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authorMohammad Akhlaghi <mohammad@akhlaghi.org>2018-12-18 16:26:13 +0000
committerMohammad Akhlaghi <mohammad@akhlaghi.org>2018-12-18 16:35:54 +0000
commitb3c8f20525edc23c68c14dedc4ff4839831863f8 (patch)
treea44867a0d18ee6c947f79f0bcc3fc760ad189ed8
parente57f8e8fbd154950e2a34782d0551c54c67d4110 (diff)
downloadgnuastro-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.h6
-rw-r--r--bin/cosmiccal/cosmiccal.c9
-rw-r--r--doc/announce-acknowledge.txt1
-rw-r--r--doc/gnuastro.texi14
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