From: Vitaliy Fadeyev (VAFadeyev@lbl.gov)
Date: Fri Jun 11 2004 - 09:41:12 PDT
Hi Greg and Serena,
I might have a bug in the fitting procedure. I'm looking into this right
now.
About the snminuit -- it fits a lightcurve data to a combination of proper
bandpass template and corresponding k-correction. The bandpass templates
have not changed in recent past. The k-corrections are going to depend
on the supplied spectral template, of course.
vitaliy
Greg Aldering wrote:
>Hi Vitaliy,
>
>I looked at the various fits you made for 99qQ with an eye towards
>understanding why the peak magnitudes change so much (well outside the
>quoted uncertainties) when the discovery point is added. I figured that
>the the poorer chi^2 when this point is added were likely caused by this
>point being fit poorly.
>
>However, this discovery point fits just fine! Instead it appears that the
>new lightcurve parameters from R->B then make the I->V fits worse. In the
>case of Peter's template, the poor fit is due to a weird drop in the
>template lightcurve at late times, which completely misses the HST point.
>
>Overall, I was struck by the highly structured (not smooth) shape of the
>templates we are now fitting. The B-band template has a straight - rather
>than rounded - pre-max face, and the templates are very pointy near
>maximum (especially in V-band). Serena's V-band template as plotted on
>these fits appears to have some numerical artifacts near max (the 2nd
>derivative is discontinuous), and as mentioned above there is a spurious
>"shelf" at late times in the Peter template.
>
>A question for the group then is do all the lightcurve fits we are now
>performing have these highly-structured template lightcurves? If so, is
>this structure thought to be real or due to artifacts in the construction
>of the templates? Perhaps this has more to do with how SNminuit is
>interpolating the lightcurves?
>
>Signed,
>
>Curious Greg
>
>
>On Thu, 10 Jun 2004, Vitaliy Fadeyev wrote:
>
>
>
>>Dear Serena,
>>
>>please find the results below. For comparison, I show the snminuit runs
>>for Robs' template, new "precise" Peter template (supplied by Rollin),
>>and the one supplied by you.
>>
>>Cases are:
>>
>>1R - HST only, Rob's template
>>1P - HST only, Peter's template
>>1S - HST only, Serena's template
>>2R - HST and discovery point, Rob's template
>>2P - HST and discovery point, Peter's template
>>2S - HST and discovery point, Serena's template
>>3R - HST and discovery point, tmax fixed to Tonry's, Rob's template
>>3P - HST and discovery point, tmax fixed to Tonry's, Peter's template
>>3S - HST and discovery point, tmax fixed to Tonry's, Serena's template
>>
>>SNMINUIT output table:
>>case m_B dm_R m_B_corr dm_B_corr s ds chisq dof m_R kcorr_R kcorr_I tmax dtmax R-I d(R-I)
>>
>>1R 22.82 0.06 23.02 0.16 1.117 0.054 5.29 8 22.06 -0.764 -0.310 2451186.54 1.444 -0.054 0.074
>>1P 22.36 0.05 22.45 0.13 1.035 0.044 5.74 8 21.66 -0.702 -0.189 2451178.16 1.676 0.005 0.049
>>1S 22.63 0.04 22.77 0.13 1.074 0.046 4.13 8 22.04 -0.585 -0.297 2451186.90 1.497 0.121 0.061
>>
>>2R 23.14 0.02 23.34 0.07 1.119 0.032 9.95 9 22.24 -0.902 -0.419 2451191.83 0.853 -0.188 0.035
>>2P 23.36 0.02 23.57 0.08 1.119 0.033 13.86 9 22.22 -1.140 -0.538 2451192.44 0.729 -0.414 0.031
>>2S 23.08 0.02 23.34 0.09 1.162 0.038 14.61 9 22.26 -0.826 -0.484 2451191.26 0.878 -0.115 0.042
>>
>>3R 23.22 0.02 23.31 0.06 1.040 0.022 26.92 10 22.23 -0.986 -0.484 2451194.65 0.000 -0.269 0.031
>>3P 23.41 0.02 23.52 0.05 1.056 0.017 24.92 10 22.22 -1.186 -0.575 2451194.65 0.000 -0.459 0.029
>>3S 23.20 0.01 23.33 0.05 1.065 0.018 34.39 10 22.25 -0.943 -0.574 2451194.65 0.000 -0.228 0.029
>>
>>
>>The snminuit plots are here:
>>(case 1R) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTonly.ps
>>(case 1P) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTonly_uberPeter.ps
>>(case 1S) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTonly_uberSerena.ps
>>(case 2R) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc.ps
>>(case 2P) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc_uberPeter.ps
>>(case 2S) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc_uberSerena.ps
>>(case 3R) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc_fixtmax.ps
>>(case 3P) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc_fixtmax_uberPeter.ps
>>(case 3S) http://www-physics.lbl.gov/~fadeyev/snminuit_sn1999q_HSTdisc_fixtmax_uberSerena.ps
>>
>>I should note that cases 1P and 1S took a lot of time to converge.
>>Cases 3R,3P,3S have fairly large Chi^2 due to the late-time behaviour
>>being somewhat incompatible with the assumed tmax from Tonry.
>>
>>Cheers,
>>vitaliy
>>
>>
>>Serena Nobili wrote:
>>
>>
>>
>>>Dear Vitaliy (cc SCPexec),
>>>
>>>as you probably know, a new set of spectral template has been produced by
>>>Peter Nugent so to solve some problems of the I-band paper. I have been
>>>working to color correct them (see attachment) repeating the analysis done
>>>in Nobili et al. 2003. I would like to ask you if you could run SNminuit
>>>to fit the B and V- band lightcurve of 1999Q using the new templates. This
>>>should close the analysis and maybe give us a better understanding of this
>>>SN. I hope this will not be too much work for you. Please, let me know if
>>>you think you don't have the time to work on it right now. Thank you very
>>>much for your help.
>>>Cheers,
>>>
>>> Serena
>>>
>>>
>>>----------------------------------------------------------------------
>>>www.physto.se/~serena
>>>Tel +33 1 44 27 75 82
>>>
>>>Give free food at:
>>>http://www.porloschicos.com/
>>>http://www.thehungersite.com/
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
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