NGC 4618

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NGC 4618
Single Arm Galaxy.jpg
Barred spiral galaxy NGC 4618 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation Canes Venatici [1]
Right ascension 12h 41m 32.8s [2]
Declination +41° 09′ 03″ [2]
Redshift 544 ± 1 km/s [2]
Apparent magnitude  (V)11.2 [2]
Characteristics
Type SB(rs)m [2]
Apparent size  (V)4'.2 × 3'.4 [2]
Notable featuresasymmetric; single spiral arm [3]
Other designations
IC 3667, [2] UGC 7853, [2] PGC 042575, [2] Arp 23, [2] VV 73 [2]

NGC 4618 is a distorted barred dwarf galaxy in the constellation Canes Venatici. The galaxy is formally classified as a Sm galaxy, which means that its structure vaguely resembles the structure of spiral galaxies. The galaxy is sometimes referred to as a Magellanic spiral because of its resemblance to the Magellanic clouds.

Contents

One supernova has been observed in NGC 4618: SN 1985F (type Ib) was discovered by Alex Filippenko and Wallace L. W. Sargent on 28 February 1985. [4] [5]

Structure

Unlike most spiral galaxies, NGC 4618 has a single spiral arm, which gives the galaxy an asymmetric appearance. [3] This galaxy was included in the Atlas of Peculiar Galaxies as one of three examples of nearby galaxies with single spiral arms. [6] Although NGC 4618 is labeled as peculiar, many similar galaxies have been identified.

It has been hypothesized that this galaxy's asymmetric structure may be the result of a gravitational interaction with NGC 4625. [3] Such asymmetric structure is commonly seen among many interacting galaxies. However, observations of neutral hydrogen gas in NGC 4618 and NGC 4625 imply that only some of the gas outside the optical disks of NGC 4618 is affected by the gravitational interaction. [7] This may indicate that NGC 4618's one-arm shape forms as the result of processes that are intrinsic to the galaxy itself.

Environment

As mentioned above, NGC 4618 is interacting with NGC 4625. [3]

See also

Related Research Articles

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<span class="mw-page-title-main">Messier 66</span> Intermediate spiral galaxy in the constellation Leo

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<span class="mw-page-title-main">Messier 74</span> Face-on spiral galaxy in the constellation Pisces

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<span class="mw-page-title-main">NGC 5195</span> Dwarf galaxy in the constellation Canes Venatici

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

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<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. They were both discovered by German-British astronomer William Herschel on 15 February 1784. 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 4088</span> Galaxy in the constellation of Ursa Major

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<span class="mw-page-title-main">NGC 7479</span> Galaxy in the constellation Pegasus

NGC 7479 is a barred spiral galaxy about 105 million light-years away in the constellation Pegasus. William Herschel discovered it in 1784. NGC 7479 is also recognized as a Seyfert galaxy and a LINER undergoing starburst activity not only on the nucleus and the outer arms, but also across the bar of the galaxy, where most of the stars were formed in the last 100 million years. Polarization studies of this galaxy indicate that it recently underwent a minor merger and that it is unique in the radio continuum, with arms opening in a direction opposite to the optical arms. This feature, along with the asymmetrical arms of the galaxy and the intense star formation activity are attributed to a merger with a smaller galaxy. This galaxy is similar in both size and morphology to the barred spiral NGC 1300.

<span class="mw-page-title-main">NGC 772</span> Galaxy in the constellation Aries

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<span class="mw-page-title-main">NGC 4027</span> Galaxy in the constellation Corvus

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<span class="mw-page-title-main">NGC 5033</span> Galaxy in the constellation Canes Venatici

NGC 5033 is an inclined spiral galaxy located in the constellation Canes Venatici. Distance estimates vary from between 38 and 60 million light years from the Milky Way. The galaxy has a very bright nucleus and a relatively faint disk. Significant warping is visible in the southern half of the disk. The galaxy's relatively large angular size and relatively high surface brightness make it an object that can be viewed and imaged by amateur astronomers. The galaxy's location relatively near Earth and its active galactic nucleus make it a commonly studied object for professional astronomers.

<span class="mw-page-title-main">NGC 5713</span> Peculiar and asymmetric galaxy in the constellation Virgo

NGC 5713 is a peculiar, asymmetric galaxy in the constellation Virgo. Although classified as a spiral galaxy by most galaxy catalogs, NGC 5713 is very different from most normal spiral galaxies. While most spiral galaxies either have either two well-defined spiral arms or a filamentary spiral-like structure, this spiral galaxy has only one visible spiral arm in its disk. This makes it a galaxy of the Magellanic type. Gravitational interactions with the nearby spiral galaxy NGC 5719 may be responsible for producing the disturbed, asymmetric structure including the single spiral arm.

<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">NGC 4625</span> Distorted dwarf spiral galaxy in the constellation Canes Venatici

NGC 4625 is a distorted dwarf galaxy in the constellation Canes Venatici. The galaxy is formally classified as a Sm galaxy, which means that its structure vaguely resembles the structure of spiral galaxies. The galaxy is sometimes referred to as a Magellanic spiral because of its resemblance to the Large Magellanic Cloud's single-arm structure.

<span class="mw-page-title-main">NGC 3432</span> Galaxy in the constellation Leo Minor

NGC 3432 is an edge-on spiral galaxy that can be found in the northern constellation of Leo Minor. It was discovered by German-British astronomer William Herschel on March 19, 1787. This galaxy is located at a distance of 40 million light-years (12.3 Mpc) from the Milky Way. It is interacting with UGC 5983, a nearby dwarf galaxy, and features tidal filaments and intense star formation. Because of these features, it was listed in Halton Arp's Atlas of Peculiar Galaxies.

<span class="mw-page-title-main">NGC 3169</span> Galaxy in the constellation Sextans

NGC 3169 is a spiral galaxy about 75 million light years away in the constellation Sextans. It has the morphological classification SA(s)a pec, which indicates this is a pure, unbarred spiral galaxy with tightly-wound arms and peculiar features. There is an asymmetrical spiral arm and an extended halo around the galaxy. It is a member of the NGC 3166 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.

A Magellanic spiral galaxy is a spiral galaxy with only one spiral arm. Magellanic spiral galaxies are classified as the type Sm ; the prototype galaxy and namesake for Magellanic spirals is the Large Magellanic Cloud, an SBm galaxy. They are usually smaller dwarf galaxies and can be considered to be intermediate between dwarf spiral galaxies and irregular galaxies.

<span class="mw-page-title-main">NGC 5668</span> Galaxy in the constellation Virgo

NGC 5668 is a nearly face-on spiral galaxy, visual magnitude about 11.5, located about 81 million light years away in the constellation Virgo. It was discovered on 29 April 1786 by William Herschel.

<span class="mw-page-title-main">NGC 4490</span> Interacting galaxy in constellation Canes Venatici

NGC 4490, also known as the Cocoon Galaxy, is a barred spiral galaxy in the constellation Canes Venatici. William Herschel discovered it in 1788. It is known to be of the closest interacting/merging galactic system. The galaxy lies at a distance of 25 million light years from Earth making it located in the local universe. It interacts with its smaller companion NGC 4485 and as a result is a starburst galaxy. NGC 4490 and NGC 4485 are collectively known in the Atlas of Peculiar Galaxies as Arp 269. The two galaxies has already made their closest approach and are rushing away from each other. It's been discovered that NGC 4490 has a double nucleus.

<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.

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 9 10 11 "NASA/IPAC Extragalactic Database". Results for NGC 4618. Retrieved 2006-11-15.
  3. 1 2 3 4 A. Sandage; J. Bedke (1994). Carnegie Atlas of Galaxies. Washington, D.C.: Carnegie Institution of Washington. ISBN   978-0-87279-667-6.
  4. ↑ Filippenko, A. V.; Sargent, W. L. W. (1985). "Unusual Object in NGC 4618". International Astronomical Union Circular (4042): 1. Bibcode:1985IAUC.4042....1F.
  5. ↑ "SN 1985F". Transient Name Server. IAU . Retrieved 5 December 2024.
  6. ↑ H. Arp (1966). "Atlas of Peculiar Galaxies". Astrophysical Journal Supplement. 14: 1–20. Bibcode:1966ApJS...14....1A. doi:10.1086/190147.
  7. ↑ S. J. Bush; E. M. Wilcots (2004). "Neutral Hydrogen in the Interacting Magellanic Spirals NGC 4618 and NGC 4625". Astrophysical Journal. 128 (6): 2789–2796. arXiv: astro-ph/0409209 . Bibcode:2004AJ....128.2789B. doi:10.1086/425876. S2CID   14636586.
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