Era algo que não podia ter sido feito com tecnologia anterior: as capacidades de observação em infravermelho do telescópio espacial James Webb mostraram, com grande resolução, a fase inicial de formação de estrelas, gás e poeira em galáxias próximas.
Mais especificamente, uma das novas imagens captada por James Webb mostra claramente estrelas jovens em torno da galáxia espiral NGC 1433. O registo consiste no maior levantamento de galáxias próximas no primeiro ano de operações científicas do Webb e foi obtido como parte de uma colaboração com a High Angular Resolution Physics in Near Galaxies (PHANGS), que inclui mais de 100 investigadores de vários países.
Os dados conduziram a uma coleção inicial de 21 trabalhos de pesquisa que fornecem uma nova visão de como alguns dos processos de menor escala no Universo - o início da formação estelar - impactam a evolução dos maiores objetos cósmicos: as galáxias.
Clique nas imagens para mais detalhes
A equipa tem estudado uma amostra diversificada de 19 galáxias espirais. Nos primeiros meses, os cientistas observaram com o Mid-Infrared Instrument (MIRI) do telescópio cinco dessas galáxias: M74 , NGC 7496 , IC 5332 , NGC 1365 e NGC 1433. As análises revelaram cavidades brilhantes de poeira e enormes bolhas cavernosas de gás que revestem os braços espirais galácticos.
Em algumas regiões, esse conjunto de características aparece construído a partir de “conchas” e “bolhas” sobrepostas onde estrelas jovens libertam energia. “As observações do infravermelho médio foram fundamentais para compreender essa fase inicial de formação estelar, uma vez que está escondida sob um véu de poeira que bloqueia a passagem da luz visível”, referem os cientistas.
Os comprimentos de onda infravermelhos observáveis pelo MIRI (7,7 e 11,3 mícrones) são sensíveis à emissão de hidrocarbonetos aromáticos policíclicos, cruciais na formação de estrelas e planetas. Estas moléculas foram detetadas pelo James Webb nas primeiras observações do programa PHANGS. Estudar tais interações pode ajudar a ter uma visão maior sobre como as galáxias evoluíram ao longo do tempo, considera a comunidade científica.
Recorde algumas das imagens que o telescópio James Webb tem vindo a captar
![This image from Webb’s NIRCam (Near-Infrared Camera) instrument shows a portion of the GOODS-North field of galaxies. At the lower right, a pullout highlights the galaxy GN-z11, which is seen at a time just 430 million years after the Big Bang. The image reveals an extended component, tracing the GN-z11 host galaxy, and a central, compact source whose colours are consistent with those of an accretion disc surrounding a black hole. [Image description: A rectangular image with thousands of galaxies of various shapes and colours on the black background of space. Some are noticeably spirals, either face-on or edge-on, while others are blobby ellipticals. Many are too small to discern any structure. One prominent foreground star at top centre features Webb’s signature eight-point diffraction spikes. At lower right, a small region is highlighted with a white box. Vertical lines extend upward like a cone to the bottom corners of a larger box at upper right, showing a zoomed-in version of the highlighted area. The pullout features a galaxy labelled GN-z11, seen as a fuzzy yellow dot. Above it is another galaxy, seen as a fuzzy red oval.]](http://mb.web.sapo.io/f6f30cda88cbe87e155871ba5170c9132f94fd15.jpg)
![This two-part graphic shows evidence of a gaseous clump of helium in the halo surrounding the galaxy GN-z11. In the top portion, at the far right, a small box identifies GN-z11 in a field of galaxies. The middle box shows a zoomed-in image of the galaxy. The box at the far left displays a map of the helium gas in the halo of GN-z11, including a clump that does not appear in the infrared colours shown in the middle panel. In the lower half of the graphic, a spectrum shows the distinct ‘fingerprint’ of helium in the halo. The full spectrum shows no evidence of other elements and so suggests that the helium clump must be fairly pristine, made almost entirely of hydrogen and helium gas left over from the Big Bang, without much contamination from heavier elements produced by stars. Theory and simulations in the vicinity of particularly massive galaxies from these epochs predict that there should be pockets of pristine gas surviving in the halo, and these may collapse and form Population III star clusters. [Image description: A graphic labelled Galaxy GN-z11, Pristine Gas Clump Near GN-z11. The graphic is divided into two sections. The top half of the graphic features a rectangular image of a field of galaxies with two pullouts, the second of them labelled Helium Two Detected. The bottom half shows a single line graph.]](http://mb.web.sapo.io/e88335c0ecb525e2977cdb7fda8db35d60433f94.jpg)
![This image of the GOODS-North field, captured by Webb’s Near-Infrared Camera (NIRCam), shows compass arrows, a scale bar, and a colour key for reference. The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above). The scale bar is labelled in angular distance on the sky, where one arcsecond is one 3600th of a degree. The scale bar is 60 arcseconds long. This image shows invisible near-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which NIRCam filters were used when collecting the light. The colour of each filter name is the visible light colour used to represent the infrared light that passes through that filter. [Image description: A rectangular image shows thousands of galaxies of various shapes and colours on the black background of space. The pullout features a galaxy labelled GN-z11, seen as a fuzzy yellow dot. Above it is another galaxy, seen as a fuzzy red oval. To the left of the small box, a scale bar is labelled 60 arcseconds. It extends about one tenth of the way across the image. Below the image, a list of NIRCam filters show what colours were used to make the image. Filters shown in blue are F090W, F115W, and F150W. Filters shown in green are F200W, F277W, and F335M. Filters shown in red are F356W, F410M, and F444W.]](http://mb.web.sapo.io/e5b881b601f585337061240e616183a872385437.jpg)
![This image from Webb’s NIRCam (Near-Infrared Camera) instrument shows a portion of the GOODS-North field of galaxies. [Image description: A rectangular image with thousands of galaxies of various shapes and colours on the black background of space. Some are noticeably spirals, either face-on or edge-on, while others are blobby ellipticals. Many are too small to discern any structure. One prominent foreground star at top centre features Webb’s signature eight-point diffraction spikes.]](http://mb.web.sapo.io/2041446b9a53fd51681679e5383d06e674e14b2e.jpg)
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