What wavelength is Lyman-alpha?
122 nm
There are clouds of gas between distant quasars and the Earth that absorb ultraviolet light at the wavelength of the Lyman alpha line of hydrogen at a wavelength of 122 nm.
What are Lyman-alpha photons?
Lyman α is light Radiation consists of light particles, or photons, which are small packets of energy. The higher the energy, the higher the frequency, but the shorter the wavelength, and vice versa. The different terms are just different ways of talking about the light.
What causes Lyman-alpha emission?
The Lyman-alpha line in most LAEs is thought to be caused by recombination of interstellar hydrogen that is ionized by an ongoing burst of star-formation. Such Lyman alpha emission was first suggested as a signature of young galaxies by Bruce Partridge and P. J. E. Peebles in 1967.
What is the energy of the Lyman-alpha photon?
13.6 eV
The Lyman limit is at the wavelength of 91.2 nm (912 Å), corresponding to a frequency of 3.29 million GHz and a photon energy of 13.6 eV. LyC energies are mostly in the ultraviolet C portion of the electromagnetic spectrum (see Lyman series).
What is a Lyman limit system?
Like the damped Lya systems (which we all know and love) the LL Systems are a class of QAL system. They are defined to be optically thick at the Lyman limit, which generally implies N(HI) > 1017 cm-2.
Is Lyman a ground state?
The Lyman series involve jumps to or from the ground state (n=1); the Balmer series (in which all the lines are in the visible region) corresponds to n=2, the Paschen series to n=3, the Brackett series to n=4, and the Pfund series to n=5.
What is the name of the Lyman alpha line?
the Lyman-alpha line. In physics, the Lyman-alpha line, sometimes written as Ly-α line, is a spectral line of hydrogen, or more generally of one-electron ions, in the Lyman series, emitted when the electron falls from the n = 2 orbital to the n = 1 orbital, where n is the principal quantum number.
How are Lyman alpha systems used in cosmology?
Lyman alpha systems and cosmology Lyman alpha systems are becoming a very useful source of information in physical cosmology. The Lyman series is the series of energies required to excite an electron in hydrogen from its lowest energy state to a higher energy state.
Which is a possible configuration of the Lyman alpha forest?
Lyman-alpha forest. A computer simulation of a possible Lyman Alpha Forest configuration at Z=3. In astronomical spectroscopy, the Lyman-alpha forest is a series of absorption lines in the spectra of distant galaxies and quasars arising from the Lyman-alpha electron transition of the neutral hydrogen atom.
What are the spectra of a Lyman alpha cloud?
The cartoon above shows a quasar with its Lyman alpha emission line redshifted from the ultraviolet into the red, and the Lyman alpha absorption lines from four intervening clouds appearing as orange, yellow and green-blue. The figure below shows two actual quasar spectra.