The first spectral line surveys searching for signals from the dark ages

Free Access

Table 18:

Estimated required background temperatures to produce absorption lines with $T_{\rm b}=-10$ mK at an observing frequency of 550 GHz assuming $T_{\rm ex} \ll T_{\rm bg}$ , and an opacity of one or 10^-3.
Transition	Redshift	Opacity	$T_{\rm bg}$	$T_{\rm CMB}$
	z	$\tau$	[K]	[K]
H₂(2-0)	18.3	1	58	53
		10^-3	260
H₂(3-1)	31.0	1	96	87
		10^-3	430
H₂(4-2)	43.4	1	132	121
		10^-3	595
H₂(5-3)	55.4	1	168	154
		10^-3	756
HD(4-3)	18.1	1	57	52
		10^-3	257
HD(5-4)	22.7	1	71	65
		10^-3	317
HeH⁺(4-3)	13.4	1	43	39
		10^-3	194
HeH⁺(5-4)	16.7	1	54	48
		10^-3	240

Notes. Note, that since the observing frequencies are the same for all transitions the source redshift is different for every transition. As a comparison, the CMB temperatures are listed for each redshift.

Source LaTeX | All tables | In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.