Status of Calibration and Data Analysis of MAXI GSC M. Sugizaki (RIKEN) on behalf of MAXI Team MAXI 20101GSC Calibration and Analysis Status

Outline In-orbit Operation and Performance –HV Operation History –Background, Sky Coverage, Exposure Calibration Status –Alignment (Position) –Light curve (Effective area) –Spectrum (Response matrix) Data Reduction and Analysis Process –Event data reduction, All-sky Image –Pre-registered source archive Light curve, Spectrum, Image Future Plan MAXI 20102GSC Calibration and Analysis Status

HV Operation History MAXI 2010GSC Calibration and Analysis Status3 GSC operation started on 2009/8/15 with a nominal 1650V for full 12 counters. 4 out of 12 counters suffered from breakdown within the first 2 months. The damage on carbon-anode wire by heavy particle irradiation is suspected. Operation at high earth latitude (Lat.>40 o ) was stopped. One another camera stopped on 3/23/2010. The nominal HV is reduced to 1550 V for suspicious counters. Count-rate map of Radiation-Belt Monitor Observation Efficiency –Detector area  8/12=66.6%, –Effective exposure  40% of the pre-flight plan.

Exposure Map (since 2010/1/2 00:00:00 UT) MAXI 2010GSC Calibration and Analysis Status4 1 orbit = 92 minutes1 day 27 days 1-day exposure = 4000 cm 2 s (typical) 100% full sky is covered by 3 weeks 85% sky coverage95% sky coverage Thanks to the two FOVs (horizon/zenith) and redundant design, almost full sky are covered every orbit!

Daily Exposure for a Celestial X-ray Source MAXI 20105GSC Calibration and Analysis Status Example: Crab / /30 1-day exposure = 4000 cm 2 s (typical) Initial 2 month

Background and Sensitivity MAXI 2010GSC Calibration and Analysis Status6 CXB Confusion is included GSC BGD rate ~2 mCrab at 4keV, ~ 10 mCrab at 10 keV Comparable to the Ginga-LAC 5-  sensitivity ~ 15 mCrab per day MAXI / GSC Ginga/LAC RXTE/PCA

Instrument Calibration Position Accuracy Effective area Energy response Timing MAXI 20107GSC Calibration and Analysis Status

Attitude and Alignment Calibration (See Poster P-59 by Sugimori et al.) Attitude of MAXI payload module is always monitored by ADS (Attitude Determination System) using Visual Star Camera and Ring Laser Gyro. Its accuracy is << 0.1 deg. (calibration is in progress) Source position of incident X-ray is determined from the attitude and alignments of collimator and detector. These alignments can be calibrated using standard X-ray sources whose positions and intensities are well-known MAXI 2010GSC Calibration and Analysis Status

Sco X-1 90% containment radius 0.9 deg Alignment Cal. Progress (See Poster P-59 by Sugimori et al.) deg 2009/ /01 PSF MAXI 2010GSC Calibration and Analysis Status Estimated systematic uncertainty = 0.2 o 5o5o

Effective Area and Light Curve MAXI 2010GSC Calibration and Analysis Status10 20 min. 1 day 100 days Sun SAA Area-corrected light curve 1bin=1orbit(90min) 1bin=1day Observed count rate for stable point source (simulation) 100 days Effective-area correction Modulated by triangular transmission function of slat collimator Area variation due to source acquisition angle Ideal case ! 1 scan per 92 minutes 15 scans per day

Effective area correction of real data Light curve of Crab Nebula (on the MAXI public web) Soft X-ray band has a large systematic errors for insufficient calibration of absorption at the beryllium window, hardware/software LD variation, … Med/Hard Bands are OK. Background subtraction error Down time for occultation by solar-battery paddle are implemented. However, the precision is not good enough. Occultation by docked shuttle vehicle was not implemented MAXI 2010GSC Calibration and Analysis Status keV keV 4-10 keV keV

Light Curve by Updated Process Info of in-orbit energy- response is implemented. –gain variation –LD change Data of a few anodes (2 out of 6 wires) with extraordinary responses are ignored V data only Need more extensive response calibration to use full data MAXI 2010GSC Calibration and Analysis Status12 Crab

MAXI 2010 Energy Response: CALDB from ground tests Gain: YZ map Energy resolution map Energy-PHA response matrix Gain: XY map on gas counter Effective area Energy [keV] PHA channels 13GSC Calibration and Analysis Status

Response Builder 14  DetX ★ X-ray source (RA, Dec) GSC cross section Weight map on detector plane collimator detector PHA(DetX,DetY)  PI Energy [keV] PI channels Energy-PI Response Matrix MAXI 2010GSC Calibration and Analysis Status Slit

In-orbit Calibration (Nakahira et al.) The gas gains should increase from the ground test. ~ 2-10% The detector gas cells expanded in the vacuum. The ground calibration test would suffer from the space charge effects. The test was done with high-rate pencil X-ray beam. 15 Ti Cu MAXI 2010GSC Calibration and Analysis Status Data: BGD spectrum including Ti, Cu lines Model: folded with a response built from ground CALDB

Crab Spectrum fit 2009/8/15 1-day all available GSC data Data of anode #1,#2 are currently not used for their insufficient calibration. (They have an extraordinary response.) Applicable to 1650V data only MAXI 2010GSC Calibration and Analysis Status16 Wabs*Powerlaw Model parameters: NH = /  = / Norm. = /- 1.0  2 = 1.08 Reasonably agree with standard Crab model

GSC event data has a 50-  s time resolution MAXI DP time clock can always be calibrated using on-board GPS. Timing will be calibrated by Crab pulsar, ms pulsar, binary X-ray pulsars. GSC Event Timing MAXI 2010GSC Calibration and Analysis Status17 GPS 1s Time Clock 1s GSC Elec. Free-Run Clock 50  s Latch FRC on DP-clock trigger Gas Counter Reset DP FRC on GPS trigger UTC time and sec. trigger Latch FRC on event trigger Free-Run Clock 1  s Data Processor Event timing scheme

Timing Cal. with Crab Pulsar (Yamamoto, Morii) Period, stability is verified (10 -9 ) Need calibration of absolute timing MAXI 2010GSC Calibration and Analysis Status18 Dot line: Radio (Jodrell Bank) Comparison of pulse period with radio-pulse period Epoch Time (3 months) Red, green: MAXI …… / /30 GSC every 3-day folded pulse Residual

Calibration Summary Effective Area, Energy response –Acceptable Level HV=1650V data Med (4-10keV), Hard Band (10-20 keV) –Not ready, Unacceptable HV=1550V data. 3 out of 8 operating counters. Important to optimize the observation efficiency. Soft band (<4 keV): Error ~25% if anode#1,#2 is included. Timing –Stability is good in level verified by Crab pulsar –Absolute-timing calibration is necessary MAXI 2010GSC Calibration and Analysis Status19

Data reduction, Analysis, and Archive MAXI 2010GSC Calibration and Analysis Status20

21 Data Reduction and Analysis flow (for standard daily data products) raw event file processed event file AUXIL file attitude orbit time target event file HK file GSCHK ISSANC … ISS telemetry Database (MAXIDB) raw count rate image (spectrum) light curve image spectrum cleaned event file CALDB Response Effective area curve (RMF) For each target MKF These processes run once per day. All required data are dumped into files (FITS formatted). every second Real-time transient search Standard HEADAS-format tools are used. Time Coordinate PI (energy) MAXI 2010GSC Calibration and Analysis Status Negro talk Ozawa, Suwa (P-63,64)

Data Archive Products ( Daily All-sky Image (3-10 keV band) Pre-registered sources (~ 200 targets) –Light Curve –Daily Image / / keV band –Daily Spectrum (first 10 targets) MAXI GSC Calibration and Analysis Status

Daily Spectrum Archive (test phase) Archive of first 10 targets starts on 10/28 –Crab, Sco X-1, Cen X-3, Her X-1, GX 9+9, GX 9+1, GX 13+1, GX 17+2, GRS , Cyg X-2 –Source, BGD spectra and response file for each UT day. –Best-fit wabs*power-law model MAXI 2010GSC Calibration and Analysis Status23 Crab 2010/10/1

Crab Daily Spectral Parameters (2009/08/ /10/31) Error bar: 90% conf. limit N H: slightly higher than the standard value Automatic analysis process is not always perfect MAXI 2010GSC Calibration and Analysis Status24 Photon index Flux (2-10 keV) Absorption column density Crab standard model

Archive Update Plan Light Curve –Soft-band calibration, Use 1550-V counter data –Early update (1.5-day delay in the current process) Energy Spectrum –Response calibration of the soft band and 1550-V data –Increase archive targets Data Access –Spectrum data of only the latest one day is accessible in the current test phase. –Extension of daily-base archive over the first year is not difficult. It will come soon. –More flexible data access will be important to increase the MAXI data analysis and the science outputs MAXI 2010GSC Calibration and Analysis Status25

Final Remarks MAXI just completed the first year operation. Although there were a some troubles for the special environmental on the ISS, the operation is getting stable. The calibration, data analysis environment, archive system are now being developed and close to ready. The time to enjoy the data will come soon ! MAXI GSC Calibration and Analysis Status

Backup MAXI GSC Calibration and Analysis Status

In-Orbit Environment on ISS Orbit: Alt.= km, Period~92 min. Incl.=51deg –Ginga,…,Suzaku : Alt.= km, Period~95 min. Incl.=31 deg. –XTE: Alt.=580 km, Period~100 min. Incl.=23 deg. Large ISS structure. ~108 m, ~408 ton Direction of Motion MAXI GSC Calibration and Analysis Status

29 GSC on MAXI GSC-Z GSC-H FOV of 6 cameras 160 o 80cm 107cm Gas Slit Cameras (GSC) Xe-filled proportional counter 2—30 keV; 5350 cm o (FWHM) ISS motion MAXI 2010GSC Calibration and Analysis Status

Scan Observation for a Celestial Target Effective-area curve for a point source MAXI 2010GSC Calibration and Analysis Status slat-collimator transmission function duration ~ 40 sec. (typical) ~ 15 scans 1 day 25 min. 1 scan per 92 min duty cycle ~ 0.8 % (typical) Outage for SAA 30 1/3 cycle 1 day 1/4 cycle from H to Z

Point-Spread Function (PSF) PSF along anode wire MAXI GSC Calibration and Analysis Status

Scan-Transit Profile MAXI 2010GSC Calibration and Analysis Status32

Residual BGD Spectrum MAXI GSC Calibration and Analysis Status Ti-K Cu-K COR dependence suggests that the origins are cosmic rays whose momentum is over the selection criteria. MIP energy loss ~ 40 keV

BGD Spatial Distribution MAXI GSC Calibration and Analysis Status Anode wire (250 mm) Efficiency of anti- coincidence cut is downed at the counter edge Sensitivity gap for support structure Residual BGD profile is almost flat.

In-orbit BGD-rate Variation BGD-rate v.s. cutoff-rigidity relation MAXI 2010GSC Calibration and Analysis Status35

36 Daily all-sky map Light curve, image, (spectrum) of pre-listed sources (130 sources on 4/10/2010) Samples of early archive products ( MAXI 2010GSC Calibration and Analysis Status

90% containment (other sources) Cyg X deg GX deg GRS deg Cyg X deg Crab 0.16 deg MAXI 2010GSC Calibration and Analysis Status

GSC HV-Down Area 38 SAA |Latitude|>40 o /15-9/ / MAXI 2010GSC Calibration and Analysis Status

HV operation efficiency MAXI 2010GSC Calibration and Analysis Status / / / /30 GSC_0 GSC_1 GSC_2 GSC_3 GSC_4 GSC_5 GSC_6 GSC_7 GSC_8 GSC_9 GSC_A GSC_B /23 40% 80% Redundant