Welcome to the Dictionary

A place to unpuzzle your mind on those tricky definitions or acronyms

A great page to visit is this one put out by NASA.There is a ton of info on any possible astronomical topic you can think of!!!

Chandra Multiwavelength Project

light that our eyes can't detect. X-rays are made up of photons that are emitted from stars, or quasars, or supernovae, the sun, or simply: anything that is undergoing a change either in size or temperature or giving out heat.

the study of the composition of stars through the light that they emit and absorb.

A view of the electromagnetic spectrum with wavelength and energy values

The space between 2 high points on a wave

different ways that light can be observed. e. g. X-rays, gamma-rays, optical, infrared, ultraviolet, and radio

Emitted probably from cosmic rays, gamma-rays have the most energetic form of radiation. When collisions occur between cosmic ray particles and atomic nuclei, gamma-rays are formed.

Cosmic Rays
Protons and electrons that contain lots of energy as they travel through space and eventually hit the Earth's atmosphere

a huge group of stars

galaxy M81 found in Ursa Major

Galaxy cluster
a group of galaxies that therefore contain many stars

in an X-ray binary star system, in which one normal star's orbit is crossed by a neutron star, when the neutron star by means of gravitational pull takes matter from the normal star X-rays form. The process of material transferring from star to star is called accretion.

X-ray Transients
X-ray sources that are bright and then fade in magnitude

a measurement of how bright a star is.

Dark Matter
unknown matter that astronomers think make up the majority of mass in the universe

a neutron star that rotates quickly. Usually a pulsar has very strong magnetic poles, forcing the matter to enter or leave through the poles.

Image of a pulsar with magnetic field lines around the star, forcing matter to come in or leave the star through either the north or the south pole. The red line symbolizes the axis, and the blue arrows show the direction that the star rotates. In this drawing, the pulsar rotates counter clockwise.

Radio Jets
beams of charged particles that are produced by a black hole in the center of an AGN

The brightest and sometimes farthest objects in our universe. The energy from quasars comes from lots of matter spilled into and around a galaxy's black hole. The matter is heated and that causes an enormous amount of radiation and light.

Image of a quasar at the center of a galaxy

Black Holes
When stars are at the end of their lives, some collapse onto themselves. Eeventually they collapse to zero volume, pulling any matter or light within its radius into infinite density.

Artists conception of a normal star (HDE 226868) and a black hole taking matter from the normal star. The matter swirls around the black hole. When the matter (gas or dust) passes the point of no return, it sends off X-rays into space (the ziggly red lines).

Image of a black hole (right) and a neutron star (left). The matter is circling around the black hole before it is pulled into infinite density. The center of that picture is black because black holes are invisible. The neurton star absorbs the matter that is circling around it, however it is not black in the middle, a star can be seen.

White Dwarf
A star with low/medium mass that is near the end of its life

white dwarf Sirius B

When a star is at the end of its life it first collapses onto itself and then it explodes causing the outer atmospheric layer to be blown away leaving the star to shine brighter then the rest of the stars in its galaxy.

Cassiopeia A supernova remnant

a cloud in the ISM that is filled with bright and/or dark gas and dust.

Image of the Trifid nebula


Active Galactic Nuclei

Cataclysmic Variable ( binary star systems that consist of a white dwarf and a normal star)

Image of a CV star system. One normal star and a white dwarf. The white dwarf star is taking the matter from the normal star. The matter is circling the white dwarf star because it cannot hold all that material at one time. The accretion disk is where X-rays are formed

Cosmic X-ray Background

Flat Spectrum Radio Quasars

Gamma-ray Observatory

Gamma-ray bursts

Animation of a Gamma-ray burst with intensity graph

ionized Hydrogen

neutral hydrogen

High-Mass X-Ray Binary

Hubble space telescope

InterStellar Medium

Kilovolts (usually the measured unit for energy )

Low-Mass X-Ray Binary

Massive Black Hole

quasi-periodic oscillations
Rossi X-ray Timing Explorer

Supernova remnant

Super soft sources

Soft X-Ray diffuse Background

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