II/321 IPHAS DR2 Source Catalogue (Barentsen+, 2014) ================================================================================ The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2) Barentsen G., Farnhill H.J., Drew J.E., Gonzalez-Solares E.A., Greimel R., Irwin M.J., Miszalski B., Ruhland C., Groot P., Mampaso A., Sale S.E., Henden A.A., Aungwerojwit A., Barlow M.J., Carter P.J., Corradi R.L.M., Drake J.J., Eisloffel J., Fabregat J., Gansicke B.T., Gentile Fusillo N.P., Greiss S., Hales A.S., Hodgkin S., Huckvale L., Irwin J., King R., Knigge C., Kupfer T., Lagadec E., Lennon D.J., Lewis J.R., Mohr-Smith M., Morris R.A.H., Naylor T., Parker Q.A., Phillipps S., Pyrzas S., Raddi R., Roelofs G.H.A., Rodriguez-Gil P., Sabin L., Scaringi S., Steeghs D., Suso J., Tata R., Unruh Y.C., Roestel J.VAN , Viironen K., Vink J.S., Walton N.A., Wright N.J., Zijlstra A.A. =2014yCat.2321....0B =2014MNRAS.444.3230B ================================================================================ ADC_Keywords: Photometry, H-alpha ; Stars, emission ; Galactic plane ; Surveys Keywords: catalogues, surveys - stars: emission-line - Galaxy: stellar content Description: The INT/WFC Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS) is a 1860 deg^2^ imaging survey of the Northern Milky Way at red visible wavelengths. It covers Galactic latitudes |b|<5{deg} and longitudes l=30 to 215{deg} in the broad-band r, i and narrow-band H-alpha filters using the Wide Field Camera (WFC) on the 2.5-m Isaac Newton Telescope (INT) in La Palma. IPHAS Data Release 2 (DR2) is the first quality-controlled and globally calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92% of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec/pixel) and to a mean 5-sigma depth of 21.2 (r), 20.0 (i) and 20.3 (H-alpha). The photometric calibration is in the Vega magnitude system and carries an external precision of 0.03mag (root-mean-square error). The catalogue includes all the sources which have been detected at a signal-to-noise ratio of 5 or better in at least one band. Many applications will require a combination of quality criteria to be applied to avoid faint stars or confused sources. The choice of quality criteria tensions completeness against reliability, and hence depends on the requirements of a project. To aid users, the data release paper (arXiv:1406.4862) recommends two sets of quality criteria, named "a10" and "a10point", which should satisfy most projects. As a minimum, the "a10" criteria select objects which have been detected at the minimum level of 10-sigma in all bands, without being saturated. Additional constraints are provided by the "a10point" criteria, which require objects to be point sources free of blending, unaffected by nearby bright stars, as well as being unsaturated >10-sigma detections in all bands. Sources in both categories are flagged in the catalogue using the boolean columns a10 and a10point. Imaging and auxiliary data are available from the project website (www.iphas.org). Acknowledging IPHAS in publications: The survey is defined in Drew et al. (2005MNRAS.362..753D) and the DR2 catalogue is presented in Barentsen et al. (arXiv:1406.4862). Users are requested to cite these papers as appropriate in journal articles and similar. Please include the following in any published material that makes use of the IPHAS data products: "This paper makes use of data obtained as part of the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS, www.iphas.org) carried out at the Isaac Newton Telescope (INT). The INT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. All IPHAS data are processed by the Cambridge Astronomical Survey Unit, at the Institute of Astronomy in Cambridge. The bandmerged DR2 catalogue was assembled at the Centre for Astrophysics Research, University of Hertfordshire, supported by STFC grant ST/J001333/1." File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file iphas2.sam 648 1000 Sample of the IPHAS DR2 release -------------------------------------------------------------------------------- Byte-by-byte Description of file: iphas2.sam -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 A19 --- IPHAS IPHAS name, based on J2000 position 21- 29 F9.5 deg RAdeg Right ascension (J2000) from r-band 31- 38 F8.5 deg DEdeg Declination (J2000) from r-band 40- 53 A14 --- sourceID Unique identification number 55- 58 F4.2 arcsec posErr RMS residual against 2MASS across the CCD 60- 61 I2 --- mergedClass Image classification flag (1) 63- 69 F7.2 --- mergedClassStat Merge stellarness-of-profile statistic 71- 74 F4.2 --- pStar Point source probability 76- 79 F4.2 --- pGalaxy Extended source probability 81- 84 F4.2 --- pNoise Noise source probability 86- 90 F5.2 mag rmi ? r-i colour 92- 96 F5.2 mag rmha ? r-Halpha colour 98-102 F5.2 mag r ? r mag using 2.3 arcsec diameter aperture (Vega scale) 104-107 F4.2 mag rErr ? Uncertainty for r (2) 109-113 F5.2 mag rPeakMag ? Alternative r mag derived from the peak pixel height (Vega scale) 115-118 F4.2 mag rPeakMagErr ? Uncertainty in rPeakMag (2) 120-124 F5.2 mag rAperMag1 ? Alternative r mag using the 1.2 arcsec diameter aperture (Vega scale) 126-133 F8.2 mag rAperMag1Err ? Uncertainty in rAperMag1 (2) 135-139 F5.2 mag rAperMag3 ? Alternative r mag using the 3.3 arcsec diameter aperture (Vega scale) 141-150 F10.3 mag rAperMag3Err ? Uncertainty in rAperMag3 (2) 152-158 F7.2 pix rGauSig ? RMS of axes of ellipse fit in r-band 160-163 F4.2 --- rEll ? Ellipticity in the r-band 165-170 F6.2 deg rPA ? Position angle in the r-band 172-173 I2 --- rClass Discrete image classification flag (3) 175-181 F7.2 --- rClassStat ? N(0,1) stellarness-of-profile statistic 183-183 I1 --- rDeblend [0,1] Blend flag for r-band. 185-185 I1 --- rSaturated [0,1] Saturation flag for r-band 187-197 F11.5 d rMJD ? Modified Julian Date for the r exposure 199-202 F4.2 arcsec rSeeing ? Average FWHM in the same CCD frame 204-217 A14 --- rDetectionID ? Unique identifier of the r detection (4) 219-225 F7.2 pix rX ? Pixel position in the r-band exposure 227-233 F7.2 pix rY ? Pixel position in the r-band exposure 235-239 F5.2 mag i ? i mag using 2.3 arcsec diameter aperture (Vega scale) 241-244 F4.2 mag iErr ? Uncertainty for i (2) 246-250 F5.2 mag iPeakMag ? Alternative i mag derived from the peak pixel height (Vega scale) 252-255 F4.2 mag iPeakMagErr ? Uncertainty in iPeakMag (2) 257-261 F5.2 mag iAperMag1 ? Alternative i mag using the 1.2 arcsec diameter aperture (Vega scale) 263-270 F8.2 mag iAperMag1Err ? Uncertainty in iAperMag1 (2) 272-276 F5.2 mag iAperMag3 ? Alternative i mag using the 3.3 arcsec diameter aperture (Vega scale) 278-286 F9.2 mag iAperMag3Err ? Uncertainty in iAperMag3 (2) 288-294 F7.2 pix iGauSig ? RMS of axes of ellipse fit in i-band 296-299 F4.2 --- iEll ? Ellipticity in the i-band 301-306 F6.2 deg iPA ? Position angle in the i-band 308-309 I2 --- iClass Discrete image classification flag (3) 311-317 F7.2 --- iClassStat ? N(0,1) stellarness-of-profile statistic 319-319 I1 --- iDeblend [0,1] Blend flag for i-band. 321-321 I1 --- iSaturated [0,1] Saturation flag for i-band 323-333 F11.5 d iMJD ? Modified Julian Date for the i exposure 335-338 F4.2 arcsec iSeeing ? Average FWHM in the same CCD frame 340-353 A14 --- iDetectionID ? Unique identifier of the i detection (4) 355-361 F7.2 pix iX ? Pixel position in the i-band exposure 363-369 F7.2 pix iY ? Pixel position in the i-band exposure 371-381 F11.2 arcsec iXi ? offset of the i-band position relative to the ra column 383-387 F5.2 arcsec iEta ? offset of the i-band position relative to the dec column 389-393 F5.2 mag ha ? H-alpha mag using 2.3" diameter aperture (Vega scale) 395-398 F4.2 mag haErr ? Uncertainty for H-alpha (2) 400-404 F5.2 mag haPeakMag ? Alternative H-alpha mag derived from the peak pixel height (Vega scale) 406-409 F4.2 mag haPeakMagErr ? Uncertainty in haPeakMag (2) 411-415 F5.2 mag haAperMag1 ? Alternative H-alpha mag using the 1.2 arcsec diameter aperture (Vega scale) 417-423 F7.2 mag haAperMag1Err ? Uncertainty in haAperMag1 (2) 425-429 F5.2 mag haAperMag3 ? Alternative H-alpha mag using the 3.3 arcsec diameter aperture (Vega scale) 431-440 F10.2 mag haAperMag3Err ? Uncertainty in iAperMag3 (2) 442-448 F7.2 pix haGauSig ? RMS of axes of ellipse fit in H-alpha 450-453 F4.2 --- haEll ? Ellipticity in H-alpha 455-460 F6.2 deg haPA ? Position angle in H-alpha 462-463 I2 --- haClass Discrete image classification flag (3) 465-471 F7.2 --- haClassStat ? N(0,1) stellarness-of-profile statistic 473-473 I1 --- haDeblend [0,1] Blend flag for H-alpha 475-475 I1 --- haSaturated [0,1] Saturation flag for H-alpha 477-487 F11.5 d haMJD ? Modified Julian Date for the Ha exposure 489-492 F4.2 arcsec haSeeing ? Average FWHM in the same CCD frame 494-507 A14 --- haDetectionID ? Unique ID of the H-alpha detection (4) 509-515 F7.2 pix haX ? Pixel position in the H-alpha exposure 517-523 F7.2 pix haY ? Pixel position in the H-alpha exposure 525-535 F11.2 arcsec haXi ? offset of the H-alpha position relative to the ra column 537-541 F5.2 arcsec haEta ? offset of the H-alpha position relative to the dec column 543-543 I1 --- brightNeighb [0,1] Nearby very bright star flag (5) 545-545 I1 --- deblend [0,1] Blend flag 547-547 I1 --- saturated [0,1] Saturation flag 549-549 I1 --- nBands Number of bands for source detection 551-551 I1 --- a10 [0,1] signal-to-noise >10 flag (6) 553-553 I1 --- a10point [0,1] quality criteria flag (7) 555-568 A14 --- fieldID Survey field identifier 570-572 A3 --- fieldGrade Internal quality control score 574-581 I8 --- night UT date at the start of the night 583-586 F4.2 arcsec seeing Maximum of rSeeing, iSeeing or HaSeeing 588-588 I1 --- ccd [1-4] CCD chip number 590-590 I1 --- nObs [1-9] Number of observations of the source 592-605 A14 --- sourceID2 ? SourceID of the alternative detection of the object in the partner exposure 607-620 A14 --- fieldID2 ? Field identifier of the partner detection 622-626 F5.2 mag r2 ? r mag in the dithered partner field (Vega scale) 628-631 F4.2 mag rErr2 ? Uncertainty for r2 633-637 F5.2 mag i2 ? i mag in the dithered partner field (Vega scale) 639-642 F4.2 mag iErr2 ? Uncertainty for i2 644-648 F5.2 mag ha2 ? Ha mag in the dithered partner field (Vega scale) 650-653 F4.2 mag haErr2 ? Uncertainty for ha2 655-659 I5 --- errBits2 ? Error bitmask for the partner detection (8) -------------------------------------------------------------------------------- Note (1): Based on all bands: 1=galaxy, 0=noise, -1=star, -2=probableStar. Note (2): Does not include systematics. For example, the uncertainty in the photometric calibration, estimated to equal 0.03 mag (root-mean-square error), is not included. Note (3): Discrete image classification flag as follows: 1 = galaxy 0 = noise -1 = star -2 = probableStar Note (4): Unique identifier of the band detection in the format "#run-#ccd-#number", i.e. composed of the INT telescope run number, the CCD number and a sequential source detection number. Note (5): True if a very bright star is nearby (defined as brighter than V<4 within 10 arcmin, or brighter than V<7 within 5 arcmin). Such very bright stars cause scattered light and diffraction spikes, which may add systematic errors to the photometry or even trigger spurious detections. Note (6): True if the source is detected at S/N>10 in all bands without being saturated, and if the photometric measurements are consistent across different aperture diameters. Algebraic condition: (rErr<0.1 & iErr<0.1 & haErr<0.1 & NOT saturated & (abs(r-rAperMag1)<3*hypot(rErr,rAperMag1Err)+0.03) & (abs(i-iAperMag1)<3*hypot(iErr,iAperMag1Err)+0.03) & (abs(ha-haAperMag1)<3*hypot(haErr,haAperMag1Err)+0.03). Note (7): True if both the a10 quality criteria above are satisfied, and if the object looks like a single, unconfused point source. Algebraic condition: a10 & pStar>0.9 & NOT deblend & NOT brightNeighb. Note (8): flag a bright neighbour (1), source blending (2), saturation (8), vignetting (64), truncation (128) and bad pixels (32768). Be careful if errBits2>0. -------------------------------------------------------------------------------- Acknowledgements: Geert Barentsen (University of Hertfordshire) ================================================================================ (End) Laurent Cambresy, Thomas Boch [CDS] 09-Sep-2014