
> Last paragraph of section 2: At the moment it just says "here is a
> plot" without a conclusion attached to it. I think it is there to
> back up the last statement from the previous paragraph. So I would
> delete the last paragraph and simply write: "with some preference
> for closer/brighter sources (SEE FIG. 1)."
>
> Caption Fig. 1: I would remove "(see text for more information)",
> since the text kind of says this is done in an, at least for the
> reader, undefined way. Also, "THE scattering time was estimated
> with THE Galactic"
>
> Footnote 2: Either in THE original ATNF (and end the sentence with
> a .)
>
> Section 3:
>
> "(beam 0 on the NOMINAL POSITION OF THE TARGET"
>
> "private sources" - clarify these is Lovell and GBT positions.
>
>
> observations at the Jodrell, Lovell -> observations with the
> Lovell telescope at Jodrell Bank
>
> in many cases the initial DM -> in many cases the DM as derived
> from higher-frequency observations
>
> “old” -> these incorrect
>
>
> of THE relative signal strength difference
>
> "for each time/frequency data cell in phase-integrated dynamic
> spectrum" - I'm not 100% sure what this means, so please clarify.
> Phase-integrated means integrated over pulse longitude? So that
> means you get 300 (nr freq channels) numbers per 5 second subint?
>
> Caption Fig. 2: An example of diagnostic plots without (left) and
> with (right) dropped packed cleaning APPLIED for one observation
> of THE bright pulsar B0809+74. The upper row of plots shows the
> statistic of THE two polarizations, the lower PLOTS SHOW THE
> dynamic and folded spectra, waterfall diagram, and the average
> profile.
>
> Figure 2: The plots should have tick marks. The horizontal
> labelling of the top plots is confusing. There are four pannels.
> The upper three have (I assume) a horizontal axis corresponding to
> frequency (as shown at the top). Only the lower panel has dP as
> the horizontal axis. However, for the middle two plots this is not
> clear from the figure. Having tickmarks in all panels would help.
> Possibly reducing the gap to zero for the first 3 panels would
> also clarify they share the same horizontal axis, but the lower
> panel not.
>
>
> For a few pulsars (namely,
> B0105+68, B0643+80, B0656+14), the data was contaminated
> to the point where no cleaning (manual or automatic) could help.
> Thus, we exclude these pulsars from our sample.
> ->
> For only 3 pulsars (namely, B0105+68, B0643+80, B0656+14), the RFI
> prevented useful analysis, hence they were exclude from our sample.
>
>
> "Overall, the fraction of band that has been deleted due to
> dropped packages or RFIs is quite substantial" - I fully agree
> with Joeri's suggestion related to this paragraph.
>
> Section 3.1
>
> We adjusted pulsar period P and DM with the PSRCHIVE pro-
> gram pdmp, maximizing integrated S/N of the frequency- and
> time-averaged profile over the set of trial values of P and DM.
> ->
> We adjusted THE FOLD PERIOD AND THE INTRA-CHANNEL DISPERSION DELAY
> (i.e. adjusting the pulse period would involve sending a missile
> to the pulsar!) with the PSRCHIVE program pdmp, maximizing (remove
> integrated) THE S/N of the frequency and time-averaged profile.
> REMOVE REST OF SENTENCE
>
> initial number of PHASE bins
>
> Caption figure 3:
> Pulsars are ordered by the maximum deleted fraction.
> ->
> Pulsars are ordered by the highest deleted fraction of the beams.
>
> Same caption: Delete "Pulsars B0656+14, B0105+68, and B0643+80,
> were excluded from the analysis due to unmanagable RFI contamina-
> tion." -> Already said in text, so no need to repeat this,
> especially given the text is quite negative.
>
> Back to section 3.1:
>
> thus for brighter pulsars THE DM may have A BIAS depending on the
> assumed profile evolution.
>
> About the same sentence: you quote the pdmp DM's right? In that
> case the "assumed profile evolution" is that there is no profile
> evolution. It would be good to clarify this.
>
> Fig. 4 shows THE CORRELATION BETWEEN DM and the estimated
> scattering time over period for the detected and non-detected pulsars.
>
> Section 3.2 - I agree with Joeri this should not be part of
> "Observations and data reduction"
>
> Section 4:
>
> Folded data files were calibrated
> ->
> The folded data were calibrated
>
> A coherence factor of 0.85 was used: is there a ref for the 0.85?
>
> The off-pulse windows
> ->
> The on and off-pulse windows (surely you need the on-pulse window
> as well as the off pulse window).
>
> Judging from the relatively well-measured spectra (e.g.
> PSRs B0809+74, B1133+16, B1508+55, and others), the LBA
> measurements stay within the spread of literature points, which
> is by a factor of few.
> ->
> For those pulsars for which multiple spectra have been published (e.g.
> PSRs B0809+74, B1133+16, B1508+55, and others), the LBA
> measurements are consistent with the reported fluxes, which vary
> by a factor of a few.
>
> adopting adopted -> adopting
>
> THE total flux density error
>
> Interestingly, 19 out of 44 detected pulsars WERE DETECTED WITH
> THE HIGHEST S/N IN A side beam
>
> TEC (like DM) should not be in italics in equation 1 and the text.
>
> 5.1
>
> combined with the literature measurements
> ->
> combined with published measurements (i.e. not a measure of
> literature, which might be so many kg of A&A papers per year).
>
> PL is undefined
>
> 5.2 - It would be great if the suggestions of Michael and Joeri
> could be used to beef up this a bit, which would also help the
> conclusion section and the abstract.
>
> That's it! Great work!
>
>
>
> On 16/08/19 07:53, Anna Bilous wrote:
>> Dear all,
>>
>> please find attached the draft of LBA census. Please let us (myself,
>> Louis, JM & Vlad) know if you have any comments on it. We would like
>> to submit it on Aug 30 due to Louis'es graduation constraints. Sorry
>> for the quite short notice, but the paper is short and very simple, so
>> it should not take long to read it.
>>
>> Cheers,
>> Anya
>>
>>
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>
>
> --
> Dr. Patrick Weltevrede, senior lecturer in pulsar astrophysics
> Jodrell Bank Centre for Astrophysics,
> School 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/
>
--
Dr. Patrick Weltevrede, senior lecturer in pulsar astrophysics
Jodrell Bank Centre for Astrophysics,
School 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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