Canes Venatici I (dwarf galaxy)

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Canes Venatici Dwarf Galaxy [1]
Observation data (J2000 epoch)
Constellation Canes Venatici
Right ascension 13h 28m 03.5s [1]
Declination +33° 33′ 21″ [1]
Distance 711 ± 33 kly (218 ± 10 kpc)
[2] 685+23
−16 kly (210+7
−5 kpc) [3]
Apparent magnitude  (V)13.9 ± 0.5 [4]
Characteristics
Type dSph
Apparent size  (V)17.8 ± 0.8′ [5]
Other designations
CVn Dwarf Galaxy, [1] PGC 4689223

Canes Venatici I or CVn I is a dwarf spheroidal galaxy situated in the Canes Venatici constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. [4] It is one of the most distant known satellites of the Milky Way as of 2011 together with Leo I and Leo II. [4] The galaxy is located at a distance of about 220  kpc from the Sun and is moving away from the Sun at a velocity of about 31 km/s. [6] It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical (ratio of axes ~ 2.5:1) shape with the half-light radius of about 550 pc. [4] [5]

CVn I is a relatively faint satellite of the Milky Way—its integrated luminosity is about 230,000 times that of the Sun (absolute visible magnitude of about −8.6). [5] However, its mass is about 27 million solar masses, which means that the galaxy's mass to light ratio is around 220. A high mass to light ratio implies that CVn I is dominated by the dark matter. [6]

The stellar population of CVn I consists mainly of old stars formed more than 10 billion years ago. The metallicity of these old stars is also very low at [Fe/H] ≈ −2.08 ± 0.02, which means that they contain 110 times less heavy elements than the Sun. [7] There are also about 60 RR Lyrae stars. [3] The galaxy also contains a small fraction of younger (1–2 billion years old) more metal-rich ([Fe/H] ≈ −1.5) stars, which account for about 5% of its mass and 10% of its light. These younger stars are concentrated in the center of the galaxy. [2] There is currently no star formation in CVn I and the measurements have so far failed to detect neutral hydrogen in it—the upper limit is 30,000 solar masses. [8]

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Local Group 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; 9×1022 metres), 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 kpc (3×10^6 ly; 2×1022 m) 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 total 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.

Dwarf spheroidal galaxy Small, low-luminosity galaxies with very little dust and an older stellar population

A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and to systems that are companions to the Andromeda Galaxy (M31). While similar to dwarf elliptical galaxies in appearance and properties such as little to no gas or dust or recent star formation, they are approximately spheroidal in shape and generally have lower luminosity.

Sculptor Dwarf Galaxy

The Sculptor Dwarf Galaxy is a dwarf spheroidal galaxy that is a satellite of the Milky Way. The galaxy lies within the constellation Sculptor. It was discovered in 1937 by American astronomer Harlow Shapley using the 24-inch Bruce refractor at Boyden Observatory. The galaxy is located about 290,000 light-years away from the Solar System. The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, the Milky Way, making it similar to primitive galaxies seen at the edge of the universe.

Carina Dwarf Spheroidal Galaxy Dwarf galaxy

The Carina Dwarf Spheroidal Galaxy is a dwarf galaxy in the Carina constellation. It was discovered in 1977 with the UK Schmidt Telescope by Cannon et al. The Carina Dwarf Spheroidal galaxy is a satellite galaxy of the Milky Way and is receding from it at 230 km/s. The diameter of the galaxy is about 1600 light-years, which is 75 times smaller than the Milky Way. Most of the stars in the galaxy formed 7 billion years ago, although it also experienced bursts of star formation about 13 and 3 billion years ago. It is also being tidally disrupted by the Milky Way galaxy.

The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group.

Andromeda III is a dwarf spheroidal galaxy about 2.44 million light-years away in the constellation Andromeda. It is part of the Local Group and is a satellite galaxy of the Andromeda Galaxy (M31). The galaxy was discovered by Sidney van den Bergh on photographic plates taken in 1970 and 1971.

The Boötes Dwarf Galaxy is a galaxy, which appears faint, with a luminosity of 100,000 L☉ and an absolute magnitude of –5.8. It lies about 197,000 light-years away in the constellation Boötes. This dwarf spheroidal galaxy appears to be tidally disrupted by the Milky Way Galaxy, which it orbits, and has two stellar tails that cross over to form a cross. Tidally disrupted galaxies usually only form one tail.

UGCA 86

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.

NGC 4449

NGC 4449, also known as Caldwell 21, is an irregular Magellanic type galaxy in the constellation Canes Venatici, being located about 12 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.

Ursa Major II Dwarf is a dwarf spheroidal galaxy situated in the Ursa Major constellation and discovered in 2006 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located approximately 30 kpc from the Sun and moves towards the Sun with the velocity of about 116 km/s. It has an elliptical shape with the half-light radius of about 140 pc.

Segue 1 is a dwarf spheroidal galaxy or globular cluster situated in the Leo constellation and discovered in 2006 by Sloan Digital Sky Survey. It is located at a distance of about 23 kpc from the Sun and moves away from the Sun with the velocity of about 206 km/s. Segue 1 has a noticeably elongated shape with the half-light radius of about 30 pc. This elongation may be caused by the tidal forces acting from the Milky Way galaxy if Segue 1 is being tidally disrupted now.

Leo IV (dwarf galaxy)

Leo IV is a dwarf spheroidal galaxy situated in the Leo constellation, discovered in 2006 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located at the distance of about 160 kpc from the Sun and moves away from the Sun with the velocity of about 130 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an approximately round shape with the half-light radius of about 130 pc.

Leo V is a dwarf spheroidal galaxy situated in the Leo constellation and discovered in 2007 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located at the distance of about 180 kpc from the Sun and moves away from the Sun with the velocity of about 173 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an approximately spherical shape with the half-light radius of about 130 pc.

Canes Venatici II or CVn II is a dwarf spheroidal galaxy situated in the Canes Venatici constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 150 kpc from the Sun and moves towards the Sun with the velocity of about 130 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical shape with the half-light radius of about 74+14
−10 pc.

Coma Berenices or Com is a dwarf spheroidal galaxy situated in the Coma Berenices constellation and discovered in 2006 in data obtained by the Sloan Digital Sky Survey. The galaxy is located at the distance of about 44 kpc from the Sun and moves away from the Sun with the velocity of about 98 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical shape with the half-light radius of about 70 pc.

Bootes II or Boo II is a dwarf spheroidal galaxy situated in the Bootes constellation and discovered in 2007 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 42 kpc from the Sun and moves towards the Sun with the speed of 120 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an approximately round shape with the half-light radius of about 51 pc.

Hercules (dwarf galaxy)

Hercules, or Her, is a dwarf spheroidal galaxy situated in the Hercules constellation and discovered in 2006 in data obtained by the Sloan Digital Sky Survey. The galaxy is located at a distance of about 140 kpc from the Sun and moves away from the Sun with a velocity of about 45 km/s. It is classified as a dwarf spheroidal galaxy (dSph). It has a noticeably elongated shape with a half-light radius of about 350 pc. This elongation may be caused by tidal forces acting from the Milky Way galaxy, meaning that Her is being tidally disrupted now. Her also shows some gradient of velocities across the galaxy's body and is embedded into a faint stellar stream, which also points towards its ongoing tidal disruption.

Pisces II is a dwarf spheroidal galaxy situated in the Pisces constellation and discovered in 2010 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located at the distance of about 180 kpc (kiloparsecs) from the Sun. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elongated shape with the half-light radius of about 60 pc and ratio of the axis of about 5:3.

Leo T is a dwarf galaxy situated in the Leo constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 420 kpc from the Sun and moves away from the Sun with the velocity of about 35 km/s. The velocity with respect to the Milky Way is around −60 km/s implying a slow infall onto the Milky Way. Leo T is classified as a transitional object between dwarf spheroidal galaxies (dSph) and dwarf irregular galaxies (dIrr). Its half-light radius is about 180 pc.

References

  1. 1 2 3 4 "NAME CVn I dSph". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2011-11-21.
  2. 1 2 Martin, N. F.; Coleman, M. G.; De Jong, J. T. A.; Rix, H. W.; Bell, E. F.; Sand, D. J.; Hill, J. M.; Thompson, D.; Burwitz, V.; Giallongo, E.; Ragazzoni, R.; Diolaiti, E.; Gasparo, F.; Grazian, A.; Pedichini, F.; Bechtold, J. (2008). "A Deep Large Binocular Telescope View of the Canes Venatici I Dwarf Galaxy". The Astrophysical Journal. 672 (1): L13–L16. arXiv: 0709.3365 . Bibcode:2008ApJ...672L..13M. doi:10.1086/525559. S2CID   14614201.
  3. 1 2 Kuehn, C.; Kinemuchi, K.; Ripepi, V.; Clementini, G.; Dall'Ora, M.; Di Fabrizio, L.; Rodgers, C. T.; Greco, C.; Marconi, M.; Musella, I.; Smith, H. A.; Catelan, M. R.; Beers, T. C.; Pritzl, B. J. (2008). "Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal Satellite Canes Venatici I". The Astrophysical Journal. 674 (2): L81. arXiv: 0709.3281 . Bibcode:2008ApJ...674L..81K. doi:10.1086/529137. S2CID   118674121.
  4. 1 2 3 4 Zucker, D. B.; Belokurov, V.; Evans, N. W.; Wilkinson, M. I.; Irwin, M. J.; Sivarani, T.; Hodgkin, S.; Bramich, D. M.; Irwin, J. M.; Gilmore, G.; Willman, B.; Vidrih, S.; Fellhauer, M.; Hewett, P. C.; Beers, T. C.; Bell, E. F.; Grebel, E. K.; Schneider, D. P.; Newberg, H. J.; Wyse, R. F. G.; Rockosi, C. M.; Yanny, B.; Lupton, R.; Smith, J. A.; Barentine, J. C.; Brewington, H.; Brinkmann, J.; Harvanek, M.; Kleinman, S. J.; Krzesinski, J. (2006). "A New Milky Way Dwarf Satellite in Canes Venatici". The Astrophysical Journal. 643 (2): L103. arXiv: astro-ph/0604354 . Bibcode:2006ApJ...643L.103Z. doi:10.1086/505216. S2CID   119421888.
  5. 1 2 3 Martin, N. F.; De Jong, J. T. A.; Rix, H. W. (2008). "A Comprehensive Maximum Likelihood Analysis of the Structural Properties of Faint Milky Way Satellites". The Astrophysical Journal. 684 (2): 1075–1092. arXiv: 0805.2945 . Bibcode:2008ApJ...684.1075M. doi:10.1086/590336. S2CID   17838966.
  6. 1 2 Simon, J. D.; Geha, M. (2007). "The Kinematics of the Ultra‐faint Milky Way Satellites: Solving the Missing Satellite Problem". The Astrophysical Journal. 670 (1): 313–331. arXiv: 0706.0516 . Bibcode:2007ApJ...670..313S. doi:10.1086/521816. S2CID   9715950.
  7. ↑ Kirby, E. N.; Simon, J. D.; Geha, M.; Guhathakurta, P.; Frebel, A. (2008). "Uncovering Extremely Metal-Poor Stars in the Milky Way's Ultrafaint Dwarf Spheroidal Satellite Galaxies". The Astrophysical Journal. 685 (1): L43–L46. arXiv: 0807.1925 . Bibcode:2008ApJ...685L..43K. doi:10.1086/592432. S2CID   3185311.
  8. ↑ Grcevich, J.; Putman, M. E. (2009). "H I in Local Group Dwarf Galaxies and Stripping by the Galactic Halo". The Astrophysical Journal. 696 (1): 385–395. arXiv: 0901.4975 . Bibcode:2009ApJ...696..385G. doi:10.1088/0004-637X/696/1/385.


Coordinates: Jupiter and moon.png 13h 28m 03.5s, +33° 33′ 21″

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