SUMMARY OF SEQUENCE NUMBER 400073

SUMMARY OF SEQUENCE NUMBER 400073

Title: HETG ZERO PHASE SPECTROSCOPY OF CIRCINUS X-1

Observer: BRANDT

Subject Category: BH and NS Binaries

Seq: 400073 ObsId: 01700

Long-term Plan bin: 7-Jun-2000

ABSTRACT

We propose to make the first grating-resolution X-ray spectra of Cir X-1 during one of its zero phase passages. Our ASCA analyses of Cir X-1 have shown that its variable iron K features can be explained using a direct flux plus scattered flux model, and HETG spectra will test our model. During zero phase `dips' we expect line emission from an accretion disk corona (ADC), since we predict predominantly ADC scattered emission below 5 keV. Line measurements will constrain the ADC ionization parameter, temperature, thickness and motion. We will also make the highest resolution iron K line/edge measurements and use them to study obscuring matter. Our observation will not cause telemetry saturation, and our dispersed spectra will not have serious photon pile up.

TARGET SUMMARY

TARGET NAME RADEC TIME SI GRAT TYPE TC ROLL PRE PHASE MULTI PRI
CIR X-1
230.170833
-57.166667
15.00000
ACIS-S
HETG
GO
yes
no
no
yes
yes
5

IMAGES

(NOTE: RASS images currently only available for targets LTS scheduled on or after Apr-09-2000)

Roll/Visibility

PARAMETERS

Obscat Parameters