X Marks the Spot


M51 X in CoreThis Hubble Space Telescope image of the core of the spiral galaxy M51 shows a dark “X” silhouetted across the galaxy’s nucleus. The “X” is caused by absorption of light by dust and marks the position of a black hole which may have a mass about one-million times the mass of the Sun. The darkest bar may be an edge-on view of a dust ring 100 light-years in diameter. It blocks the black hole its accretion disk as seen from Earth. The second bar of the “X” could be a second disk seen edge on, or it might be rotating gas and dust in M51 intersecting with the jets and ionization cones from the black hole.

Image Credit: NASA

Multi-Wavelength Astronomy


These four images show the Whirlpool Galaxy (aka M51) in different wavelengths of light.

View A uses visible light data from the 2.1-m telescope at the Kitt Peak National Observatory. View B combines two visible light wavelengths, 400 nm (blue) and 700 nm (green) with infrared data from the Spitzer Space Telescope. The IR data is shown in red.

Views C and D are false color images assembled using more IR data from Spitzer. C uses data from three wavelengths—8 µm (red), 4.5 µm (green), and 3.6 µm (blue). The galaxy’s stars shine brightly in the shorter (“blue”) IR wavelengths, while the cooler interstellar dust glows red in the false color image. D add longer 24 µm data (also in red).

Image Credit: NASA