6 papers
Molecular gas hidden in plain sight in the early Universe
Pasquier Noterdaeme, Jens-Kristian Krogager, Sergei Balashev
We report the discovery of an extreme intervening molecular absorber at zabs = 4.1 towards the z = 4.7 quasar SDSS J080023.02+305101.22 revealed through strong H2 absorption that h…
Low-Frequency Recombination Lines from Galaxies and AGN over Cosmic Time
Kimberly L. Emig, Sergei Balashev, Francoise Combes +10
Radio recombination lines (RRLs) at low frequencies (<10 GHz) can provide a multi-phase view of interstellar gas in nearby galaxies, absorption-line-systems, and AGN. Hydrogen RRLs…
Tracing Cold Gas in Absorption Across Cosmic Time with the SKA
Elizabeth K. Mahony, Neeraj Gupta, Sergei A. Balashev +12
Observing the 21-cm HI line in absorption provides a powerful means of tracing the cold neutral gas in normal and active galaxies across cosmic time. The frequency coverage and sen…
H I Properties of Field Galaxies at -0.6: Insights into Declining Cosmic Star Formation
David DePalma, Neeraj Gupta, Hsiao-Wen Chen +18
We report statistically significant detection of H I 21-cm emission from intermediate-redshift (-0.6) galaxies. By leveraging multi-sightline galaxy survey data from t…
Quasar radiation transforms the gas in a merging companion galaxy
Sergei Balashev, Pasquier Noterdaeme, Neeraj Gupta +7
Quasars, powered by gas accretion onto supermassive black holes, rank among the most energetic objects of the Universe. While they are thought to be ignited by galaxy mergers and a…
First detections of CO absorption in the Magellanic Clouds and direct measurement of the CO-to-H ratio
Sergei Balashev, Daria Kosenko, Pasquier Noterdaeme
Molecular hydrogen (H) is by far the most abundant molecule in the Universe. However, due to the low emissivity of H, carbon monoxide (CO) is widely used instead to trace m…