Transcript Supernova! Toledo Astronomical Association, February 2009

SUPERNOVA!
David Corliss
Toledo Astronomical Association
February 6, 2009
SN 1994D in NGC 4526, NASA / ESA / Hubble Key Project
Team / High-Z Supernova Search Team
http://www.spacetelescope.org/images/html/opo9919i.html
OUTLINE
BASIC FACTS
TYPES OF SUPERNOVAE
1a SN - HOW THEY HAPPEN
SUPERNOVA SURVEYS
RESEARCH
REFERENCES
A SUPERNOVA IS …..
BRIGHT
They can briefly outshine their entire galaxy
ENERGETIC
In just a few weeks, a supernova can give off as
much energy as the sun in it’s entire lifetime
RARE
On average, only one every 50
years in the entire Milky Way
FAST
Up to 3% of the speed of light
TWO TYPES
Type Ia
Violent explosion of a White
Dwarf star caused by a
runaway nuclear reaction
Ib , Ic and Type II
Complex core collapse of a
giant star releases energy,
blowing off the outer layers
into space and leaving behind
a Pulsar or Black Hole
Tycho’s
Supernova
X-ray image of
the SN 1572
remnant as seen
by Calar Alto
Observatory
www.nasa.gov/multimedia/imagegallery
SN 185
CHANDRA X-ray image
of the SN 185 remnant
Observed by Chinese
astronomers in 185 - the
earliest known record of
a supernova
Type Ia
NASA/CXC/Univ. of Utrecht/J.Vink et al. XMM-Newton:
ESA/Univ. of Utrecht/J.Vink et al
http://chandra.harvard.edu/photo/2006/rcw86
SN 1006
CHANDRA X-ray
image of the SN
1006 remnant
Brightest
Apparent
Magnitude event
ever recorded –
brighter than
Venus
Type Ia
NASA/CXC/Rutgers/J.Hughes et al.
http://chandra.harvard.edu/photo/2005/
sn1006/
Cassiopeia A
CHANDRA
X-ray image
Type IIb
The Pulsar is
very bright at
Radio
wavelengths but
the SN remnant
is very faint
optically
NASA/CXC/SAO/Rutgers/J.Hughes
http://chandra.harvard.edu/photo/199
9/casajph/
SN 1987A
Type II
Exploded 168,000 years ago in the LMC but the light
only got to us in 1987
NASA / ESA http://www.spacetelescope.org/index.html
ENERGY RELEASED BY
CORE COLLAPSE PUSHES
OUTER LAYER AWAY TO
BECOME A PLANETARY
NEBULA
TYPE Ib, Ic &
TYPE II
SUPERNOVA:
Core Collapse
CARBON & OXYGEN
CORE COLLAPSES,
BECOMES PULSAR
OR BLACK HOLE
SNR 1054
CRAB
NEBULA
TYPE 2:
CORE
COLLAPSE
WITH A
CENTRAL
PULSAR
M1, the Crab Nebula.
Courtesy of NASA/ESA
TYPE 1a SUPERNOVA: STEP 1
White Dwarf star accumulates mass
from a binary companion
http://hubblesite.org/newscenter/newsdesk/archive/releases/1995/23/image/a
TYPE 1a SUPERNOVA: STEP 2
Carbon Detonation
THIN OUTER LAYER OF
HYDROGEN AND
HELIUM
CARBON / OXYGEN CORE
WHEN THE MASS OF
THE STAR REACHES
1.38 SOLAR MASSES, THE
TEMPERATURE IN THE CORE
BECOMES HIGH ENOUGH TO
MAKE THE CARBON FUSE
TYPE 1a SUPERNOVA: STEP 3
Explosion
LIGHT
Mv = -19.3
5 BILLION
TIMES AS
BRIGHT AS
THE SUN
CARBON / OXYGEN
CORE VANISHES
LOTS AND
LOTS AND
LOTS OF
NEUTRINOS
THIN SHELL OF GAS
EXPANDS AT UP TO
3% THE SPEED OF LIGHT
SUPERNOVA SURVEYS
SLOAN DIGITAL SKY SURVEY
PURPOSE
Map 25% of the Sky and Everything in it
CRITERIA
Anything and Everything in the
Survey Area
HOW MANY
100 M Objects; 580 Supernovae
INSTRUMENT
Automated 2.5m APO Telescope
SUPERNOVA SURVEYS
ESSENCE
PURPOSE
Measure the Amount of Dark Energy
CRITERIA
Type Ia
Early Universe: z = 0.2 to 0.8
HOW MANY
Seeking 200 Type Ia; 90 so far
INSTRUMENT
CTIO 4m and others
SUPERNOVA SURVEYS
SUPERNOVA LEGACY SURVEY
PURPOSE
Detect and Monitor, Measure Characteristics
CRITERIA
High Redshift
Early Universe
HOW MANY
Seeking 2,000 Supernovae
INSTRUMENT
CFHT 3.58m / 340 MP
SUPERNOVA SURVEYS
VIMOS
PURPOSE
Find the rate at which supernovae happen
CRITERIA
Redshift from ~0.1 to ~1.2
HOW MANY
14 Confirmed, another
23 possibles
INSTRUMENT
VIMOS Wide-Field MultipleObject Spectrograph
Eric Linder
University of California, Berkeley
Lawrence Berkeley National Lab
What We Can Learn From Supernovae
For accurate and precision cosmology,
need to identify and control systematic uncertainties.
Systematic
Control
Host-galaxy dust
extinction
Wavelength-dependent absorption identified with high S/N
multi-band photometry.
Supernova evolution
Supernova subclassified with high S/N light curves and peakbrightness spectrum.
Malmquist bias
Supernova discovered early with high S/N multi-band
photometry.
K-correction
Construction of a library of supernova spectra.
Gravitational lensing
Measure the average flux for a large number of supernovae in
each redshift bin.
Non-Type Ia
contamination
Classification of each event with a peak-brightness spectrum.
REFERENCES
• SN 1994D in NGC 4526, NASA / ESA / Hubble Key
Project Team / High-Z Supernova Search Team
• X-ray image of the SN 1572 remnant / Calar Alto
Observatory / NASA
• NASA/CXC/Univ. of Utrecht/J.Vink et al. XMMNewton: ESA/Univ. of Utrecht/J.Vink et al
• NASA/CXC/Rutgers/J.Hughes et al.
• SN 1987A - NASA / ESA
• NASA /HST
hubblesite.org/newscenter/newsdesk/archive/release
s/1995/23/image/a
• Sloan Digital Sky Survay / Sloan Foundation
• Eric Linder / University of California, Berkeley
Lawrence Berkeley National Lab