NASA·APOD每日天文一圖2022.5.17 [超高清]

Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Investigations indicate that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just on the upper right. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls and shells of stars and gas visible in this wide and deep image. One thing that >remains unexplained is the unusually small globular star clusters, seen as faint dots on the image. Most elliptical galaxies have more and brighter globular clusters than NGC 1316. Yet the observed globulars are too old to have been created by the recent spiral collision. One hypothesis is that these globulars survive from an even earlier galaxy that was subsumed into NGC 1316. Another surprising attribute of NGC 1316, also known as Fornax A, is its giant lobes of gas that glow brightly in radio waves.?
當(dāng)天文學(xué)家試圖找出NGC1316等令人震驚的景象的原因時(shí),他們會(huì)變成偵探。研究表明,NGC 1316是一個(gè)巨大的橢圓星系,大約在1億年前開始吞噬右上角一個(gè)較小的旋渦星系鄰居NGC 1317。支持證據(jù)包括螺旋星系特有的暗塵埃帶,以及在這張寬而深的圖像中可見的恒星和氣體的微弱漩渦和外殼。有一件事仍然無法解釋,那就是異常小的球狀星團(tuán),在圖像上被視為暗點(diǎn)。大多數(shù)橢圓星系的球狀星團(tuán)比NGC 1316更多、更亮。然而,觀測(cè)到的球狀星體太古老了,不可能是最近的螺旋碰撞產(chǎn)生的。一種假設(shè)是,這些球狀星體來自一個(gè)更早期的星系,該星系被歸入NGC1316。NGC 1316的另一個(gè)令人驚訝的特性,也被稱為Fornax A,是其巨大的氣體葉,在無線電波中發(fā)出明亮的光。