Začarovaný kruh
V levé horní části snímku vidíme pár překrývajících se spirálních galaxií, NGC 3314a a b, zachycené při svém vesmírném tanci teleskopem ESO/VTS (VLT Survey Telescope).
Ale nenechte se zmást perspektivou. Ve skutečnosti spolu galaxie totiž vůbec neinteragují. Obě se sice nachází v souhvězdí Hydry ve vzdálenosti 117 až 140 milionů světelných let, ale fyzicky spolu nesouvisí a jejich zdánlivý překryv je jen důsledkem pozorování ze Země. Jedinečné uspořádání těchto dvou galaxií dává astronomům možnost měřit mnoho jejich vlastností, například jak prach pohlcuje světlo hvězd, a tím získat vhled do jejich složení a vývoje.
Snímek však ukrývá i další tajemství, které odhalíte, zadíváte-li se na pravou spodní část obrázku. Nachází se tam nepatrný žlutavý flíček, známka ultra-difúzní galaxie (UDG). Tyto galaxie jsou velikostí srovnatelné s Mléčnou dráhou, ale obsahují 100 – 1000krát méně hvězd. Jsou proto extrémně slabé a postrádají hvězdotvorný plyn, což jim dává tento charakteristický vzhled. Tato ultra-difúzní galaxie s názvem UDG 32 je jednou z nejslabších, ale nejrozsáhlejších galaxií v kupě Hydra I.
Snímek byl pořízen v rámci velkého projektu VEGAS (VST Early-type Galaxy Survey), jehož cílem je zkoumat velmi slabé struktury v galaktických kupách - velkých skupinách gravitačně vázaných galaxií. Projekt pod vedením Enrichetty Iodice z Istituto Nazionale di Astrofisica in Italy naznačuje, že se UDG 32 mohla zformovat z filamentů galaxie NGC 3314a, ale k potvrzení je zapotřebí více pozorování.
Kredit:ESO/Iodice et al.
O snímku
| Id: | potw2145a |
| Jazyk: | cs |
| Typ: | Pozorování |
| Datum zveřejnění: | 8. listopadu 2021 6:00 |
| Velikost: | 1717 x 1725 px |
O objektu
Souřadnice
| Position (RA): | 10 37 8.92 |
| Position (Dec): | -27° 41' 55.30" |
| Field of view: | 6.01 x 6.04 arcminutes |
| Orientace: | Sever je 0.2° levá od svislé osy |
Barvy & filtry
| Pásmo | Vlnová délka | Dalekohled |
|---|---|---|
| Optický g | 480 nm | VLT Survey Telescope OmegaCAM |
| Optický r | 625 nm | VLT Survey Telescope OmegaCAM |
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