Le Galassie Antenne osservate con ALMA
Le Galassie Antenne (conosciute anche come NGC 4038 e 4039) sono una coppia di galassie a spirale distorte, in collisione, a circa 70 milioni di anni luce da noi, nella costellazione del Corvo. Questa veduta mostra un’immagine delle galassie ottenuta con ALMA, in due diverse bande di lunghezza d’onda durante la fase iniziale di sperimentazione dell’osservatorio.
La maggior parte delle osservazioni sperimentali di ALMA utilizzate per creare quest’immagine sono state compiute utilizzando solo dodici antenne attive simultaneamente, molte meno di quelle che verranno utilizzate per le prime osservazioni scientifiche e anche molto più vicine tra loro. Entrambi i fattori rendono questa nuova immagine solo un assaggio di ciò che sarà: con lo sviluppo dell’osservatorio, la nitidezza, la velocità e la qualità delle osservazioni aumenteranno sensibilmente, a mano a mano che un maggior numero di antenne diventeranno disponibili e completeranno la schiera. In ogni caso, questa è l’immagine delle Galassie Antenne a lunghezze d’onda submillimetriche migliore di sempre e apre una nuova finestra sull’Universo submillimetrico.
La visione di ALMA ci mostra qualcosa che non è visibile a lunghezze d’onda visibili o infrarosse, ossia le nubi di denso gas freddo da cui hanno origine le nuove stelle. Le osservazioni con ALMA sono state fatte a specifiche lunghezze d’onda di luce millimetrica e submillimetrica (bande ALMA 3 e 7), regolate per il rilevamento delle molecole di monossido di carbonio nelle altrimenti invisibili nuvole di idrogeno, dove stanno nascendo nuove stelle.
Sono presenti massicce concentrazioni di gas non solo nel cuore delle due galassie, ma anche nella caotica regione in cui esse collidono. Qui, la quantità complessiva di gas corrisponde a miliardi di volte la massa del Sole: una ricca scorta di materiale per le future generazioni di stelle. Osservazioni simili saranno fondamentali nell’aiutarci a capire come la collisione tra galassie possa innescare la nascita di nuove stelle. Questo è solo uno degli esempi di come ALMA sveli parti dell’Universo che non possono essere viste in luce visibile e con telescopi a infrarossi.
Crediti:ALMA (ESO/NAOJ/NRAO)
Riguardo l'immagine
| Identificazione: | eso1137c |
| Lingua: | it-ch |
| Tipo: | Osservazione |
| Data di rilascio: | Lunedì 03 Ottobre 2011 11:30 |
| Notizie relative: | eso1137 |
| Annunci a riguardo: | ann21013 |
| Grandezza: | 3375 x 3362 px |
Riguardo all'oggetto
| Nome: | Antennae Galaxies, NGC 4038, NGC 4039 |
| Tipo: | Local Universe : Galaxy : Type : Interacting |
| Distanza: | 75 Milione Anni luce |
| Constellation: | Corvus |
Formati delle immagini
Coordinate
| Position (RA): | 12 1 52.99 |
| Position (Dec): | -18° 52' 36.10" |
| Field of view: | 2.93 x 2.92 arcminutes |
| Orientazione: | Il Nord è a 29.9° a destra della verticale |
Colori e filtri
| Banda | Lunghezza d'onda | Telescopio |
|---|---|---|
| Millimetro ALMA band 3 | 2.6 mm | Atacama Large Millimeter/submillimeter Array |
| Millimetro ALMA band 7 | 870 μm | Atacama Large Millimeter/submillimeter Array |
| Millimetro ALMA Band 7 | 870 μm | Atacama Large Millimeter/submillimeter Array |
| Millimetro ALMA Band 7 | 870 μm | Atacama Large Millimeter/submillimeter Array |
| Millimetro ALMA Band 3 | 2.6 mm | Atacama Large Millimeter/submillimeter Array |
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