Astronomy:NGC 4593

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Short description: Galaxy in the constellation of Virgo
NGC 4593
NGC 4593 legacy dr10.jpg
NGC 4593 (right) and MCG-01-32-033 by legacy surveys
Observation data (J2000 epoch)
ConstellationVirgo
Right ascension 12h 39m 39.4s[1]
Declination−05° 20′ 39″[1]
Redshift0.008312 ± 0.000020 [1]
Helio radial velocity2,492 ± 6 km/s[1]
Distance120 ± 57 Mly (34.3 ± 16.8 Mpc)[1]
Apparent magnitude (V)11.67
Characteristics
Type(R)SB(rs)b [1]
Apparent size (V)3.9′ × 2.9′[1]
Notable featuresSeyfert galaxy
Other designations
MRK 1330, MCG -01-32-032, PGC 42375[1]

NGC 4593 is a barred spiral galaxy located in the constellation Virgo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 4593 is about 125,000 light years across.[1] It was discovered by William Herschel on April 17, 1784.[2] It is a Seyfert galaxy.[1]

Characteristics

NGC 4593 is a barred spiral galaxy with a nearly complete ring. The galaxy has a large elliptical/boxy pseudobulge with the bar emerging from its northeast and southwest corner. From its end of the bar begin two diffuse smooth spiral arms that can be traced for about half a revolution. At the south part of the ring there could emerge a third, smaller spiral arm.[3] One arm emerges from the ring at one end of the bar while a second emerges about 15 degrees before the other end.[4]

Active nucleus

The central region of NGC 4593 by the Hubble Space Telescope.

The nucleus of NGC 4593 has been found to be active and it has been categorised as a type I Seyfert galaxy.[5] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 4593 is estimated to be (9.8±2.1)×106 M☉ based on reverberation mapping[6] or (5.8±2.1)×106 M☉ based on X-ray flux variations.[7]

The nucleus has been found to be a bright X-rays source. The source is variable both in flux and spectrum, varying at a timescale of few kiloseconds.[8] The changes in the X-ray band are followed by variations in the ultraviolet and visual light band, with the lag being 1.3 ± 0.5  days in the V-band.[9] The X-rays observations by Chandra X-ray Observatory indicate the presence of a warm absorber and outflows of ionised gas that are generated at different distances from the nucleus.[10] The overall X-ray spectrum indicates the presence of a hot corona, which generates the hard X-rays, and a warm medium, which is responsible for the soft X-rays excess.[7]

A circumnuclear dust ring with a radius of 5 arcseconds that is connected with the dust lanes in the bar of the galaxy is seen in visible light.[4] Similar rings in other galaxies have been found to exhibit intense star formation, but that isn't the case with NGC 4593, indicating that starburst activity is episodic.[4] Inside the ring lies a single spiral arm and no other dust features.[11]

Nearby galaxies

NGC 4593 is the foremost galaxy in a galaxy group known as NGC 4593 group. Other members of the group the spiral galaxy NGC 4602 and the smaller galaxies MCG-01-32-37, MGC-01-32-33, SVEN 314, and SVEN 328.[12] Markarov et al. consider NGC 4604 to be a member of this group as well.[13] SVEN 314 is a dwarf galaxy which lies at a projected distance of 22 kpc and is the closest galaxy to NGC 4593.[12] There are evidence that NGC 4693 is interracting with MGC-01-32-33, which lies about two disk radii away, as the spiral pattern is slightly distorted towards the direction of that galaxy, possibly as a result of tidal forces.[4]

Other galaxies near NGC 4593 group include UGC 7798 and its group, IC 804, NGC 4626, NGC 4628, and NGC 4671.[13] These galaxies were considered to be part of the Virgo II Groups, but that isn't accepted anymore,[12] and they are considered to lie between the Local Supercluster and Hydra-Centaurus Supercluster.[14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 "NASA/IPAC Extragalactic Database". Results for NGC 4593. http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+4593. 
  2. ↑ Seligman, Courtney. "NGC 4593". https://cseligman.com/text/atlas/ngc45a.htm#4593. 
  3. ↑ Eskridge, Paul B.; Frogel, Jay A.; Pogge, Richard W.; Quillen, Alice C.; Berlind, Andreas A.; Davies, Roger L.; DePoy, D. L.; Gilbert, Karoline M. et al. (November 2002). "Near-Infrared and Optical Morphology of Spiral Galaxies". The Astrophysical Journal Supplement Series 143 (1): 73–111. doi:10.1086/342340. 
  4. ↑ 4.0 4.1 4.2 4.3 Kormendy, John; Cornell, Mark E.; Block, David L.; Knapen, Johan H.; Allard, Emma L. (10 May 2006). "Pseudobulges in the Disk Galaxies NGC 7690 and NGC 4593". The Astrophysical Journal 642 (2): 765–774. doi:10.1086/501341. 
  5. ↑ MacAlpine, G. M.; Williams, G. A.; Lewis, D. W. (December 1979). "Spectrophotometry of the Seyfert galaxy NGC 4593". Publications of the Astronomical Society of the Pacific 91: 746. doi:10.1086/130580. 
  6. ↑ Denney, Kelly D.; Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.; Cackett, Edward M.; Dietrich, Matthias; Fogel, Jeffrey K. J.; Ghosh, Himel et al. (10 December 2006). "The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping". The Astrophysical Journal 653 (1): 152–158. doi:10.1086/508533. 
  7. ↑ 7.0 7.1 Middei, R; Bianchi, S; Petrucci, P-O; Ursini, F; Cappi, M; De Marco, B; De Rosa, A; Malzac, J et al. (11 March 2019). "High-energy monitoring of NGC 4593 II. Broad-band spectral analysis: testing the two-corona model". Monthly Notices of the Royal Astronomical Society 483 (4): 4695–4705. doi:10.1093/mnras/sty3379. 
  8. ↑ Ursini, F.; Petrucci, P.-O.; Matt, G.; Bianchi, S.; Cappi, M.; De Marco, B.; De Rosa, A.; Malzac, J. et al. (21 November 2016). "High-energy monitoring of NGC 4593 with XMM–Newton and NuSTAR . X-ray spectral analysis". Monthly Notices of the Royal Astronomical Society 463 (1): 382–392. doi:10.1093/mnras/stw2022. 
  9. ↑ Pal, Main; Naik, Sachindra (11 March 2018). "Correlated X-ray/UV/optical emission and short-term variability in a Seyfert 1 galaxy NGC 4593". Monthly Notices of the Royal Astronomical Society 474 (4): 5351–5362. doi:10.1093/mnras/stx3103. 
  10. ↑ Ebrero, J.; Kaastra, J. S.; Kriss, G. A.; de Vries, C. P.; Costantini, E. (11 November 2013). "The X-ray/UV absorber in NGC 4593". Monthly Notices of the Royal Astronomical Society 435 (4): 3028–3044. doi:10.1093/mnras/stt1497. 
  11. ↑ Martini, Paul; Regan, Michael W.; Mulchaey, John S.; Pogge, Richard W. (June 2003). "Circumnuclear Dust in Nearby Active and Inactive Galaxies. I. Data". The Astrophysical Journal Supplement Series 146 (2): 353–406. doi:10.1086/367817. 
  12. ↑ 12.0 12.1 12.2 Kollatschny, W.; Fricke, K. J. (1 February 1985). "The NGC 4593 group of active galaxies.". Astronomy and Astrophysics 143: 393–398. ISSN 0004-6361. https://articles.adsabs.harvard.edu/pdf/1985A%26A...143..393K. 
  13. ↑ 13.0 13.1 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. doi:10.1111/j.1365-2966.2010.18071.x. Bibcode: 2011MNRAS.412.2498M. http://www.sao.ru/hq/dim/groups/galaxies.dat. Retrieved 12 January 2019. 
  14. ↑ Richter, O. -G.; Huchtmeier, W. K. (1 March 1987). "HI observations of galaxies in between the Local and the Hydra/Centaurus superclusters.". Astronomy and Astrophysics Supplement Series 68: 427–467. ISSN 0365-0138. https://ui.adsabs.harvard.edu/abs/1987A%26AS...68..427R/abstract. 

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