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Rotating stripe in the image?

PostPosted: Wed Apr 22, 2020 7:35 pm
by yihan Liu
Hi,

I planned to exclude the intense flux from the pulsar via pulsar binning mode.
When I used PSRPLT to see the radio pulse profile of the pulsar, there was no pulse at all.
However, the position of pulsar indeed has flux because a stripe can be seen in the image going through the pulsar's position, which is "rotating" with the phase of the pulsar.
Is that from the telescope, and how can I get rid of that?

Please check the attached document for details and the images.
Many thanks!

Yihan

Re: Rotating stripe in the image?

PostPosted: Thu Apr 23, 2020 10:44 am
by Mark.Wieringa
Hi Yihan,

interesting question!
I'm no expert on pulsar processing, but the stripes seem to indicate that you may have used a slightly wrong pulse period for the pulsar binning.
This would cause the pulse to shift through the phase binned images with time and only show up for a short time in each image.
I would have expected a wider fan instead of a single stripe in that case, but it must be something similar.
You could try plotting short time periods with psrplt to see if the (smeared) pulse shows up.

Cheers,

Mark

Re: Rotating stripe in the image?

PostPosted: Thu Apr 23, 2020 6:55 pm
by yihan Liu
:D Thanks, Mark.
The pulse shows up. May I further inquire about how to modify the period of the pulsar in this dataset? I checked the header of data but did not find any information about the period or frequency of this pulsar.
Or is it simply due to the task PSRPLT or others giving the wrong period? Is there any method to fix that?

Thank you so much!
Yihan

Re: Rotating stripe in the image?

PostPosted: Fri Apr 24, 2020 9:41 am
by Mark.Wieringa
Hi Yihan,

The task psrfix can be used to correct for dispersion or a wrong period, however you do need to know and enter the correct values - it doesn't figure them out for you. Maybe https://www.atnf.csiro.au/research/pulsar/psrcat/ can be of use here.
I'm afraid you've reached the limit of my knowledge on pulsar processing, I'll send you the email of our local expert in case you need more assistance.

Cheers,

Mark

Re: Rotating stripe in the image?

PostPosted: Fri Apr 24, 2020 3:40 pm
by yihan Liu
Hi, Mark.

I don't think the dedispersion process could work actually. I have manually selected data in this case.
Thank you again for your help. I would be happy to see if there is a solution to this problem in the future!

Best wishes
Yihan