look-back time

look-back time

The time elapsed since a certain redshift.

look-back time

[′lu̇k ‚bak ‚tīm]
(astronomy)
The time in the past at which the light now being received from a distant object was emitted.
References in periodicals archive ?
First results on the look-back time star formation rate tomography of the Small Magellanic Cloud," (https://www.eso.org/public/archives/releases/sciencepapers/eso1714/eso1714a.pdf) the paper can also be found on ESO's website.
Estimated Market-Wide Benchmark Event Revenue For the week of March 24, 2008, we evaluate the market wide impact of the Benchmark Quote Exception and assess the sensitivity of Benchmark Compliant Volumes and revenue to the length of Benchmark Quote look-back time. As the Benchmark Quote look-back time decreases, trades that occur outside of the Benchmark Quote are dropped from the analysis since under the Order Protection Rule, these trades would be re-routed to exchanges posting better prices.
The main effect of paragraph (200 ms longer look-back time for first than second paragraphs), F(1, 41) = 4.88, p < .04, was qualified by a marginal paragraph X sentence type interaction, F(2, 82) = 2.85, p < .08.
"It's not necessarily such a huge gain in look-back time, but 5 was thought of as one of the earliest epochs in which galaxies might form."
But 83 years is a mere instant, of course, when contemplating the look-back times of celestial objects.
11.8 billion years HSC 8.4 billion years KIDS 8 billion years DES Look-back time (billions of years) to a Milky Way-like galaxy SURVEY COLORS While the DES and HSC surveys use five "color" filters each, the KIDS survey looks farther into both the ultraviolet and infrared, using nine filters total to get a better handle on the photometric redshifts, and hence distances, of its galaxies, (filter colors are representative.)
Recent long-exposure Hubble images taken by Mark Dickinson (now at the National Optical Astronomy Observatory) had shown misshapen "train-wreck" galaxies at a redshift of 1.2, corresponding to a look-back time of two-thirds of the age of the universe.
Most galaxies of interest to astronomers working on CANDELS have a look-back time of at least 10 billion years, when the universe was only a few billion years old.
On March 19, 2008, a record-breaking GRB went off at redshift 0.937, a look-back time of 7.5 billion years--more than halfway back to the Big Bang.
GALEX can also image starburst galaxies (galaxies that are rapidly forming stars) out to redshifts of nearly 1, corresponding to a look-back time of roughly 6 billion years.
There are also links to some of the documents from Astronomical Formulas, including coordinate transformations, lunar phases, and cosmological look-back time. Sample documents from each of my electronic book's chapters are available online at http://www.tiac.net/users/mvz/mcd/.