I. CATALOGUE COMPILATION The Swift catalogue was compiled from 4 catalogues: Tycho-2, GVCS III, NGC, and the Yale Bright Star Catalogue. All catalogues were preprocessed before compiling the Swift catalogue to acheive uniform columns and units. Next, they were merged into one catalogue before eliminating "red" objects and precessing all coordinates to epoch 2000.0. The catalogue was then corrected for missing decimal points. Finally, the catalogue was sorted by R.A. for ease of locating objects within the catalogue. II. COLUMN NAMES AND FLAGS There are up to 8 columns listed from left to right in the Swift catalogue: 1. Right Ascension (degrees) 2. Declination (degrees) 3. V magnitude (Johnson system) 4. B magnitude (Johnson system) 5. Epoch (always J2000.0) 6. Catalogue Name 7. B or V flag (this flag is only present if B or V has been invented) 8. Years (number of years between original and precessed coordinates) III. GENERATING MISSING MAGNITUDES All missing V or B magnitudes were genereated in preprocessing. If V was missing, V was set to "B - 0.3"; likewise, missing B was set to "V + 0.3". These values were chosen to indicate that the object could be "very blue". A "B - V" value of less than "-0.3" causes the object to be retained in the Swift catalogue after the "red" objects are eliminated. Even if this "B - V" value is invented, the UVOT monitor is prevented from looking at potentially bright objects. IV. PROCESSING RED STARS The aim of the Swift Catalogue is to prevent the Swift UVOT from looking at very bright objects, particularly in the blue range. Therefore, some fainter objects deemed "too red" to harm the UVOT havebeen eliminated from the catalogue. This process was done through an awk script that retained objects in the catalogue according to these limits: A. B - V < -0.3, V <= 12.0 B. -0.3 <= B-V < -0.17, V <= 11.0 C. -0.17 <= B-V < 0.01, V <= 10.0 D. 0.01 <= B-V, V <= 9.5 Most faint objects with Vt higher than Bt could be thrown out according to these rules. This reduced the number of objects in the Swift catalogue by almost half. V. PRECESSING STARS TO J2000.0 Just over 800 of the stars from the Tycho-2 catalogue gave data in epoch 1991.5, while around 3000 variable stars from the GCVS gave information in epoch 1950 coordinates. An awk script precessed right ascension and declination, both given in degrees, using these equations: "R.A. new" = "R.A. old" + (15/3600)*years*(3.074+1.336*sin((pi/360)* "R.A. old")*tan((pi/360)* "Dec old")) "Dec new" = "Dec old" + (1/3600)*years*(20.038*cos((pi/360)* "R.A. old")) where "years" is the number of years between 2000.0 and the epoch given. This precession equation produces values accurate to < 1 second of right ascension and 5 arcseconds of decliation. The equation was found on an Arizona State University astronomy class webpage: http://ircamera.as.arizona.edu/astr_250/ProblemSets/tele_solv.html VI. CORRECTED DECIMAL POINTS AND CATALOGUE SORTING Decimal points were corrected for three reasons. The first two were very similar; some numbers in the component catalogues were listed as ".n" or "n.", and these numbers were corrected to read "0.n" and "n.0". The third reason for correcting a decimal point occured when a whole number was found with no decimal point. Occasionally, this occured from data in a component catalogue listed as "n". Numbers also occured without decimal points after mathematical functions that produced a number with more than four "0's" after the decimal point: awk removes the decimal point and subsequent zeros, simply transcibing the numbers as whole. In both cases, the numbers were corrected to read "n.0". The catalogue was sorted by right ascension (in degrees) using the Unix function "sort". Right ascension values of less than 10 degrees were padded with two leading zeros, and values less than 100 degrees were padded with a single leading zero to simplify the sorting process. VII. COMPONENT CATALOGUES A. Tycho-2 The Tycho-2 catalogue gives astrometric and photometric (Vt and Bt) information for the 2.5 million brightest stars in the sky. 99% of all stars with Vt mag < 11.0 and 90% of all stars with Vt mag < 11.5 are included. Observation data from the ESA Hipparcos satellite provides the catalogue positions and magnitudes. Information about the Tycho-2 catalogue (ref. The Tycho-2 Catalogue of the 2.5 Million Brightest Stars Hog E., et al can be found on the Tycho homepage, http://www.astro.ku.dk/~erik/Tycho-2/. Tycho-2 was subdivided into 3 files for processing: filteredtycho2.dat, extrablue.dat, and blanks.dat. 1. Filteredtycho2.dat contains all stars in Tycho 2 a) with Bt-Vt <= 0.18 down to a Vt of <= 11.25 b) with Bt-Vt > 0.18 down to a Vt of <= 10.25. This file was preprocessed by adding the catalogue name "Tycho2" and converting Vt and Bt to Johnson magnitudes. 2. Extrablue.dat contains all the stars in Tycho2 with a) with Bt-Vt < -0.35 in the range 11.25 < Vt <= 12.0 This file was preprocessed by adding the catalogue name "XBLUE" and converting Vt and Bt to Johnson magnitudes. 3. Blanks.dat contains all the stars in Tycho2 a) with either Bt or Vt not given, and the remaining Vt <= 12.0 This file was preprocessed by first determining whether the Vt or Bt magnitude was missing. If Vt was missing, flag "V" was added and Vt set to "Bt + 0.3". If Bt was missing, the flag "B" was added and Bt set to "Vt - 0.3". Finally, Vt and Bt were converted to Johnson magnitudes and catalogue name "BLANKS" was added. B. GCVS III The General Catalogue of Variable Stars lists coordinates, maximum light magnitude, and minimum light magnitude for ovre 28,000 varaible stars in the Milky Way. The maximum magnitude in the V and B light have been retained in the Swift catalogue. (ref. Kholopov, P.N. (editor), et al, "The General Catalogue of Variable Stars" 4th Ed., vol. 1, Moscow, NAUKA, 1987). Gcv.dat contains all stars listed in the General Catalog of Variable Stars a) with max V <= 11.0 This file was preprocessed by removing all extraneous characters and removing the spectral type column. Next, the RA and Dec cloumns were separated and both columns converted from h m s and d m s to degrees. Missing B values were set to "V - 0.3" and the "B" flag was added. Catalogue name "GCVS" was added, and columns were reordered to R.A. Dec V B Epoch Name (B flag). Seven objects were removed from the GCVS catalogue prior to processing. These 5 supernova remnants were removed completely because their maximum V magnitudes had faded significantly since the supernova events had occured: NAME RA (hhmmss) DEC(ddmmss) All J2000 coords. S And 00 42 43.0 +41 16 04 B Cas 00 09 10.7 +59 08 59 Z Cen 13 39 57 -31 32.2 V0843 Oph 17 30 37.2 -21 28 51 CM Tau 05 34 32.0 +22 00 52.1 Another 2 objects were removed from the GCSV catalogue because they already existed in the Yale Bright Star Catalogue: NAME RA (hhmmss) DEC(ddmmss) All J2000 Coords SS UMa 14 02 03 +54 27.9 VW Vir 12 27 16 +09 25.1 C. NGC The Tycho catalogue does not include extended sources, thus the NGC2000 catalogue (ref. J.L.E. Dreyer (edited by) R.W. Sinnott, ) was used as the source of the brightest extended objects in the sky (800 objects brighter than 11th magnitude). As we are interested in the brightness per unit MIC-coincidence-loss-area and not the total magnitude, an IDL program (extended_sources.pro) was written to calculate the average surface brightness given the magnitude and spatial extent of the object. A difference in brightness between the nucleus and extended regions of the source was allowed for galaxies with bright nuclei; this difference was found empirically. Ngc.dat contains extended sources from the NGC catalogue a) with core V <= 11.0 In preprocessing this file, all columns were removed except R.A., Dec, and core magnitude. R.A. and Dec. were converted from h m s and d m s to degrees. Core Bt magnitudes were inserted with value "V - 0.3" and the "B" flag added. Epoch "J2000.0" and catalogue name "NGC" were added, and columns were printed in order R.A. Dec V B Epoch Name (B flag). D. Yale Bright Star Catalogue The Yale Bright Star Catalogue (ref. Yale Bright Star Catalogue, 5th Revised Ed. (Hoffleit, Warren 1991)). lists coordinates, magnitudes, and spectral information for over 9,000 of the sky's brightest stars. This catalogue was added since some of the very brightest stars (i.e., Sirius) seemed to be missing from Tycho-2. The catalogue contains stars and 14 other sources a) with V <= 6.5 This catalogue required the most preprocessing: several fields were first deleted, keeping only R.A. Dec V and B-V. Empty "B-V" fields were set to "0.3" and the "B" flag added. "B" fields were determined by "V + (B-V)". R.A. and Dec. were converted from h m s and d m s to degrees. Epoch "J2000.0" and catalogue name "Yale" were added, and columns were printed in order R.A. Dec V B Epoch Name (B flag).