HOW To Access MAXI Data Products

The available three versions of MAXI data products are on the tab at the top.

Data products (ver3) is the standard process. daily update.
Data products (ver3 4h) is the standard with frequent updates. 4 hour update.
Data products (ver4l) is the being-developed process with Acam0 data. daily update.

ver3 4 hour contains sources with rapid flux changes.
ver 4l is effective for sources with many data gaps by Acam0.
Those are north ones around Cygnus, Hercules, Perseus, and so on.
Thus it depends on a source that which version is available.
The list of the processes are in the

Source list

All the monitored sources are listed. 

Product notes

 The light curves are in three and the total bands in the unit of ph/s/cm2 since the start of the MAXI observation (UT date=2009/8/15, MJD=55058). The data of 1-day bin or 1 orbit ( 90-minute) bin can be interactive-plotted or downloaded through the download tabs. The file-format is "MJD, 2-20 keV, error, 2-4 keV, error, 4-10 keV, error, 10-20 keV, error".  The Crab spectrum is assumed in the efficiency correction for each band. Therefore generally the value in 2-20 keV is not equal to the sum of the three bands.

1 Crab equals 3.21 ph/s/cm2 in the total band, and
1.67, 1.15, 0.36 ph/s/cm2 for 2-4, 4-10, 10-20 keV band, respectively (v3, v3rkn).

The image is that of the last one-day in the total and 3 energy bands. The MJD can be specified by typing in the tab. Also day, week, month images can be selected.


Sequential lack of data points may be due to the source location close to the Sun, near scan poles, or a down time for a system maintenance.

The data may contain some bad-quality points, which may exhibit flare-like profiles for unexpacted background increase or dip-like profiles for a shadow of solar-battery paddles. The flux in the 2-4 keV band has a larger uncertainty for an unsufficeint calibration of window absorption (see Crab light curve). The process of data reduction and the calibration of instrument responses are still in progress. These problems will be improved. The data may be modified/updeted without any previous notice.

MAXI observation field of views were sometimes obstructed by the Space Shuttle when the vehicle was docked on the space station (2009/8/31-9/8, 11/18-25, 2010/2/10-20).  These down time has not been taken into account.

The data is updated every day. The data with the process version 0.8 are updated in every 4 hours.

When you use the data, please do it with your own risk.


Notice of erratum:
In the archived MAXI/GSC light-curve data version 1.4 which has been released since 2012 September,  values of the flux errors due to the statistical uncertainty had been incorrectly stored since 2012 November to 2013 April 24 and since 2013 July 22 to December 20. (They were the halves of those supposed to be. )
The error was fixed on 2013 December 21.  If you have these light curve data, please download the latest one from our archive site, again.  
We apologize for the inconvenience. 
(2013 December 21)


When you publish a scientific paper utilizing the MAXI data, please acknowledge as
"This research has made use of the MAXI data provided by RIKEN, JAXA and the MAXI team."
and please cite the paper:
"The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images"  
Matsuoka, M. et al., PASJ, 61, 999 (2009)

Change Log

  2011.12.5. One Crab numbers are written. (Mihara)

  2016.12.28.  modyfied for temporal (Mihara)


   You have a question about MAXI, please contact us via the Contact Form.


copyright (c) RIKEN, JAXA, MAXI team.