NGC 1569

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NGC 1569
Starburst in a Dwarf Irregular Galaxy.jpg
A Hubble Space Telescope (HST) image of NGC 1569
Observation data (J2000 epoch)
Constellation Camelopardalis
Right ascension 4h 30m 49.1s [1]
Declination +64° 50′ 53″ [1]
Redshift -104 km/s [1]
Distance 10.96 ± 0.65 Mly (3.36 ± 0.20 Mpc [2] )
Apparent magnitude  (V)11.9 [1]
Characteristics
Type IBm [1]
Apparent size  (V)3.6′ × 1.8′ [1]
Notable featuresContains two super star clusters
Other designations
UGC 3056, [1] PGC 15345, [1]
VII Zw 016, [1] Arp 210 [1]

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. [3] The distance to the galaxy was previously believed to be only 2.4 Mpc (7.8 Mly). [4] 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. [2] [5]

Contents

Physical characteristics

NGC 1569 is smaller than the Small Magellanic Cloud, but brighter than the Large Magellanic Cloud [6]

Starburst

NGC 1569 is characterized by a large starburst. It has formed stars at a rate 100 times greater than that of the Milky Way during the last 100 million years. [5] It contains two prominent super star clusters with different histories. [3] [7] Both clusters have experienced episodic star formation. Super star cluster A, located in the northwest of the galaxy and actually formed of two close clusters (NGC 1569 A1 and NGC 1569 A2), [8] contains young stars (including Wolf-Rayet stars) that formed less than 5 million years ago (in NGC 1569 A1) as well as older red stars (in NGC 1569 A2). [7] [9] Super star cluster B, located near the center of the galaxy, contains an older stellar population of red giants and red supergiants. [3] [7] [9] Both of these star clusters are thought to have masses equivalent to the masses of the globular clusters in the Milky Way (approximately (6-7) × 105 solar masses [2] ). Numerous smaller star clusters, some of them having masses similar to those of small globular clusters or R136 in the Large Magellanic Cloud, with relatively young ages (between 2 million years and 1 billion years) have also been identified. [3] These results, along with the results from other dwarf galaxies such as the Large Magellanic Cloud and NGC 1705, demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.

Center of NGC 1569 as imaged by the Hubble Space Telescope. At center left the two super star clusters NGC 1569 A1 and NGC 1569 A2 are visible. NGC 1569.jpg
Center of NGC 1569 as imaged by the Hubble Space Telescope. At center left the two super star clusters NGC 1569 A1 and NGC 1569 A2 are visible.

The numerous supernovae produced in the galaxy as well as the strong stellar winds of its stars have produced filaments and bubbles of ionized hydrogen with respective sizes of up to 3,700 and 380 light years that shine excited by the light of the young stars contained within them and that are conspicuous on images taken with large telescopes. [5]

The NGC 1569 starburst is believed to have been triggered by interactions with other galaxies of the IC 342 group, in particular a nearby cloud of neutral hydrogen. [5] [10] A 2013 study suggested the presence of tidal tails linking this galaxy with IC 342 and the dwarf galaxy UGCA 92 (see below) whose nature, however, is unclear and may actually be structures within our galaxy. [11]

Blueshift

The spectrum of NGC 1569 is blueshifted. [1] This means that the galaxy is moving towards the Earth. In contrast, the spectra of most other galaxies are redshifted because of the expansion of the universe.

Environment

The dwarf irregular galaxy UGCA 92 is often assumed to be a companion of NGC 1569; however, its relationship to the starburst the latter is experiencing is unclear, with some authors suggesting UGCA 92 has not started it [12] and others suggesting it has interacted with NGC 1569, being connected with it by a tidal tail and several filaments of neutral hydrogen; however, it is still unclear if those structures are associated with them or actually within the Milky Way, being unrelated with those two galaxies. [11]

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. 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">Triangulum Galaxy</span> Spiral galaxy in the constellation Triangulum

The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC (New General Catalogue) 598. With the D25 isophotal diameter of 18.74 kiloparsecs (61,100 light-years), the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way.

<span class="mw-page-title-main">H II region</span> Large, low-density interstellar cloud of partially ionized gas

An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light years, and density from a few to about a million particles per cubic centimetre. The Orion Nebula, now known to be an H II region, was observed in 1610 by Nicolas-Claude Fabri de Peiresc by telescope, the first such object discovered.

<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">IC 10</span> Irregular starburst galaxy in the constellation Cassiopeia

IC 10 is an irregular galaxy in the constellation Cassiopeia. It was discovered by Lewis Swift in 1887 and in 1935 Nicholas Mayall became the first to suggest that the object is extragalactic. Edwin Hubble suspected it might belong to the Local Group of galaxies, but its status remained uncertain for decades. The radial velocity of IC 10 was measured in 1962, and it was found to be approaching the Milky Way at approximately 350 km/s, strengthening the evidence for its membership in the Local Group. Its membership in the group was finally confirmed in 1996 by direct measurements of its distance based on observations of Cepheids; most estimates place the galaxy 2-3 million light years from Earth, with some estimates ranging from 1.5-4.5 million light years. Despite its closeness, the galaxy is rather difficult to study because it lies near the plane of the Milky Way and is therefore heavily obscured by interstellar matter.

<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">Dwarf galaxy</span> Small galaxy composed of up to several billion stars

A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition.

<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 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 6822</span> Galaxy in the constellation Sagittarius

NGC 6822 is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.

<span class="mw-page-title-main">Dwarf spiral galaxy</span> Dwarf counterparts of spiral galaxies

A dwarf spiral galaxy is the dwarf version of a spiral galaxy. Dwarf galaxies are characterized as having low luminosities, small diameters, low surface brightnesses, and low hydrogen masses. The galaxies may be considered a subclass of low-surface-brightness galaxies.

A super star cluster (SSC) is a very massive young open cluster that is thought to be the precursor of a globular cluster. These clusters called "super" because they are relatively more luminous and contain more mass than other young star clusters. The SSC, however, does not have to physically be larger than other clusters of lower mass and luminosity. They typically contain a very large number of young, massive stars that ionize a surrounding HII region or a so-called "Ultra dense HII region (UDHII)" in the Milky Way Galaxy or in other galaxies. An SSC's HII region is in turn surrounded by a cocoon of dust. In many cases, the stars and the HII regions will be invisible to observations in certain wavelengths of light, such as the visible spectrum, due to high levels of extinction. As a result, the youngest SSCs are best observed and photographed in radio and infrared. SSCs, such as Westerlund 1 (Wd1), have been found in the Milky Way Galaxy. However, most have been observed in farther regions of the universe. In the galaxy M82 alone, 197 young SSCs have been observed and identified using the Hubble Space Telescope.

<span class="mw-page-title-main">UGCA 86</span> Magellanic spiral galaxy in the constellation Camelopardalis

UGCA 86 is a Magellanic spiral galaxy. It was first thought to be part of the Local Group, but after the brightest stars in the galaxy were observed, it became clear that it was located in the IC 342/Maffei Group. UGCA 86 is thought to be a satellite galaxy of IC 342, however the separation between the two galaxies is over 50% larger than the distance between the Milky Way and the Magellanic Clouds.

<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">NGC 346</span> Open cluster in the constellation Tucana

NGC 346 is a young open cluster of stars with associated nebula located in the Small Magellanic Cloud (SMC) that appears in the southern constellation of Tucana. It was discovered August 1, 1826 by Scottish astronomer James Dunlop. J. L. E. Dreyer described it as, "bright, large, very irregular figure, much brighter middle similar to double star, mottled but not resolved". On the outskirts of the cluster is the multiple star system HD 5980, one of the brightest stars in the SMC.

<span class="mw-page-title-main">NGC 2366</span> Galaxy in the constellation Camelopardalis

NGC 2366 is a Magellanic barred irregular dwarf galaxy located in the constellation Camelopardalis.

<span class="mw-page-title-main">NGC 4449</span> Galaxy in the constellation Canes Venatici

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. 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.

<span class="mw-page-title-main">Westerhout 43</span> Region of star formation in the constellation Aquila

Westerhout 43, also known as W43, is a region of star formation of our galaxy located in the constellation of Aquila at a distance of 6 kilo-parsecs of the Sun, that is considered the region of the Milky Way that is most actively forming stars. Despite this, however, it is so heavily obscured by the interstellar dust that it is totally invisible in the optical and must be studied using other wavelengths that are not affected by it, such as the infrared or the radio waves.

<span class="mw-page-title-main">NGC 299</span> Open star cluster in the constellation Tucana

NGC 299 is an open cluster of stars in the main body of the Small Magellanic Cloud – a nearby dwarf galaxy. It is located in the southern constellation of Tucana, just under 200,000 light years distant from the Sun. The cluster was discovered on August 12, 1834 by English astronomer John Herschel.

<span class="mw-page-title-main">NGC 541</span> Galaxy in the constellation Cetus

NGC 541 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of circa 230 million light years from Earth, which, given its apparent dimensions, means that NGC 541 is about 130,000 light years across. It was discovered by Heinrich d'Arrest on October 30, 1864. It is a member of the Abell 194 galaxy cluster and is included in the Atlas of Peculiar Galaxies in the category galaxies with nearby fragments. NGC 541 is a radio galaxy of Fanaroff-Riley class I, also known as 3C 40A.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 "NASA/IPAC Extragalactic Database". Results for NGC 1569. Retrieved 2007-03-15.
  2. 1 2 3 Grocholski, Aaron J.; Aloisi, Alessandra; van der Marel, Roeland P.; Mack, Jennifer; et al. (October 20, 2008). "A New Hubble Space Telescope Distance to NGC 1569: Starburst Properties and IC 342 Group Membership". Astrophysical Journal Letters. 686 (2): L79–L82. arXiv: 0808.0153 . Bibcode:2008ApJ...686L..79G. doi:10.1086/592949. S2CID   9877496.
  3. 1 2 3 4 D. A. Hunter; R. W. O'Connell; J. S. Gallagher; T. A. Smecker-Hane (2000). "The Star Clusters in the Starburst Irregular Galaxy NGC 1569". Astronomical Journal. 120 (5): 2383–2401. arXiv: astro-ph/0009280 . Bibcode:2000AJ....120.2383H. doi:10.1086/316810. S2CID   6445978.
  4. ↑ Makarova, L. N.; Karachentsev, I. D. (2003). "On the Distance to Nearby Dwarf Galaxy NGC 1569". Astrophysics (English Translation of Astrofizika). 46 (2): 144–150. Bibcode:2003Ap.....46..144M. doi:10.1023/A:1024055702766. S2CID   119037879.
  5. 1 2 3 4 Hubble Resolves Puzzle about Loner Starburst Galaxy Newswise, Retrieved on November 17, 2008.
  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. 1 2 3 L. Origlia; C. Leitherer; A. Aloisi; L. Greggio; et al. (2001). "The Stellar Content of the Super-Star Clusters in NGC 1569". Astronomical Journal. 122 (2): 815–824. arXiv: astro-ph/0105195 . Bibcode:2001AJ....122..815O. doi:10.1086/321152. S2CID   1947177.
  8. ↑ G. de Marchi; M. Clampin; L. Greggio; C. Leitherer; et al. (1997). "The Structure of the Super--Star Clusters in NGC 1569 from HST WFPC2 Images". Astrophysical Journal Letters. 479 (1): L27–L30. Bibcode:1997ApJ...479L..27D. doi: 10.1086/310579 .
  9. 1 2 G. J. Bendo; R. D. Joseph (2004). "Nuclear Stellar Populations in the Infrared Space Observatory Atlas of Bright Spiral Galaxies". Astronomical Journal. 127 (6): 3338–3360. arXiv: astro-ph/0403133 . Bibcode:2004AJ....127.3338B. doi:10.1086/420712. S2CID   14169689.
  10. ↑ Stil, J. M.; Israel, F. P. (2002). "HI distribution and kinematics of NGC 1569". Astronomy and Astrophysics. 392 (2): 473–487. arXiv: astro-ph/0209444 . Bibcode:2002A&A...392..473S. doi:10.1051/0004-6361:20020953. S2CID   7553380.
  11. 1 2 Johnson, Megan (2002). "Determining the Nature of the Extended H I Structure around LITTLE THINGS Dwarf Galaxy NGC 1569". The Astronomical Journal. 145 (6): 146. arXiv: 1304.1484 . Bibcode:2013AJ....145..146J. doi: 10.1088/0004-6256/145/6/146 . S2CID   118407903.
  12. ↑ Makarova, Lidia; Makarov, Dmitry; Savchenko, Sergey (2012). "Star formation history and environment of the dwarf galaxy UGCA 92". Monthly Notices of the Royal Astronomical Society . 423 (1): 294–303. arXiv: 1203.1397 . Bibcode:2012MNRAS.423..294M. doi:10.1111/j.1365-2966.2012.20872.x. S2CID   118479246.


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