2001gn

This supernova was discovered at the time of the research campaign of spring 2001 by instrument CFH12K with the CFHT. It was detected on April 16, on 2001, then confirmed April 20.

Its spectrum (B.5 of Keck. An exposure time of 2h allowed its identification and the measurement of its redshift (1.1) by using the lines of the supernova.

A line which could correspond to a galactic line was observed in the spectrum indicating a shift towards the red of 1.12 in very good agreement with that measured on the spectrum of the supernova.

It was then observed with 5 resumptions out of I and a resumption in Z by the space telescope Hubble starting from its maximum of luminosity (B.7 table ).

**Appear B.5:** In black, the spectrum of 2001gn. This spectrum was observed the 23 and on April 24, 2001 with the Keck telescope and the spectrograph scale ESI. The time of integration is $2 \times 6100$ seconds distributed over the two nights. The spectrum is compared with the spectra of 1990N with various phases (respectively 7 and 14 days before the maximum in red and blue). To note, the spectrum was smoothed to emphasize the lines characteristic of the supernova (broad lines) to the detriment of the narrow lines.
$\begin{figure}\it \begin{center} \epsfig{file=Images/2001gnspectre, width=12cm}\end{center}\end{figure}$

B.7 table: Summary of the observations of 2001gn.

Telescope	Instrument	Go back to observationa	filter	Expositionb	seeingc
CFHT	Cfht12K	51999.48	I	9240	0.67
CFHT	Cfht12K	52016.49	I	9900	0.65
CFHT	Cfht12K	52020.38	I	3300	0.61
CFHT	Cfht12K	52350.56 $\dag$	I	1200	0.82
CFHT	Cfht12K	52353.55 $\dag$	I	4800	0.73
CFHT	Cfht12K	52377.58 $\dag$	I	3600	0.64
CFHT	Cfht12K	52378.52 $\dag$	I	3000	0.79
CFHT	Cfht12K	52382.52 $\dag$	I	1800	0.77
CFHT	Cfht12K	52385.49 $\dag$	I	1800	0.78
CFHT	Cfht12K	52387.37 $\dag$	I	1800	0.78
CFHT	Cfht12K	52407.28 $\dag$	I	1800	0.64
CFHT	Cfht12K	52413.31 $\dag$	I	1800	0.77
CFHT	Cfht12K	52416.30 $\dag$	I	1800	0.57

aDate Julienne $\dag$ Images of reference without the supernova.

B.8 table: Summary of the observations with the space telescope Hubble of 2001gn.

Instrument	Go back to observationa	filtreb	Exposure C
HstWfpc2	52030.54	F814W	2300
HstWfpc2	52040.51	F814W	3600
HstWfpc2	52051.35	F814W	4700
HstWfpc2	52064.53	F814W	7100
HstWfpc2	52078.37	F814W	7200
HstACS	52765.89 $\dag$	F814W	946
HstWfpc2	52036.36	F850LP	7100
HstACS	52765.95 $\dag$	F850LP	946

aDate Julienne $\dag$ second of reference without the supernova.

**Appear B.6:** Supernova 2001gn in band I observed by the Hubble telescope on the left and the CFHT on the right, the magnitudes of some objects of the field are presented in B.9 table .

B.9 table: Magnitudes of some stars of the field of 2001gn.

Stars	I	R
With	18.28 $\pm$ 0.01	-
B	19.52 $\pm$ 0.01	-
C	17.14 $\pm$ 0.06	-
D	19.93 $\pm$ 0.02	-
E	20.40 $\pm$ 0.02	-
F	20.21 $\pm$ 0.02	-

B.10 table: Curve of light of 2001gn in band I

Phase $\dag$	I $\ddag$
52016.50(0.01)	24.83(0.14)a
52020.40(0.01)	24.56(0.10)a
52030.54(0.01)	24.28(0.09)b
52040.51(0.01)	24.65(0.10)b
52051.34(0.01)	24.95(0.12)b
52064.52(0.01)	26.01(0.27)b
52078.37(0.01)	27.52(1.07)b

$\ddag$ standard Magnitude in filter I aObservations with the CFHT bObservations with HST

B.11 table: Curve of light of 2001gn in band Z the points all are measured with the HST.

Phase $\dag$	Z $\ddag$
52036.37(0.01)	23.59(0.11)

$\ddag$ standard Magnitude in filter Z

**Appear B.7:** Curves of light of 2001gn in standard magnitudes in the filters R and I
$\begin{figure}\it\begin{center} \epsfig{file=Images/2001gn_LC_I.eps, width=12cm}... ...sfig{file=Images/2001gn_LC_Z.eps, width=12cm}\vskip 2cm \end{center}\end{figure}$

**Appear B.8:** Curves of light of 2001gn in standard fluxes in the filters R and I
$\begin{figure}\it\begin{center} \epsfig{file=Images/2001gn_LC_flux_I.eps, width=... ...file=Images/2001gn_LC_flux_Z.eps, width=12cm}\vskip 2cm \end{center}\end{figure}$