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NGC4216, NGC4206, NGC4222 Galaxy Group, The Virgo Triplet
NGC4216, NGC4206, NGC4222 Galaxy Group, The Virgo Triplet
NGC4216 is a large spiral galaxy in the constellation of Virgo, morphological class SAB(s)b, intermediate between barred and unarred spirals. The Carnegie Atlas of Galaxies (1994) regards it as prototypical because it appears in many textbooks to illustrate the nucleus, bulge, disk, dust lanes, and spiral structure of major spiral galaxies. More recently it has been the subject of several studies related to galaxy mergers, stellar streams, and multi-band analysis of its gas and dust content. Along with its two large companions, NGC4206 and NGC4222, the galaxy is a peripheral member of the Virgo Galaxy Cluster. All three are rapidly moving toward us around the cluster's center of gravity. High "peculiar velocities" through space render their redshifts unsuitable for distance calculations. See Section 5, Fig. 6.
www.cloudynights.com/articles/cat/articles/basic-extragal...
In the chart on the annotated image, their derived properties (except for the redshift radial velocity) are calculated from the mean of the redshift independent distance measurements, and are enclosed in parentheses. Integrated apparent magnitudes and derived absolute magnitudes for all three galaxies are understated due to their edge-on orientation which presents a smaller luminous area to the observer, and also due to light absorption and scatter by gas and dust in the galactic plane. The three galaxies are gravitationally bound to each other and to the Virgo Cluster, but do not show evidence of significant tidal disruption.
NGC4216 has a small, very bright active galactic nucleus of the Hii LINER type which hosts an actively accreting supermassive black hole. Silchenko et al. (1999) report that high resolution spectroscopy reveals a distinct high metallicity nucleus and a circumnuclear ring of starburst activity, resulting in a star population much younger than the surrounding bulge. In most spiral galaxies the nuclear region and the bulge are composed of ancient, very low metallicity stars. It is thought that NGC4216 has a small bar which triggers new star formation by attracting and disrupting interstellar gas and dust clouds. Although some sources describe NGC4216 as a low hydrogen content "anemic galaxy", optical images clearly show numerous bright blue floccules of starburst activity in the disk. In their VLA (Very Large Array radio telescope) study of Virgo spirals, Chung et al. (2010) report moderate atomic hydrogen (Hi) flux and mass within the disk, but low Hi density on the surface. It appears the galaxy has undergone surface stripping by thermal evaporation, gravitational interaction, or "ram stripping". At inclination angle of 85*, the galaxy's disk is ideally oriented to present prominent dust lanes and pillar-like "plumes" of stars arising above the galactic plane, which appear as low-lying blue clouds on the attached photograph. The origin of the plumes is not well understood, but is presumed to be caused by interactions with the intergalactic medium within the Virgo Cluster.
NGC4216 is surrounded by a large, diffuse stellar halo containing 2-4 stellar streams (not visible on my image) and a complex system of around 700 globular clusters, nearly 5 times as many as the Milky Way. The stellar streams appear to be gravitationally deformed remnants of at least two satellite dwarf galaxies in the process of accretion. Compared to other galaxies in the Virgo Cluster, NGC 4216 appears to be undergoing a high rate of galaxy mass assembly.
iopscience.iop.org/article/10.1088/0004-637X/767/2/133/pdf
On the annotated image, several faint, diffuse objects which I suspect to be dwarf candidates are marked as DC. The large number of globular clusters were probably brought in by dwarf galaxies during numerous mergers.
The field includes a number of remote faint objects described in the chart on the annotated image. Among these are three very luminous quasars which are presently receding at superluminal velocities, and lie beyond the cosmic event horizon. Two of the quasars (marked with +) appear to be significantly brighter than their listed apparent magnitudes. Since quasar luminosity depends on the rate of accretion, which can change depending on the availability of matter, quasars commonly manifest variability of up to several magnitudes over a period of days to years. See Section 25 here
www.cloudynights.com/articles/cat/articles/basic-extragal...
The most distant object is [VV2006] J121506.9+130559, lying at a light travel distance (lookback time) of 12 billion ly. In the present cosmological epoch, its proper (comoving) distance is approximately 23.3 Bly.
Image details:
-Remote Takahashi TOA 150 x 1105 mm, Paramount GT GEM
-OSC 20 x 300 sec + 25 x 300 sec taken in 2021, 2x drizzle, 50% linear crop
-Software: DSS, XnView, Starnet++ 2, StarTools 1.3 and 1.7, Cosmological Calculator 3
Compared to the last year's image, there is a mild gain in resolution, and >0.5 mag gain in the limiting magnitude.
NGC4216, NGC4206, NGC4222 Galaxy Group, The Virgo Triplet
NGC4216, NGC4206, NGC4222 Galaxy Group, The Virgo Triplet
NGC4216 is a large spiral galaxy in the constellation of Virgo, morphological class SAB(s)b, intermediate between barred and unarred spirals. The Carnegie Atlas of Galaxies (1994) regards it as prototypical because it appears in many textbooks to illustrate the nucleus, bulge, disk, dust lanes, and spiral structure of major spiral galaxies. More recently it has been the subject of several studies related to galaxy mergers, stellar streams, and multi-band analysis of its gas and dust content. Along with its two large companions, NGC4206 and NGC4222, the galaxy is a peripheral member of the Virgo Galaxy Cluster. All three are rapidly moving toward us around the cluster's center of gravity. High "peculiar velocities" through space render their redshifts unsuitable for distance calculations. See Section 5, Fig. 6.
www.cloudynights.com/articles/cat/articles/basic-extragal...
In the chart on the annotated image, their derived properties (except for the redshift radial velocity) are calculated from the mean of the redshift independent distance measurements, and are enclosed in parentheses. Integrated apparent magnitudes and derived absolute magnitudes for all three galaxies are understated due to their edge-on orientation which presents a smaller luminous area to the observer, and also due to light absorption and scatter by gas and dust in the galactic plane. The three galaxies are gravitationally bound to each other and to the Virgo Cluster, but do not show evidence of significant tidal disruption.
NGC4216 has a small, very bright active galactic nucleus of the Hii LINER type which hosts an actively accreting supermassive black hole. Silchenko et al. (1999) report that high resolution spectroscopy reveals a distinct high metallicity nucleus and a circumnuclear ring of starburst activity, resulting in a star population much younger than the surrounding bulge. In most spiral galaxies the nuclear region and the bulge are composed of ancient, very low metallicity stars. It is thought that NGC4216 has a small bar which triggers new star formation by attracting and disrupting interstellar gas and dust clouds. Although some sources describe NGC4216 as a low hydrogen content "anemic galaxy", optical images clearly show numerous bright blue floccules of starburst activity in the disk. In their VLA (Very Large Array radio telescope) study of Virgo spirals, Chung et al. (2010) report moderate atomic hydrogen (Hi) flux and mass within the disk, but low Hi density on the surface. It appears the galaxy has undergone surface stripping by thermal evaporation, gravitational interaction, or "ram stripping". At inclination angle of 85*, the galaxy's disk is ideally oriented to present prominent dust lanes and pillar-like "plumes" of stars arising above the galactic plane, which appear as low-lying blue clouds on the attached photograph. The origin of the plumes is not well understood, but is presumed to be caused by interactions with the intergalactic medium within the Virgo Cluster.
NGC4216 is surrounded by a large, diffuse stellar halo containing 2-4 stellar streams (not visible on my image) and a complex system of around 700 globular clusters, nearly 5 times as many as the Milky Way. The stellar streams appear to be gravitationally deformed remnants of at least two satellite dwarf galaxies in the process of accretion. Compared to other galaxies in the Virgo Cluster, NGC 4216 appears to be undergoing a high rate of galaxy mass assembly.
iopscience.iop.org/article/10.1088/0004-637X/767/2/133/pdf
On the annotated image, several faint, diffuse objects which I suspect to be dwarf candidates are marked as DC. The large number of globular clusters were probably brought in by dwarf galaxies during numerous mergers.
The field includes a number of remote faint objects described in the chart on the annotated image. Among these are three very luminous quasars which are presently receding at superluminal velocities, and lie beyond the cosmic event horizon. Two of the quasars (marked with +) appear to be significantly brighter than their listed apparent magnitudes. Since quasar luminosity depends on the rate of accretion, which can change depending on the availability of matter, quasars commonly manifest variability of up to several magnitudes over a period of days to years. See Section 25 here
www.cloudynights.com/articles/cat/articles/basic-extragal...
The most distant object is [VV2006] J121506.9+130559, lying at a light travel distance (lookback time) of 12 billion ly. In the present cosmological epoch, its proper (comoving) distance is approximately 23.3 Bly.
Image details:
-Remote Takahashi TOA 150 x 1105 mm, Paramount GT GEM
-OSC 20 x 300 sec + 25 x 300 sec taken in 2021, 2x drizzle, 50% linear crop
-Software: DSS, XnView, Starnet++ 2, StarTools 1.3 and 1.7, Cosmological Calculator 3
Compared to the last year's image, there is a mild gain in resolution, and >0.5 mag gain in the limiting magnitude.