Astrophysics Research - Image Credits
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A cosmic eclipse. The centre of galaxy cluster RCS 0220.9-0333, at redshift z=1.03 (~8 billion light years), is obscured by a face-on nearby spiral galaxy, similar to our own Milky Way. Swinburne astronomers have observed galaxies in this cluster using the Gemini-North telescope, in Hawaii (USA), in order to investigate the physical properties of galaxies when the universe was 'only' 5 billion years old. The composite colour image, obtained by combining images from the ESO Very Large Telescope (Chile) and the Hubble Space Telescope, covers an approximate area of 0.8 x 1.6 million light years. Credit: Pierluigi Cerulo |
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This is a microlensing magnification map: a map that describes the gravitational lensing effect of a few thousand stars in a distant galaxy. Such 'natural telescopes' help us observe the otherwise unobservable accretion disc and supermassive black hole of background quasars. Producing such a map is a very computationally demanding task, however, GPUs turn out to be really effective in doing this. You can find more details about the GERLUMPH project here. Credit: Georgios Vernardos |
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The HI-deficient galaxy NGC 1515 has 10 times less neutral hydrogen (HI) than the average galaxy of the same size. The colours in the image show optical (green), UV (blue) and HI (red) light. Normal spiral galaxies have their HI distributed in a disk that is about twice the size of their stellar disk visible in the optical and UV light. In the case of NGC 1515 its HI disk is smaller than its stellar disk. Credit: Helga Denes |
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The image shows how a sample of 106 'test stars' trace the gravitational potential, and hence the mass distribution, generated by a Milky Way-like galaxy. In this simulation the Galaxy is described as a multi-component fully-analytic model. By following the behaviour of these 'test stars' and comparing the theoretical results with observations, it is possible to calibrate a realistic mass model of the Milky Way. This numerical simulation was run on gStar, the GPU Supercomputer for Theoretical Astrophysics Research. Credit: Luca Rossi |
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The HI-deficient galaxy ESO 009-G 010 has 6 times less neutral hydrogen (HI) than the average galaxy of the same size. The colours in the image show optical (green), UV (blue) and HI (red) light. Normal spiral galaxies have their HI distributed in a disk that is about twice the size of their stellar disk visible in the optical and UV light. In the case of ESO 009-G 010 its HI disk is the same size as its stellar disk. Credit: Helga Denes |
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The Sculptor galaxy (NGC 253) is a nearby (distance ~ 3.5 Mpc), spectacular late-type spiral galaxy, featuring a large-scale bar. This colour image was produced by combining 3 infrared mosaics. Each mosaic is composed of almost 600 frames. The observations come from IRAC, an infrared imager on-board the Spitzer Space Telescope. When we observe a nearby galaxy in infrared, we see its old stellar population and its dusty regions. Dust is often associated with recent star formation activity, which is typically concentrated in the spiral arms of disc galaxies. NGC 253 hosts a supermassive black hole with mass ~107 Msun, one of the smallest black holes with a direct measure of their mass. (RGB image: red = 5.8 um, green = 4.5 um, blue = 3.6 um) Credit: Giulia Savorgnan |
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Merging galaxies in a merging cluster. The cluster RX J0152.7-1357, at redshift z=0.84 (~7 billion light years), is a complex system in which two clusters of galaxies are colliding on to each other at an epoch when the universe was 6 billion years old. The composite colour image, obtained by combining a series of Hubble Space Telescope observations, covers a region of about 0.8 x 1.6 million light years. At its centre there are two giant elliptical galaxies which are merging and will result in an other bigger elliptical galaxy at later epochs. The high mass of this cluster allows astronomers, thanks to the gravitational lensing effect predicted by General Relativity, to use it as a telescope to image even more distant galaxies which are visible as blue stretched and warped edge-on discs around the central galaxies. Credit: Pierluigi Cerulo |