Program: FLUX Purpose: Program to calculate flux in user defined box. Category: ANALYSIS, CALCULATION, TABLES File: flux.c Author: M.G.R. Vogelaar Keywords: INSET= Give input set, subsets: Input set (and subsets). Maximum number of subsets is 2048. ** POLYGON= Define polygons instead of boxes? Y/[N] If you want the flux in a polygon select POLYGON=Y. The keyword VERTICES%= (%=1,2,3,...) is prompted instead of BOX%= The Polygon option can be used for two dimensional subsets only. VERTICES%= Give vertices of polygon: Asked if POLYGON=Y The vertices are given in two dimensional coordinate pairs x1,y1, x2,y2, ..... The minimum number of vertices is 3, the maximum is 128. The program closes the polygon. The maximum number of pixels in the box that encloses the polygon cannot exceed 16384. BOX%= Frame for input subsets. [entire subset] Asked if POLYGON=N It is possible to give more than one box (% indicates box number). The keyword is repeated until user pressed carriage return. CLEANBEAM= Do you want to give values of a clean beam? Y/[N] If data is radio data and there is no AP available, use CLEANBEAM=Y and BEAM= to calculate the sum in the AP. HEADER= Antenna Pattern from header? [Y]/N If your data is radio data and there is a reference to an antenna pattern (AP) in the header, you can choose to select this antenna pattern by specifying HEADER=Y. If you want to get the APSET prompt to select another AP, specify HEADER=N if HEADER=Y: ** APSET= Give set, subs. of ant.pat.: [AP from header] if HEADER=N or no reference to AP: APSET= Give set, subs. of ant.pat.: [NO AP]] Set and subset(s) of AP. This keyword is prompted if your data is radio data and there is no reference to an AP in the header, or there was a reference, but you selected HEADER=N. The program recognizes several radio telescopes. BEAM= Maj. and min. axis of beam (arcsec) [none] Asked if CLEANBEAM=YES The sum in the AP is now the integral from -inf. to inf. of a gaussian with the specified FWHM. CDELT%= Give grid spacing in 'axis type' in 'axis units': If a clean beam is wanted, the grid spacings are needed. If a spacing is not found in the header, you are prompted to give the spacing in units as found in the header. FREQUENCY= Give frequency: [1.415 GHZ] If FLUX cannot find a proper frequency for primary beam, correction, a frequency is asked with FREQUENCY= The keyword accepts a number and a unit. If no unit is given, the number is in Ghz. Otherwise, a conversion is done to Ghz. The possible units to convert from are for example MHz, Hz, but also cm (all upper- or lowercase). The keyword is asked unhidden only once. GRDEVICE= Plot device: [List of devices] Destination of plot, Screen or Hardcopy. FILENAME= Name of ASCII file: [No output to file] If a name is specified, an ASCII file is created where fit parameters are listed in a row. If you press carriage return, there will be no output to an ASCII file. APPEND= File exists, ok to append? [Y]/N The file specified in FILENAME= already exists. You can append to this file with APPEND=Y. If APPEND=N you will be prompted for another name. PLOTTING: OPTION= 0)Exit 1)Sum 2)SumPBC 3)Flux 4)FluxPBC 5)GRdev [3] Plot results. Default is a plot of the flux if the flux is calculated else the default is a plot of the sum. Option 5 offers the possibility to change the plot device. You are prompted with the GRDEVICE= keyword again. Also the hidden 'PG" keywords (PGMOSAIC=, PGPAPER= etc. accept new values if you define them at this point. ** PGMOSAIC= View surface sub divisions in x,y: [calculated] View surface can contain a number of plots in in X and Y direction (mosaic). Default the program tries to put the same number of columns as rows in 1 plot. ** PGPAPER= Give width(cm), aspect ratio: [calc, calc] Aspect ratio is height/width. ** PGBOX= Corners of box Xl,Yl,Xh,Yh: [default by application] It is possible to overrule the calculated PGPLOT box size with PGBOX=. The coordinates (x,y) of the lower point are given first. ** PGTICKS= Coord. int. between maj. tick marks in X,Y: [calc, calc] World coordinate interval between major tick marks on X and Y axis. The default is 0 0 which results in values calculated by PGPLOT. ** PGNSUB= Number of subintervals between maj. ticks: [calc, calc] The number of subintervals to divide the major coordinate interval into. The default is calculated by PGPLOT. ** PGCOLOR= Give color 1..15: [1] See description for the available colors. ** PGWIDTH= Give line width 1..21: [1] ** PGHEIGHT= Give character height: [1.0] ** PGFONT= Give font 1..4: [2] ** TABNAME= Give name of table to store results: [FLUX] Columns are created on set level. ** TABAPPEND= Append to existing columns? Y/[N] If a table already exists, it is possible to append to this table with TABAPPEND=Y The default always creates a new table. Description: Inside the box in which one wants to know the flux, all non blank pixel values are summed and then, if possible, the sum is converted to a flux in appropriate units. This conversion is case dependent: a) RADIO DATA Data is considered radio data, if the instrument name in the header is equal to one of 'WSRT', 'VLA' ,'FST', or 'DRAO'. Primary Beam Correction is available for 'WSRT', 'VLA' ,'FST'. What is needed for the conversion from sum to flux is the 'SUMAP' in an equivalent box, i.e. the sum over all pixels in a box of the corresponding antenna pattern (AP) that has a size equal to the size of the box in which the flux is wanted. A warning is generated if the AP cannot be summed symmetrically. The axes in such a box will be extended in length until they are all symmetrical. Be warned that your box is changed then! Also a Primary Beam Corrected (PBC) sum and flux is determined. This is a correction for the response of one antenna and it depends on distance of a position to the beam center and on frequency. The distance is corrected for projection effects. If it is greater than a certain distance (validity range of PBC), there is no contribution to the sum or flux. PBC possible if: 1) An instrument name can be found in the set header. 2) The instrument is one of WSRT, VLA or FST. 3) The dimension of the selected subset must be 1 or 2 4) The subset axes are spatial. 5) The subset is 2-dimensional, and the spatial axes are be different. 6) The reference values CRVAL% & CDELT% can be found in the header. 7) There is a spectral axis available and the units can be converted to GHZ (if no spectral axis is available, a frequency is asked with FREQUENCY=). If the RA-DEC pointing center of the telescope can not be found in the header, it is assumed they are equal to CRVAL1 and CRVAL2 (position of grid 0,0). If an image value is not a blank and its position is within the validity region of the primary beam correction, the value is corrected and added to 'sumPBC'. If a polygon is defined, the AP is centered at the position weighted center of the data inside the polygon and only the part of the AP inside the polygon is summed. b) NON-RADIO DATA The grid spacings from the header are read and converted to steradian/pixel. The sum in the requested box is multiplied by this number. 'flux' has a different definitions. For radio data you need an antenna pattern because sum = sum / sumAP. For other data: sum = sum * steradians/pixel. The units of the flux are the units found in the header. 'fluxPBC' is calculated if there is a 'sumPBC' and an antenna pattern. It is comparable to 'flux', but in this case the sum is the primary beam corrected sum. If the data was in Westerbork Units (WU), a conversion to mJy's is applied, where 1 W.U. ==> 5 mJy/Beam. Plotting: It is possible for each given box, to make a plot of sum against subset index. The subset index always runs from 0 to the number of subsets you specified minus 1. A plot can be created only if the number of subsets is greater than 1; Tables: Results are always stored in a table. The name of the table is FLUX by default. You can change this with TABNAME=. The name is appended by a number that corres- ponds to the number of the used box (FLUX1, FLUX2, ...). The names of the columns are: SUM Sum of data SUMPBC Primary beam corrected sum FLUX Flux FLUXPBC Primary beam corrected flux SUMAP Sum in Antenna pattern NDATA Number of non blank points in statistics NBLANKS Number of blanks in statistics XLO Lowest X value of box YLO Lowest Y value of box XHI Highest X value of box YHI Highest Y value of box SUBGRIDn Used subset in grid coordinates n is a number of an axis outside the subset. If there are no axes outside the subset, this column is not created. Axisname If there are n axes outside the subset, there will be n extra columns with the name equal to the name of the (secondary) axis, containing physical units. Use the application TABLE to print, plot and process the column entries. Color indices: 0 Background 1 Default (Black if background is white) 2 Red 3 Green 4 Blue 5 Cyan 6 Magenta 7 Yellow 8 Orange 7 Yellow 8 Orange 9 Green + Yellow 10 Green + Cyan 11 Blue + Cyan 12 Blue + Magenta 13 Red + Magenta 14 Dark Gray 15 Light Gray 16-255 Undefined Available fonts: 1 single stroke "normal" font 2 roman font 3 italic font 4 script font Notes: ....... Example: ....... Updates: Mar 20, 1990: VOG, Document created. Apr 10, 1992: VOG, New call to PRIBEAM. May 26, 1992: VOG, Rewritten in C. Oct 5, 1992: VOG, Units bug with 'strtok' Tables implemented. Apr 16, 1996: VOG, Implemented code for unequal column lengths when appending tables.