Supernova rates

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Supernova rates
Enrico Cappellaro
Osservatorio Astronomico di Padova Istituto
Nazionale di Astrofisica
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SN discovery recordhttp//web.oapd.inaf.it/supern
/snean.txt
O?gt0
1998bw GRB
1988T z 0.28
1995at z 0.66
end of Palomar search
Southern SN searches
1987A
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SN and galaxy types
Asiago SN catalogue RC3 galaxy sample
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Rates vs. recent discovery recordrates from
Cappellaro et al. 1999
z lt 0.01, period 2000-2006, RC3 normalization
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where the difference come from ?

• over-estimate of search efficiency
• adopted SN luminosity function biased against
  faint objects
• under-estimate of extinction correction
• for Ib/c bias in classification of 70-80 Sne
  

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Apparent magnitude distribution of nearby
(zlt0.01) SNe
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Core collapse from blue supergiants SN 1998A -
Pastorello et al. 2005 MNRAS 360, 950
SN 1987A is not unique
87A-like are likely 10 of SNII
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SN and galaxy luminosity
SN rate is proportional to luminosity 80 of SNe
in galaxies brighter than B -20
LGRB occur in low luminosity galaxies They are
associated to SN Ib/c
fraction of Ib/c over core collapse independent
on luminosity
Only a small fraction of SNIb/c are linked to LGRB
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SNIa progenitor population
SN Ia explode (also) in Elliptical galaxies van
den Bergh (1959) Ann.Ap. 22,123 Bertaud (1961)
Ann.Ap. 24, 516
progenitors are long lived, low mass stars
High rate of SN Ia in spirals
Oemler Tinsley (1979)
most type Ia SNe come from short lived stars
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Cosmic evolution of SN Ia rate
Dahlen et al. 2004 ApJ 613,189 Strolger et al
2004 ApJ 613,200
SN Ia progenitors are 4 Gyr old
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SN rate per unit massMannucci et al. 2005 AA
433,807

• SN rate in SNu from Cappellaro et al. 1999
• B ? K galaxy magnitude normalization (from
  2MASS)
• log (M/Lk) ? B-K

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Hubble type of SN Ia host galaxies of the local
Universe
Two channels for SN Ia evolution
SNr(Ia) 0.0470.35 SNr(CC)
see also Scannapieco Bildsten 2005
Half of the SNIa in the local Universe are from
young progenitors
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Southern Intermediate Redshift ESO SN Search
Cappellaro et al. 2005, Botticella et al. in
preparation
ESO WFI_at_2.2m field of view 34x 33 pixel scale
0.238 arcsec/pix effective search area
5.1sq.deg 25(13) nights
ESO VLTFORS1/2 spectroscopic follow-up 13 nights
SN 2000fc Ia z0.42
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Pros
Cons

• only 35 SN spectroscopic
• classification
• U band not available
• limited redshift range

• unbiased candidate selection
• both Ia and CC rates
• well defined galaxy sample
• detailed error analysis
• improved treatment of extinction correction

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Southern Intermediate Redshift SN
search Botticella et al. 2007
200 candidates
60 long term variability AGN
41 direct spectroscopy
15 Ia 14 II 5 Ib/c 7
AGN
44 host galaxy spectra
22 AGN
Photometric redshifts for 40000 galaxies
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Extinction correction
Riello Patat 2005
AV 9 mag
2002cv
2002bo
AV 1.1 mag
I band
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what is not accounted forSN in the nucleus of
starburst galaxies
M82 radio remnants indicate 1 SN / 20yr only SN
2004am observed (5 mag abs)
wait for the talk of Filippo Mannucci
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SN rates are derived from maximum likelihood fit
of the observed SN redshift distribution
SNu
SNu
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Core collapse rate evolution
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SN Ia rate evolution
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SN Ia rate evolution
Greggio 2005 AA
Star formation rate evolution
Delay time distribution
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Neill et al. 2007 (astro-ph/0701161)
Blanc Greggio in prep.
SFR from Cole et al. 2001 Hopkins Beacom 2006
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SFR from Cole et al. 2001 Hopkins Beacom 2006
Star formation rate evolution
SFR from Chary Elbaz 2001
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SN progenitor age with redshift
Most local SN Ia are from old progenitors High-z
SN Ia are from young progenitors
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SN Ia rate evolution
Sullivan et al. 2007
0.2ltzlt0.75
local and medium redshift SNIa show the same
dependence on galaxy mass and SFR
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SN Ia diversity vs. parent population
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PREDICTED AND OBSERVED EVOLUTION IN THE MEAN
PROPERTIES OF TYPE IA SUPERNOVAE WITH REDSHIFT
Howell et al. 2007 astro-ph/0701912
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Age distribution of exploding SN Ia at different
redshift
a)
b)
c)
age Gyr a b c 4.2 7.3 3.5 3.7
6.2 3.2 1.8 2.8 1.8 1.2 1.7 1.2 0.9 1.0
0.8 0.7 0.6 0.5
z
0
0.1
0.5
0.75
1.0
1.5
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Conclusions
Possible inconsistency in the calibration of SFR
and CC SN rates. From SN side problem may be
extinction correction.
For rate determination systematics is now more
important than statistics
Star formation history causes uncertainties in
the SNIa rate prediction as large as the delay
time function
Most of SN Ia in the local and low-z Universe are
from middle age progenitors.
All current scenarios predict that at high-z SN
Ia progenitor are young (0.5 Gy at z1.5)