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Table A.1
Field description for the single-band photometric catalogs.
| Field name | Format | Units | Description |
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| Source identification and position information | |||
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| DESIGNATION | A25 | − | Designation of the source based on its Galactic position in the form LLL.llll±b.bbbb. The naming convention for the Hi-GAL catalogue has the form HIGALPXLLL.llll±b.bbbb, where HIGALP stands for the preliminary catalogue, X stands for the band where the source has been identified among the possible choices: B – blue band; R – red band; S – PSW band; M – PMW band; L – PLW band. |
| GLON | F12.6 | degrees | Galactic longitude of the source. |
| GLAT | F12.6 | degrees | Galactic latitude of the source. |
| DGLON | F5.2 | arcsec | Uncertainty in the Galactic longitude coordinate derived from the fitting procedure. 0 indicates that the fitting process hit the boundary limits imposed on the fit. |
| DGLAT | F5.2 | arcsec | Uncertainty in the Galactic latitude coordinate derived from the fitting procedure. 0 indicates that the fitting process hit the boundary limits imposed on the fit. |
| RA | F12.6 | degrees | J2000 Right Ascension of the source. |
| DEC | F12.6 | degrees | J2000 Declination of the source. |
| ATLAS_IMAGE | A40 | − | Atlas image file identifier from which the source was extracted. |
| X | F9.3 | pixel | x-pixel coordinate of this source in the original image. |
| Y | F9.3 | pixel | y-pixel coordinate of this source in the original image. |
| DX | F9.3 | pixel | Uncertainty in the x coordinate of this source derived from the fitting procedure. |
| DY | F9.3 | pixel | Uncertainty in the y coordinate of this source derived from the fitting procedure. |
| SOURCE_ID | A10 | − | Unique source identification in the form lLLL NNNN, where lLLL is a unique identifier of the original image over which source extraction was carried out, and NNNN is a progressive four-digit, zero-filled number indicating the sequential order of extraction. |
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| Primary photometric information | |||
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| FINT_UNCORR | F15.3 | Jy | Source-integrated flux measured from the fitting process. |
| FINT | F15.3 | Jy | Source-integrated flux measured from the fitting process after applying photometric corrections as a function of the source size, to account for source non-Gaussianity and for scan speed. |
| ERR_FINT | F15.3 | Jy | Uncertainty on the integrated flux computed by multiplicating the fitted source residual rms (RMS_TOTAL) by the fitted source area as estimated by FWHMA and FWHMB. |
| FPEAK | F15.3 | MJy/sr | Source peak flux measured from the fitting process. |
| FWHMA | F10.2 | arcsec | Full width at half maximum of the source along axis a of the elliptical Gaussian as determined by fitting engine. |
| FWHMB | F10.2 | arcsec | Full width at half maximum of the source along axis b of the elliptical Gaussian as determined by fitting engine. |
| PA | F6.1 | degrees | Position angle of the elliptical Gaussian (N→E). |
| BACKGROUND | F15.3 | MJy/sr | Background value determined at the source peak position. |
| BACK_ACOEFF | F12.5 | MJy/sr | Coefficient a of the zero-order term of the background obtained by the fit at the source peak position. |
| BACK_BCOEFF | F12.5 | MJy/sr/pxl | Coefficient b of the first-order term x of the background obtained by the fit at the source peak position. |
| BACK_CCOEFF | F12.5 | MJy/sr/pxl | Coefficient c of the first-order term y of the background obtained by the fit at the source peak position. |
| BACK_DCOEFF | F12.5 | MJy/sr/pxl2 | Coefficient d of the second-order term x2 of the background obtained by the fit at the source peak position. |
| BACK_ECOEFF | F12.5 | MJy/sr/pxl2 | Coefficient e of the second-order term y2 of the background obtained by the fit at the source peak position. |
| BACK_FCOEFF | F12.5 | MJy/sr/pxl2 | Coefficient f of the second-order term xy of the background obtained by the fit at the source peak position. |
| RMS_TOTAL | F12.5 | MJy/sr | Standard deviation, σloc, of the residuals computed within the source area defined by FWHMA and FWHMB after subtracting the best fit. |
| RMS_SURROUND | F12.5 | MJy/sr | Standard deviation, σloc, of the residuals computed within the fitting window after subtracting the best fit, excluding both the pixels that belong to the source and the pixels belonging to other sources that fall within the fitting window. |
| SNR | F12.5 | − | Signal-to-noise ratio obtained by dividing FPEAK by the residual rms over a source area with FWHMA and FWHMB as semi-axes. |
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| Basic detection information | |||
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| DET_X | F10.3 | − | Relevance of the source in the second-derivative map along the x-axis defined as the ratio between the measured second derivative at source peak position and the adopted local threshold value. |
| DET_Y | F10.3 | − | Relevance of the source in the second-derivative map along the y-axis defined as the ratio between the measured second derivative at source peak position and the adopted local threshold value. |
| DET_X45 | F10.3 | − | Relevance of the source in the second-derivative map along the bisector of the xy-axis defined as the ratio between the measured second derivative at source peak position and the adopted local threshold value. |
| DET_Y45 | F10.3 | − | Relevance of the source in the second-derivative map along the bisector of the yx-axis defined as the ratio between the measured second derivative at source peak position and the adopted local threshold value. |
| DETLIM_X | F10.3 | MJy/sr/pxl2 | Absolute value for the local detection limit threshold adopted for the second derivative along the x-axis coordinate. |
| DETLIM_Y | F10.3 | MJy/sr/pxl2 | Absolute value for the local detection limit threshold adopted for the second derivative along the y-axis coordinate. |
| DETLIM_X45 | F10.3 | MJy/sr/pxl2 | Absolute value for the local detection limit threshold adopted for the second derivative along the bisector of the first and third quadrant. |
| DETLIM_Y45 | F10.3 | MJy/sr/pxl2 | Absolute value for the local detection limit threshold adopted for the second derivative along the bisector of the second and fourth quadrant. |
| CLUMP_FLAG | I5 | − | Flag for confusion at detection level. A value equal to 0 means that the source was identified from an isolated group of pixels above the threshold in all the four derivative directions. Sources belonging to the extraction of the same atlas image having the same value of this flag belong to the same group of pixels above the threshold. |
| NCOMP | I2 | − | Number of Gaussian components used simultaneously in the fitting process. This number includes the source, so the minimum value is 1, this number is greater than 1 if the source is fit with other nearby detections. |
| XCENT | F9.1 | pxl | The x-pixel coordinate of the centre of the source fitting window in the original image. |
| YCENT | F9.1 | pxl | The y-pixel coordinate of the centre of the source fitting window in the original image. |
| XWINDOW | I2 | pxl | Half-width size of the source fitting window along x coordinate and centred at XCENT. |
| YWINDOW | I2 | pxl | Half-width size of the source fitting window along y coordinate and centred at YCENT. |
| NCONTAM | I2 | − | Number of other sources falling inside the fitting window whose presence is taken into account at fitting stage. Not all those other sources might have been fitted at the same time. |
| CENT_TOL | F5.2 | pxl | Maximum variation in pixels for adjustment of the fit centre with respect to the position of detection, measured as the distance between the latter and the brightest local (within three pixels) pixel in the fitting window. |
| DOF | I4 | − | Degrees of freedom of the source Gaussian fit. |
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| Quality flags | |||
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| CHI2 | F12.5 | − | χ2 determined by the fitting engine. |
| CHI2_OPP | F12.5 | − | Estimator of the fidelity between the fit and the data computed as φ = (O(i)−F(i))2/F(i), where O(i) is the observed data in the i pixel of the fitting window and F(i) is the fitted value in the same position. |
| FIT_STATUS | I1 | − | Flag returned from the fitting engine. Possible values of the flag are: 0 – fit convergence failed; 1 – convergence reached; 2 – convergence reached despite the initial accuracy requested to fitting engine was set too low; 3 – maximum number of iterations in the fitting process reached; 4 – problems in fitting due to the initial guess. |
| GUESS_FLAG | A3 | − | Flag on quality of guessed source parameters as determined at the detection stage. The form of the flag is GN, where G is a letter defined as A – optimal number of positions to estimate the size; B – sufficient number of positions to estimate the size; C – low number of positions to estimate the size; and N is a number defining the quality of inital guess size: 0 – initial estimate failed; 1 – good initial estimate for sizes; 2 – one of the two guessed sizes was initially estimate as smaller than the PSF; 3 – initial estimates of source sizes were higher than three times the PSF. |
| GROUP_FLAG | I5 | − | Flag on quality of guessed source parameters as determined at the detection stage. The form of the flag is GN, where G is a letter defined as A – optimal number of positions to estimate the size; B – sufficient number of positions to estimate the size; C – low number of positions to estimate the size; and N is a number defining the quality of initial guess size: 0 – initial estimate failed; 1 – good initial estimate for sizes; 2 – one of the two guessed sizes was initially estimated as smaller than the PSF; 3 – initial estimates of source sizes were higher than three times the PSF. |
| CONSTRAINTS | I1 | − | Flag indicating the number of parameters that reached the tolerance limits allowed to the fit process. Values of 4 indicate that the source flux has higher unreliability since either the centre and its sizes have reached the maximum (or the minimum) allowed for the fit engine. |
| SHIFT_FLAG | F9.3 | arcsec | Amount of shift of the source peak position from its original detection position, due to Gaussian fitting. |
| Basic extraction information | |||
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| RDETP2DX | F9.3 | − | Ratio between the second-derivative value along x direction expected by the fitted model of the source and the second derivative derivative measured at the detection stage. Values closer to one indicate a higher reliability of the source. |
| RDETP2DY | F9.3 | − | Ratio between the second-derivative value along y direction expected by the fitted model of the source and the second derivative measured at the detection stage. Values closer to one indicate a higher reliability of the source. |
| RDETP2DX45 | F9.3 | − | Ratio between the second-derivative value along the bisector of the xy direction expected by the fitted model of the source and the second derivative measured at the detection stage. Values closer to onea indicate a higher reliability of the source. |
| RDETP2DY45 | F9.3 | − | Ratio between the second-derivative value along the bisector of the yx direction expected by the fitted model of the source and the second derivative measured at the detection stage. Values closer to one indicate a higher reliability of the source. |
| OVERLAP_FLAG | F9.3 | − | Flag to indicate whether the source has been detected and extracted in one or more adjacent tiles. H indicates that the source has been detected in the tile named in column ATLAS_IMAGE; E,W indicate that the source is detected only in the eastern or western adjacent tile, respectively (east is higher Galactic longitude); if the source has been detected in both H and E or W, then the name of the adjacent tile is also listed (e.g. H_l060). In these cases, the entry in the catalogue is the one with the highest S/N. |
| OVFLUX_FLAG | I | − | Flag to indicate which flux values were adopted if detected and extracted in two adjacent tiles. 0 indicates that the source has been detected only once and therefore all fluxes refer to this detection. –1 indicates that the two fluxes differ by more than 15%; the one listed is that with the highest S/N. 1 indicates that both integrated fluxes lie within 15%, the one in the catalogue is that with the highest S/N. 2 indicates that the integrated fluxes differ by more than 15% but FPEAK are within 15%; the one listed is that with the highest S/N. |
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