Question ID = 0170
Question ID = 0170
Assigned Member (担当者)2013-08-22 A.BambaName and Institute (質問者/機関)Eda Sonbas (Adiyaman University)Question (質問)I have been working on timing analysis with Suzaku hxd/pin detector using so called poison (z$_1^2$) timing analysis method. I followed this page , and downloaded crab.fits file for crab pulsar and run the file through my test to find frequency/period of the pulsar and compare what you indicated in your example.When i calculated pulsar frequency of the pulsar using ephemeris i expect to find the signal at 29.778 hz. 0531+21 05 34 31.972 22 00 52.07 53614 53644 53629.000000169 29.7788212287594 -3.72971D-10 3.74D-21 0.7 J DE200 0531+21 (see, http://www.jb.man.ac.uk/pulsar/crab/all.gro) But in the analysis web page (see, http://www.darts.isas.jaxa.jp/outreach/classroom/main/crab/index.html.en) you quoted as "The revolving period of the Pulsar is found to be 0.03357701 (sec) by the precise measurement. " Which corresponds to 29.78228 hz frequency which is same what i found with the z$_1^2$ timing analysis method but there is an offset with corresponding crab ephemeris frequency on this date. I would like to ask you what would be the reason for this differences? Answer from(回答の文責)A. Bamba (Helpdesk) and K.Ebisawa (ISAS)Answer (答え)Thank you very much for using our materials. The crab.fits file we created is just for education and public outreach purposes, and is not very precise. As a matter of fact, the barycentric correction (correction of the orbital motion of the earth around the sun) is NOT taken into account.If this correction is taken into account the period should agree with the radio period you have mentioned. This is a good point, and we are planing to revise the description, where we will explain how the difference is explained by the doppler effect due to the orbital motion of the the earth. Meanwhile, we let you know that our DARTS is under a complete replacement in every five year. The page you found, http://www.isas.jaxa.jp/home/ttamura/classroom/main/crab/index.html will be gone soon, and the new page will be http://www.isas.jaxa.jp/home/ttamura/classroom/main/crab/index.html Currently, crab.fits is not available from there though. We will revise the page taking into account the question you have raised. Thank you very much again for pointing out this important thing. Status （詳細なステータス）2013-08-22 Accept2013-08-22 Check the data and understand the situation 2013-08-23 Forward message to C-SODA 2013-08-27 Identify that the data is only for education and no barycentric correction 2013-09-21 Answer from C-SODA 2013-09-25 Done 
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