[Lofarpwg] TULIPP paper draft for final review

[Aris Karastergiou]

Hi Charlotte,

That's a nice paper. I wish I had the time and energy this past year and a half to follow this work closer, but I didn't. I was reading through it now and had a comment that you might want to consider. Simply put, I think you are comparing two different quantities when you compare the fractional linear polarization in the images to what is traditionally published in pulsar papers. In fact, I did not see the formulas you use to determine the average L/I in these two cases, but could they be the following?


  1.  In imaging, L = sqrt( Sum(Q)^2 + Sum(U)^2 ), and I is just Sum(I), where the sums are over the entire integration time.
  2.  In time domain obs, L = Sum( sqrt(Q^2+U^2) ), and I is again Sum(I). Here the sums are across pulse phase. I think this is what is traditionally published in pulsar papers.

I have ignored the L bias correction in both cases.

If so (as per the norm), then the imaging L/I is always going to be less than the timing L/I, depending in fact on the PA swing and the shape of the profile. I think this is clear in your figure 2, where in the timing data the pulsar is very highly polarized.

We are currently writing up a MeerKAT paper where we are highlighting this distinction in definitions, and I have been thinking about the impact this could have in identifying pulsars in images. You may want to consider this here, and even perhaps write a few sentences along the lines mentioned above. If somehow I have missed relevant discussion that exists in the manuscript already, please ignore the above.

Cheers,
Aris




________________________________
From: lofarpwg <lofarpwg-bounces at astron.nl> on behalf of Sobey, Charlotte (S&A, Kensington WA) <Charlotte.Sobey at csiro.au>
Sent: 21 October 2021 15:19
To: lofarpwg at astron.nl <lofarpwg at astron.nl>; Evan Keane <evan.keane at nuigalway.ie>; e.vanderwateren at science.ru.nl <e.vanderwateren at science.ru.nl>
Subject: [Lofarpwg] TULIPP paper draft for final review


Dear All,



I hope this email finds you well.



It is a pleasure to share the initial ‘TULIPP’ paper with the PWG.

The paper title is currently “A pulsar survey of polarized point sources from the LOFAR imaging surveys: description and initial discoveries”

It can be viewed/downloaded from google drive here:

https://drive.google.com/file/d/1rdfFh8njcF4639sBtREP9ZNJyWv9kZIc

Please feel free to email me with any impressions/comments before your close of business on Friday 29 October.

I hope to submit the final version of the paper shortly afterwards.



Many thanks and best wishes,

Charlotte

--

Dr Charlotte Sobey (she/her/they/them)

Postdoctoral Fellow

Space & Astronomy  |  CSIRO

charlotte.sobey at csiro.au<mailto:charlotte.sobey at csiro.au>  |  +61 8 6436 8781

PO Box 1130, Bentley, WA 6102, Australia

CSIRO acknowledges the Traditional Owners of the land, sea and waters, of the area that we live and work on across Australia. We acknowledge their continuing connection to their culture and we pay our respects to their Elders past and present.

CSIRO Australia’s National Science Agency  |  csiro.au<http://www.csiro.au/>


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.astron.nl/pipermail/lofarpwg/attachments/20211029/e47ae05c/attachment.html>