To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

How to transfigure the Wikipedia

Would you like Wikipedia to always look as professional and up-to-date? We have created a browser extension. It will enhance any encyclopedic page you visit with the magic of the WIKI 2 technology.

Try it — you can delete it anytime.

Install in 5 seconds
4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
Great Wikipedia has got greater.
.
Leo
Newton
Brights
Milds

NGC 7172

From Wikipedia, the free encyclopedia

NGC 7172
NGC 7172 by the Hubble Space Telescope[1]
Observation data (J2000 epoch)
ConstellationPiscis Austrinus
Right ascension22h 02m 01.9s[2]
Declination−31° 52′ 11″[2]
Redshift0.008683 ± 0.000040 [2]
Heliocentric radial velocity2,603 ± 12 km/s[2]
Distance110 Mly (34 Mpc)[2]
Apparent magnitude (V)11.9
Characteristics
TypeSa pec [2]
Apparent size (V)2.5′ × 1.4′[2]
Notable featuresSeyfert galaxy
Other designations
ESO 466- G 038, AM 2159-320, MCG -05-52-007, PGC 67874[2]

NGC 7172 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 110 million light years from Earth, which, given its apparent dimensions, means that NGC 7172 is about 100,000 light years across.[2] It was discovered by John Herschel on September 23, 1834.[3]

Characteristics

NGC 7172 is a spiral galaxy that is seen edge-on. A thick dark dust lane runs across the galaxy, obscuring the nucleus of the galaxy.[1][4] The galaxy appears in deep photographs to be tidally distorted, and a diffuse tail is extending towards the north-west.[5]

Nucleus

The nucleus of NGC 7172 was originally considered to be normal,[6] but later observations revealed that it emitted X-rays[7][8] and was a powerful infrared source, which exhibited variation.[5] These findings indicated that NGC 7172 has an active galactic nucleus which is obstructed in optical wavelengths.[5] The nucleus was classified as a type 2 Seyfert galaxy in the optical, but observations in other wavelengths suggest it is type 1 Seyfert galaxy.[9] The source of activity of the nucleus is an accretion disk around a supermassive black hole. The mass of the supermassive black hole in the centre of NGC 7172 is estimated to be 5.5×107 M☉ based on the MBH–σ⋆ relation[10] or (1.03±0.35)×107 M☉ based on the X-ray scaling method.[11]

NGC 7172 has been found to exhibit variability in X-rays. As observed by the Advanced Satellite for Cosmology and Astrophysics (ASCA), the galaxy exhibited short term variability of about 30% in the time scale of hours, which is common for Seyfert I galaxies. It also exhibits long term variability, as it dimmed three to four times between 1995 and 1996.[12] This was also observed by BeppoSAX.[13] The FeKα line appeared constant when observed with BeppoSAX, but appeared to variate by a factor of two by ASCA, and thus it is associated with an accretion disk.[14] The hard X-ray spectrum appears similar to that of a Seyfert I galaxy, indicating that the nucleus is seen though a Compton-thin absorber.[15]

In infrared observations of the nucleus dominates the spectrum of the active nucleus, with 3.4-μm carbonaceous dust absorption detected, but no 3.3-μm PAH emission, indicating that the nucleus is obstructed. A strong obsurption feature is observed, probably the 9.7-μm silicate dust absorption line.[16] X-rays and mid-infrared have similar absorption columns.[17] It is possible that an outflow towards the southwest is detected in radiowaves.[9]

Nearby galaxies

NGC 7172 is part of the Hickson Compact Group 90. NGC 7172 lies 6 arcminutes north of the core of the compact group, which is comprised by the elliptical galaxies NGC 7173, and NGC 7174, and disturbed spiral galaxy NGC 7176; these three galaxies lie within 6 arcminutes from each other.[18]

The compact group is surrounded by a more loose group, with 19 galaxies of similar redshift within 1.5 degrees from the core group.[18] Garcia identified as members of this group the galaxies NGC 7154, ESO 404- 12, NGC 7163, ESO 466- 36, ESO 466- 46, ESO 404- 27, NGC 7187, IC 5156, ESO 404- 39, and ESO 466- 51.[19] Other nearby galaxies include NGC 7135 and its group, NGC 7204, and NGC 7208.[20]

See also

References

  1. ^ a b "More Than Meets the Eye". www.spacetelescope.org. 28 March 2022. Retrieved 6 May 2023.
  2. ^ a b c d e f g h i "NASA/IPAC Extragalactic Database". Results for NGC 7172. Retrieved 2023-05-06.
  3. ^ Seligman, Courtney. "NGC 7172 (= HCG 90A)". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ Turner, T. J.; George, I. M.; Nandra, K.; Mushotzky, R. F. (November 1997). "ASCA Observations of Type 2 Seyfert Galaxies. I. Data Analysis Results". The Astrophysical Journal Supplement Series. 113 (1): 23–67. arXiv:astro-ph/9608170. doi:10.1086/313053.
  5. ^ a b c Sharpies, R. M.; Longmore, A. J.; Hawarden, T. G.; Carter, D. (1 May 1984). "NGC 7172: an obscured active nucleus". Monthly Notices of the Royal Astronomical Society. 208 (1): 15–24. doi:10.1093/mnras/208.1.15.
  6. ^ Rubin, V. C. (August 1974). "Two chains of interesting southern galaxies : NGC 7172-7173-7174-7176and NGC 7201-7203-7204". The Astrophysical Journal. 191: 645. doi:10.1086/153005.
  7. ^ Marshall, F. E.; Boldt, E. A.; Holt, S. S.; Mushotzky, R. F.; Rothschild, R. E.; Serlemitsos, P. J.; Pravdo, S. H. (July 1979). "New hard X-ray sources observed with HEAO A-2". The Astrophysical Journal Supplement Series. 40: 657. doi:10.1086/190600.
  8. ^ Turner, T. J.; Pounds, K. A. (1 October 1989). "The EXOSAT spectral survey of AGN". Monthly Notices of the Royal Astronomical Society. 240 (4): 833–880. doi:10.1093/mnras/240.4.833.
  9. ^ a b Smajić, S.; Fischer, S.; Zuther, J.; Eckart, A. (August 2012). "Unveiling the nucleus of NGC 7172". Astronomy & Astrophysics. 544: A105. doi:10.1051/0004-6361/201118256.
  10. ^ Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D. (1 April 2012). "THE LINK BETWEEN THE HIDDEN BROAD LINE REGION AND THE ACCRETION RATE IN SEYFERT 2 GALAXIES". The Astrophysical Journal. 748 (2): 130. arXiv:1201.5397. doi:10.1088/0004-637X/748/2/130.
  11. ^ Shuvo, Onic I.; Johnson, Megan C.; Secrest, Nathan J.; Gliozzi, Mario; Fischer, Travis C.; Cigan, Phillip J.; Fernandez, Luis C.; Dorland, Bryan N. (1 September 2022). "FRAMEx. III. Radio Emission in the Immediate Vicinity of Radio-quiet AGNs". The Astrophysical Journal. 936 (1): 76. arXiv:2208.05848. doi:10.3847/1538-4357/ac874a.
  12. ^ Guainazzi, M.; Matt, G.; Antonelli, L. A.; Fiore, F.; Piro, L.; Ueno, S. (11 August 1998). "The X-ray spectrum and variability of the Seyfert 2 galaxy NGC 7172". Monthly Notices of the Royal Astronomical Society. 298 (3): 824–830. arXiv:astro-ph/9803151. doi:10.1046/j.1365-8711.1998.01702.x.
  13. ^ Dadina, M.; Bassani, L.; Cappi, M.; Palumbo, G. G. C.; Piro, L.; Guainazzi, M.; Malaguti, G.; Di Cocco, G.; Trifoglio, M. (April 2001). "On the origin of the FeK α line in the Seyfert 2 galaxy NGC 7172". Astronomy & Astrophysics. 370 (1): 70–77. doi:10.1051/0004-6361:20010132.
  14. ^ Akylas, A.; Georgantopoulos, I.; Comastri, A. (June 2001). "BeppoSAX observations of the Seyfert 2 galaxies NGC 7172 and ESO 103-G35". Monthly Notices of the Royal Astronomical Society. 324 (2): 521–528. doi:10.1046/j.1365-8711.2001.04375.x.
  15. ^ Awaki, Hisamitsu; Murakami, Hirokatsu; Ogawa, Yuu; Leighly, Karen M. (10 July 2006). "Variability Study of Seyfert 2 Galaxies with XMM-Newton". The Astrophysical Journal. 645 (2): 928–939. doi:10.1086/504405.
  16. ^ Imanishi, M. (4 April 2002). "The 3.4-μm absorption feature towards three obscured active galactic nuclei: The 3-4-μm absorption feature". Monthly Notices of the Royal Astronomical Society. 319 (1): 331–336. doi:10.1046/j.1365-8711.2000.03873.x.
  17. ^ Roche, P. F.; Packham, C.; Aitken, D. K.; Mason, R. E. (11 February 2007). "Silicate absorption in heavily obscured galaxy nuclei". Monthly Notices of the Royal Astronomical Society. 375 (1): 99–104. arXiv:astro-ph/0610583. doi:10.1111/j.1365-2966.2006.11207.x.
  18. ^ a b White, P. M.; Bothun, G.; Guerrero, Martin A.; West, Michael J.; Barkhouse, Wayne A. (10 March 2003). "Extraordinary Diffuse Light in Hickson Compact Group 90". The Astrophysical Journal. 585 (2): 739–749. doi:10.1086/346075.
  19. ^ Garcia, A. M. (1 July 1993). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47–90. Bibcode:1993A&AS..100...47G. ISSN 0365-0138.
  20. ^ Makarov, Dmitry; Karachentsev, Igor (21 April 2011). "Galaxy groups and clouds in the local (z~ 0.01) Universe". Monthly Notices of the Royal Astronomical Society. 412 (4): 2498–2520. arXiv:1011.6277. Bibcode:2011MNRAS.412.2498M. doi:10.1111/j.1365-2966.2010.18071.x. S2CID 119194025. Archived from the original on 31 January 2016. Retrieved 23 December 2018.

External links

Wikimedia Commons has media related to NGC 7172.
This page was last edited on 14 March 2024, at 04:03
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.
Contact WIKI 2
Introduction
Terms of Service
Privacy Policy