HST rate

   CC up to z=0.7 and SNe Ia up to z=1.6
  42 SNe (!)  
    - 17 CC 
      0.3<z<0.7 increase of rate by 1.6 
      at z=0.7 increase of 7 
      (consistent with SFR) 
    - 25 SNe Ia
      3-5 times higher compared to z<0.5 
      decrease z>1 
      (consistent with Type Ia progenitor model) 


 past measurements
 data from GOODS survey (ACS)
      2 fields, 150 arcmn2/field, up to m(F850LP) 25.9, 5 epochs, 45 days   
   
redshifts:
      29/42 have spectro redshifts 
      photo-z for 12      
      1 no host (visible)
    
types:
      use all information (dont say how/what) 
      25 "consistent" with Ia, 17 CC 
      20 Ia confident 
      7 confident CC
      (include misclassification in systematics) 

simulation: generate SN 

      K-cor following KGP 

CC (follow Richardson 2002)
      subtypes : Ibc, Ibc-bright, IIL, IIL-Bright, IIP, IIn
      all gaussian distrib with peak mag        
      Fraction of subtypes from Dahlen et al. (1999)
      SN spectra= black body at 25000 K near explosion to 5000K late
      LC from Fillipenko 1997
      Extinction model from Hatano et al 1998

Type Ia
      subtypes: 
      20% bright (-19.6 s=0.3)
      64% normal (-19.3 s=0.45)
      16% faint (-17.8, s=0.5)
      Kcor from 1994D  (how does that do at z=1.6?)
      LC mean B-band LC
      Extinction model from Hatano et al. 1998

Results
   CC rates in 2 z bins   
      0.1-0.5 (6SNe) and 0.5-0.9 (10SNNe) 
      2+/-0.8 (stat)+07-1.8(syst)
      4+/-1(stat)+2-2.6(syst)
      higher by factors 4 and 7 compared to local rate of Capellaro et al.
      (converted in volume)
   
   Ia rates in 4 z bins
      0.2<z<0.6   3 SN 
      0.6<z<1.0   14 
      1.0<z<1.4   6 
      1.4<z<1.8   2

their finding
    z=0.4 Rate higher that previous measurements
     suggest that underestimated due to systematics effects
    z=0.8 much higher than previous measurements at lower z
    z>1 consistent with declining 
    factor 5 increase at z=1 
    consistent with SFR 

Relation SFR-SNR 
    various models 

Systematics: 
    they conclude that nothing matters 

Discussion 
    they find rate consistent with SFR 
     + increase then decrease z>1
 
referee D. Maoz

--------paper II
 
Contains more info

 bins    0.3 0.5 0.7 0.9 1.1 1.3 1.5           
 nsn      1   2   6   8   1   6   1 
 chosen         0.2-0.6 3
                0.6-1.0 14
                1.0-1.4 7   
                1.4-1.6 1 
 
why 2 papers ? 
much better written - although verbose 
   (main conclusion 4Gy for Ia)

---------------------------------------------------
Rate recalculation (after the meeting)

Exercise:
Change binning from 0.2-0.6, 0.6-1.0, 1.0-1.4, 1.4-1.8 
                              to 
                    0.4-0.8, 0.8-1.2, 1.2-1.6 

 N(z)= SNR(z)*dt(z)*dv(z)/(1+z)

1) calculate dt(z) from their data
   dt(0.4)=3*1.4/0.69/4.32 =1.41
   dt(0.8)=14x1.8/1.57/10.74 = 1.49
   dt(1.2)=6*2.2/1.15/15.56 = 0.74 
   dt(1.6)=2*2.6/0.44/18.36 = 0.64

2) interpolate dt(z) at 0.6, 1.0, 1.4
   dt(0.6)=1.45
   dt(1.0)=1.12
   dt(1.4)=0.69

3) compute dv at 0.6, 1.0, 1.4 and calculate SNR(z)
   SNR(0.6)=8x1.6/1.45/7.6 = 1.16 
   SNR(1.0)=9x2/1.12/13.43 = 1.20 
   SNR(1.4)=7x2.4/0.69/17.19 = 1.41     

each number has about 35% statistical uncertainty

Conclusions:
  compare to our rate of 0.52 at <z>=0.55 
          = 0.58 +/-0.15  extrapolated at z=0.6
  their rate of 1.16+/-0.41(stat) is about 1.5 sigma higher
  
  no sharp increase below z=1 no drop above z=1  
  continue increase if anything 
     (1.16 at z=0.6, 1.20 at z= 1.0, 1.41 at z=1.4)  

Note however that this in not the correct way to analyse this data.

R.Pain June 29, 04