STUDI DUA ULTRALUMINOUS X-RAY SOURCE (ULX) TRANSIEN DI GALAKSI M31

• Main Author: Dian Siwiutami, Rizqani
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43055
• Institution: Institut Teknologi Bandung

Ultraluminous X-ray Source (ULX) is defined as non-nuclear point-like object, that is not located in the cental region of a galaxy, with luminosity ????X ? 1039 ???????????? ?????1within 0,3?10,0 ????????????. There are two scenarios that can explain ULX luminosity, the first scenario is Intermediate Mass Black Hole (IMBH) accreting at sub-Eddington accretion rate, and the second scenario is Stellar Mass Black Hole (StMBH) accreting at super-Eddington accretion rate. Study of two transient ULXs on the M31, CXOM31 J004253. 1+411422 and XMMU J004243.6+412519 was conducted to review their relation with ULX in general, other ULX transients, and Galactic Black Hole Binary (GBHB). These two transient ULXs had never previously been detected, but suddenly appeared with strong X-ray emission. Sometime later, the luminosity increases up to ?1039 ?????????????????1, until finally it decreases below observation limit. The decrease in luminosity is consistent with that observed in GBHB. It supports the interpretation that transient ULX can be explained by stellar mass black holes in the Low Mass X-ray Binary (LMXB) system, with accretion rates around the Eddington limit. Data from XMM-Newton show that the spectra of the objects are dominated by disk-like component, and not powerlaw as predicted if the object is an intermediate-mass black hole accreting at sub-Eddington rate. This shows the link between the accretion process that occurs in GBHB and ULX-like objects. However, one should keep in mind that the transient nature of the two objects is not commonly found in the ULX population in general.