Fuse View of Primordial Helium Traces the Structure of Early Universe

As the universe evolves, density fluctuations in the intergalactic gas (hydrogen and helium) grow into clumps and filaments under gravity's pull. The densest clumps form galaxies and quasars whose radiation energizes (ionizes) the remaining intergalactic gas.

Observations using NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) reveal the structure of ionized helium that traces the lowest density regions of the intergalactic medium.

About the data

Technical facts about this news release: Principal Astronomers: G. A. Kriss (STScI/JHU), J. M. Shull (U. Colorado), W. Oegerle (GSFC), W. Zheng (JHU), A. F. Davidsen (JHU), A. Songaila (U. Hawaii), J. Tumlinson (U. Colorado), L. L. Cowie (U. Hawaii), J.-M. Deharveng (Laboratorie d'Astronomie Spatiale, France), S. D. Friedman (JHU), M. L. Giroux (U. Colorado), R. F. Green (KPNO/NOAO), J. B. Hutchings (Herzberg Inst. of Astrophysics,Canada), E. B. Jenkins (Princeton U. Obs.), J. W. Kruk (JHU), H. W. Moos (JHU), D. C. Morton (Herzberg Inst. of Astrophysics/Canada), K. R. Sembach (JHU), T. M. Tripp (Princeton U. Obs.)

About this Object: Object Name: HE2347-4342 Object Description: Quasar R.A.: 23h 50m 34.24s Dec.: -43° 26' 00.0" Constellation: Phoenix Distance: 3,070 Mpc (10 billion light-years). Redshift: Z2.885 Magnitude: V16.1

About the Data: Instrument: HST–STIS, HST–FUSE Exposure Dates: August 21, 2000 and October 16, 2000, Exposure Time: 55 minutes (STIS); August 17 - 27, 2000, and October 11- 21, 2001, Exposure Time: 105 hours (FUSE)