Proc. of the GHOU 2007 in Tokyo

Using JAXA's Space Science Data for Education and Public Outreach

*1 Ken EBISAWA

JAXA (Japan Aerospace Exploration Agency) is Japan's sole space organization, which is launching space science missions such as astronomical satellites, lunar and planetary missions and solar-terrestrial physics satellites, as well as practical missions such as whether satellites and communication satellites. I will introduce JAXA's space satellite missions and data, and our efforts to utilize these data for education and public outreach purposes.

1. Introduction

Currently, JAXA's three astronomical satellites, Suzaku (X-rays), Akari (infrared) and Hinode (Solar), are operational, and continuously taking superior data in each field of astronomy. Furthermore, Hayabusa, an asteroid sample return mission, has produced excellent images of the asteroid Itokawa. The SELENE lunar orbiter, named “Kaguya” after the launch on Sep 14, 2007, is going to provide the most complete lunar reconnaissance data as well. Most of these data taken by JAXA satellites will become public after short proprietary periods, and be freely used not only for scientific researches but also for educational purposes and public outreach. Fig.1. Omnibus of Hinode and Suzaku archival data We are maintaining the JAXA’s space science at DARTS. Taken from “DARTS of the month” in archives named DARTS (Data ARchives and June, 07;http://darts.isas.jaxa.jp/month/200706.html. Transmission System; http://darts.isas.jaxa.jp), which myself am an X-ray astronomer. X-ray satellite keeps most extensive Japanese scientific satellite date, from educational point of view, have the database (Fig.1). DARTS’s prime purpose is to serve following characteristics: (1) Almost all the X-ray professional space scientists all over the world, but it astronomical satellite data are archived. Usually, may be used by educators and/or students. after one-year proprietary period, data are put in the Since DARTS is designed for professional archives, and everybody may freely use them. (2) scientist, significant efforts are required to make Data are highly processed. Users do not need to these data reachable to teachers and students, and to calibrate or reduce the data, but they can maximally utilize these precious data for education. immediately start data “analysis” (Fig.2). (3) X-ray We have a plan to start such systematic efforts in astronomy is a scientific field Japan is particularly collaboration with JAXA’s scientists and educators. strong at. Japan has been launching five X-ray

satellites, and there are more than 100 professional 2. Using X-ray Data in Education Japanese X-ray astronomers, who are diversely

distributed at universities or institutes all over Japan. As an example, I will present some ideas to I present two examples of the lesson plans using utilize X-ray satellite data for education, since I X-ray data in the following. *1 Center for Planning and Information Systems (PLAIN Timing analysis of Crab pulsar: center), Institute of Space and Astronautical Science Since X-ray photon can be counted by detectors (ISAS), Japan Aerospace eXploration Agency one-by-one, we will have “an X-ray event file” when (JAXA), [email protected] 1 © 2007, Japan Association for Hands-On Universe Proc. of the GHOU 2007 in Tokyo photon events are recorded. For each X-ray event, the photon arrival time is recorded with an accuracy of up to microseconds. For fast-rotating pulsars, such as Crab pulsar (P~30msec), the pulsation can be readily seen from the list of photon arrival time. If you see the raw light curve by naked eye, you may not notice the pulsation, since signal-to-noise ratio is too small. However, if you “fold” the light curve at the correct period of the pulsar (=put each photon in to the corresponding phase-bin), pulsation shall emerge. Such an analysis can be easily made using an EXEL-type spread-sheet. Thorough this lesson using real satellite data, students learn the concept of “phase” of pulsation/oscillation, and basic Fig.2. Explanation of the X-ray astronomical satellite statistics. data. Highly processed data are sent to guest users, Search for Black hole candidate on the Galactic so that they can start data “analysis” immediately, plane: not being worried about instrument calibration and The Ginga satellite, which was operational from data “reduction”. 1987 to 1991, carried out many Galactic scan observations to search for new X-ray sources. 3. Public Outreach using DARTS From the scan profile analysis with several different energy bands, Ginga could determine the accurate In DARTS, we have been developing systems position and approximate X-ray energy spectra of the which are useful for professional scientists to quickly new sources. For example, A new X-ray source browse a large amount of data, and are also easily was discovered in the Norma region on the Galactic used by ordinary people, in particular for science plane in 1988 April ([3]), which is considered to be lovers, to take a look at the latest satellite data. a black hole candidate because of its characteristic For example, beautiful solar pictures and movies X-ray energy spectrum. taken by the Yohkoh data (1991-2001) are found Most X-ray transient sources on the Galactic plane at http://darts.isas.jaxa.jp/solar/yohkoh/data.html. are either neutron star binaries or black hole binaries. Auroral movies taken by Akebono satellite are at One of the big differences is in their energy spectra. http://darts.isas.jaxa.jp/akbn/akebono/aurora. Using Since black holes are more massive than neutron JUDO (JAXA’s Universe Data Oriented; stars and their Schwarzschild radii are larger, the http://darts.isas.jaxa.jp/astro/judo), one can navigate black hole accretion disk inner-radii are also larger the universe using mouse by browsing the Suzaku than those of neutron stars. Consequently, disk X-ray color pictures. temperature is, in general, lower for black hole We have a plan to put explanations for ordinary candidates than neutron stars. people to understand the meaning of these satellite In this lesson plan, students are given the Ginga data. We would need to cooperate with schools or Galactic plane scan data and a dedicated program to educational institutes for this project. carry out the scan profile analysis. Students analyze the data, and find out position of the new source, and References its energy spectrum. If students compare the energy [1] Yamauchi, S. 2005, “An Ultrasoft Transient spectrum of the new black hole candidate and other X-ray Source in the Norma Region Discovered with neutron star sources that are simultaneously observed, Ginga”, Publication of the Astronomical Society they will understand the black hole energy spectrum Japan, 57, 465 has lower characteristic temperature.

2 © 2007, Japan Association for Hands-On Universe