EROSITAwiki: Diff for "timing"

PSR 0656+14 timing analysis

G. Lamer with contributions by J. Kurpas, A. Schwope, and I. Traulsen (AIP).

The pulsar PSR 0656+14 was observed on 14/15-Oct-2019 for 115 ksec. The cameras of all telescopes TM1-TM7 observed with the filter wheel in "FILTER" position. However, it turned out that the data are incomplete during an electronics issue and are only of limited use for this analysis. A simultaneous observation of PSR 0656+14 was carried with XMM-Newton.

The pulsations of PSR 0656+14 have a period of P=0.385 sec and have beeen observed at radio frequencies, in X-rays and Gamma-rays.

In order to analyse the pulsations of PSR 0656+14 a barycentric correction of the event tinmes needs to be applied. Until the eSASS task with this functionality is implemented, a workaround using the HEASOFT barycen task can be used. We have converted the orbit file omnia_orbit_october_2019.log into a FITS file with the format required by barycen.

October 2019 orbit file: orbit_october_2019_scc.fits

Also the headers of the event files to be corrected need to be modified:

keyword RADECSYS="ICRS" keyword TIMEREF="LOCAL" keyword TIMESYS="TT"

Since barycen only recognizes the extension name "GTI", the name of the GTI extension needs to changed to "GTI" before calling barycen and then changed back to its original name.

The barycen task was called with the following command line:

• barycen infile="ICRS"

keyword TIMEREF="LOCAL" keyword TIMESYS="TT"

Since barycen only recognizes the extension name "GTI", the name of the GTI extension needs to changed to "GTI" before calling barycen and then changed back to its original name.

The barycen task was called with the following command line:

• barycen infile=src_events_tm2.fits \
  

  • outfile=src_events_tm2_bary_icrs.fits \
    rbfile=orbit_october_2019_scc.fits \
    ra=104.9507468 \
    dec=14.23963084 \
    orbext="ORBIT" \
    orbform="COMPONENTS" \
    orbcol="X,Y,Z,VX,VY,VY,VZ" \
    startcol="START" \
    stopcol="STOP" \
    refframe="ICRS" \
    orbinterp="WEIGHTED" \
    timecol="TIME" \
    chatter=3 \
    clobber=yes \
    debug=yes
    

Example bash script: run_bary.sh

Before and after barycentric correction a chi^2 period search was applied to the data and a Gaussian was fit to the chi^2 peak near the published pulse period. The XMM-Newton data were reduced and barycenter corrected using the XMMSAS package and the pulse period was determined, details will be described elsewhere.

Resulting eROSITA periods before and afterbarycentric correction:

* Based on Fermi LAT data (Ray et al. 2011), corrected for spin down to 14-Oct-2019

• \
  

  • outfile=$corrfile \
    orbfile=$orbitfile \
    ra=104.9507468 \
    dec=14.23963084 \
    orbext="ORBIT" \
    orbform="COMPONENTS" \
    orbcol="X,Y,Z,VX,VY,VY,VZ" \
    startcol="START" \
    stopcol="STOP" \
    refframe="ICRS" \
    orbinterp="WEIGHTED" \
    timecol="TIME" \
    chatter=3 \
    clobber=yes \
    debug=yes
    

Example bash script: run_bary.sh

Before and after barycentric correction a chi^2 period search was applied to the data and a Gaussian was fit to the chi^2 peak near the published pulse period. The XMM-Newton data were reduced and barycenter corrected using the XMMSAS package and the pulse period was determined, details will be described elsewhere.

Resulting eROSITA periods before and afterbarycentric correction:

* Based on Fermi LAT data (Ray et al. 2011), corrected for spin down to 14-Oct-2019