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a ds9 activity

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SNR G292.0+1.8 Tycho s SNR – PowerPoint PPT presentation

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Title: a ds9 activity


1
The X-Ray Spectroscopy of SNR
a ds9 activity
SNR G292.01.8
Tychos SNR
2
Beaming home the cosmos
3
"To make an apple pie from scratch,you must
first invent the universe."
Carl Sagan
4
From
The elements have their ultimate origins in
cosmic events. Further, different elements come
from a variety of different events. So the
elements that make up life itself reflect a
variety of events that take place in the
Universe. The hydrogen found in water and
hydrocarbons was formed in the moments after the
Big Bang. Carbon, the basis for all terrestrial
life, was formed in small stars. Elements of
lower abundance in living organisms but essential
to our biology, such as calcium and iron, were
formed in large stars. Heavier elements
important to our environment, such as gold, were
formed in the explosive power of supernovae. And
light elements used in our technology were formed
via cosmic rays. The solar nebula, from which
our solar system was formed, was seeded with
these elements, and they were present at the
Earth's formation. Our very existence is
connected to these elements, and to their cosmic
origin.
5
The Periodic Table of the Elements
(coded according to the dominant processes which
produce the elements)
What elements are in formed in supernova
remnants? Can the types of supernova event be
determined from their spectra?
6
Determining the type of supernova from a
supernova remnant using ds9 analysis tools.
Tychos SNR Type 1a supernova
In the thermonuclear explosion of a white dwarf,
the core is completely destroyed. Note the lack
of a central point source in Tychos SNR.
Analyze Tychos Supernova Remnant following the
instructions at http//www.geocities.com/donnas_st
ars/chandra_activities/xrayspectroscopyofsnrds9.do
c
7
Sherpa Spectral Fit
PROCEDURE
8
What is Bremsstrahlung radiation?
A supernova remnant can have a temperature of
millions of degrees Kelvin. Bremsstrahlung
radiation occurs in such a hot gas where many
electrons are stripped from their nuclei, leaving
a population of electrons and positive ions. When
an electron passes close to a positive ion, the
strong electric forces cause its trajectory to
change. The acceleration of the electron in this
way causes it to radiate electromagnetic energy -
this radiation is called bremsstrahlung and
produces a continuous X-ray spectrum.
In addition, emission lines can appear
superimposed on this spectrum, corresponding to
the ejection of K and L shell electrons knocked
out of atoms by collisions with high-energy
electrons. Higher energy electrons then fall into
the vacated energy state in the outer shell, and
so on, emitting X-ray photons. The energies of
these emissions lines can be matched to energies
in the CHIANTI Atomic Database to identify the
elements in plasmas such as supernova remnants.
9
Tychos SNR Type 1a supernova
Zoom in on each peak (left click and drag a box)
to determine its energy in keV.
10
Identify the elements in Tycho's SNR
11
Si 1.8 keV
Fe 0.8 keV
Mg 1.3 keV
S 2.4 keV
Ar 3.1 keV
Ca 3.9 keV
Fe 6.4 keV
Tychos SNR Type 1a supernova
12
SNR G292.01.8 Type II
A Type II supernova occurs when a massive star
has used up its nuclear fuel and its core
collapses to form either a black hole or a
neutron star.
13
SNR G292.01.8
Identify the elements in this SNR.
14
Identify the elements in SNR G292.01.8
15
SNR G292.01.8
Hughes, et al 2001
16
Using an energy cut from 2-7 KeV can help you see
the central core.
Hard-band x-ray image (energy cut from 2-7 KeV)
SNR G292.01.8
pulsar?
17
From Imagine! The Universe The observed
elements and abundances are very different for
different type of SN explosions (massive star vs.
white dwarf). Type Ia remnants (from white
dwarfs) should have relatively strong Si, S, Ar,
Ca, and Fe, and weak O, Ne, and Mg Type II (from
massive stars) generally have the reverse
pattern.
SNR G292.01.8
Tychos SNR
18
Cas A OBS ID 114
19
Cas A
Identify the elements in this SNR. What type do
you think it is?
20
How did you do?
21
Cas A in Color
Can you find the central point-like X-ray source
in the last image? These images were creating
by making energy cuts in ds9, choosing a
different color scheme for soft, medium and
hard x-rays (red, green and blue, respectively)
and then overlapping them as transparent layers
in Adobe Photoshop to create a three-color
composite image.
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