過去五十年來，存在於星系間的星光逐漸被觀測到。然而，這些星光的來源仍然無法被清楚的解釋。2006年，Stanghellini et al. 提出橢圓星系吞併的理論，他們認為，橢圓星系吞併時所拋出的星，可能是這些存在於星系間星光的來源。在他們的研究中發現，依據相對質量或相對速度的不同，大約有5.5%~21%的星會從橢圓星系中被拋出而存在於星系間。我們利用多體模擬來研究disc galaxy吞併時所拋出的星是否可能為星系間星光的來源。我們發現，在disc galaxy正面碰撞下，大約有2%~5%的星會被拋出而存在於星系間。

Intracluster stars have been observed and studied in the past fifty years but the origin of these stars is still not clear. Stanghellini et al. (2006) suggested that the scenario of elliptical galaxy merging is a possible origin of intergalactic stellar population. They conclude that there are 5.5% ∼ 21% intergalactic stars are produced depending on the initial mass ratio and the initial relative velocities of the elliptical galaxies. We use N-body simulations of the mergers of disc galaxies to investigate its importance on the production of intracluster stellar population. In our simulations, the galaxies have head-on collisions with different relative orientations and different relative velocities. Although the final density profile of stellar components are very different for different models, the fractions of escaping stars are all around 2% ∼ 5%.

[1] Binney, J., & Tremaine, S. 1987, Galactic Dynamics (Princeton Univ. Press)
[2] Durrell, P. R., Ciardullo, R., Feldmeier, J. J., Jacoby G. H., & Sigurdsson, S.
2002, ApJ, 570, 119
[3] Hernquist, L. 1993, ApJS, 86, 389
[4] Lewis,J., & Freeman,K. C. 1989, AJ, 97, 139
[5] Mayer, L., Governato, F., Colpi, M., Moore, B., Quinn, T., Wadsley, J., Stadel,
J., & Lake, G. 2001, ApJ, 547, L123
[6] Merritt, D. 1984, ApJ, 276, 26
[7] Mihos, J. C., Harding, P., Feldmeier, J., & Morrison, H. 2005, ApJ, 631, L41
[8] Moore, B., Katz, N., Lake, Ge., Dressler, A., & Oemler, A. 1996, Nature, 379,
613
[9] Schombert, J. M., 1986, ApJS, 60, 603
[10] Springel, V., Yoshida, N., & White, S.D.M., 2001, NewA, 6, 79
[11] Stanghellini, L., Gonzalez-Garcia, A. C., & Manchado, A. 2006, ApJ, 644, 843
[12] Toomre, A., 1963, ApJ, 138, 385
92
BIBLIOGRAPHY 93
[13] van der Kruit, P. C., & Searle, L. 1981, A&A, 95, 105
[14] Zwicky, F., 1951, PASP, 63, 61