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supernova question?
"WG" wrote in message
... Is there an online catalogue for supernovas which lists data? specifically redshift and distances determined by light curves? If I have this right, the distance determined by light curves [supernova as standard candles], differs from distance determined by redshift [hubbles law] by a significant amount. This difference I believe was the reason why dark energy was postulated and currently accepted. Thanks --------------------------------------------------------------------------------------- These days the data files are often published along with the papers themselves. Probably on the CDS database. The links would be given with the ADS listing of the papers, or you could try searching the CDS for catalogues with supernova data. You might even find the spectra, etc. in FITS format. You might well find tables of the data you need. -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) |
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supernova question?
On 19 Pa¼, 19:17, "WG" wrote:
Is there an online catalogue for supernovas which lists data? specifically redshift and distances determined by light curves? If I have this right, the distance determined by light curves [supernova as standard candles], differs from distance determined by redshift [hubbles law] by a significant amount. This difference I believe was the reason why dark energy was postulated and currently accepted. Thanks Dark energy and matter are fabulist"s wishes. IMHO H. C. Andersen had better real physical base. |
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supernova question?
Is there an online catalogue for supernovas which lists data?
specifically redshift and distances determined by light curves? If I have this right, the distance determined by light curves [supernova as standard candles], differs from distance determined by redshift [hubbles law] by a significant amount. This difference I believe was the reason why dark energy was postulated and currently accepted. Thanks |
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supernova question?
Dear WG:
On Oct 19, 10:17*am, "WG" wrote: Is there an online catalogue for supernovas which lists data? specifically redshift and distances determined by light curves? I'd try the references in these recent papers: http://arxiv.org/abs/0809.0537 http://arxiv.org/abs/0808.2655 http://arxiv.org/abs/0807.1244 http://arxiv.org/abs/0805.4136 http://arxiv.org/abs/0803.3441 If I have this right, the distance determined by light curves [supernova as standard candles], differs from distance determined by redshift [hubbles law] by a significant amount. Papers I have read have this as an insignificant amount up to a z of 1.3 or so, after which it becomes very difficult to determine what object the supernova'd star was actually in. This difference I believe was the reason why dark energy was postulated and currently accepted. Not at all. Standard redshift of "stellar" spectra is all that is required, and the "Drunkard's Walk" of course. And Dark Energy is not so much "accepted" as tolerated in light of our current understanding. It is always being challenged, as is everything else in Science. David A. Smith |
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supernova question?
In article ,
"WG" writes: Is there an online catalogue for supernovas which lists data? See http://supernova.lbl.gov/Union/ If I have this right, the distance determined by light curves [supernova as standard candles], differs from distance determined by redshift [hubbles law] by a significant amount. This difference I believe was the reason why dark energy was postulated and currently accepted. That's a bit confusing, but I think you are on the right track. The two distances differ _if you don't include dark energy_ in Hubble's Law. If you do include dark energy, the redshift distance and the standard candle distance agree just fine, and the amount of dark energy is consistent with other data (such as microwave background fluctuations). You might want to take a look at http://www.astro.ucla.edu/~wright/sne_cosmology.html -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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supernova question?
http://www.astro.ucla.edu/~wright/sne_cosmology.html
In article , John Polasek writes: Maybe you can clarify the logic. The y-axis is cz which boldly goes to 900000km/s. No logic needed, but the plot units are confusing. The y axis really is the product of c and z. Yes, that makes no physical sense, but I'm afraid plotting those units is fairly common. Just mentally change the units to z and divide the values by 3E5, and all will be well. As you say, (1+z) is just the ratio of observed to emitted wavelength, and there's no limit on how large it can be. I'm going to email Ned and ask him to change the plot. By the way, the Kowalski et al. paper is well worth reading: http://arxiv.org/abs/0804.4142 -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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