Effective Area of the Cosmic Origins Spectrograph below 1150 Å
Abstract
The G140L segment B channel (R 2,000) of the Cosmic Origins Spectrograph (COS) recently installed on the Hubble Space Telescope (HST) has an effective area consistent with 10 cm2 in the bandpass between the Lyman edge at 912 Å and Lyβ. It has a slight plateau of 20 cm2 near 1050 Å and rises to a peak in excess of 1100 cm2 longward of 1140 Å. Up until now the general astronomical community has had only limited access to a low resolving power R 2,000 far-UV spectrograph, extending down to the Lyman limit, in the form of the shuttle carried instruments; the Hopkins Ultraviolet Telescope and the Berkeley Extreme and Far-UV Spectrograph. The low resolving power provides a unique capability to reach extremely faint flux limits and will enable new science investigations, such as those seeking to quantify the escape fraction of Lyman continuum photons from galaxies at low redshift, study the He II Gunn-Peterson effect in the redshift range 2 < z < 2.8, measure CO/H2 in dense interstellar environments, or make observations of the O VI λλ 1032, 1038 doublet. Observations of point sources will have the highest spectral resolution, since the small 2."5 diameter entrance aperture of COS is not optimized for extended source observations.
- Publication:
-
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21546407M