Star formation near and far

…or rather unimaginably far and then far, far, farther.

The WISE infrared space telescope has captured an image of the star cluster Berkeley 59 as well as the associated stellar remnant nebula, NGC 7822. The cluster is filled with young stars bursting from a central point, but also surrounded by dust and gas. The green indicated stuff is the outer shell of relatively dense cold dust. Inside it, the red stuff is warmer gas within which new stars are being formed. Further information on the image can be found in the JPL press release.

Image credit: NASA/JPL-Caltech/UCLA

Berkeley 59 is a mere 3,300 light years away in the direction of the constellation of Cepheus. Ten billion light years away, the furthest indication of star formation ever seen has been observed.

The romantically named SMM J2135-0102 is only visible to us due to a gravitational lensing event by a cluster of galaxies between it and us. Even so, the light is hidden by there being plenty of dust and it took the Atacama Pathfinder Experiment (APEX) to spot the submillimetre radiation it emitted.

Follow-up observations using the Submillimetre Array telescope have shown that the galaxy is forming stars at a rate twenty-five times faster than our own Milky Way (which itself provides about ten solar masses worth of new stars a year). If any of the four stellar nurseries the data suggests are in the galaxy were to be placed beside the Orion nebula, they would shine one hundred times brighter and be three times as large.

It is the second time this team of astronomers has found such a distant star factory and this all lends credence to the idea that star formation hit a peak about 11 billion years ago. It’s also nice to see gravitational lensing providing so much information about the early universe. This effect is one of General Relativity’s earliest tested predictions (most notably in 1919 by Eddington). Of course, Relativity still gets tested today, including precise measurements of the Earth’s gravitational field by Gravity probe B and this effort by astronomers using the Sloan Digital Sky Survey, which observed weak lensing effects and compared them to modelled lenses using cold dark matter and lenses using other gravitational models. Relativity won, extending the range to which it has been tested over to 3.5 billion light years.


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