Library of Sounds
References are given to the papers from which I took the spectral details. ApJ = Astrophysical
Journal, A&A = Astronomy and Astrophysics.
This work is licensed under a Creative Commons Attribution 2.5 License.
You may freely use these sounds in any way you like, subject only to acknowledging me. I'm
interested in how these sounds are used, so please let me know what you do with them.
Quasars are massive black holes, sitting in the middle of galaxies. They devour any passing objects,
and as the objects are torn apart, radiation is emitted. Here is what this radiation sounds like.
There are different sounds emitted from different regions.
- Quasar Emission-line Spectrum (352kb). This is combined emission from all
the gas clouds circling the black hole, between 0.1 and 10 light years out. Data taken from
my own paper Francis et al. 1991, ApJ 373, 465
- Seyfert 2 (352kb). This is the radiation coming from the outskirts
of the quasar, a few light-years out. Line ratios compiled from multiple sources.
- Intermediate Line Region (352kb), Radiation from gas clouds about a light year from the central black hole. Based on another of my own papers, Brotherton et al. 1994,
ApJ 430, 495
- Very Broad Line Region (352kb), Radiation from gas clouds about a tenth of a light year from the central black hole. Also based on Brotherton et
al. 1994, ApJ 430, 495
- Quasar Spectrum including continuum (584kb). This is all the radiation
coming from the quasar, and is dominated by the hissing noise coming from gas very close to the
black hole, just outside the event horizon. Based on the
average QSO spectrum from Francis et al. 1991, ApJ 373, 465 extended further into the red, as
These are the expanding clouds of gas left behind when a massive star comes to the end of
its life and explodes, producing a supernova.
Star Forming Regions
New-born stars emerge from within vast clouds of interstellar gas. As they do so, the can light up
this gas, producinga so-called HII region.
- The Orion Nebula, M42 (120kb). A stellar nursery. These signals
are from the gas, which is heated up and made to emit by radiation from the Trapezium stars. I've not included the signal of reflected light from these stars. Data from Walter, Dufour & Hester 1992,
ApJ 397, 196
When stars like our Sun run out of fuel and die, instead of exploding, they spew turn into planetary nebulae - glowing clouds of gas that was blown from their surfaces in their dying days, illuminated by light from the ember left in the middle (a white dwarf star).
The signals from stars sound more hissy: rather than emitting certain frequencies only, they
emit power at a wide range of frequencies, which produces the hissing sound. Unless stated to
the contrary, all the sounds are based on model stellar atmospheres from Kurucz (1992), IAU Symposium 149, p225. Sounds are in order of increasing temperature.