Astronomers discover unusual monster galaxy in the early universe

phys.org

39 points·dnetesn··5 comments

How do they get information about stellar formation history from a single observation?

The used a series of observations across a broad spectrum I didn't read the paper, but I suspect the number of observations was quite large.

Thanks. But I meant that they only see the thing at one time. So talking about events over billions of years seems iffy.

Only an amateur observer and occasional paper browser, but my general take is that there are an awful lot of prior models of everything from the stellar nucleophysics up through environmental effects in nurseries, nebulae, galaxies, clusters, etc.

Years and years of observations, hypothesizing, and refining with even more observations combine to give a halfway decent storyline of many processes at all scales.

These are then fit against new observations and either refined or modified or expanded to give new data a home as well.

All in all, a very cool example of the scientific process working itself out just as it should and can.

Based on the total flux, and photometry, usually they will assume a model for the star formation history. Sometimes a single burst, a constant star formation rate, an exponentially declining star formation rate, or maybe a combination of multiple bursts. The strength of the Balmer Break and the UV slope can be good indicators but even in this case, there are large uncertainties. I haven't read the paper but this is how it's often done in general. Of course, the type of stellar populations you use, impacts from dust, and the fact that star formation histories are rather complicated can impact accuracy.

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