Halton Christian "Chip" Arp (March 21, 1927 – December 28, 2013) was an American astronomer. He is remembered for his 1966 book Atlas of Peculiar Galaxies, which catalogued unusual-looking galaxies and presented their images.
Arp was also known as a critic of the Big Bang theory and for advocating a non-standard cosmology incorporating intrinsic redshift. Arp developed those views in a book, Seeing Red: Redshift, Cosmology and Academic Science, in 1998.
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology. The primary goal of the catalog was to present photographs of examples of the different kinds of peculiar structures found among galaxies.
A non-standard cosmology is any physical cosmological model of the universe that was, or still is, proposed as an alternative to the then-current standard model of cosmology. The term non-standard is applied to any theory that does not conform to the scientific consensus. Because the term depends on the prevailing consensus, the meaning of the term changes over time. For example, hot dark matter would not have been considered non-standard in 1990, but would have been in 2010. Conversely, a non-zero cosmological constant resulting in an accelerating universe would have been considered non-standard in 1990, but is part of the standard cosmology in 2010.
Several major cosmological disputes have occurred throughout the history of cosmology. One of the earliest was the Copernican Revolution, which established the heliocentric model of the Solar System. More recent was the Great Debate of 1920, in the aftermath of which the Milky Way's status as but one of the Universe's many galaxies was established. From the 1940s to the 1960s, the astrophysical community was equally divided between supporters of the Big Bang theory and supporters of a rival steady state universe; this is currently decided in favour of the Big Bang theory by advances in observational cosmology in the late 1960s. Nevertheless, there remained vocal detractors of the Big Bang theory including Fred Hoyle, Jayant Narlikar, Halton Arp, and Hannes Alfvén, whose cosmologies were relegated to the fringes of astronomical research. The few Big Bang opponents still active today often ignore well-established evidence from newer research, and as a consequence, today non-standard cosmologies that reject the Big Bang entirely are rarely published in peer-reviewed science journals but appear online in marginal journals and private websites.
NGC 383 is a double radio galaxy with a quasar-like appearance located in the constellation Pisces. It was discovered by German-British astronomer William Herschel on 12 September 1784. It is listed as Arp 331 in Halton Arp's Atlas of Peculiar Galaxies.
Recent discoveries by the National Radio Astronomy Observatory in 2006 reveal that NGC 383 is being bisected by high energy relativistic jets traveling at relatively high fractions of the speed of light. The relativistic electrons in the jets are detected as synchrotron radiation in the x-ray and radio wavelengths. The focus of this intense energy is the galactic center of NGC 383. The relativistic electron jets detected as synchrotron radiation extend for several thousand parsecs and then appear to dissipate at the ends in the form of streamers or filaments.
NGC 169 is an unbarred spiral galaxy located in the constellation Andromeda. It was discovered on September 18, 1857, by R. J. Mitchell.
NGC 169 has a smaller companion named NGC 169A, also designated IC1559. The two are currently interacting, and the pair is included in Halton Arp's Atlas of Peculiar Galaxies.