README

MAXI Public Data

Three versions of MAXI data products are available from the tab at the top page.

Basic data : Data product (ver 7L)
 The latest version. Daily update.
 Using Low-rate data. A-camera 0 data is used until ~58000 MJD.

Recent data : Data product (ver 7L 4h)
 requent (4 hour) update for some variable sources. Data before 2 days ago is the same as ver 7L.
 Using Low-rate data. A-camera 0 data is used until ~58000 MJD.

With degraded cemeras : Data product (ver 6m)
 Better coverage for nothern bright sources. Daily update.
 Using medium-rate data. A-camera 0 data is used until ~58000 MJD.
 Degraded cameras (A-camera 3 and B-camera 0) are used.
 (The 2-4, and 10-20 keV data of these cameras are only transferred through medium-rate data.)

ver 7L has less dropping data than ver 6L, because it uses better shadow estimation of the ISS solar panels.
ver 7L 4 hour contains sources with rapid flux changes.
ver 6m is useful for sources with many data gaps of degraded cameras, A-camera 3 and B-camera 0.
ver 6m is good for bright sources in the northern sky such as in Cygnus, Hercules, Cassiopeia, and Perseus.
Thus the best version depends on the source.

Source list
Available processes for each source are listed in the "Source list" in the left column,
where all the monitored sources are listed.
"standard" is taken from ver 7L 4h or ver 7L in this priority.
Since it does not contain data from degraded cameras (A-camera 3 and B-camera 0), please look at ver 6m data for them.

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)
( http://ads.nao.ac.jp/abs/2009PASJ...61..999M )

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 looked at or downloaded through the download tabs. The data-format of the standard data is
MJD, 2-20 keV, error, 2-4 keV, error, 4-10 keV, error, 10-20 keV, error.
The data-format of the each version page is
center MJD, low-end MJD, high-end of 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 3.8 ph/s/cm2 in the total (2-20 keV) band, and 2.2, 1.25, 0.40 ph/s/cm2 for 2-4, 4-10, 10-20 keV band,
respectively in versions v7L, v7Lrkn, and v6m.

The image is that of the latest day in the total and 3 energy bands.
Previous daily images are also available.

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 panels.
The flux in the 2-4 keV band has a larger uncertainty for an unsufficeint calibration of window absorption (see Crab light curve).

MAXI on-demand data

You can get an image, a light curve and a spectrum from any time from any part of the sky through MAXI ondemand.
Please visit from the "On-demand" tab on the top page.

Usage may be as follows.
 type "cygnus X-1" in search by name
 click "search"
 image change, (but here RA DEC may not change. 83.633 220.014 is crab nebula by default.)
 click the image, (then somehow the RA, DEC changes to 299,590316 35.201606 which is Cyg X-1.
 This is necessary since the RA, DEC is used for the process. Make sure the RA, DEC.)
 type in target name as "cygx1" or "Cyg_X-1" or whatever. (this is only used for filename. Not use special character as "+".)
 time in MJD (We recommend you to start for 1 day at first, not for the 10 years [It takes several hours.])
 light curve bin in day unit. (or if you type in 0.02 or smaller, it means for every scan.)
 two energy bands
 click "send query"
 The process cannot be stopped. So, please be careful to proceed.
 stay at the page for 1 minutes. Then it changes to the processing page.

When the process takes a long time, you can remember the URL, close the browser and visit it later.

For advanced usage
 You can set your own region files for the source and the background.
 It may be convenient to run an automatic short process first, download the auto-made regions and edit them.
 When you want to clear the uploaded region, you once click the file-selection and click "cancel".
 You can set your GTI (Good Time Interval). Upload a text file as
  55100 55102
  56100 56102
  ... ...
  58100 58102
 then, for time inputs above, please type in the very first MJD and the very last MJD. (55100, 58102 for the case above.)

Change Log

  2020.7.3.  process versions v7L, v7L.rkn, v6m (Mihara)
  2020.5.20.  process versions v7L, v6L.rkn, v6m (Mihara)
  2016.12.28.  modyfied for machine change of maxi.riken.jp. (Mihara)
  2011.12.5.  one Crab numbers are written. (Mihara)

 


   You have any question about MAXI, please contact the mail address at the top page.

 

copyright (c) RIKEN, JAXA, MAXI team.