Research Highlight

ALMA Resolves Gas Impacted by Young Jets 11 billion years away (press release)

Our research team (PI: Kaiki Taro Inoue, Kindai University, Satoshi Matsushita, Academia Sinica, Koichiro Nakanishi, NAOJ and Takeo Minezaki, University of Tokyo)  carried out an observation with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that gas clouds in a galaxy 11 billion years away are impacted by young jets ejected from a super massive black hole. The discovery will pave the way for a better understanding of the evolutionary process of galaxies in the early Universe.

It is commonly known that super massive black holes are residing in the center of galaxies. However, it is less well known that they have fast-moving streams of ionized matter, called jets. In some nearby galaxies, it has been observed that evolved jets blow off galactic gaseous clouds, resulting in suppressed star formation or shock waves created by jets may induce star formation. To understand the coevolution of galaxies with accompaning super massive black holes, it is crucial to understand the interaction between black hole jets and gaseous clouds throughout the cosmic history. However, it had been difficult to obtain clear evidence of such interaction in the early universe due to lack of spatial resolution.

To overcome the difficulty, our team used ALMA to observe an interesting object known as MG J0414+0534.  A distinctive feature of MG J0414+0534 is that the paths of light traveling from it to Earth are significantly distorted by the gravity of another ‘lensing’ galaxy between MG J0414+0534 and us, causing significant magnification. Combining this cosmic telescope and ALMA’s high-resolution observations, our team was able to obtain exceptionally sharp vision, that is 9,000 times better than human eyesight. Another feature is that MG J0414+0534 has a supermassive black hole with bipolar jets at the center of the host galaxy.

 

 

ALMA image of MG J0414+0534   The emissions from dust and ionized gas are shown in orange and

emissions from carbon monoxide gas are shown in green.

Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue at al.

 

 

With careful analysis, our team succeeded in resonstructing the image of what MG J0414+0534 would look like if gravitional lens effects were completely turned off.  We found that gaseous clouds along the jets have violent motion with speeds as high as 600 km/s, showing clear evidence of impacted gas. Moreover, it turned out that the size of the impacted gaseous clouds and the jets are much smaller than the typical size of a galaxy like the Milky-Way, implying that the jets are at an infant stage of evolution.　

The result is published in The Astrophysial Journal Letters on 27 March 2000.

 

 

  

Reconstructed composite images of what MG J0414+0534 would look like if gravitational lensing

effects were turned off. The emissions from dust and ionized gas around a quasar are shown in orange.

The emissions from carbon monoxide gas are shown in green.

 Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue at al.