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| author | Mohammad Akhlaghi <mohammad@akhlaghi.org> | 2018-12-18 16:26:13 +0000 |
|---|---|---|
| committer | Mohammad Akhlaghi <mohammad@akhlaghi.org> | 2018-12-18 16:35:54 +0000 |
| commit | b3c8f20525edc23c68c14dedc4ff4839831863f8 (patch) | |
| tree | a44867a0d18ee6c947f79f0bcc3fc760ad189ed8 | |
| parent | e57f8e8fbd154950e2a34782d0551c54c67d4110 (diff) | |
| download | gnuastro-b3c8f20525edc.tar.gz | |
Annum as unit of year in abbreviated CosmicCalculator units
Until now, we were simply using the non-standard "Gyr" for representing
billion years. However, the official IAU-recognized abbreviation for year
is "a" (for annum), and it is widely used in other scientific branches like
geology, palaeontology, etc. The IAU published units are available here:
https://www.iau.org/publications/proceedings_rules/units/
Therefore with this commit, all mentions of "Gyr" in CosmicCalculator were
corrected to "Ga". A short explanation is also added for those that may not
be familiar with this standard: In the output of `--help', it is written as
"Ga: Giga Annum". In the output with all measurements it is written as
(Ga*), with the star pointing to a footnote in the end. And finally, in the
book its written as "Ga (Giga annum, or billion years)".
This issue was raised up by David Valls-Gabaud.
| -rw-r--r-- | bin/cosmiccal/args.h | 6 | ||||
| -rw-r--r-- | bin/cosmiccal/cosmiccal.c | 9 | ||||
| -rw-r--r-- | doc/announce-acknowledge.txt | 1 | ||||
| -rw-r--r-- | doc/gnuastro.texi | 14 |
4 files changed, 17 insertions, 13 deletions
diff --git a/bin/cosmiccal/args.h b/bin/cosmiccal/args.h index 6c7d5cd..12d7c57 100644 --- a/bin/cosmiccal/args.h +++ b/bin/cosmiccal/args.h @@ -110,7 +110,7 @@ struct argp_option program_options[] = UI_KEY_AGENOW, 0, 0, - "Age of universe now (Gyr).", + "Age of universe now (Ga: Giga Annum).", UI_GROUP_SPECIFIC, &p->specific, GAL_OPTIONS_NO_ARG_TYPE, @@ -222,7 +222,7 @@ struct argp_option program_options[] = UI_KEY_AGE, 0, 0, - "Age of universe at z (Gyr).", + "Age of universe at z (Ga: Giga Annum).", UI_GROUP_SPECIFIC, &p->specific, GAL_OPTIONS_NO_ARG_TYPE, @@ -236,7 +236,7 @@ struct argp_option program_options[] = UI_KEY_LOOKBACKTIME, 0, 0, - "Look back time to z (Gyr).", + "Look back time to z (Ga: Giga Annum).", UI_GROUP_SPECIFIC, &p->specific, GAL_OPTIONS_NO_ARG_TYPE, diff --git a/bin/cosmiccal/cosmiccal.c b/bin/cosmiccal/cosmiccal.c index 1ce4ad2..49a4929 100644 --- a/bin/cosmiccal/cosmiccal.c +++ b/bin/cosmiccal/cosmiccal.c @@ -113,7 +113,7 @@ cosmiccal_printall(struct cosmiccalparams *p) printf("\n\n Universe now\n"); printf( " ------------\n"); - printf(FLTFORMAT, "Age of Universe now (Gyr):", curage); + printf(FLTFORMAT, "Age of Universe now (Ga*):", curage); printf(EXPFORMAT, "Critical density now (g/cm^3):", ccritd); printf(FLTFORMAT, "Proper distance to z (Mpc):", pd); printf(FLTFORMAT, "Angular diameter distance to z (Mpc):", ad); @@ -127,13 +127,16 @@ cosmiccal_printall(struct cosmiccalparams *p) printf("\n\n Universe at desired redshift z\n"); printf( " ------------------------------\n"); - printf(FLTFORMAT, "Age of Universe at z (Gyr):", outage); - printf(FLTFORMAT, "Look-back time to z (Gyr):", curage-outage); + printf(FLTFORMAT, "Age of Universe at z (Ga*):", outage); + printf(FLTFORMAT, "Look-back time to z (Ga*):", curage-outage); printf(EXPFORMAT, "Critical density at z (g/cm^3):", zcritd); printf("\n\n Comoving universe (time independent)\n"); printf( " ------------------------------------\n"); printf(FLTFORMAT, "Comoving volume over 4pi stradian to z (Mpc^3):", vz); + + printf("\n-------\n"); + printf("*: Ga is short for Giga Annum, or billion years (IAU standard).\n"); } diff --git a/doc/announce-acknowledge.txt b/doc/announce-acknowledge.txt index 0b5a011..2a42585 100644 --- a/doc/announce-acknowledge.txt +++ b/doc/announce-acknowledge.txt @@ -8,3 +8,4 @@ Johan Knapen Mamta Pommier Michael Stein Ignacio Trujillo +David Valls-Gabaud diff --git a/doc/gnuastro.texi b/doc/gnuastro.texi index a4d4e01..b6257cf 100644 --- a/doc/gnuastro.texi +++ b/doc/gnuastro.texi @@ -21629,8 +21629,8 @@ option which has the units along with a short description. @item -G @itemx --agenow -The current age of the universe (given the input parameters) in Giga-years -(Gyr). +The current age of the universe (given the input parameters) in Ga (Giga +annum, or billion years). @item -C @itemx --criticaldensitynow @@ -21673,14 +21673,14 @@ the apparent magnitude to give the object's absolute magnitude. @item -g @itemx --age -Age of the universe at given redshift in Giga-years (Gyr). +Age of the universe at given redshift in Ga (Giga annum, or billion years). @item -b @itemx --lookbacktime -The look-back time to given redshift in Giga-years (Gyr). The look-back -time at a given redshift is defined as the current age of the universe -(@option{--agenow}) subtracted by the age of the universe at the given -redshift. +The look-back time to given redshift in Ga (Giga annum, or billion +years). The look-back time at a given redshift is defined as the current +age of the universe (@option{--agenow}) subtracted by the age of the +universe at the given redshift. @item -c @itemx --criticaldensity |
