NGC 4395

Last updated
NGC 4395
Ngc4395.jpg
An ultraviolet image of NGC 4395 taken with GALEX
Observation data (J2000 epoch)
Constellation Canes Venatici [1]
Right ascension 12h 25m 48.9s [2]
Declination +33° 32′ 48″ [2]
Redshift 319 ± 1 km/s [2]
Distance ~14 million light-years
Apparent magnitude  (V)10.6 [2]
Characteristics
Type SA(s)m [2]
Size50,000 ly (diameter)
Apparent size  (V)13.2′ × 11.0′ [2]
Other designations
NGC 4395, [3] UGC 7542, [2] PGC 40596 [2]

NGC 4395 is a nearby low surface brightness spiral galaxy located about 14 million light-years (or 4.3 Mpc) from Earth in the constellation Canes Venatici. [4] The nucleus of NGC 4395 is active and the galaxy is classified as a Seyfert Type I known for its very low-mass supermassive black hole. [5]

Contents

Physical characteristics

NGC 4395 has a halo that is about 8′ in diameter. It has several patches of greater brightness running northwest to southeast. The one furthest southeast is the brightest. Three of the patches have their own NGC numbers: 4401, 4400, and 4399 running east to west. [3]

The galaxy is highly unusual for Seyfert galaxies, because it does not have a bulge and is considered to be a dwarf galaxy. [5]

Observational history

NGC 4395 was imaged and classified as a "spiral nebula" in a 1920 paper by astronomer Francis G. Pease. [6] Now, it is known to be a galaxy distinct from the Milky Way (see Great Debate). Along with several other nearby galaxies, resolved stars in NGC 4395 were used to measure the expansion rate of the Universe by Allan Sandage and Gustav Andreas Tammann in their 1974 paper. [7] More recently, NGC 4395 was discovered to contain a very low-luminosity active galactic nucleus. [8] Since then, its nucleus has been the subject of several academic papers and attempts to measure the mass of its central black hole.

Nucleus

NGC 4395 is one of the least luminous and nearest Seyfert galaxies known. [5] The nucleus of NGC 4395 is notable for containing one of the smallest supermassive black holes with a well-measured mass. [9] The central black hole has a mass of "only" 300,000 M☉. [10] However, a recent study found a black hole mass of just 10,000 M☉. [11] The low-mass black hole in NGC 4395 would make it a so-called "intermediate-mass black hole". [12] The black hole may have a truncated disk. [13]

Related Research Articles

An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands. A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the center of its host galaxy.

<span class="mw-page-title-main">Seyfert galaxy</span> Class of active galaxies with very bright nuclei

Seyfert galaxies are one of the two largest groups of active galaxies, along with quasar host galaxies. They have quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.

<span class="mw-page-title-main">Sombrero Galaxy</span> Galaxy in the constellation Virgo

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.

<span class="mw-page-title-main">NGC 3982</span> Galaxy in the constellation Ursa Major

NGC 3982(also known as UGC 6918) is an intermediate spiral galaxy approximately 68 million light-years away in the constellation Ursa Major. It was discovered by William Herschel on April 14, 1789, and misclassified as a planetary nebula. NGC 3982 is a part of the M109 Group.

<span class="mw-page-title-main">NGC 3227</span> Galaxy in the constellation Leo

NGC 3227 is an intermediate spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies. Both galaxies may be found in the constellation Leo. It is a member of the NGC 3227 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.

<span class="mw-page-title-main">NGC 3226</span> Dwarf elliptical galaxy in the constellation Leo

NGC 3226 is a dwarf elliptical galaxy that is interacting with the spiral galaxy NGC 3227. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies. Both galaxies may be found in the constellation Leo. It is a member of the NGC 3227 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.

<span class="mw-page-title-main">NGC 5548</span> Type I Seyfert galaxy in the constellation Boötes

NGC 5548 is a Type I Seyfert galaxy with a bright, active nucleus. This activity is caused by matter flowing onto a 65 million solar mass (M☉) supermassive black hole at the core. Morphologically, this is an unbarred lenticular galaxy with tightly-wound spiral arms, while shell and tidal tail features suggest that it has undergone a cosmologically-recent merger or interaction event. NGC 5548 is approximately 245 million light years away and appears in the constellation Boötes. The apparent visual magnitude of NGC 5548 is approximately 13.3 in the V band.

<span class="mw-page-title-main">NGC 5005</span> Galaxy in the constellation Canes Venatici

NGC 5005, also known as Caldwell 29, is an inclined spiral galaxy in the constellation Canes Venatici. The galaxy has a relatively bright nucleus and a bright disk that contains multiple dust lanes. The galaxy's high surface brightness makes it an object that is visible to amateur astronomers using large amateur telescopes.

<span class="mw-page-title-main">Low-ionization nuclear emission-line region</span> Type of galactic nucleus

A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission. The spectra typically include line emission from weakly ionized or neutral atoms, such as O, O+, N+, and S+. Conversely, the spectral line emission from strongly ionized atoms, such as O++, Ne++, and He+, is relatively weak. The class of galactic nuclei was first identified by Timothy Heckman in the third of a series of papers on the spectra of galactic nuclei that were published in 1980.

<span class="mw-page-title-main">NGC 3621</span> Spiral galaxy in the constellation Hydra

NGC 3621 is a field spiral galaxy about 22 Mly (6.7 Mpc) away in the equatorial constellation of Hydra. It is comparatively bright and can be well seen in moderate-sized telescopes. The galaxy is around 93,000 ly (29,000 pc) across and is inclined at an angle of 25° from being viewed edge on. It shines with a luminosity equal to 13 billion times that of the Sun. The morphological classification is SA(s)d, which indicates this is an ordinary spiral with loosely wound arms. There is no evidence for a bulge. Although it appears to be isolated, NGC 3621 belongs to the Leo spur.

<span class="mw-page-title-main">NGC 4041</span> Spiral galaxy in the constellation Ursa Major

NGC 4041 is the New General Catalogue identifier for a spiral galaxy in the northern circumpolar constellation of Ursa Major. It is located an estimated 70 million light years from the Sun. The morphological classification of SA(rs)bc indicates this is a spiral galaxy the lacks a bar; the 'rs' means it has a weakly-formed ring structure, and the 'bc' indicates the spiral arms are moderately to loosely wound.

<span class="mw-page-title-main">NGC 4596</span> Galaxy in the constellation Virgo

NGC 4596 is a barred lenticular galaxy located about 55 million light-years away in the constellation Virgo. NGC 4596 was discovered by astronomer William Herschel on March 15, 1784. NGC 4596 is a member of the Virgo Cluster and has an inclination of about 38°.

<span class="mw-page-title-main">NGC 708</span> Galaxy in the constellation Andromeda

NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.

<span class="mw-page-title-main">NGC 3367</span> Spiral galaxy in the constellation Leo

NGC 3367 is a barred spiral galaxy located in the constellation Leo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 3367 is about 85,000 light years across. It was discovered by William Herschel on March 19, 1784.

<span class="mw-page-title-main">NGC 7674</span> Galaxy located in the constellation Pegasus

NGC 7674 is a spiral galaxy located in the constellation Pegasus. It is located at a distance of about 350 million light years from Earth, which, given its apparent dimensions, means that NGC 7674 is about 125,000 light years across. It was discovered by John Herschel on August 16, 1830.

<span class="mw-page-title-main">NGC 4278</span> Galaxy in the constellation Coma Berenices

NGC 4278 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4278 is about 65,000 light years across. It was discovered by William Herschel on March 13, 1785. NGC 4278 is part of the Herschel 400 Catalogue and can be found about one and 3/4 of a degree northwest of Gamma Comae Berenices even with a small telescope.

<span class="mw-page-title-main">NGC 4074</span> Galaxy in the constellation Coma Berenices

NGC 4074 is a peculiar lenticular galaxy located 310 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 27, 1785 and is a member of the NGC 4065 Group.

<span class="mw-page-title-main">NGC 2273</span> Galaxy in the constellation Lynx

NGC 2273 is a barred spiral galaxy located in the constellation Lynx. It is located at a distance of circa 95 million light years from Earth, which, given its apparent dimensions, means that NGC 2273 is about 100,000 light years across. It was discovered by Nils Dunér on September 15, 1867.

<span class="mw-page-title-main">NGC 4299</span> Spiral galaxy in the constellation Virgo

NGC 4299 is a featureless spiral galaxy located about 55 million light-years away in the constellation Virgo. It was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.

<span class="mw-page-title-main">NGC 5252</span> Galaxy in the constellation of Virgo

NGC 5252 is a lenticular galaxy located in the constellation Virgo. It is located at a distance of about 220 to 320 million light years from Earth, which, given its apparent dimensions, means that NGC 5252 is about 100,000 light years across. It was discovered by William Herschel on February 2, 1786.

References

  1. ↑ Celestia version 1.4.1. Laurel, Chris, 2006.
  2. 1 2 3 4 5 6 7 8 "NASA/IPAC Extragalactic Database". Results for. Retrieved 2006-11-04.
  3. 1 2 Kepple, George Robert; Glen W. Sanner (1998). The Night Sky Observer's Guide, Volume 2. Willmann-Bell, Inc. p. 48. ISBN   978-0-943396-60-6.
  4. ↑ Thim, F.; Hoessel, J. G.; Saha, A.; Claver, J.; Dolphin, A.; Tammann, G. A. (April 2004). "Cepheids and Long-Period Variables in NGC 4395". The Astronomical Journal. 127 (4): 2322–2343. arXiv: astro-ph/0401558 . Bibcode:2004AJ....127.2322T. doi:10.1086/382244. ISSN   0004-6256. S2CID   14631171.
  5. 1 2 3 Filippenko, Alexei V.; Ho, Luis C. (25 March 2003). "A Low-Mass Central Black Hole in the Bulgeless Seyfert 1 Galaxy NGC 4395". The Astrophysical Journal Letters. 588 (1): L13. arXiv: astro-ph/0303429 . Bibcode:2003ApJ...588L..13F. doi:10.1086/375361. S2CID   14411746 . Retrieved 20 August 2020.
  6. ↑ Pease, F. G. (1920). "1920ApJ....51..276P Page 17". The Astrophysical Journal. 51: 276. Bibcode:1920ApJ....51..276P. doi: 10.1086/142552 .
  7. ↑ Sandage, A.; Tammann, G. A. (December 1974). "Steps toward the Hubble constant. IV. Distances to 39 galaxies in the general field leading to a calibration of the galaxy luminosity classes and a first hint of the value of H0". The Astrophysical Journal. 194: 559–568. Bibcode:1974ApJ...194..559S. doi:10.1086/153275. ISSN   0004-637X.
  8. ↑ Filippenko, Alexei V.; Sargent, Wallace L. W. (July 1989). "Discovery of an Extremely Low Luminosity Seyfert 1 Nucleus in the Dwarf Galaxy NGC 4395". The Astrophysical Journal. 342: L11. Bibcode:1989ApJ...342L..11F. doi:10.1086/185472. ISSN   0004-637X.
  9. ↑ Merritt, David (2013). Dynamics and Evolution of Galactic Nuclei. Princeton, NJ: Princeton University Press. ISBN   9781400846122.
  10. ↑ Peterson, Bradley; et al. (2005). "Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. I. A Reverberation-based Measurement of the Black Hole Mass". The Astrophysical Journal. 632 (2): 799–808. arXiv: astro-ph/0506665 . Bibcode:2005ApJ...632..799P. doi:10.1086/444494. S2CID   13886279.
  11. ↑ Woo, Jong-Hak; Cho, Hojin; Gallo, Elena; Hodges-Kluck, Edmund; Le, Huynh Anh N.; Shin, Jaejin; Son, Donghoon; Horst, John C. (August 2019). "A 10,000-solar-mass black hole in the nucleus of a bulgeless dwarf galaxy". Nature Astronomy. 3 (8): 755–759. arXiv: 1905.00145 . Bibcode:2019NatAs...3..755W. doi:10.1038/s41550-019-0790-3. ISSN   2397-3366. S2CID   189762554.
  12. ↑ Shih, D. C.; Iwasawa, K.; Fabian, A. C. (2003-05-21). "Evidence for an intermediate-mass black hole and a multi-zone warm absorber in NGC 4395". Monthly Notices of the Royal Astronomical Society. 341 (3): 973–980. arXiv: astro-ph/0302108 . doi:10.1046/j.1365-8711.2003.06482.x. ISSN   0035-8711.
  13. ↑ McHardy, I M; Beard, M; Breedt, E; Knapen, J H; Vincentelli, F M; Veresvarska, M; Dhillon, V S; Marsh, T R; Littlefair, S P; Horne, K; Glew, R; Goad, M R; Kammoun, E; Emmanoulopoulos, D (2022-11-22). "First detection of the outer edge of an AGN accretion disc: very fast multiband optical variability of NGC 4395 with GTC/HiPERCAM and LT/IO:O". Monthly Notices of the Royal Astronomical Society. 519 (3): 3366–3382. arXiv: 2212.08015 . doi:10.1093/mnras/stac3651. ISSN   0035-8711.


This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.