It was back to science this week for the astronomy twitter journal club, with a discussion of the origin of the steep slope in the stellar initial mass function based on this paper.
Why was the paper chosen?
Suggested this paper because it is a very simple idea & ‘natural explanation’ of the slope, coming from a simple -2 slope. – @MarcelAstroph
had this for journal club in Hawai`i, seems a good model but a lot of the interesting physics is at the lower mass end – @nialldeacon
How original is the model put forward?
Is it a new idea? Or have people been focusing on more complicated explanations? – @astronomyjc
Igimf is not new at all, I think realizing that the imf itself is an igimf is new. – @MarcelAstroph
(Igimf = Integrated galaxy initial mass function – @astronomyjc)
Some more details on the model might help
They don’t show very much at all. There doesn’t seem to be very much info on their model even – @astronomyjc
indeed, it usually uses an input imf being salpeter-like, these people take a -2 input and find salpeter back. – @MarcelAstroph
Other models rely on turbulence to get Salpeter slope then interesting physics (variable m_Jeans, accretion) happens at lower mass – @nialldeacon
What about the most massive stars?
I also think their sampling method is extreme in biasing against high mass stars and not physically motivated. Any thoughts? – @MarcelAstroph
It does seem rather like a toy model (as far as I know) – @astronomyjc
I don’t think a model with this amount of simplicity should be used to constrain complicated physics… – @MarcelAstroph
But is it interesting if even a toy model does match slope solely from built-in mass selection? – @NGC3314
yes, but as I showed in my paper, you can get out any shape by choosing the input mass functions and limits right, – @MarcelAstroph
Overall we liked it
It is, imho, nice to see that papers with just a very simple idea, that is not even fully new gets published and attention! – @MarcelAstroph
Completely agree with that. It’s good to see people playing around with simple ideas which could develop in future – @astronomyjc
#astrojc today reminds me of a chat at JCMT: what’s more complex physics, dN(M)/dM of rocks on HP summit or stellar IMF? We thought rocks… – @StephenSerjeant