Uma galáxia cheia de surpresas: a galáxia espiral NGC 3621
Esta imagem, obtida pelo Very Large Telescope (VLT) do ESO, mostra uma galáxia verdadeiramente notável conhecida por NGC 3621. Para começar, trata-se de uma galáxia de disco puro. Tal como outras espirais, tem um disco plano permeado por faixas escuras de material e braços espirais proeminentes onde se estão a formar enxames de estrelas jovens (os pontos azuis que vemos na imagem). Mas enquanto a maioria das galáxias espirais tem um bojo central, um grande grupo de estrelas velhas agrupadas numa região compacta e esferoidal, a NGC 3621 não tem. Nesta imagem, vemos claramente uma parte simplesmente mais brilhante no centro, mas não se trata de nenhum bojo real como, por exemplo, o da galáxia NGC 6744 (eso1118).
A NGC 3621 também é interessante, pois acredita-se que possua um buraco negro supermassivo ativo no seu centro, que está a engolir matéria e a produzir radiação, o que é algo invulgar, já que a maioria destes núcleos galácticos ativos existe em galáxias com bojos proeminentes. Neste caso particular, pensa-se que o buraco negro supermassivo tenha uma massa relativamente pequena, cerca de 20 mil vezes a massa do Sol.
Outra característica interessante é que parece também existirem, perto do núcleo da galáxia, dois buracos negros mais pequenos, com massas de apenas alguns milhares de vezes a massa do Sol. Ou seja, tudo isto torna a NGC 3621 um objeto extremamente interessante, pois apesar de não apresentar um bojo central, pode bem ter um sistema de três buracos negros na sua região central.
Esta galáxia está situada na constelação da Hidra e pode ser observada através um pequeno telescópio. Esta imagem, obtida através dos filtros B, V e I com o instrumento FORS1 montado no VLT, apresenta detalhes impressionantes deste objeto, para além de revelar também uma infinidade de galáxias de fundo. Na imagem vemos ainda, em primeiro plano, várias estrelas brilhantes pertencentes à nossa Via Láctea.
Créditos:ESO
Sobre a imagem
| Id: | potw1148a |
| Língua: | pt |
| Tipo: | Observação |
| Data de divulgação: | 28 de Novembro de 2011 às 10:00 |
| Notícias relacionadas: | eso2520 |
| Tamanho: | 2044 x 2044 px |
Sobre o objeto
| Nome: | NGC 3621 |
| Tipo: | Local Universe : Galaxy : Type : Spiral Local Universe : Galaxy : Component : Central Black Hole |
| Distância: | 22 milhão anos-luz |
| Constellation: | Hydra |
Formatos de imagens
Papéis de parede
Coordenadas
| Position (RA): | 11 18 16.56 |
| Position (Dec): | -32° 48' 50.91" |
| Field of view: | 6.81 x 6.81 arcminutes |
| Orientação: | O norte está a 89.8° à esquerda da vertical |
Cores e filtros
| Banda | Telescópio |
|---|---|
| Óptico B | Very Large Telescope FORS1 |
| Óptico V | Very Large Telescope FORS1 |
| Infravermelho I | Very Large Telescope FORS1 |
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