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| A Small Galaxy Blows Large Bubbles | ||
Figure 1: In the centre of the image the stellar light of the galaxy J1044+0355 is shown in black. The galaxy is very small (diameter 7100 light-years) and consists of several star clusters, each of which contains about 1 million stars. We now discovered that the galaxy is surrounded by a more than 20.000 light-year extended filamentary structure of diffuse ionised gas. This gas is detected in Hydrogen Balmer-α line emission in a 1.5 hour exposure with the Multi Unit Spectroscopic Explorer on the 8 meter diameter telescope “Yepun” at the European Southern Observatory in Chile. The detection is here visualised in hues of bright yellow to red. These filaments connect along several elliptical loops, which are indicated with dot-dashed lines. These loops are the dense surfaces of bubbles that are likely blown by more than 50000 supernovae explosions in the last 20 million years.
(Image based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 0103.B-0531)
Stars that are 25 to 100 times more massive than our sun do not live very long. After three to five million years their cores collapse and giant nuclear explosions, dubbed supernovae, blast vast amounts of material into the surrounding space. In our Milky Way such supernovae occur, on average, thrice a century. Given our home Galaxy's large mass and size, these explosions only have a modest effect on the overall interstellar gas distribution.
However, similar supernovae rates may have dramatic consequences for galaxies that are ten thousand times less massive than the Milky Way. This is because their gravitational pull cannot hold back the high-velocity gas released from all the explosions in such systems. Thus, gas is being blown out in a so-called galactic wind. Making direct images of this wind material is challenging, even with the largest telescopes, since the wind material is very diffuse.
Two astronomers from IUCAA in collaboration with an astronomer from the University of Tokyo have now captured a truly spectacular galactic wind phenomenon around a very extreme galaxy – J1044+0354 (see Figure). This tiny galaxy (diameter 7.100 light-years) is vigorously forming stars. It is at a distance of 170 million light-years from us. We were surprised to find that J1044+0335 is surrounded by seven giant bubbles. The diameter of those bubbles, 23.000 light-years, is almost as large as the distance from Earth to the black hole in the centre of the Milky Way. While a few of these bubbles look like they have popped, others are still remarkably intact.
Large-scale wind-driven bubbles around small galaxies have been known for two decades, but the newly discovered bubbles are twice to thrice as large as anything seen before. In fact, classical models of large scale bubble formation due to the combined effect from supernovae fail to reproduce the properties of the observed structure around J1044+0353.
Understanding wind phenomena around starburst galaxies is key for grasping galaxy formation and evolution in the early universe, where galaxies such as J1044+0353 are the norm. Yet, to comprehend how these winds really work, we need to collect more such images of diffuse gas around tiny galaxies. Currently, we even do not know whether the structure around J1044+0353 is truly special or whether many more tiny galaxies may blow similar super-sized bubbles.
However, similar supernovae rates may have dramatic consequences for galaxies that are ten thousand times less massive than the Milky Way. This is because their gravitational pull cannot hold back the high-velocity gas released from all the explosions in such systems. Thus, gas is being blown out in a so-called galactic wind. Making direct images of this wind material is challenging, even with the largest telescopes, since the wind material is very diffuse.
Two astronomers from IUCAA in collaboration with an astronomer from the University of Tokyo have now captured a truly spectacular galactic wind phenomenon around a very extreme galaxy – J1044+0354 (see Figure). This tiny galaxy (diameter 7.100 light-years) is vigorously forming stars. It is at a distance of 170 million light-years from us. We were surprised to find that J1044+0335 is surrounded by seven giant bubbles. The diameter of those bubbles, 23.000 light-years, is almost as large as the distance from Earth to the black hole in the centre of the Milky Way. While a few of these bubbles look like they have popped, others are still remarkably intact.
Large-scale wind-driven bubbles around small galaxies have been known for two decades, but the newly discovered bubbles are twice to thrice as large as anything seen before. In fact, classical models of large scale bubble formation due to the combined effect from supernovae fail to reproduce the properties of the observed structure around J1044+0353.
Understanding wind phenomena around starburst galaxies is key for grasping galaxy formation and evolution in the early universe, where galaxies such as J1044+0353 are the norm. Yet, to comprehend how these winds really work, we need to collect more such images of diffuse gas around tiny galaxies. Currently, we even do not know whether the structure around J1044+0353 is truly special or whether many more tiny galaxies may blow similar super-sized bubbles.
Reference:
The extreme starburst J1044+0353 blows kiloparsec-scale bubblesEdmund Christian Herenz, Haruka Kusakabe, Soumil Maulick
Publications of the Astronomical Society of Japan, 2025; psaf073
Follow this link to access the paper - [ https://academic.oup.com/pasj/advance-article/doi/10.1093/pasj/psaf073/8209789 ]
Research contacts:
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Dr. Edmund Christian Herenz (Vaidya-Raychaudhuri Fellow) IUCAA, Pune E-mail: edmund.herenz_at_iucaa.in |
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Mr. Soumil Maulick IUCAA, Pune E-mail: soumil_at_iucaa.in |