These companion images show wide and close-up views of a long ribbon of gas called the Magellanic Stream, which stretches nearly halfway around our Milky Way galaxy.
In the combined radio and visible-light image at top, the gaseous stream is shown in pink. The radio observations, taken from the Leiden-Argentine-Bonn (LAB) Survey, have been combined with visible-light views from the Mellinger All-Sky Panorama. The Milky Way is the light blue band in the center of the image. The brown clumps are interstellar dust clouds in our galaxy. The Magellanic Clouds, satellite galaxies of the Milky Way, are the white regions at bottom right.
The image at bottom, taken at radio wavelengths, is a close-up map of the Magellanic Stream that also was generated from the LAB Survey. Researchers determined the chemistry of the gas filament by using Hubble's Cosmic Origins Spectrograph (COS) to measure the amount of heavy elements, such as oxygen and sulfur, at six locations (marked with an "x") along the Magellanic Stream. COS observed faraway quasars whose emitted light passes through the stream and detected the spectral fingerprints of these elements from the way they absorb ultraviolet light. Quasars are the brilliant cores of active galaxies.
The astronomers found a low amount of oxygen and sulfur along most of the stream. This matches the levels in the Small Magellanic Cloud (SMC) about 2 billion years ago, when the gaseous ribbon was thought to have been formed. As the SMC plows though the galactic halo, its gas is torn out via processes called ram-pressure and tidal stripping. The observation identifies the SMC as the primary source of lost gas in the stream.
The team, however, also discovered a much higher level of sulfur in a region closer to the Magellanic Clouds. This measurement corresponds to the current amount of heavier elements in the Large Magellanic Cloud (LMC). The observations offer evidence that the LMC also has contributed material to the stream. The pink circles at right mark the location of the Small and Large Magellanic Clouds.
Credits
Radio/visible-light image: David L. Nidever et al., NRAO/AUI/NSF and A. Mellinger, LAB Survey, Parkes Observatory, Westerbork Observatory, and Arecibo Observatory;Radio image: LAB Survey
| About The Object | |
|---|---|
| Object Name | Milky Way Magellanic Stream |
| About The Data | |
| Data Description | The Hubble data used in this science finding are from proposal : A. Fox (STScI/ESA), B. Wakker (University of Wisconsin, Madison), J. Smoker (European Southern Observatory, Chile), P. Richter (University of Potsdam and Leibniz Institute for Astrophyics, Potsdam), N. Lehner and J.C. Howk (University of Notre Dame), and J. Bland-Hawthorn (University of Sydney). The science team consists o:f A. Fox (STScI/ESA), P. Richter (Universitat Potsdam, Germany), B. Wakker (University of Wisconsin, Madison), N. Lehner and J.C. Howk (University of Notre Dame), N. Bekhti (Universitat Bonn, Germany), J. Bland-Hawthorn (University of Sydney), and S. Lucas (University College London). |
| Filters | Gratings: G130M and G160M |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
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| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
