Local emptiness

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Void
local emptiness
Position
equinox : J2000.0
Right ascension 18h 38m 00.0s
declination + 18 ° 00 ′ 00.0 ″
Further data
diameter 200,000,000 ly
history
Catalog names
local void
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As Local void (engl. Local Void ) is referred to an extended region of the empty space, which directly to the local group is adjacent. The local void was discovered in 1987 by Brent Tully and Rick Fischer and consists of three separate sectors separated by thin filaments . The exact extent of the void is not known, but it is estimated to be at least 45 million parsecs (150 million light years) and up to 70 million parsecs (230 million light years ). In the local emptiness there seem to be significantly fewer galaxies than would be expected cosmologically.

Position and extent

Empty spaces are the result of the way gravity "clumps" matter together in the universe . Galaxies are driven in clusters and chains that are separated by regions that mostly contain no galaxies.

Astronomers previously noted that the Milky Way is in a large, flat array of galaxies called the local leaf, which delimits the local void. The local void extends for about 60 megaparsecs and begins at the edge of the local group. It is believed that the distance from Earth to the center of the local void must be at least 23 megaparsecs.

The size of the local void was calculated based on an isolated dwarf galaxy. The larger and emptier the void, the greater the force of gravity and the faster the dwarf should flee from the void in the direction of the matter concentrations. Dark energy has been suggested as an alternative explanation for the dwarf galaxy's rapid displacement.

An earlier "Hubble Bubble" model, based on the measured speeds of the 1a supernova type , suggested a relative void in the center of the Milky Way. However, a recent analysis of this data suggested that interstellar dust had led to misleading measurements.

Several authors have shown that the local universe is 15–50% less dense than the surrounding areas within a radius of up to 300 MPc from the Milky Way. This is called a local void or local hole. In some media reports this was also referred to as KBC-Void, although this name was not used in other publications.

Effects on the environment

Scientists believe that the local void is growing and that the nearest extragalactic region, which forms a wall of the void, is moving away from the center of the void at a rate of 260 kilometers per second. Concentrations of matter usually contract, creating a larger void for matter to migrate. The local void is evenly surrounded by matter in all directions, with the exception of one sector in which there is nothing that leads to more matter being extracted from that sector. The effect on the nearby Milky Way is astonishing. The speed at which the Milky Way is moving away from the local void is 270 kilometers per second.

Galaxies in the local void

Galaxy Type Distance (Lj) Redshift source
ESO 461-36 dIrr 11 million 0.001425
NGC 6503 SA (s) cd 18 million 0.000083
UGCA 433 in the 21 million 0.002765
MCG-01-57-015 IBm 24 million 0.002966
NGC 7077 E. 36 million 0.003843
MCG-01-41-006 dIrr 42 million 0.002770
MCG-02-41-001 SAB (r) b 48 million 0.003252

Individual evidence

  1. ↑ Kouichiro Nakanishi, Tadafumi Takata, Toru Yamada, Tsutomu T. Takeuchi, Ryuichi Shiroya: Search and Redshift Survey for IRAS Galaxies behind the Milky Way and Structure of the Local Void . In: The Astrophysical Journal Supplement Series . tape 112 , no. 2 , October 1997, ISSN  0067-0049 , p. 245–270 , doi : 10.1086 / 313039 ( online [accessed February 14, 2019]).
  2. ^ Simbad data for RMC 136
  3. ↑ a b c d e David Shiga: Dwarf-flinging void is larger than thought. Retrieved February 14, 2019 (American English).
  4. ↑ a b c d R. Brent Tully, Edward J. Shaya, Igor D. Karachentsev, Hélène M. Courtois, Dale D. Kocevski: Our Peculiar Motion Away from the Local Void . In: The Astrophysical Journal . tape 676 , no. 1 , March 20, 2008, ISSN  0004-637X , p. 184–205 , doi : 10.1086 / 527428 ( online [accessed February 14, 2019]).
  5. ↑ Nearby Galaxies Atlas - RB Tully & JR Fisher. Retrieved February 14, 2019 .
  6. ^ A b T. Shanks, JR Whitbourn: The galaxy luminosity function and the Local Hole . In: Monthly Notices of the Royal Astronomical Society . tape 459 , no. 1 , June 11, 2016, ISSN  0035-8711 , p. 496–507 , doi : 10.1093 / mnras / stw555 ( online [accessed February 14, 2019]).
  7. ↑ a b R. C. Keenan, AJ Barger, LL Cowie: EVIDENCE FOR A ∼300 MEGAPARSEC SCALE UNDER-DENSITY IN THE LOCAL GALAXY DISTRIBUTION . In: The Astrophysical Journal . tape 775 , no. 1 , September 5, 2013, ISSN  0004-637X , p. 62 , doi : 10.1088 / 0004-637X / 775/1/62 ( iop.org [accessed February 14, 2019]).
  8. ↑ Adi Nusser, PJE Peebles: Nearby galaxies as pointers to a better theory of cosmic evolution . In: Nature . tape 465 , no. 7298 , June 2010, ISSN  1476-4687 , p. 565–569 , doi : 10.1038 / nature09101 ( online [accessed February 14, 2019]).
  9. ^ I. Iwata, K. Ohta, K. Nakanishi, P. Chamaraux, AT Roman: The Growth of the Local Void and the Origin of the Local Velocity Anomaly . In: arXiv: astro-ph / 0505530 . May 26, 2005.
  10. ^ Adam Moss, James P. Zibin, Douglas Scott: Precision cosmology defeats void models for acceleration . In: Physical Review D . tape 83 , no. 10 , May 10, 2011, ISSN  1550-7998 , doi : 10.1103 / PhysRevD.83.103515 ( online [accessed March 7, 2019]).
  11. ↑ Ethan Siegel: We're Way Below Average! Astronomers Say Milky Way Resides In A Great Cosmic Void. Retrieved March 7, 2019 .
  12. ↑ Published: Tuesday, June 12, 2007: Milky Way moving away from void. Retrieved February 14, 2019 .
  13. ↑ a b David C. Nicholls, Helmut Jerjen, Michael A. Dopita, Hassan Basurah: NEBULAR METALLICITIES IN TWO ISOLATED LOCAL VOID DWARF GALAXIES . In: The Astrophysical Journal . tape 780 , no. 1 , December 13, 2013, ISSN  0004-637X , p. 88 , doi : 10.1088 / 0004-637X / 780/1/88 ( iop.org [accessed March 7, 2019]).
  14. ↑ Lost in space - New Hubble image of galaxy NGC 6503 [heic1513]. Retrieved March 7, 2019 (UK English).
  15. ↑ a b c d Luca Rizzi, R. Brent Tully, Edward J. Shaya, Ehsan Kourkchi, Igor D. Karachentsev: DRAINING THE LOCAL VOID . In: The Astrophysical Journal . tape 835 , no. 1 , January 19, 2017, ISSN  1538-4357 , p. 78 , doi : 10.3847 / 1538-4357 / 835/1/78 ( iop.org [accessed March 7, 2019]).