by alter-ego » Tue Jan 10, 2017 5:53 am
Boomer12k wrote:40 million years ago.... how many Supernova, and Planetary Nebula have come and gone in that time?
Well, for what it's worth, involved rate calculations were made in this
2010 paper using the Lick
Observatory Supernova Search (LOSS). The raw numbers were 2.3 million
SN observations over 11 years of data consisting of 14,882 galaxies within 200Mpc.
The simplest analysis A simple average yields an
SN observation period of ~9 days.
The formal analysis entailed galaxy types, SN types, galaxy inclination angle, color, luminosity normalization and more. Also some unexpected cosmological evolution effects were seen within the 200 MPC distance range which added further binning for their analyses.
For all the galaxies, a total of 1036 SNe were counted (Type Ia, Type 1bc and Type II).
The graph shows the distribution of the SNe over distance.
In any case, over 40 million years there's a heck of a lot supernovae that occurred,
certainly likely in the billions just within 200 Mpc!
Edit: I woke up this morning and out of the blue realized the numbers and my interpretation of the graph did not make sense, and I'm correcting that. These numbers are now reasonable - I fell into the classic case of not seeing the forest for the trees
[quote="Boomer12k"]40 million years ago.... how many Supernova, and Planetary Nebula have come and gone in that time?[/quote]
Well, for what it's worth, involved rate calculations were made in this [url=https://arxiv.org/pdf/1006.4611v2.pdf]2010 paper[/url] using the Lick
Observatory Supernova Search (LOSS). The raw numbers were 2.3 million [s]SN[/s] observations over 11 years of data consisting of 14,882 galaxies within 200Mpc. [s]The simplest analysis[/s] A simple average yields an [s]SN[/s] [color=#0000FF]observation[/color] period of ~9 days.
[attachment=0]SNe Tally - SN types.JPG[/attachment]
The formal analysis entailed galaxy types, SN types, galaxy inclination angle, color, luminosity normalization and more. Also some unexpected cosmological evolution effects were seen within the 200 MPC distance range which added further binning for their analyses.
[color=#0000FF]For all the galaxies, a total of 1036 SNe were counted (Type Ia, Type 1bc and Type II).
The graph shows the distribution of the SNe over distance.[/color]
In any case, over 40 million years there's a heck of a lot supernovae that occurred, [s]certainly[/s] [color=#0000FF]likely[/color] in the billions just within 200 Mpc!
[i]Edit:[/i] I woke up this morning and out of the blue realized the numbers and my interpretation of the graph did not make sense, and I'm correcting that. These numbers are now reasonable - I fell into the classic case of not seeing the forest for the trees :)