NGC 4449

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NGC 4449
Starburst in NGC 4449 (captured by the Hubble Space Telescope).jpg
A Hubble Space Telescope (HST) image of NGC 4449.
Observation data (J2000 epoch)
Constellation Canes Venatici [1]
Right ascension 12h 28m 11.9s [2]
Declination +44° 05′ 40″ [2]
Redshift 207 ± 4 km/s [2]
Distance 13.08 ± 0.98  Mly (4.01 ± 0.30  Mpc) [3]
Apparent magnitude  (V)10.0 [2]
Characteristics
Type IBm [2]
Apparent size  (V)6′.2 × 4′.4 [2]
Other designations
UGC 7592, [2] PGC 40973, [2] Caldwell  21

NGC 4449, also known as Caldwell 21, is an irregular Magellanic type galaxy in the constellation Canes Venatici, being located about 13 million light-years away. [3] It is part of the M94 Group or Canes Venatici I Group that is relatively close to the Local Group hosting our Milky Way galaxy. [4] [5]

Contents

Characteristics

This galaxy is similar in nature to the Milky Way's satellite galaxy, the Large Magellanic Cloud (LMC), [6] though is not as bright nor as large. NGC 4449 has a general bar shape, also characteristic of the LMC, with scattered young blue star clusters.

Unlike the Large Magellanic Cloud, however, NGC 4449 is considered a starburst galaxy due to its high rate of star formation (twice the one of the LMC) [7] and includes several massive and young star clusters, [8] [9] one of them in the galaxy's center. [10]

Photos of the galaxy show the pinkish glow of atomic hydrogen gas, the telltale tracer of massive star forming regions.

NGC 4449 is surrounded by a large envelope of neutral hydrogen that extends over an area of 75 arc minutes (14 times larger than the optical diameter of the galaxy). The envelope shows distortions and irregularities likely caused by interactions with nearby galaxies. [11]

Interactions with nearby galaxies are thought to have influenced star formation in NGC 4449 and, in fact, in 2012 two small galaxies have been discovered interacting with this galaxy: a very low surface brightness disrupted dwarf spheroidal with the same stellar mass as NGC 4449's halo but with a ratio of dark matter to stellar matter between 5 and 10 times that of NGC 4449 [12] and a highly flattened globular cluster with two tails of young stars that may be the nucleus of a gas-rich galaxy. [13] Both satellites have apparently been disrupted by NGC 4449 and are now being absorbed by it. [12] [13]

At least one ultraluminous X-ray source (ULX) is known in NGC 4449, called NGC 4449 X7. There are three candidates that have been identified as optical counterparts to NGC 4449 X7 (i.e. they may be associated with the ULX). They are all early (B-type to F-type) supergiants that are estimated to be about 40 to 50 million years old and about 8 times the mass of the Sun. [14]

NGC 4449, resembling early star-forming galaxies, observed with Webb's MIRI and NIRCam instruments for detailed study. NGC 4449 observed by James Webb Space Telescope.jpg
NGC 4449, resembling early star-forming galaxies, observed with Webb's MIRI and NIRCam instruments for detailed study.

In May 2024, the James Webb Space Telescope captured a detailed image of NGC 4449, [15] highlighting widespread starburst activity. This infrared image revealed intricate structures of gas, dust, and newly forming stars, [16] further enriching our understanding of star formation processes influenced by interactions with nearby galaxies. This discovery emphasizes NGC 4449's role as a key site for studying galaxy evolution and stellar birth.

Related Research Articles

<span class="mw-page-title-main">Local Group</span> Group of galaxies that includes the Milky Way

The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×1019 kilometres), and a total mass of the order of 2×1012 solar masses (4×1042 kg). It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kiloparsecs (3×10^6 ly; 2×1019 km) and are moving toward one another with a velocity of 123 km/s. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

<span class="mw-page-title-main">Large Magellanic Cloud</span> Satellite galaxy of the Milky Way

The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (163,000 light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal (c. 16 kiloparsecs (52,000 light-years) away) and the possible dwarf irregular galaxy called the Canis Major Overdensity. Based on the D25 isophote at the B-band (445 nm wavelength of light), the Large Magellanic Cloud is about 9.86 kiloparsecs (32,200 light-years) across. It is roughly one-hundredth the mass of the Milky Way and is the fourth-largest galaxy in the Local Group, after the Andromeda Galaxy (M31), the Milky Way, and the Triangulum Galaxy (M33).

<span class="mw-page-title-main">Tarantula Nebula</span> H II region in the constellation Dorado

The Tarantula Nebula is a large H II region in the Large Magellanic Cloud (LMC), forming its south-east corner.

<span class="mw-page-title-main">NGC 404</span> Galaxy in the constellation Andromeda

NGC 404 is a field galaxy located about 10 million light years away in the constellation Andromeda. It was discovered by William Herschel in 1784, and is visible through small telescopes. NGC 404 lies just beyond the Local Group and does not appear gravitationally bound to it. It is located within 7 arc-minutes of second magnitude star Mirach, making it a difficult target to observe or photograph and granting it the nickname "Mirach's Ghost".

<span class="mw-page-title-main">Messier 32</span> Dwarf elliptical galaxy in the constellation Andromeda

Messier 32 is a dwarf "early-type" galaxy about 2,650,000 light-years (810,000 pc) from the Solar System, appearing in the constellation Andromeda. M32 is a satellite galaxy of the Andromeda Galaxy (M31) and was discovered by Guillaume Le Gentil in 1749.

<span class="mw-page-title-main">Sculptor Galaxy</span> Intermediate spiral galaxy in the constellation Sculptor

The Sculptor Galaxy is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.

<span class="mw-page-title-main">NGC 185</span> Galaxy in the constellation Cassiopeia

NGC 185 is a dwarf spheroidal galaxy located 2.08 million light-years from Earth, appearing in the constellation Cassiopeia. It is a member of the Local Group, and is a satellite of the Andromeda Galaxy (M31).

<span class="mw-page-title-main">NGC 3603</span> Open cluster in the constellation Carina

NGC 3603 is a nebula situated in the Carina–Sagittarius Arm of the Milky Way around 20,000 light-years away from the Solar System. It is a massive H II region containing a very compact open cluster HD 97950.

<span class="mw-page-title-main">NGC 1569</span> Galaxy in the constellation Camelopardalis

NGC 1569 is a dwarf irregular galaxy in Camelopardalis. The galaxy is relatively nearby and consequently, the Hubble Space Telescope can easily resolve the stars within the galaxy. The distance to the galaxy was previously believed to be only 2.4 Mpc. However, in 2008 scientists studying images from Hubble calculated the galaxy's distance at nearly 11 million light-years away, about 4 million light-years farther than previously thought, meaning it is a member of the IC 342 group of galaxies.

<span class="mw-page-title-main">NGC 1705</span> Galaxy in the constellation Pictor

NGC 1705 is a peculiar lenticular galaxy and a blue compact dwarf galaxy (BCD) in the southern constellation of Pictor, positioned less than a degree to the east of Iota Pictoris, and is undergoing a starburst. With an apparent visual magnitude of 12.6 it requires a telescope to observe. It is estimated to be approximately 17 million light-years from the Earth, and is a member of the Dorado Group.

<span class="mw-page-title-main">NGC 2976</span> Galaxy in the constellation Ursa Major

NGC 2976 is a peculiar dwarf galaxy in the northern circumpolar constellation of Ursa Major. It was discovered by German-born astronomer William Herschel on November 8, 1801, and catalogued as H I.285. J. L. E. Dreyer described it as, "bright, very large, much extended 152°, star involved". It is a member of the M81 Group and lies 1° 20′ to the southwest of Messier 81. The projected separation of this galaxy from the M81 Group is 190 kpc.

<span class="mw-page-title-main">NGC 1850</span> Super star cluster in the constellation Dorado

NGC 1850 is a double cluster and a super star cluster in the Dorado constellation, located in the northwest part of the bar of the Large Magellanic Cloud, at a distance of 168 kly (51.5 kpc) from the Sun. It was discovered by Scottish astronomer James Dunlop in 1826.

<span class="mw-page-title-main">NGC 4214</span> Galaxy in the constellation Canes Venatici

NGC 4214 is a dwarf barred irregular galaxy located around 10 million light-years away in the constellation Canes Venatici. NGC 4214 is a member of the M94 Group.

<span class="mw-page-title-main">HD 97950</span> Multiple star system in the constellation Carina

HD 97950, is the central core of a super star cluster within the NGC 3603 H II region. It was catalogued as a single star, but has now been resolved into one of the densest clusterings of stars in the galaxy.

<span class="mw-page-title-main">NGC 1313</span> Galaxy in the constellation Reticulum

NGC 1313 is a field galaxy and a irregular galaxy discovered by the Scottish astronomer James Dunlop on 27 September 1826. It has a diameter of about 50,000 light-years, or about half the size of the Milky Way.

<span class="mw-page-title-main">R. Jay GaBany</span> American astronomer and astrophotographer

Robert Jay GaBany is an American amateur astronomer and astrophotographer who is also known for his work with an international team of astrophysicists led by Dr. David Martínez-Delgado. GaBany helped pioneer the use of modest size telescopes and off the shelf CCD-cameras to produce long exposure images that revealed ancient galactic merger remnants in the form of star streams surrounding nearby galaxies that were previously undetected or suspected.

<span class="mw-page-title-main">NGC 5204</span> Galaxy in the constellation Ursa Major

NCG 5204 is a Magellanic spiral galaxy located about 14.5 million light-years away from Earth in the constellation of Ursa Major and is a member of the M101 Group of galaxies. It has a galaxy morphological classification of SA(s)m and is highly irregular, with only the barest indication of any spiral arm structure. The galaxy's most prominent feature is an extremely powerful X-ray source designated NGC 5204 X-1. This has resulted in the galaxy being the target of several studies due to the strength of the source and its relative proximity to Earth.

<span class="mw-page-title-main">NGC 121</span> Globular cluster in the constellation Tucana

NGC 121 is a globular cluster of stars in the southern constellation of Tucana. It is the oldest globular cluster in the Small Magellanic Cloud (SMC), which is a dwarf satellite galaxy of the Milky Way. This cluster was first discovered by English astronomer John Herschel on September 20, 1835. The compiler of the New General Catalogue, Danish astronomer John Louis Emil Dreyer, described this object as "pretty bright, pretty small, little extended, very gradually brighter middle". The cluster is located at a distance of around 200,000 light-years (60 kpc) from the Sun.

<span class="mw-page-title-main">LH 41-1042</span> Wolf Rayet star in the constellation Dorado

LH 41-1042 is a Wolf–Rayet star located in the Large Magellanic Cloud (LMC). It is an extremely rare member of the WO oxygen sequence, the second to be discovered in the LMC and one of only three found so far in that galaxy.

<span class="mw-page-title-main">NGC 4861</span> Irregular galaxy in constellation Canes Venatici

NGC 4861, also known as Arp 266, is a galaxy in the constellation Canes Venatici. It was discovered by William Herschel on May 1, 1785.

References

  1. ↑ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN   978-0-933346-51-2.
  2. 1 2 3 4 5 6 7 8 "NASA/IPAC Extragalactic Database". Results for NGC 4449. Retrieved 13 July 2007.
  3. 1 2 Sabbi, E.; et al. (2018). "The Resolved Stellar Populations in the LEGUS Galaxies". The Astrophysical Journal Supplement Series. 235 (1): 23. arXiv: 1801.05467 . Bibcode:2018ApJS..235...23S. doi: 10.3847/1538-4365/aaa8e5 . S2CID   54968426.
  4. ↑ Karachentsev, I. D. (2005). "The Local Group and Other Neighboring Galaxy Groups". The Astronomical Journal. 129 (1): 178–188. arXiv: astro-ph/0410065 . Bibcode:2005AJ....129..178K. doi:10.1086/426368. ISSN   1538-3881. S2CID   119385141.
  5. ↑ "Nearby Groups of Galaxies". ned.ipac.caltech.edu. Retrieved 3 March 2018.
  6. ↑ Karachentsev, Igor D.; Karachentseva, Valentina E.; Huchtmeier, Walter K.; Makarov, Dmitry I. (2003). "A Catalog of Neighboring Galaxies". The Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi: 10.1086/382905 .
  7. ↑ Annibali, F.; Aloisi, A.; Mack, J.; Tosi, M.; et al. (2008). "Starbursts in the Local Universe: New Hubble Space Telescope Advanced Camera for Surveys Observations of the Irregular Galaxy NGC 4449". The Astronomical Journal. 135 (5): 1900–1916. arXiv: 0708.0852 . Bibcode:2008AJ....135.1900A. doi:10.1088/0004-6256/135/5/1900. S2CID   121102530.
  8. ↑ Reines, Amy E.; Johnson, Kelsey E.; Goss, W. M. (2008). "Emerging Massive Star Clusters Revealed: High-Resolution Imaging of NGC 4449 from the Radio to the Ultraviolet". The Astronomical Journal. 135 (6): 2222–2239. arXiv: 0804.0005 . Bibcode:2008AJ....135.2222R. doi:10.1088/0004-6256/135/6/2222. S2CID   2507423.
  9. ↑ Larsen, Søren S.; Brodie, Jean P.; Hunter, Deidre A. (2004). "Dynamical Mass Estimates for Five Young Massive Stellar Clusters". The Astronomical Journal. 128 (5): 2295–2305. arXiv: astro-ph/0407373 . Bibcode:2004AJ....128.2295L. doi:10.1086/424538. S2CID   36220968.
  10. ↑ Böker, Torsten; van der Marel, Roeland P.; Mazzuca, Lisa; Rix, Hans-Walter; et al. (2001). "A Young Stellar Cluster in the Nucleus of NGC 4449". The Astronomical Journal. 121 (3): 1473–1481. arXiv: astro-ph/0010542 . Bibcode:2001AJ....121.1473B. doi:10.1086/319415. S2CID   6191573.
  11. ↑ Bajaja, E.; Huchtmeier, W. K.; Klein, U. (1994). "The extended HI halo in NGC 4449". Astronomy and Astrophysics. 285: 385–388. Bibcode:1994A&A...285..385B.
  12. 1 2 Martínez-Delgado, David; Romanowsky, Aaron J.; Gabany, R. Jay; Annibali, Francesca; et al. (2012). "Dwarfs Gobbling Dwarfs: A Stellar Tidal Stream around NGC 4449 and Hierarchical Galaxy Formation on Small Scales". The Astrophysical Journal Letters. 748 (2): L24. arXiv: 1112.2154 . Bibcode:2012ApJ...748L..24M. doi:10.1088/2041-8205/748/2/L24. S2CID   54890773.
  13. 1 2 Annibali, F.; Tosi, M.; Aloisi, A.; van der Marel, R. P.; et al. (2012). "Cluster 77 in NGC 4449: The Nucleus of a Satellite Galaxy Being Transformed into a Globular Cluster?". The Astrophysical Journal Letters. 745 (1): L1. arXiv: 1111.5861 . Bibcode:2012ApJ...745L...1A. doi:10.1088/2041-8205/745/1/L1. S2CID   119227799.
  14. ↑ Ela, M Ozdogan; Akyuz, A.; Aksaker, N.; Avdan, S.; Oralhan, I Akkaya; Vinokurov, A.; Allak, S.; Solovyeva, Y.; Atapin, K.; Bizyaev, D. (2021). "Optical counterparts of ULXs in two dwarf galaxies: NGC 4861 and NGC 4449". Monthly Notices of the Royal Astronomical Society. 505: 771–782. arXiv: 2105.02302 . doi: 10.1093/mnras/stab1321 .
  15. ↑ information@eso.org. "Fireworks of stellar starbursts | ESA/Webb". esawebb.org. Retrieved 29 May 2024.
  16. ↑ "Webb Telescope Captures Stunning Star Formation in Dwarf Galaxy NGC 4449". www.jameswebbdiscovery.com. Retrieved 29 May 2024.
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