Celestial hemisphere:  Southern  ·  Constellation: Centaurus (Cen)  ·  Contains:  NGC 5253
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NGC 5253  : a Peculiar Blue Compact Dwarf Galaxy, Los_Calvos
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NGC 5253 : a Peculiar Blue Compact Dwarf Galaxy

Getting plate-solving status, please wait...
NGC 5253  : a Peculiar Blue Compact Dwarf Galaxy, Los_Calvos
Powered byPixInsight

NGC 5253 : a Peculiar Blue Compact Dwarf Galaxy

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Description

We present an image from last year not processed before, it’s an interesting galaxy by its properties even if the image isn’t spectacular.
NGC 5253 : a peculiar Blue Compact Dwarf galaxy
This object is a blue compact dwarf (BCD) galaxy located 11 million light years away in the constellation of Centaurus.  It is a magnitude 10.5 galaxy and size is 4 arc-minutes.BCD galaxies are believed to be young galaxies having the following characteristics:
-          Small size
-          Starburst galaxy, with active star formation
-          Blue color, due to the high energy radiation of massive young stars
-          Low metal contentNGC 5253 is one of the nearest BCD galaxies to us.  For its small size, this object has vivid blue and purple colors due to its active star formation. It also has interesting tiny dust lanes, as better seen in the Hubble image on the web.The most characteristic signature of these galaxies is that they harbor very active star-formation regions. This is in spite of their low dust content and comparative lack of elements heavier than hydrogen and helium, which are usually the basic ingredients for star formation.These galaxies contain molecular clouds that are quite similar to the pristine clouds that formed the first stars in the early Universe, which were devoid of dust and heavier elements. Hence, astronomers consider the BCD galaxies to be an ideal test bed for better understanding the primordial star-forming process.NGC 5253 does contain some dust and heavier elements, but significantly less than the Milky Way galaxy. Its central regions are dominated by an intense star forming region that is embedded in an elliptical main body. The central starburst zone consists of a rich environment of hot, young stars concentrated in star clusters, which glow in blue in the image. Traces of the starburst itself can be seen as a faint and diffuse glow produced by the ionized oxygen gas.Being composed of many star clusters, BCD galaxies do not have a uniform morphology and consume their gas intensely because of these bursts of star formation. In doing so, they cool down at the same time as they change morphology over time. NGC 5253 is most famous for its supercluster of more than one million stars, 3 million years old, with a total luminosity of about a billion times that of the Sun! It is completely hidden from us by a giant dust cloud with a mass of approximately 15,000 solar masses and carbonaceous and oxygenated elements. NGC 5253 has hundreds of other large clusters. The one in Cloud D is just the most spectacular of them.The study of this truly exceptional cluster raises several questions ... First, the Milky Way hasn't formed such superclusters in billions of years. It continues to form new stars, but no longer in such quantities. And it was even considered until recently that such clusters could only form when the universe was still young. The second concerns the rate of amount of gas cloud transformed into stars within cloud D. Although this rate is known to vary between regions of the universe (for example, this rate is less than 5% within a cloud of comparable size to that of cloud D in the Milky Way), it is at least 10 times higher within cloud D.As an additional reason for questioning, there should have been several thousand supernovae in a cluster of this size, but astronomers have not observed traces of SN. Another curiosity, this cluster also contains more than 7000 massive O-type stars, the brightest of all stars, several million times brighter than the sun.The true nature of BCD galaxies has puzzled astronomers for a long time. Numerical simulations following the current leading cosmological theory of galaxy formation, known as the Lambda Cold Dark Matter model, predict that there should be far more satellite dwarf galaxies orbiting big galaxies like the Milky Way. Astronomers refer to this discrepancy as the Dwarf Galaxy Problem.

Nota : the version B is the complete field of imaging.
The luminance is a mix of L Ha and OIII, the 3 layers being very bright and detailed and which correspond to the details of the Hubble image

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  • NGC 5253  : a Peculiar Blue Compact Dwarf Galaxy, Los_Calvos
    Original
  • Final
    NGC 5253  : a Peculiar Blue Compact Dwarf Galaxy, Los_Calvos
    C

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NGC 5253  : a Peculiar Blue Compact Dwarf Galaxy, Los_Calvos