NGC 3147

Source: Wikipedia, the free encyclopedia.
129 ± 29 Mly (39.6 ± 8.9 Mpc)[1]
Apparent magnitude (V)10.6
Characteristics
TypeSA(rs)bc [1]
Apparent size (V)3.9′ × 3.5′[1]
Notable featuresSeyfert galaxy
Other designations
UGC 5532, MCG +12-10-025, PGC 30019[1]

NGC 3147 is a

light years from Earth, which, given its apparent dimensions, means that NGC 3147 is about 140,000 light years across. It was discovered by William Herschel on April 3, 1785.[2] It is a Type II Seyfert galaxy
.

Structure

The galaxy has a small and bright nucleus and tightly wound multiple spiral arms. The overall appearance of the galaxy resembles that of

HII regions can be detected in the arms.[3]

Active galactic nucleus

NGC 3147 has been characterised as a Seyfert II galaxy. It is considered the best candidate to be a true type II Seyfert galaxy,

X-rays.[5]

The galaxy was observed simultaneously in the optical and X-ray spectrum by Bianchi et al. and concluded that the X-ray spectrum is unabsorbed while its optical spectrum lacks broad lines, a mismatch with respect to the Unification Model.[6] Birghtman et al. confirmed their findings and also noted that the hard X-ray flux dropped by a factor of ~2 between the observation by Chandra (2001) and XMM-Newton (2006).[7] Further flux variation was observed by Suzaku in 2010, confirming the variability of the source.[4] The nuclear emission in the UV band shows negligible variability.[8] Shi et al. used data from Spitzer Space Telescope and ground-based optical spectropolarimeteric observations and observed lack of polarised broad emission lines in NGC 3147.[9] NGC 3147 was observed by NuSTAR at the 3-40 keV X-ray spectrum, which is characterised by a simple power-law, with a standard Γ ~ 1.7 and an iron emission line, with no need for any further component up to ~ 40 keV.[5]

There is a debate whether the lack of broad lines detection observed with NGC 3147 is caused by the presence of a Compton-thick column with the presence of a highly ionised reflector to account for the X-ray spectrum or not.[5] Bianchi et al. rejected the presence of a Compton thick column on the grounds of low-equivalent width of the iron Kα line (≃130 eV), and of the large ratio between hard X-ray and [O III] fluxes.[6] Birghtman et al. confirmed their findings using data from XMM-Newton and Chandra. They also found that the X-ray flux is variable, meaning that the nucleus may be observed directly. However, they noted the presence of a Compton-thick column cannot be ruled out.[7] The observations by Suzaku in the hard X-rays spectrum did not cast more light,[4] but along with the observations performed by XMM-Newton put tight constraints on the column density.[5]

After the observations by NuStar in 2015, Bianchi et al. concluded that the spectral properties and the significant variability on time-scales as short as weeks strongly support an unobscured line-of-sight for the nucleus of NGC 3147 and the Compton-thick scenario is strongly disfavoured.[5]

Central black hole with thin disk

Artist's impression of NGC 3147 black hole disc.[10]

In July 2019 researchers using the

gravitational well of the black hole and rotates around it at more than 10% of the speed of light. Its high velocity results in the effect known as relativistic beaming, in which the light coming from the side moving toward the Earth is brighter than that coming from the side that is receding.[11][12]

Supernovae

Six

type Ic),[17] and SN 2021hpr (mag. 13.8, type Ia[18]
).

Nearby galaxies

NGC 3147 is the brightest galaxy in the NGC 3147 group, which also includes NGC 3155, UGC 5570, UGC 5686, and UGC 5689. A bit further away lie NGC 3183, NGC 3348, NGC 3364, and NGC 3516.[19]

See also

References

  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for NGC 3147. Retrieved 2016-01-18.
  2. ^ NGC 3147 cseligman.com
  3. ^ Sandage, A.; Bedke, J. (1994). The Carnegie Atlas of Galaxies, Volume 1. Carnegie Institution of Washington. p. 20.
  4. ^
    S2CID 59123588
    .
  5. ^
    S2CID 9282918
    .
  6. ^
    S2CID 8859750
    .
  7. ^
    S2CID 17253782
    .
  8. S2CID 119187239
    .
  9. S2CID 119106848
    .
  10. ^ "Hubble Discovers Mysterious Black Hole Disc". www.spacetelescope.org. Retrieved 13 July 2019.
  11. ^ "Hubble discovers mysterious black hole disc", ESA/Hubble Information Center news release, 11 July 2019.
  12. ^ "Hubble uncovers black hole that shouldn't exist", NASA/Goddard Space Flight Center news release, 11 July 2019.
  13. ^ "1972H - The Open Supernova Catalog". sne.space. Archived from the original on 2018-04-26. Retrieved 2018-04-25.
  14. ^ "1997bq - The Open Supernova Catalog". sne.space. Archived from the original on 2018-04-26. Retrieved 2018-04-25.
  15. ^ "2006gi - The Open Supernova Catalog". sne.space. Archived from the original on 2018-04-26. Retrieved 2018-04-25.
  16. ^ "2008fv - The Open Supernova Catalog". sne.space. Archived from the original on 2018-04-26. Retrieved 2018-04-25.
  17. ^ Transient Name Server entry for SN 2021do. Retrieved 25 March 2023.
  18. ^ "2008fv - The Open Supernova Catalog". sne.space. Archived from the original on 2021-04-12. Retrieved 2021-04-12.
  19. S2CID 119194025. Archived from the original
    on 31 January 2016. Retrieved 25 April 2018.

External links

Wikimedia Commons has media related to NGC 3147.
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