SN 1991T Ia in NGC 4527 (SABb) in the Virgo Cluster
OBJECT: SN 1991T Ia in NGC 4527 (SABb) in the Virgo cluster. In Leda it is
NGC 4527 (Leda).
DISCOVERY: 1991apr13.17 by S. Knight (1991) (mazzali1995).
MAXIMUM: 1991apr29.2 (JD 2448375.7 +/- 0.5) in B (lira1998) and this supercedes on the old value
1991apr28.5 (JD 2448375.0) in B (phillips1992). The lira1998 authors include Mark Phillips.
See the US Navy Observatory Julian Date Converter.
This day of the year 119.
SUPERNOVA of the YEAR: 20.
HEADER: Header Common header information for this supernovae.
The common header may (or may not) be updated relative to the header information here
(D. J. Jeffery (2007jan01)).
COMMENTS: A shallow silicon (SS) SN Ia.
Between the phillips1992 1991apr25 spectrum and the CfA supernova archive 1991may05 spectrum,
there seems to be a real gap.
ruiz-lapuente1992 only goes as late as apr22.
So maximum light was missed for spectra.
Must have been bad weather---or someone kicked everyone off the telescopes.
Then CfA has spectra from 1991may05 to 1991may19 with one combined CTIO spectrum in jeffery1992
for 1991may08--09.
SPECTRUM LOG:
JD times for the SN 1991T spectra of many references.
Bmax 1991apr29.2 (JD 2448375.7 +/- 0.5) (lira1998)
JD Bmax Heliocentric velocity (Leda, 2007jul05)
8375.7 1736.
Heliocentric velocity Z redshift
1736.0000000000 0.0057906727
Index JD of some kind Observer phase Rest phase
1 8362.5700000000 -13.1300000000 -13.0544062065 ! ruiz-lapuente1992 1991apr16.07 3200--8430 (observer) with 250 error
2 0.0000000000****************************** ! but there is something wrong with
3 0.0000000000****************************** ! wavelength scale and I add 250 A
4 0.0000000000****************************** ! to put the 7600 A telluric line
5 0.0000000000****************************** ! where it should be. This makes the
6 0.0000000000****************************** ! apr16 and apr17 spectra agree nicely.
7 8363.6500000000 -12.0500000000 -11.9806241270 ! ruiz-lapuente1992 1991apr17.15 3300--8150 (observer)
8 8364.6500000000 -11.0500000000 -10.9863814609 ! ruiz-lapuente1992 1991apr18.15 3300--8150 (observer)
9 8365.7600000000 -9.9400000000 -9.8827721015 ! jeffery1992 1991apr19.26 4470.-- 10120.82487 (observer)
10 8366.6500000000 -9.0500000000 -8.9978961286 ! ruiz-lapuente1992 1991apr20.15 3150--10030 (observer)
11 8367.6200000000 -8.0800000000 -8.0334807424 ! ruiz-lapuente1992 1991apr21.12 3150--10030 (observer)
12 8368.6800000000 -7.0200000000 -6.9795835163 ! ruiz-lapuente1992 1991apr22.18 3150--10030 (observer)
13 8371.5000000000 -4.2000000000 -4.1758191978 ! phillips1992 1991apr25.0 3056.261609--10424.865185 (observer)
14 0.0000000000****************************** ! The phase might anywhere from 1.5 to 2.
15 8381.7500000000 6.0500000000 6.0151681302 ! cfa sn archive 1991may05.25 4730.6477409--7150.0002071 (observer)
16 0.0000000000****************************** ! Unpublished?
17 8382.7900000000 7.0900000000 7.0491805030 ! cfa sn archive 1991may06.29 4657.893--7064.662092 (observer)
18 0.0000000000****************************** ! Unpublished?
19 8395.7900000000 20.0900000000 19.9743351628 ! cfa sn archive 1991may19.29 4579.1--7064.642969 (observer)
20 0.0000000000****************************** ! Unpublished?
21 8457.8000000000 82.1000000000 81.6273228904 ! filippenko et al. 1991jul20.3 3150.000--9886.000 (observer?)
22 0.0000000000****************************** ! Unpublished.
REFERENCES:
CfA List of Supernovae
where SN 1991T is noted.
CfA Supernova Archive
This has 23 SN 1991T spectra which probably are some of the ones I have, but in different versions.
The FITS headers should give the time of observation.
conley2006 General value
of 19.4 days for Ia rise time in B.
jeffery1992 On early 91T spectra.
mazzali1995 On early 91T spectra.
paturel2003 (Leda) Leda refererence.
phillips1992 On early 91T photometry.
ruiz-lapuente1992 On the early spectra.
schmidt1994 On the 91T light echo at late times.
SUSPECT Index.
SUSPECT Index: SN 1991T Ia.
There are 13 SN 1991T spectra from various sources though they mostly seem to passed through the hands of Asiago.
CORRECTIONS: Heliocentric velocity 1736 +/- 1 km/s (2007jul05) from
NGC 4527 (Leda).
Galactic foreground reddening .09/4=.0225
NGC 4527 (Leda).
The reddening is derived from
Schlegel et al. (1998).
OBSERVATIONS: From
1) David Jeffery's old catalog: some.
2) Eddie Baron: none.
3) SUSPECT:
4) CfA supernova archive.
PHASE:
For consistency we always use rest phase and for explicitness to more digits than are significant.
observer phase =
rest phase =
&specnamelist
aname='sn1991t Ia 1992_04_'
ebv=.0225
epoch= ! This parameter needs to updated for the particular spectrum.
idifmake=0
iformat=1 ! This has to be checked for every spectrum.
ismooth=0 ! Smoothing?
itick=2
itickln=4
t_rise=19.4d0 ! conley2006: just a mean rise time.
v_helio=1736.
ymin2=1.e-15
ymax2=7.e-14
ymin3=.3
ymax3=3.
wlammin1=
wlammax1=
wlammin2=
wlammax2=
wlammin3=
wlammax3=
/
Postscript plot of the spectrum.
Postscript plot of the spectrum with local normalization.
Information from somewhere and someone.
