The states of Scorpius X-1 The states of Scorpius X-1 v.s. the 107 eventsv.s. the 107 events

吳宇智吳宇智 (Yu-chih, Wu)(Yu-chih, Wu)2006/10/242006/10/24

Scorpius X-1Scorpius X-1

The brightest X-ray source in the sky.The brightest X-ray source in the sky. Low-mass X-ray binary(LMXB)—Low-mass X-ray binary(LMXB)— neutron star &neutron star & donor donor DistanceDistance ：： 2.8kpc2.8kpc inclination to the eciptic ： 6o Z source

Z sourceZ source

A group of LMXBs.A group of LMXBs. CDs(color diagrams) and HIDs(hardnCDs(color diagrams) and HIDs(hardn

ess intensity diagrams) have 3 brancess intensity diagrams) have 3 branches, which look like the shape of ”Zhes, which look like the shape of ”Z”.”.

Actually, it’s not like “Z” for Sco Actually, it’s not like “Z” for Sco X-1.X-1.

StatesStates

3 branches means 3 branches means 3 states:3 states: H(horizontal)H(horizontal) N(normal)N(normal) F(flaring)F(flaring) F

H

N

107 events107 events

Everybody knows.Everybody knows.

Rossi X-ray Timing Rossi X-ray Timing ExplorerExplorer RXTE 1996~2002 archival dataRXTE 1996~2002 archival data PCA(proportional counting array) “sPCA(proportional counting array) “s

tandard 2” modetandard 2” mode

Good Time IntervalsGood Time Intervals

ELV(elavation angle): the angle between thELV(elavation angle): the angle between the Earth's limb and the pointing direction.e Earth's limb and the pointing direction.

ELV>10 degreeELV>10 degree OFFSET: the difference between the source OFFSET: the difference between the source

position and the pointing of the satellite. position and the pointing of the satellite. OFFSET<0.02 degreeOFFSET<0.02 degree SAA(South Atlantic Anomaly): a ‘hole’ in SAA(South Atlantic Anomaly): a ‘hole’ in

the geomagnetic field which allows cosmic the geomagnetic field which allows cosmic rays to penetrate further than usual. rays to penetrate further than usual.

Time before SAA or 30min after entering SAATime before SAA or 30min after entering SAA

Hard Intensity Hard Intensity DiagramsDiagrams X-axis: intensity(counts/sec) X-axis: intensity(counts/sec) Y-axis: hard color ratio, or HCRY-axis: hard color ratio, or HCR bin time: 160secbin time: 160sec HCR: (9.1~18.2keV)/(6.9~9.1keV)HCR: (9.1~18.2keV)/(6.9~9.1keV)

epoch1

~3/21/1996

(exposure: 16,697 sec)

epoch3

3/21/1996~4/15/1999

(exposure: 473,415 sec)

epoch4

3/22/1999~5/13/2000

(exposure: 58,991 sec)

epoch5

5/13/2000~

(exposure: 15,168 sec)

Take this data as an example: Take this data as an example:

Observe time: Apr. 18~24, 1997Observe time: Apr. 18~24, 1997

Exposure time: 68,068 secExposure time: 68,068 sec It moves continuously with time.It moves continuously with time. slowly at slowly at

HB, NB, but HB, NB, but

fast at FB.fast at FB.

hard color- soft colorSCR:

(2.3~4.4keV)/(4.4~6.9keV)

soft color- soft intensity

hard color- hard intensity soft color- total intensity

H

NF

H

N

F

(5.1~18.5keV)/(3.4~5.1keV) (5.8~14.8)/(3.7~5.8keV)

(6.5~14.8keV)/(4.1~6.5keV) (7.6~14.8keV)/(5.8~7.6keV)

bin time: 16 sec bin time: 1600 sec

It seems no relationship between the It seems no relationship between the “states” and the events.“states” and the events.

Thnak you!Thnak you!