Tycho’s SNR

SNR G292.0+1.8

"To make an apple pie from scratch,you must first invent the universe." ~Carl Sagan

“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.”

What elements are in formed in supernova remnants? Can the types of supernova event be determined from their spectra?

(coded according to the dominant processes which produce the elements)

Tycho’s 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 Tycho’s SNR.

Analyze Tycho’s Supernova Remnant following the instructions at

http://www.geocities.com/donnas_stars/chandra_activities/xrayspectroscopyofsnrds9.doc

Determining the type of supernova from a supernova remnant using ds9 analysis tools.

PROCEDURE

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.

Zoom in on each peak (left click and drag a box) to determine its energy in keV.

Tycho’s SNR

Type 1a supernova

Table 1. Energies of X-ray Emission Lines element Energy (Kev) element Energy (Kev) element Energy (Kev)

O 0.18 Mg 1.33 Ar 3.32 Mg 0.25 Mg 1.45 Ar 3.69 Mg 0.27 Fe 1.66 Ca 3.86 O 0.64 Si 1.87 Ca 3.89 O 0.66 Si 1.98 Ca 4.11 Fe 0.80 Si 2.14 Ca 4.95 Fe 0.81 S 2.42 Fe 6.47 Ne 0.92 S 2.44 Fe 6.54 Ne 0.93 S 2.63 Fe 6.97 Ne 1.02 Ar 3.10 Fe 7.80

Tycho’s SNR (Type Ia) SNR G292.0+1.8 SNR (Type II) Energy of

emission line (KeV)

chemical symbol

of element

Energy of emission line

(KeV)

chemical symbol

of element

Fe0.8 keV Mg

1.3 keV

Si1.8 keV

S2.4 keV

Ar3.1 keV

Ca3.9 keV

Fe6.4 keV

Tycho’s SNR

Type 1a supernova

SNR G292.0+1.8

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.

SNR G292.0+1.8

Identify the elements in this SNR.

Table 1. Energies of X-ray Emission Lines element Energy (Kev) element Energy (Kev) element Energy (Kev)

O 0.18 Mg 1.33 Ar 3.32 Mg 0.25 Mg 1.45 Ar 3.69 Mg 0.27 Fe 1.66 Ca 3.86 O 0.64 Si 1.87 Ca 3.89 O 0.66 Si 1.98 Ca 4.11 Fe 0.80 Si 2.14 Ca 4.95 Fe 0.81 S 2.42 Fe 6.47 Ne 0.92 S 2.44 Fe 6.54 Ne 0.93 S 2.63 Fe 6.97 Ne 1.02 Ar 3.10 Fe 7.80

Tycho’s SNR (Type Ia) SNR G292.0+1.8 SNR (Type II) Energy of

emission line (KeV)

chemical symbol

of element

Energy of emission line

(KeV)

chemical symbol

of element

SNR G292.0+1.8

Hughes, et al 2001

“Hard-band” x-ray image

(energy cut from 2-7 KeV)

pulsar?

Using an energy cut from 2-7 KeV can help you see the central core.

SNR G292.0+1.8

Tycho’s SNR

SNR G292.0+1.8

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.”

Cas A

OBS ID 114

Identify the elements in this SNR.

What type do you think it is?

Cas A

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.