17. Glossary

accelleration

Dataformat used in the falcon package. Related to the potential in NEMO, except one can use multiple accelleration descriptors, normally separated by a semi-colon.

bodytrans

Dataformat (normally a C function) that is used to perform arbitrary operations on expression variables used in snapshot’s. Example: xvar=x

ccd

Synonymous for image; most programs in NEMO which handle images start or end with ccd, e.g. ccdfits, fitsccd, ccdmath. Most programs handle 1D, 2D and 3D “ccd” images.

ECSV

(Enhanced Character Separated Values) a popular self-describing ASCII table format popularized by astropy. https://docs.astropy.org/en/stable/io/ascii/ecsv.html

falcon

A subpackage in NEMO that hosts the gyrfalcON code and many related tools. See $NEMO/usr/dehnen/falcON.

fie

Most expressions that you give to program keyword s are parsed by nemofie and eventually fie. (Nomenclature borrowed from GIPSY). Example: a=’sqrt(pi)*G’

FITS

“Flexible Interchange Transport System”, a standard dataformat used to interchange data between machines. Commonly used for images, but has since its inception be modified to store tables as well. See also SDFITS

FWHM

(Full Width Half Max): the effective resolution of the beam if normally given in FITS keywords BMAJ,BMIN,BPA. The term resolution is used interchangeably. The FWHM of a gaussian beam is 2.355 \(\sigma\).

GIPSY

The Groningen Image Processing System. A number of concepts in NEMO, and a few routines, have been taken liberally from GIPSY. See also https://www.astro.rug.nl/~gipsy/

history

Each NEMO dataset normally contains a data processing history in the form of of history items at the beginnging of the dataset. They are normally kept track of by the data processing programs, and can be displayed with the program hisf.

image

Dataformat in NEMO, used to represent 2- and 3-D images/data cubes. See also ccd.

MIRIAD

Another astronomical data reduction package, from which we have borrowed some user interfaces which are plug-compatible with our command-line syntax.

orbit

Dataformat in NEMO used to represent a stellar orbit; most programs in NEMO which handle orbits start or end with orb, for example orbint, an orbit integrator.

pixel

PIXEL/voxel: an area in 2D or 3D representing selected phase space coordinates.

potential

Dataformat in NEMO used to represent a potential; most programs in NEMO which handle potentials start or end with pot, for example potlist. Related to the accelleration

program keyword

Keywords that are defined by the program only. They can be seen by using the help= keyword (in itself being a system keyword).

review

A small user interface that pops up when a program is interrupted. Type quit to exit it, or ? for help. This feature of the user interface may not be installed in your version.

SDFITS

A FITS extension that allows efficient storage of single dish spectra. See also FITS

set

Compound hierarchical data-structure of a structured file. They are the equivalent of a C struct.. A set is alwayd closed with a tes.

snapshot

Dataformat used in NEMO to represent an N-body system. Many programs that handle {it snapshot}’s in NEMO start or end with snap, for example snapplot.

structured file

The binary data NEMO writes is in a hierarchical structured format. Programs like tsf rsf, and csf perform general and basic I/O functions on such files. They are hierarchical structured sets, much like how binary XML files would look.

system keyword

Global keyword that every NEMO program knows about, and are not listed in the program keyword s that can be seen by issuing e.g. help= (in itself being a system keyword). This concept originated in GIPSY where hidden keywords are also used.

table

A table consists of rows and columns of values, numbers or text. Most commonly stored in ASCII. Less well defined, it is one of the four data types commonly used in NEMO. Most programs that handle tables start or end with tab, for example tabplot.

voxel

A three dimensional pixel. See also pixel.

yapp

“Yet Another Plotting Package”, the library definition API that is used by all programs that produce graphics output. It is deliberately kept very simple to promote portability to lower level graphics packages. The yapp= system keyword controls the graphics device definitions/capabilities. Examples are the ps and pgplot implementations.