ACDS V10.0 - Thu Jul 18 10:57:47 CEST 2019
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Detailed Description of II/321 :
IPHAS DR2 Source Catalogue (Barentsen+, 2014)
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Note : this is the description file of the original catalog.
This HTML page corresponds well to the original description, but some minor
changes in the format may have been introduced in the FITS output
files in order to allow for arithmetic operations on quantities
such as coordinates and times. h:m:s and d:m:s units are normally
converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the
units; the value given in the HTML files supersedes the value indicated in the ReadMe
file for this catalogue.
II/321 IPHAS DR2 Source Catalogue (Barentsen+, 2014)
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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.
<Mon. Not. R. Astron. Soc., 444, 3220--3257 (2014)>
=2014yCat.2321....0B
=2014MNRAS.444.3230B
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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 deg2 imaging survey of the Northern Milky Way at red
visible wavelengths. It covers Galactic latitudes |b|<5° and
longitudes l=30 to 215° 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:
File Summary:
FileName Lrecl Records Explanations
× 80 . This file
× ReadMe 80 . This file
× iphas2.sam 659 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 I1 --- rDeblend [0,1] Blend flag for r-band.
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 I1 --- iDeblend [0,1] Blend flag for i-band.
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 I1 --- haDeblend [0,1] Blend flag for H-alpha
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 I1 --- brightNeighb [0,1] Nearby very bright star flag (5)
545 I1 --- deblend [0,1] Blend flag
547 I1 --- saturated [0,1] Saturation flag
549 I1 --- nBands Number of bands for source detection
551 I1 --- a10 [0,1] signal-to-noise >10 flag (6)
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 I1 --- ccd [1-4] CCD chip number
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)
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(End) Laurent Cambresy, Thomas Boch [CDS] 09-Sep-2014