Searching Potential X-Ray Counterparts of GeV Sources J 盧亭霓 盧亭霓 Lu Ting-Ni Lu Ting-Ni

Outline Introduction - Science purpose - GeV J Data - download data - data reduction - analysis Results Conclusion Reference

Introduction Science purpose - try to find next γ-ray pulsar. Gev J an unidentified γ-ray source. - with a X-ray counterpart candidate AX J (Roberts M. S. E. et al, 2001, ApJS, 133, ).

Roberts M. S. E. et al, 2001, ApJS, 133,

Introduction GeV J Roberts M. S. E. et al, 2001, ApJS, 133,

Data Download data - constrain: a. center offset < 25 arcmin. b. exposure time > 10 ksec.

Data Download data Satellite name ROSAT ASCA BeppoSax Mission ID RP N Obs. date Exposure time (s) SIS GIS SIS GIS LECS MECS LECS MECS 42605

Data Data reduction - abandon ROSAT data: cannot find any point-like source near the area with RA~18h37m, Dec~-06h10m.

The green circle is the region with center at (RA, Dec)=(18:37:29.000,-6:09:38.000), radius=90arcsec.

Data Data reduction - abandon SIS data of ASCA: there ’ s only FAST mode data can be used to do timing analysis, but the FAST mode data isn ’ t offered by the archieve data. - abadon LECS data of Beppo-SAX: the exposure time is too short. Also, there ’ s not any point-like source near the area with RA~18h37m, Dec~-06h10m

Data Satellite name ASCA BeppoSax Mission ID Obs. date Exposure time (s) GIS GIS MECS MECS Expansion time (s) ~37.3k~40.1k~94.5k~105.1k Data reduction

Data - filter region and determine position: a. ASCA: *The point spread function (PSF) of GIS alone is a Gaussian with a FWHM of 0.5×(5.9/E 〔 keV 〕 ) arcmin. *The main energy band of the photons is at between 2.3keV and 7.1keV.

The corresponds of the PI channel of ASCA to the energy band.

Data Data reduction - filter region and determine position: b. BeppoSAX: Originated from the cookbook for BeppoSAX NFI spectral analysis V1.2

The corresponds of the PI channel of BeppoSAX to the energy band.

Data Data reduction - filter region and determine position: besides, the region need to encloses the most photons of source but least photons of background.

Data Data reduction - filter energy: a. ASCA:

Data Data reduction - filter energy: b. BeppoSAX: Originated from the cookbook for BeppoSAX NFI spectral analysis V1.2

Data Satellite name ASCA Beppo-Sax Mission ID Obs. date Position (RA.Dec)(18:37:29.000,-6:09:38.000)(18:37:32.500,-06:09:49.000) Radius of region (arcsec) Energy band 2-10 keV

Data Data reduction - barycentric time correction: to make the time on satellite be accordance with the time on earth.

Left: before doing barycentric time correction; Right: after doing barycentric time correction. Example of ASCA data ( )

Data Analysis - a. epoch folding. b. Zm 2 -Test. c. H-Test.

Data Satellite name ASCA BeppoSax Mission ID Obs. date Exposure time (s)GIS GIS MECS MECS Expansion time (s)~37.3k~40.1k~94.5k~105.1k Number of photons Search frequency (Hz)(0.01, 10) (0.01, 100)

Data 1998/04/2 2001/03/12 MJD= e+04 MJD= e+04 T=37.3 (ks) T=94.5 (ks) ASCA Period (s)H valuer.p.BeppoSAX Period (s)H valuer.p E E E E E E E E E E E E E E E E E E E E E E E E /10/ /04/17 MJD= e+04 MJD= e+04 T=40.1 (ks) T=105.1 (ks) ASCA Period (s)H valuer.p.BeppoSAX Period (s)H valuer.p E E E E E E E E E E E E E E E E E E-08 Trial periods at which H value is larger than about 35

Data Analysis - search counterpart periods of data: use the condition that the age of a pulsar should be larger than 1000 years to find possible periods in other data (which is observed at different time).

Result dateperiod (s)H valuedate counterpart period (s) H value dp/dt ( s/s) P1 2001/04/ /03/ P2 2001/03/ /04/ P3 1998/04/ /04/ P4 1998/10/ /04/ P5 2001/03/ /10/ P6 1998/04/ /04/ Tentative counterpart periods in ASCA and BeppoSAX data Periods are reported with digits accurate to about one tenth of corresponding Fourier widths. The random probability (r.p.) is for one single trial only.

Result period (s) Τ c (year) dp/dt ( s/s) S.P.E. (erg s -1 ) B field (G) P E E+12 P E E+12 P E E+13 P E E+13 P E E+13 P E E+14 Properties of the six tentative counterpart periods Periods are reported with digits accurate to about one tenth of corresponding Fourier widths. Here used the period that has larger H value. The Τc is the characteristic age and equals to P/2P ’. S.P.E. is the spin down energy.

Comparison between the six tentative counterpart periods and the high energy pulsar

Conclusion Age: the age of Crab is about 1300 years, but P1, P4 and P6 is young than Crab. Period: the period of existent γ-ray pulsar is at the scale of millisecond, but P6 has period of 2 seconds. S.P.E.: the S.P.E. of existent γ-ray pulsar is about ~10 38 (erg s -1 ), but the S.P.E. of P1 is about (erg s -1 ). Compare with existent γ-ray pulsar, I thought P2 is more possible period within the six case, and infered from above that Gev J may be a crab-like pulsar.

Reference Roberts M. S. E., et al, 2001, ApJS, 133, Gottfried Kanbach, 2002, 2002nsps. Conference P. M. Wallace and N. J. Griffis, et al, 2000, APJ, 540: M. Tavani, et al, 1997, APJ, 479: L109-L112 Takanori Sakamoto, 2001, 2001ASPC, Vol e_area.html

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