Resum

This beautiful galaxy is tilted at an oblique angle on to our line of sight, giving a "birds-eye view" of the spiral structure. The galaxy is similar to our Milky Way, but our favorable view provides a better picture of the typical architecture of spiral galaxies.

M81 may be undergoing a surge of star formation along the spiral arms due to a close encounter it may have had with its nearby spiral galaxy NGC 3077 and a nearby starburst galaxy (M82) about 300 million years ago.

M81 is one of the brightest galaxies that can be seen from the Earth. It is high in the northern sky in the circumpolar constellation Ursa Major, the Great Bear. At an apparent magnitude of 6.8 it is just at the limit of naked-eye visibility. The galaxy's angular size is about the same as that of the Full Moon.

This image combines data from the Hubble Space Telescope, the Spitzer Space Telescope, and the Galaxy Evolution Explorer (GALEX) missions. The GALEX ultraviolet data were from the far-UV portion of the spectrum (135 to 175 nanometers). The Spitzer infrared data were taken with the IRAC 4 detector (8 microns). The Hubble data were taken at the blue portion of the spectrum.

File info

Individual images

see https://www.spitzer.caltech.edu/image/sig07-009-multiwavelength-m81 High quality tif files also avaliable.

Llicència

	Aquest fitxer és en el domini públic perquè ha estat creat per la NASA. L'avís legal de la NASA diu que «el material de la NASA no està protegit per copyright si no es diu el contrari». (NASA copyright policy page o JPL Image Use Policy).
	Atenció: L'ús dels logotips de la NASA, insígnies i emblemes està restringit la llei dels EUA 14 CFR 1221. El lloc web de la NASA disposa d'un gran nombre d'imatges de l'Agència Espacial Russa, o soviètica, i d'altres agències no nord-americanes. Aquestes imatges no són necessàriament en el domini públic. El material del Telescopi espacial Hubble pot tenir els drets reservats si no prové explícitament del STScI. [1] Tot el material de la sonda SOHO està reservat i requereix d'autorització per a un ús comercial no educatiu. [2] Les imatges destacades en el lloc web Astronomy Picture of the Day (APOD) poden tenir drets d'autor. [3]