397 0101 10762 30 e-mail: matsunaga@ioa.s.u-tokyo.ac.jp 8 3 20 2 3 3 7 2 3 1. 100 1912 1 1 4 12 10 3 1 20 2,500 2 1 3 4 374 2012 6
1 Credit: NASA/JPL-Caltech/R. Hurt SSC-Caltech 3 2. 5 3 6 100 7 8, 9 10 105 6 375
11 12 V 30 K 2 μm 3 Keck VLT 13 10 25,000 5 14 24 15 PtSi PANIC * 1 1994 1997 400 K 10 11 3. IRSF SIRIUS 17 PANIC SIRIUS 3 HAWAII J 1.25 μm H 1.63 μm Ks 2.14 μm 7.7 IRSF/SIRIUS 18 19 IRSF/SIRIUS 2005 98 3, 4 IRSF/SIRIUS 12 20 30 2 PANIC 2005 2006 * 2 * 1 PANIC PANIC 16 * 2 20 NEC 376 2012 6
2 IRSF20 30 3 2005 2001 2008 90 J 16.4 H 14.5 Ks 13.1 PANIC Ks 2 4. 8 105 6 377
60 45 100 21 1.5 2 2 2 22 * 3 23 2 24 2007 25 PANIC K J H 146 27,000 26 OGLE Optical Gravitational Lensing Experiment 10 * 3 500 378 2012 6
27 RR 2 OGLE I 0.8 μm 28 J I 2 2 1.5 2 2 45 3 25,000 17 23 1 RR δ 2 3 2 3 3 5. 3 3 20 105 6 379
4 3 3 20 20 4 500 3 20 3 5 20 20 2 3 2 10 2 3 8 10 3 2 3 10 3 10 1 9 3 7 2 3 4 1 2 3 6. 1 380 2012 6
NGC4038/39 ASTE 29, 30 2 1 31, 32 100 33, 34 2,000 35 36, 37 7. 3 1 4 Kiso Wide-Field Camera KWFC CCD 2012 4 105 6 381
KWFC 38 4 IRSF SIRIUS IRSF/SIR- IUS 365 24 1 Leavitt H. S., Pickering E. C., 1912, Harvard College Observatory Circ. 173, 1 2 Bono G., et al., 2005, ApJ 621, 966 3 Fernie J. D., et al., 1995, Inform. Bull. Variable Stars 4148, 1 4 Matsunaga N., et al., 2011, Nature 477, 188 5 Genzel R., et al., 2010, Rev. Mod. Phys. 82, 3121 6 Gillessen S., et al., 2011, Nature 481, 51 7 Zoccali M., et al., 2003, A&A 399, 931 8 Serabyn E., Morris M., 1996, Nature 382, 602 9 Yusef-Zadeh F., et al., 2009, ApJ 702, 178 10 Figer D.F., et al., 1999, ApJ 525, 750 11 van Loon J. Th., et al., 2003, MNRAS 338, 857 12 Gallart C., et al., 2005, ARA&A 43, 387 13 Schödel R., et al., 2003, Nature 419, 694 14 Rafelski M., et al., 2007, ApJ 659, 1241 15 Glass I. S., et al., 2001, MNRAS 321, 77 16 1996, 89, 111 17 2004, 18 Nishiyama S., et al., 2005, ApJ 621, L105 19 Nishiyama S., et al., 2006, ApJ 647, 1093 20 2007, 21 2010, 103, 124 22 Harris H. C., 1985, AJ 90, 756 23 Harris H. C., Wallerstein G., 1984, AJ 89, 379 24 Fernie J. D., Ehlers P., 1999, AJ 117, 1563 25 Matsunaga N., et al., 2009, MNRAS 399, 1709 26 Gillessen S., et al., 2009, ApJ 692, 1075 27 Soszyński I., et al., 2008, Acta Astronomica 58, 293 28 Laney C. D., Stobie R. S., 1993, MNRAS 260, 408 29 Tamura Y., et al., 2009, Nature 459, 61 30 Hatsukade B., et al., 2011, MNRAS 411, 102 31 Weinberg M. D., Blitz L., 2006, ApJ 641, L33 32 Purcell C. W., et al., 2011, Nature 477, 301 33 Binney J., et al., 1991, MNRAS 252, 210 34 Kim S. S., et al., 2011, ApJ 735, L11 35 Stark A. A., et al., 2004, ApJ 614, L41 36 Baba J., et al., 2010, PASJ 62, 1413 37 Wada K., et al., 2011, ApJ 735, 1 382012, Star Formation and Evolution of the Galactic Nuclear Bulge Revealed with Cepheid Variable Stars Noriyuki Matsunaga Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, 10762 30 Mitake, Kiso-machi, Kiso-gun, Nagano 397 0101, Japan Abstract: After the eight year monitoring survey using the IRSF/SIRIUS, we discovered three classical Cepheid variable stars around the Galactic Center. Based on the relation between the pulsation period and age, all of them are 25 Myr old. On the other hand, we found none whose age falls between 30 and 70 Myr old. This indicates the variation in star formation rate around the Galactic Center. We discuss its impact on the evolution of the Galaxy. 382 2012 6