Weidong Li Jesse Leaman Alex Filippenko Department of AstronomyUniversity of California, Berkeley

Nearby Supernova Rates from the Lick Observatory Supernova Search

JesseJesse Leaman

Thesis work

Supernova RatesSupernova Rates

Cappellaro et al. 1999 (C99 hereafter)* 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

Benchmark for z = 0 SN rate:

Lick Observatory, near San Jose, CA

the Katzman Automatic Imaging Telescope; 0.76 m mirror.

The KAIT SN Search at Lick Obs.• 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: 32http://astron.berkeley.edu/~bait/kait.html

LOSS results (1998-2006): LOSS results (1998-2006): Leaman, Li, & AVF (2008, in prep.)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 | ? | TotalB 247 97 284 14 642K 235 93 274 13 615 B&K 227 87 265 12 591*Only SNe for which we have all host galaxy information were included

SN rate = No. of Supernovae

∑ Li x Monitoring_Timeii=1

15000

Rate calculation: Control time method

KAIT/LOSS: snapshot (20 s, 7’x7’) imagesof individual nearby galaxies (~15000), not an all sky survey.

Control time (one epoch)

d = 100 MpcMag limit = 19

Could see SN Ia for 80d, SN Ib/c for 35d, SN II-P for 110d (L08).

L08D=100MpcLim_mag = 19

110d

Control time (one epoch)

L08: R band - 110d (SN II)C99: B band - 15d (SN II)

Observation interval (days)

Nu

mb

er o

f ob

serv

atio

ns

20012003 After June 2004

t1 t2 t3

7d 14d

CT=110d 110d 110d

Total ct = 110d + 7d +14d

Obs intervals

Control time (multi epochs)

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 effecta)

Ia

Ibc

II

II

Face-on Inclined/edge-on

Scd-Sm

ScSbcSb

Effect of peak mag and light curve shape

Peak mag

L08 vs C99 light curve

+0.5 mag

-0.5 mag

Radial distribution of LOSS SNe

Survey completnessa) We missed ~1% (5-10) of SNe near the galaxy nucleii.

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

L08

Z=0 0.34 ± 0.04 x 10-4

(From SNuK only)

ConclusionsConclusionsUncertainties are significantly reduced• 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:• 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

• 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)