Transcript Document

Nearby Supernova Rates from the Lick
Observatory Supernova Search
Weidong Li
Jesse Leaman
Alex Filippenko
Department of Astronomy
University of California, Berkeley
Jesse
Jesse
Leaman
Thesis
work
Supernova Rates
Benchmark for z = 0 SN rate:
Cappellaro et al. 1999 (C99 hereafter)
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5 surveys (1 visual, 4 photographic plates)
137 SNe in about 104 galaxies
B-band luminosity normalization
SN rate as a function of SN type (Ia, Ib/c, II)
and host morphology (E/S0, Sa/b, Sbc/d, Irr)
Mannucci et al. 2005 (M05 hereafter)
• Same database as C99
• K-band luminosity normalization
• SNr versus galaxy color (B-K), mass
the Katzman
Automatic
Imaging
Telescope;
0.76 m mirror.
Lick Observatory,
near San Jose, CA
The KAIT SN Search at Lick Obs.
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1997: 1 (SN 1997bs)
1998: 20 (world record)
1999: 40 (world record)
2000: 38 (including SN 2000A)
2001: 68 (world record; SN 2001A)
2002: 82 (world record)
2003: 95 (world record)
2004: 83 2005: 82 2006: 84
2007: 69 2008: 32
http://astron.berkeley.edu/~bait/kait.html
LOSS results (1998-2006):
Leaman, Li, & AVF (2008, in prep.)
• 844 SNe observed (600 LOSS discoveries &
240 independent confirmations)
• SNe used* in the SN rate calculation for a
given normalization technique and SN type:
Filter| Ia | Ib/c | II
B
247 97 284
K
235 93 274
B&K 227 87 265
| ? | Total
14 642
13 615
12 591
*Only SNe for which we have all
host galaxy information were included
Rate calculation: Control time method
KAIT/LOSS: snapshot (20 s, 7’x7’) images
of individual nearby galaxies (~15000), not
an all sky survey.
No. of Supernovae
SN rate =
15000
∑ Li x Monitoring_Timei
i=1
Control time (one epoch)
L08
d =D=100Mpc
100 Mpc
Lim_mag = 19
Mag limit = 19
110d
Could see SN Ia for 80d, SN Ib/c for 35d, SN II-P for 110d (L08).
Control time (one epoch)
L08: R band - 110d (SN II)
C99: B band - 15d (SN II)
20012003
t1
CT=110d
7d
t2
t3
110d
110d
14d
Total ct = 110d + 7d +14d
Obs intervals
After June 2004
Number of observations
Control time (multi epochs)
Observation interval (days)
For SN Ia, 92% of the observations use the
obs interval for the control time ~ a nearly
continuous coverage!
Detailed log files
• The limiting magnitude was calculated for every single
observation over the course of the survey.
• (Not done for previous nearby SN rate calculations.)
Lmag =
Lmag(intensity,
FWHM,
sky)
No clear inclination effect
a)
Sb
Sbc
Sc
Scd-Sm
Ia
II
Ibc
II
Face-on
Inclined/edge-on
Effect of peak mag and light curve shape
Peak mag
+0.5 mag
-0.5 mag
L08 vs C99
light curve
Survey completness
a) We missed ~1% (5-10) of SNe near the galaxy nucleii.
Radial distribution of LOSS SNe
b) We missed very few SNe otherwise.
Repeated survey with a small interval;
Heavy SN search competition in these nearby galaxies
SN Ia rate - SNu(K)
C99
SN Ibc rate - SNu(K)
C99
SN II rate - SNu(K)
C99
Volume SN Ia rate versus redshift
Z=0 0.34 ± 0.04 x 10-4
(From SNuK only)
L08
Conclusions
Uncertainties are significantly reduced
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Increased number of SNe (~140 vs. ~600)
No inclination correction factor
CCD camera and image subtraction
Limiting magnitude calculated for every obs
SN rates normalized in K band:
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Nearly continuous search for SNe Ia: rates are not
strongly affected by light curve shape and extinction
For SNe Ibc and II, the impact of different peak mag
for the chosen light curve can be easily quantified.
The SN II light curve shape plays an important role
in the rate calculation.
The rates increase from early to late type galaxies
for all three types of SNe.
Work in progress/Future refinements
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Finalizing rates normalized in B and mass
More SN bins (e.g., IIn, IIb, II-P, II-L)
Rates vs environment: cluster, AGN, radio
More representative light curves
(~1000 SNe have been monitored in the KAIT SN search
unfiltered data: average light curve and luminosity function).
Katzman Automatic Imaging Telescope (KAIT)
(Laurie Hatch)