Transcript Document 7219104

The Lick Observatory Supernova Search
(LOSS) and Follow-up Program
Alex Filippenko
Department of Astronomy
University of California, Berkeley
(with W. Li, S. Jha, J. Leaman, M. Ganeshalingam, et al.)
Caprielle Corona Nikole Filippenko
03W-01a, total eclipse
the Katzman Automatic
Imaging Telescope; 0.75
m, at Lick Observatory
• Fully
robotic observations
• Fully automatic image
processing
• Humans verify SNe
• Monitor many galaxies
• Maintain small interval
Weidong Li (UCB)
14,000  7,500 (06/2004)
2. No. of images per night
7001300
images/night
20012003 After Jun 2004
Number of observations
1. No. of galaxies monitored:
3. Interval distribution
Observation interval (days)
SN 1998de before/after
SN Ia 1998dh before/after
New image
NGC 523
Difference (after
much processing)
SN 2001en
Cosmic ray
Template
Undergraduate
students confirm,
and find the
trickier ones, by
eye. (Autoobserve some
candidates.)
KAIT Supernova Search & Analysis Team, May 2005
LOSS SNe, m < 19 mag at time of discovery
Year N(SN)
1998
1999
2000
2001
2002
2003
2004
2005
20
40
38
68
82
95
83
82
Total nearby SNe, m < 19 mag
LOSS SNe
http://astron.berkeley.edu/~bait/kait.html
•755 SNe in the galaxies monitored by
LOSS during 1998-2005.
•508 (67%) discovered by LOSS.
•716 have SN type and host-galaxy
redshift.
•Can study rates, systematics, etc.
Supernova rate (Leaman, Li, AF 2006)
Gal. Type
N(gal)
Ia
Ib/c
II
E
1049
30 0
0
S0
2566
17 2
9
Sa
962
13 6 15
Sab
728
14 5 15
Sb
1777
47 15 53
Sbc 1237
21 20 36
Sc
1771
32 28 61
Ir
2618
10
7 13
Total:
566 SNe in 13,000 galaxies
Previous: 137 SNe in 4,000 galaxies
(5 combined searches: visual & photographic) Cappellaro et al. 1999
Jesse
Jesse
Leaman
Luminosity function of SNe
All SNe (716)
Discovery mag
We have unfiltered light
curves for all 716 SNe from
the galaxy monitoring data!
a) Discovery mag;
peak mag from light
curve
b) Monte Carlo
completeness
simulation of our
search
N(SN type, Gal type, L)
A network of SN observers
• Prompt alerts to 70 astronomers/SN observers
• Carnegie Supernova Program (CSP), CfA
group, Caltech Core-Collapse Program (CCCP),
CTIO group, ESO group, etc.
• Follow-up with our own telescopes
KAIT
10-20% of time
Photometry
calibration
Lick 1-m
2-3 nights/mon
Calibration
photometry
Lick 3-m
3 nights/mon
spectroscopy
Keck I/II 10-m
Occasional
spectroscopy
Filtered photometry database
Some Good Great
Total
SN Ia
59
21
95
175
SN II
27
24
31
82
4
5
12
21
SN Ibc
Total: 278
(As of Dec 19, 2005)
KAIT BVRI follow-up of bright SNe Ia;
data reduced by hand (labor intensive!)
I
R
V
B
Mohan
Ganeshalingam
Sample light curves from LOSS photometry pipeline (1)
Sample light curves from LOSS photometry pipeline (2)
• For details, see Li, Filippenko, Chornock, & Jha
2003b, PASP, 115, 844
• Respond automatically to GRB alerts.
• Interrupt KAIT’s normal observations;
take a pre-arranged sequence of images.
• Reach 19th mag within 60 s of alerts.
• Unfiltered obs.; now V, I, unfiltered.
GRB 020211 KAIT2
GRB 021212 KAIT3
(Li, Filippenko, Chornock, & Jha 2003a)
• Obs. started at t = 105s
• 18 data points in 10 min
• One of the 2 GRBs (through 2002) with reverse-shock
emission detected
Nearby SNe Ia: Physics and progenitors
High-quality data for modeling
SN subclasses/statistics: progenitors
Li et al. 2006 in prep
•
•
•
•
91T-like: only in spiral galaxies
91bg-like: prefer E galaxies
Normal: in all kinds of galaxies
Peculiar/bizarre SNe Ia
(Jha et al. 2006, in press)
I
2002cx
R
V
B
Also observed
by HST, Swift
U
SN 2002cxlike: a new
subclass of
SN Ia…
but we
really don’t
know what
produces
them!
Nearby SNe Ia: Cepheid distances
•
SN Ia HST Calibration team (Saha et al.)
• 11 observed, 2 were ideal calibrators
• Subset analyzed by the HST H0 Key project (Freedman et al.)
•
Recent efforts led by Riess et al. (2005)
• 2 ideal calibrators observed. 2 more are being observed (1995al; 2002fk).
H0 = 73 ± 4 ± 5 km s-1 Mpc-1
Correcting for Intrinsic Variations and
Dust
shape of the light
curve lets us read
the label on our
cosmic light bulb
measuring colors
lets us correct for
attenuation of the
light by dust
Si
MLCS2k2 light curve fits
KAIT BVRI photometry
Si
μ = 33.46 ± 0.07 mag
μ = 33.49 ± 0.10 mag
SN 1999cp and SN 2002cr, both in NGC 5468
Correcting for Intrinsic Variations and
Dust
Si
Going with the Flows
(Jha et al. 2006)
Nearby SNe Ia: Anchor for Hubble diagram
A Hubble Bubble?
a 6% difference in the
expansion rate at a
radius of 300 million light
years
statistical signifcance is
3σ,
but robust with
subsamples, other
distance techniques
Jha, Riess, & Kirshner
A Hubble Bubble?
• a real local void?
• K-corrections?
• photometric offset?
– new data vs. Calán/Tololo?
– morphology/extinction?
Jha, Riess, & Kirshner
a potentially huge systematic
➔ test with more nearby objects!
Systematic Effects
• These are now beginning to dominate
statistical uncertainties in studies like
ESSENCE, SNLS, etc.
• Will be completely overwhelming for
SNAP/JDEM, LSST, etc.
• Need to understand effects of metallicity,
progenitor evolution, dust, demographics…
• The NEARBY samples are crucial!
SN 2004dj
(SN II-P) in
NGC 2403
Spectropolarimetric
study (Doug
Leonard, AF,
et al.; mostly
Lick 3-m);
Nature, 23
March issue
SN II-P
Polarization of SN 2004dj
SN 2002ap (Ic-pec): Leonard+ 03
Conclusions for core-collapse SNe
• The deeper we peer into the heart of
the explosion, the greater the
asphericity (Wang, Wheeler, et al.
also discovered this).
• In Type II-plateau events, the
asphericity at early times is cloaked
by a thick hydrogen envelope.
> Implies an intrinsically
aspherical explosion mechanism!
(Leonard et al. 2005, ApJ, 632, 450)
(Leonard et al. 2005, ApJ, 632, 450)
Conclusions, SNe Ia
• All are intrinsically polarized.
• Continuum pol.: suggests minor-to-major
axis ratio of ~0.9 if viewed equator-on
(Höflich 1991 models).
• Line pol.: suggests partial obscuration of
the photosphere by clumpy, newly
synthesized intermediate-mass elements.
• High-velocity SNe Ia have the strongest
line pol.: clumps have greater optical
depth than in normal SNe Ia. High EWs.
More of the C and O fused to IMEs.