|Development of the MAXI Nova Alert System and the Photon Event Database
|461, Astronomical Data Analysis Software and Systems XXI
|Negoro, H.; Ozawa, H.; Suwa, F.; Asada, M.; Serino, M.; the MAXI Team
|Monitor of All-sky X-ray Image, MAXI, is an all-sky X-ray monitor on the ISS.
MAXI has provided prompt alert information on transient phenomena in X-rays to
the world since the beginning of the observation, August, 2009. Here, we
present recent development on the MAXI nova alert system and the related photon
event database. Real-time background subtraction in the MAXI nova alert system
enables us not only to detect fainter objects with flux down to 10–15 mCrab a
day, but also to send a prompt e-mail alert automatically to our mailing list
members. Another progress is about the photon-event database. Currently a
large number of X-ray events, about more than 10 Giga records, are accumulated
in the PostgreSQL database. We have investigated the fastest way to retrieve a
large number of events from the database using an SSD RAID array, and found that
the access time to the normal index table in the SSD RAID array is comparable to
that to the cluster index table in a HDD RAID array.