Photograph of the Large Magellanic Cloud taken by the Hubble Space Telescope (c) NASA
The impact of the Large Magellanic Cloud on the galaxy is a study by the University of Edinburgh
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The Large Magellanic Cloud also has a larger mass than it seems, and the huge mass has continued to have a great influence on the galaxy.
Have you ever seen the Large Magellanic Cloud?Unfortunately it cannot be seen from the Northern Hemisphere, but in the 16th century ... → Continue reading
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Magellanic cloud(Magellan Yeah,Magellanic Clouds, Nubeculae Magellani) IsGalaxyTwo nearGalaxy,Large Magellanic Cloud (Large Magellanic Cloud = LMC) and Small Magellanic Cloud It is a general term for (Small Magellanic Cloud = SMC).bothLocal group of galaxiesBelongs toDwarf galaxyIs.RarelyMagellan Nebula (Magellanic Nebulae),Magellan Galaxy (Magellanic Galaxies) Tomo.Galaxy OfSatellite galaxy(And has been regarded until recently by dogma).
- Apparent position etc.
地球From now onHeavenly South PoleNot far from赤経About 1-5 o'clock,赤緯It can be seen around -70 degrees.The Large Magellanic Cloud and the Small Magellanic Cloud are 7 each otherLight yearsFar away, apparentlyCelestial sphere21 degrees apart above.
Until the end of the 20th century, the Large Magellanic Cloud and the Small Magellanic Cloud were considered to be the closest galaxy to the galaxy and the second closest to the galaxy.But, 1994ToSagittarius small elliptical galaxy (SagDEG) was discovered and the ranking was lowered.
- Magellanic Stream
High-concentration gases are distributed in both the Large Magellanic Cloud and the Small Magellanic Cloud (about 10 times the concentration of the galaxy), and as a result, new stars are still being born.And both galaxies movedTrajectoryIncluded in both galaxiesNeutral hydrogenGas was left behind, and as a result, just on the trajectory of the jetContrailsA huge gas zone (gas streaks) in the trajectory (outer space) where the Magellanic Cloud moved so thatMagellanic Stream"Is left. (Note that the gas band is affected by the gravitational pull of both the revolving galaxy and the rotating galaxy, and the gravitational pull of the gas itself.InteractionDue to this, the movement is quite complicated, which is difficult to analyze with a simplified model. )
- Shape distortion due to the influence of the galaxy
Both galaxies have a strong galaxyTidal forceIs receiving.Both galaxiesBarred spiralIt has a similar structure, but it is greatly disturbed by the tidal force.On the other hand, in the galaxydiskIs also slightly deformed due to the influence of the Magellanic Clouds.
- The theory of revolution around the galaxy
Both the Large Magellanic Cloud and the Small Magellanic Cloud are of the galaxy.Satellite galaxy("Satellite galaxy"), that is, around the galaxy including the earth where human beings liverevolutionThat you are doingHubbleSince the explanation byThe dogmaContinued to be.
- Estimate and actual measurement of moving speed.Progress of review of the established theory.
What is the speed of movement of both galaxies?Regarding the question, using the theory that the Magellanic Cloud is a satellite galaxy, which has been almost established since Hubble pointed out, and a rough estimate of the total mass of the galaxy at that time, the moving speeds of both galaxies ( The calculation of the estimated value of the revolution speed) was done several times.Eventually, it became possible to actually measure, not just estimate by calculation.However, even if it is measured, the entire Magellanic Cloud is moving (parallel) while maintaining its shape, so it cannot be measured simply by observing the stars of the Magellanic Cloud, and it exists far away from the Magellanic Cloud. To doquasarBy using the above as a background marker, I came up with a method of measuring the relative (lateral) movement of the Magellanic Clouds and the change in the angle seen from the earth over time.However, based on the estimated values estimated in advance, the change in the angle is very small, and even if it is observed with the current high-precision (high-resolution, high-resolution) telescope, it is difficult to detect it in units of days to months. It was expected that it would not be detected without an annual time interval.The expected change in angle to be detected is small enough to detect a movement of about 100 mm 1 km away, and it was expected to be extremely difficult.Even if the current high-resolution Hubble Telescope is used, it is almost in the limit area.It was also thought that the slight distortion of the telescope caused by the change in gravity exerted on the telescope by moving the earth's telescope would make it impossible to measure correctly.Space Telescope Science Institute OfThe groupHubble Space TelescopeWe measured the velocity of movement at 4 locations in the Magellanic Cloud over a four-year period using the near-limit level of resolution of the telescope, and analyzed the measured images over a year.The moving speed was calculated to be 25km / s (1km / s).This speed obtained by observation is more than several percent higher than the estimated value that was made in advance.This speed also suggests that both galaxies may not be gravitationally bound to the galaxy.If this is correct, he also says that the phenomenon described as the effect of the Magellanic Cloud needs to be corrected... Very recently (although astronomers are surprised), the Magellanic Clouds are not the "satellite galaxy around the galaxy" that has been said since Hubble, but the Magellanic Clouds are apparently somewhere. It was a galaxy that came near the galaxy from the beginning, and just because it happened to be near the galaxy, it eventually shook off the attraction of the galaxy and left, and then the galaxy and the Magellanic Clouds again. It is becoming understood that we never meet.
Middle EastAlthough it is not visible, it seems that it was known by tourists by the Islamic period.The first record was in 964Persian OfAstronomerAl sufiBut"Book of constellations" Kitāb Ṣu war al-Kawākib al-Thābita LMC "white"male牛Recorded as Al Bakr,Bab el Mandeb StraitIt states that it cannot be seen north of (12.5 degrees north latitude).The Large Magellanic Cloud is located slightly north and can be seen relatively easily.
EuropeanBecame known to 1519から 1522 OfFerdinand MagellanbyAround the worldParticipated in the voyageヴ ェ ネ ツ ィ ア OfAntonio PigafettaAfter recording.When sailing around the world, it continues to sail at night, so it is necessary to check the direction of travel and the position of the ship even at night (in the Northern Hemisphere).Polaris(Because the North Star disappears as the latitude gets lower in the Southern Hemisphere) Magellanic Clouds said that they did it by finding a whitish nebula (Magellanic Cloud) among the stars in the night sky. is there.However, at that time, of course, it was not called the "Magellan cloud", and it was not long before the nebula was named "Magellan" after this anecdote.
1603 OfJohann Bayerof"Uranometria], "Nubecula Major" (meaning "big cloud"), "Nubecula Minor" (meaning "small cloud"). 1795of"Flamsteed Atlas Coelestis』(3rd edition)," Le Grand Nuage ", "Le Petit Nuage" (same meaningFrench) Was listed.
The position of the Magellanic Cloud on the celestial sphere isSouthern skyBecause it is located in, the main observatory is on the earth, considering its advantages.Southern hemisphereIt is in.European Southern ObservatoryOne of the observatories in South AmericaParanar ObservatoryThere are seven telescopes installed on the mountain at an altitude of 2600m, and they are being used extensively.Among the telescopes at Paranal Observatory, it was completed at the end of 7.VISTAThe telescope named is proud of its wide viewing angle and can observe large and small Magellanic Clouds at once, andNear infraredSince the image can be recorded with, the dust of the Magellanic Cloud appears like a white and dark cloud when shooting with normal visible light, and each star is almost invisible, but it seems as if the near-infrared shooting cleared the haze. As you can see, each star in the Magellanic Cloud can be photographed clearly and clearly, and new globular clusters are discovered by this VISTA, so you can understand the stars in the Magellanic Cloud in more detail than before. I came.
- ^ http://www.centauri-dreams.org/?p=1468 See second Paragraph below inserted picture.
- ^ http://www.usno.navy.mil/library/rare/BayerUran1661PiscisBot.jpg Usno.navy.mil Retrieved on 2007-05-31+XNUMX
- ^ http://www.usno.navy.mil/library/rare/flamsteed12.jpg Usno.navy.mil Retrieved on 2007-05-31+XNUMX
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