CDROM/APJS/V101/P259 Second EGRET Catalog (Thompson+ 1995) ================================================================================ The Second EGRET Catalog of High-Energy Gamma-Ray Sources D. J. Thompson, D. L. Bertsch, B. L. Dingus, J. A. Esposito, A. Etienne, C. E. Fichtel, D. P. Friedlander, R. C. Hartman, S. D. Hunter, D. J. Kendig, J. R. Mattox, L. M. McDonald, C. von Montigny, R. Mukherjee, P. V. Ramanamurthy, P. Sreekumar, J. M. Fierro, Y. C. Lin, P. F. Michelson, P. L. Nolan, S. K. Shriver, T. D. Willis, G. Kanbach, H. A. Mayer-Hasselwander, M. Merck, H.-D. Radecke, D. A. Kniffen, and E. J. Schneid <1995, ApJS, 101, 259> =1995ApJS..101..259T ================================================================================ Abstract: The second catalog of high-energy gamma-ray observations from the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory includes data from phase 1 (1991 April-1992 November) and phase 2 (1992 November-1993 September) of the mission. In addition to including more data than the first EGRET catalog, this catalog uses an improved model of the diffuse Galactic gamma radiation. The 129 sources in the catalog include one solar flare bright enough to be detected as a source, the Large Magellanic Cloud, five pulsars, 40 high-confidence identifications of active galactic nuclei (AGNs), 11 AGN identifications with lower confidence, and 71 sources not yet identified with known objects. Also included are approximate upper limits for gamma-ray sources at any point in the sky and information about sources listed in the first EGRET catalog but not appearing in this one. Keywords: catalogs -- diffuse radiation -- gamma rays: observations -- methods: data analysis Description: Postscript files for figures 1, 3, 4 and 5 are included. The 22 parts of figure 2 (a-v) are not included in total in the printed paper. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table1a.dat 59 56 EGRET viewing periods: phase 1 table1b.dat 59 33 EGRET viewing periods: phase 2 table2.dat 24 6 Source location accuracy for identified sources near the Galactic plane table3.dat 24 8 Source location accuracy for selected AGNs table4.dat 143 1041 Second EGRET source catalog table5.dat 21 31 Sources from the first EGRET catalog not appearing in the second catalog -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1a.dat table1b.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- VP Viewing period 6- 7 2X --- --- Blank 8-24 A17 --- Start Start time, YYYY MMM DD HH:SS 25-26 2X --- --- Blank 27-43 A17 --- End End time, YYYY MMM DD HH:SS 44-51 F8.2 deg GLon Galactic longitude 52-59 F8.2 deg GLat Galactic latitude -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-15 A15 --- Source Source name 16-20 F5.1 arcmin Offset Offset of measured position from true pos. 21-24 I4 % Contour Nearest error contour -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-14 A14 --- Name *Source name 15-22 F8.2 deg RAdeg []? Right ascension, J2000 23-29 F7.2 deg DEdeg []? Declination, J2000 30-37 F8.2 deg GLon []? Galactic longitude 38-44 F7.2 deg GLat []? Galactic latitude 45-49 I5 arcmin A *[]? Semimajor axis, fitted 95% conf. contour 50-53 I4 arcmin B *[]? Semiminor axis, fitted 95% conf. contour 54-59 I6 deg Phi []? Position angle of major axis, E from N 60 A1 --- e_Box [*] Indicates error box not well represented by an ellipse 61-64 A4 --- Mor *Morphology code 65 1X --- --- Blank 66 A1 --- l_F *[<] Flux limiting character 67-72 F6.1 --- F *Flux (E> 100 MeV) or upper limit 73-78 F6.1 --- dF []? 1-sigma statistical uncertainty in F 79-83 F5.1 --- g *[]? Gamma, the photon number spectral index 84-88 F5.1 --- dg []? 1-sigma statistical uncertainty in g 89 1X --- --- Blank 90 A1 --- l_Counts [<] Counts limiting character 91-95 I5 --- Counts *Number of e>100 MeV photons 96-102 F7.1 --- TS *Significance of e>100MeV detection 103-110 A8 --- VP *Viewing period 111-112 2X --- --- Blank 113 A1 --- ID *Coded source identification 114-115 2X --- --- Blank 116-129 A14 --- Other *Other names 130-131 2X --- --- Blank 132 I1 --- Note *Coded note 133-134 2X --- --- Blank 135-143 A9 --- Ref *Coded reference -------------------------------------------------------------------------------- Notes for file: table4.dat -------------------------------------------------------------------------------- Name: Name based on the J2000 coordinates for the best position of the source, following the IAU naming convention (PASP 102, 1231). It should be emphasized that the measured positions are generally not as precise as the name might suggest. If this field is blank, the data in fields l_F, F, dF, g, dg, l_Counts, Counts, TS, VP, ID, Other, Note, and Ref are continuations of the previous record. A, B: Semimajor and semiminor axes, respectively, of an ellipse fitted to the 95% confidence error contour. Mor: Morphology: E=extended source (applies only to the LMC); em=possibly extended source or multiple sources (based on source location maps inconsistent with a single point source or poor fit to the calibrated point-spread function; C=source confusion may affect flux, significance, or position. Sources with no entry in this column are consistent with the EGRET point-spread function for a single source. F: Flux (E> 100 MeV) in 10^{-8} photons/cm^2 s, or upper limit in the same units for observations in which the source was not detected. g: Gamma, the photon number spectral index F(E) ~ E^{-gamma} in the energy range 100-2000 MeV. Spectra have not been determined for all sources. The flux F for most sources was determined assuming an energy spectrum with a photon number index of 2. Counts: Number of E>100 MeV photons represented by the flux or upper limit. The uncertainty in the counts is proportional to DeltaF/F. TS: sqrt{TS} -- Statistical significance of the E>100 MeV detection. It is approximately equal to the statistical sigma for a single measurement at a fixed position. VP: Viewing period of the observation. P1 = phase 1 summed map 4/91 - 11/92; P2 = phase 2 summed map 11/92 - 9/93; P12 = phase 1 + phase 2 summed map 4/91 - 9/93; 0.2+ = sum of viewing periods 0.2-0.5, all of which covered the same region of the sky during the verification phase of the mission; 36.+ = sum of 36.0 and 36.5, which cover the same region of the sky. ID: Coded source identification: P=pulsar (indicates detection of pulsed gamma radiation); G=galaxy (the LMC is the only such object in the catalog); A=active galactic nucleus; a=active galactic nucleus (marginal). In this catalog, a marginal identification is defined as one in which the candidate object lies near but outside the 95% uncertainty contour. Note that this is a different notation from that used in the first EGRET catalog, which distinguished identifications by their statistical significance. Other: The source name from the first EGRET catalog or other gamma-ray references. In some cases, the source position has moved from that given in earlier references. For identified sources, the name or names of the object is given in this column. Note: Positional coincidences with objects of interest which might be the gamma-ray source, or special information about the detection. 1 2EG J0241+6119 is positionally consistent with the variable radio source GT0236+610 2 2EG J0618+2234 is positionally consistent with supernova remnant IC443 3 2EG J1324-4317 is positionally consistent with radio galaxy Cen A, but the map is not fully consistent with a single point source 4 2EG J1626-2452 is strongly affected by the Rho Oph cloud. More detailed modeling by Hunter et al (1994) show that the source is positionally consistent with 1622-253 5 2EG J1746-2852 is positionally consistent with the galactic center. The diffuse model has larger uncertainties in this direction than in most parts of the galactic plane (Hunter, et al., 1995). 6 2EG J2023-0836 is positionally consistent with AGN 2022-077 in viewing period 7.2, based on E > 1000 MeV analysis. The Phase 1 map suggests the presence of a second source with a steeper spectrum. Ref: Previous EGRET references to the source. a Fichtel, et al. 1994 (First EGRET Catalog), ApJS, 94, 551 b Thompson, et al. 1993a, ApJ, 415, L13 c Lin, et al. 1995b, ApJ, submitted d Montigny et al. 1995 e Nolan, et al. 1995, ApJ, submitted f Bertsch, et al. 1993a, ApJ, 405, L21 g Dingus, et al. 1995, ApJ, submitted h Hunter, et al. 1993b, A&A, 272, 59 i Kniffen, et al. 1995, ApJ, submitted j Radecke, et al. 1995, ApJ, 438, 659 k Kanbach, et al. 1993, A&A, 97, 349 l Lin, et al. 1995a, ApJ, 442, 96 m Hunter, et al. 1993a, ApJ, 409, 134 n Sreekumar, et al. 1992, ApJ, 400, L67 o Nolan, et al. 1993a, ApJ, 409, 697 p Thompson, et al. 1993c, ApJ, 410, 87 q Bertsch, et al. 1992, Nature, 357, 306 r Mayer-Hasselwander, et al. 1994, ApJ, 421, 276 s Mukherjee, et al. 1995a, ApJ, 445, 189 t Kanbach, et al. 1994, A&A, 289, 855 u Kanbach, et al. 1995, ApJ submitted v Sreekumar, et al. 1995, ApJ, in press w Fierro, et al. 1993, ApJ, 413, L27 x Lin, et al. 1992, ApJ, 401, L61 y Montigny, et al. 1993 z Hartman, et al. 1992, ApJ, 385, L1 aa Kniffen, et al. 1993, ApJ, 411, 133 bb Wagner, et al. 1995, ApJ, submitted cc Bertsch, et al. 1995, ApJ, submitted dd Hunter, et al. 1994, ApJ, 436, 216 ee Mattox, et al. 1993, ApJ, 410, 609 ff Thompson, et al. 1992, Nature, 359, 615 gg Mayer-Hasselwander, et al. 1995, A&A, submitted hh Mattox, et al. 1995b, ApJ, submitted ii Nolan, et al. 1993b, ApJ, 414, 82 jj Hartman, et al. 1993, ApJ, 407, L41 kk Ramanamurthy et al. 1995, ApJ, 450, 791 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-14 A14 --- Name Source name 15 1X --- --- Blank 16 A1 --- l_TS [<] Limiting character for TS 17-19 F3.1 --- TS *Significance of e>100MeV detection 20 1X --- --- Blank 21 A1 --- n_TS [*] Indicates best position has |b| < 10 deg -------------------------------------------------------------------------------- Notes for file: table5.dat -------------------------------------------------------------------------------- TS: sqrt{TS} -- the statistical significance of the E>100 MeV detection. It is approximately equal to the statistical sigma for a single measurement at a fixed position. -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 06-Nov-95