Title: Evidence of an interaction from resolved stellar populations: The curious case of NGC1313 Authors: Esteban Silva-Villa, Soeren Larsen
The galaxy NGC1313 has attracted the attention of various studies due to the peculiar morphology observed in optical bands, although it is classified as a barred, late-type galaxy with no apparent close-by companions. However, the velocity field suggests an interaction with a satellite companion. Using resolved stellar populations, we study different parts of the galaxy to understand further its morphology. Based on HST/ACS images, we estimated star formation histories by means of the synthetic CMD method in different areas in the galaxy. Incompleteness limits our analysis to ages younger than ~100Myr. Stars in the red and blue He burning phases are used to trace the distribution of recent star formation. Star formation histories suggest a burst in the southern-west region. We support the idea that NGC1313 is experiencing an interaction with a satellite companion, observed as a tidally disrupted satellite galaxy in the south-west of NGC1313. However, we do not observe any indication of a perturbation due to the interaction with the satellite galaxy at other locations across the galaxy, suggesting that only a modest-sized companion that did not trigger a global starburst was involved.
Astronomers using NASA's Hubble Space Telescope have found that young stellar nurseries, called open star clusters, have very short lives. Hubble's Advanced Camera for Surveys gleaned these new observations during a "Where's Waldo" search for blue stars tossed out of their open cluster "nest" in the nearby galaxy known as NGC 1313. Only Hubble has the resolution needed to distinguish individual stars in galaxies at NGC 1313's distance — about 14 million light-years. Astronomers have long known that young or "open" star clusters must eventually disrupt and dissolve into the host galaxy. They simply don't have enough gravity to hold them together, unlike their much more massive cousins, the globular star clusters. Before Hubble, astronomers have had very few observational clues. It's been difficult to observe exactly how star clusters dissolve due to the fact that they are easily lost in the cluttered star field background of the host galaxy.
VLT Image of Starburst Galaxy NGC 1313 The captivating appearance of this image of the starburst galaxy NGC 1313, taken with the FORS instrument at ESO's Very Large Telescope, belies its inner turmoil. The dense clustering of bright stars and gas in its arms, a sign of an ongoing boom of star births, shows a mere glimpse of the rough times it has seen. Probing ever deeper into the heart of the galaxy, astronomers have revealed many enigmas that continue to defy our understanding. This FORS image of the central parts of NGC 1313 shows a stunning natural beauty. The galaxy bears some resemblance to some of the Milky Way's closest neighbours, the Magellanic Clouds. NGC 1313 has a barred spiral shape, with the arms emanating outwards in a loose twist from the ends of the bar. The galaxy lies just 15 million light-years away from the Milky Way - a mere skip on cosmological scales. The spiral arms are a hotbed of star-forming activity, with numerous young clusters of hot stars being born continuously at a staggering rate out of the dense clouds of gas and dust. Their light blasts through the surrounding gas, creating an intricately beautiful pattern of light and dark nebulosity.