Detailed study of nearby SNIa. Stefano Benetti based on data from literature and. (astro-ph/0411059). Aim: understanding the diversity among “all normal” SNIa through a sample of best studied, archive and recent objects (26). SN 2003du. (Stanishev et al 2005). SN 2002er. - PowerPoint PPT Presentation
Stefano Benetti Stefano Benetti based on data from literature and Detailed study of nearby SNIa Detailed study of nearby SNIa (astro-ph/0411059) (astro-ph/0411059)
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Stefano BenettiStefano Benetti based on data from literature and
Detailed study of nearby SNIaDetailed study of nearby SNIa
(astro-ph/0411059)(astro-ph/0411059)
Aim:Aim:understanding the diversity among understanding the diversity among “all normal” SNIa“all normal” SNIa
through a sample of best studied, through a sample of best studied, archive and recent objects (26)archive and recent objects (26)
sbenetti
I though about this study while working on the new SNIa observed by ESC and in particular studing SN 2002bo. the aim is to see if there are diversity among SNIa and if yes look for correlations
SN 2003duSN 2003du(Stanishev et al 2005)
sbenetti
when I say new SNIA observed by ESC I mean this kind of data quality. here is the example of SN 2003du which vallery stanishev is about to finish a paper
SN 2002erSN 2002er(Pignata et al 2004)
sbenetti
here is another example (pignata et al 2004)
Trento, September 2003
premax spectrapremax spectra (Benetti et al 2004)
SN 1994D -8d (1.32)
SN 2002bo -8d (1.13)
SN 1990N -8d (1.07)
SN 1998bu -7d (1.01)
Profile and intensity of SiII 6355Profile and intensity of SiII 6355
structures in H&K absorptionstructures in H&K absorption
Trento, September 2003
at max ….at max ….SN 1994D -1d
SN 2002bo +0.1d
SN 1990N +1d
SN 1998bu -1d
(SiII)
(Benetti et al 2004)
SN94D –8.5d
SN02bo –8.5d
SN99ee –9d
SN02bo +11.1d
SN99ee +8d
SN99ee +32d
SN02bo +29.4d
after max after max more more
homogeneoushomogeneous
intensity and shape of MgII line intensity and shape of MgII line premax inhomogeneity premax inhomogeneity
IR(Benetti et al 2004)
ΔΔmm1515 or or (SiII) (SiII)
m
15(B
)
Nugent et al. 95
Hamuy et al. (1996)
multidimensionalHatano et al. 2000
t=10d
sbenetti
but already hatano et al some years ago suggested that the SNIa description must be multidimensional: they showed that V10(SiII) is NOT related to Dm15 as a one param. sequence of SNIa should provide (Lum should be porportional to kinetic energy
19881988
an observer`s modern versionan observer`s modern versionS
iII
sbenetti
so I went back and collected all spectra of a sample of old and new SNIa Branch-normal and extreme SNIa (91bg and T-like objects) and redid the SiII velocity measurements on published and unpublished material. Here is the result! Is a messy one?!?probably not!
snguest
measuments made from mosltly from ASA and ESC-RTN database!!!!
Some systematics come outSome systematics come out
sbenetti
for example, if you look at the post-max trend you easily see that there are a group of SNIa (including normal SNIa and 91T-like object) which cluster in a norrow strip and they show shallower slopes in velocity with respect to the others. On the other hands the others SNIa shows a larger range of expansion velocities and a higher postmax velocity evolution.
at this point to see if what we were finding had a physical suppor,t we collect these physical parameters for each SNIa (list the parameters) and we porformed a hierarchical cluster analysis to see how the sample grouped. they indeed grouped "well" with the faint SNIa which form a well separated group, while also the other SNIa diveded in two well separated groups with the green SNIa, those which populoated the previous narrow strip in the velocity evolution diagram, which really form a separated class. the other group consists of high velocity expanding objects, like 84A and 02bo. the separation between these two last classes takes place for a velocity gradient of about 60-70 km/s/day. but what about photometry?
blue and green same luminosity!blue and green same luminosity!
<M<MBB> = -19.2 > = -19.2 ± 0.3± 0.3
<M<MBB> = -19.3 > = -19.3 ± 0.3± 0.3
<M<MBB> = -17.2 > = -17.2 ± 0.6± 0.6
Photometry:Photometry:
sbenetti
given the fact that the luminosity of blue and green is the same, that they however span a range of Dm15, this should be tell us taht there is something weird going on!!! (that Dm15 does not fully describe the SNIa photometric properties?!? In fact, for example see next!)
red and blue form the Nugent’s relation? red and blue form the Nugent’s relation?
(SiII) vs. (SiII) vs. ΔΔmm1515
sbenetti
most of the green's does not conform with peter relation: either there is a break in the relation or they define a new looser and shallower one!
Velocity gradient vs. Velocity gradient vs. ΔΔmm1515
sbenetti
how the velocity gradient correlates with Dm15??? well here it is! SNIA with large Dm15b have a unique gradient, while Branch-normal SNe may have an ample range of velocity gradient!
greens show no evolution!greens show no evolution!
(SiII) evolution(SiII) evolution
sbenetti
another interesting properties distingushing green and blue SNIa is the pre-max evolution of R(SiII). Unfortunately we do not have (to my knowlodge) any spectra of faint SNIA in pre-max!
Padova, June 2004
SII expansion velocitySII expansion velocity(Benetti et al 2004)
sbenetti
what about other ions? well the dichotomy seem to also hold, where this time the difference seems to be in pre-max!
SVGSVG(green)(green)
HVGHVG (blue)(blue)
FAINTFAINT (red)(red)
2.5
0.6
-1.4
((~3-4!)~3-4!)
sbenetti
what about the environment in which the SNIa appear? T is the galaxy type as given in RC3. there appear to be a sistematic increase of the galaxy type going from red to green: these tend to be associated to younger stellar population, even if the standard deviation of the mean is quite large....
SummarySummary
1. detailed observations new clues for SNIa interpretation
2. velocity gradient is an important observational parameter
3. three families: green – blue (see also Wang et al 2004) - red
4. in average: green are +homogeneous, +young population, but same brightness of blue
5. Reasons ?? Different explosions; mixing; CSM-ejecta interaction?
sbenetti
also lifang in his recent paper on specpol of 04dt suggest that blue (he does not call them so....) SNIa may be a different class related to 91T-like object: however we do not see such relation...well, I think we may have a lot of discussion here!!!
