Scientists used Atacama Large Millimeter/submillimeter Array to observe an interstellar medium in a distant star-forming galaxy SPT0346-52. The data is essential for improving our knowledge about SPT0346-52 and other similar star-forming systems. The study has been published in arXiv pre-print repository.
Interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. ISM in distant galaxies is diﬃcult to study directly due to cosmological dimming and angular resolution limitations.
So, scientists employed ALMA to investigate ISM in the high-redshift galaxy SPT0346-52. ALMA is an excellent tool for such observations. It enables new opportunities to explore the physical conditions in early galaxies through their rest-frame far-infrared emission.
SPTS J034640-5204.9 is a gravitationally lensed dusty star-forming galaxy at a redshift of approximately 5.66. It has an apparent luminosity in far-infrared at a level of 110 trillion solar luminosities. It has an intrinsic star formation rate density of about 4,200 solar masses/year/kpc2.
Scientists decided to conduct a multi-phase study of the ISM in SPT0346-52 with ALMA. It was one of the ﬁrst multi-line, spatially resolved studies of the ISM at high redshift.
The research finds out that the ISM in SPT0346-52 has lower ionization parameter and hydrogen density than other high-redshift DSFGs. It turns out that the ISM in this galaxy has a supersolar metallicity. It is similar to what would be expected from the gas to dust ratio in SPT0346-52. The dust temperature of ISM in SPT0346-52 was measured to be 48.3 K. It is lower than the value obtained by previous studies. Scientists noted that the ionized gas was found to be less dense than gas of ISMs in comparable galaxies.