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J/A+A/614/A140    Large Quasar Astrometric Catalogue 4, LQAC-4  (Gattano+, 2018)

LQAC-4: Fourth release of the Large Quasar Astrometric Catalogue. Compilation of 443 725 objects including cross-identifications with Gaia DR1. Gattano C., Andrei A.H., Coelho B., Souchay J., Barache C., Taris F. <Astron. Astrophys. 614, A140 (2018)> =2018A&A...614A.140G (SIMBAD/NED BibCode)
ADC_Keywords: Combined data ; Cross identifications ; Active gal. nuclei ; Positional data ; Photometry, UBVRIJKLMNH ; Photometry, millimetric/submm ; Redshifts ; Magnitudes, absolute ; Morphology Keywords: catalogs - astrometry - reference systems - quasars: general Abstract: From an astrometric point of view, quasars constitute the best and almost ideal reference objects in the celestial sphere, with a priori no significant proper motion. Since the third release of the Large Quasar Astrometric Catalogue (LQAC-3, Cat. J/A+A/583/A75), a large number of quasars have been discovered, in particular those coming from the DR12Q release of the SDSS (Paris et al., 2017, Cat. VII/279). Moreover, for cross-matched objects, we have taken advantage of the very accurate determinations of the quasars identified within the recent Gaia DR1 catalogue (2018, Cat. I/345). Following the same procedure as in the three previous releases of the LQAC, our aim is to compile the large majority of all the quasars recorded so far. Our goal is to record their best coordinates and substantial information concerning their physical properties such as the redshift as well as multi-bands apparent and absolute magnitudes. Emphasis is given to the results of the cross-matches with the Gaia DR1 catalogue. New quasars coming from the DR12Q release were cross-matched with the precedent LQAC-3 compilation with a 1" search radius, in order to add the objects without counterpart to the LQAC-4 compilation. A similar cross-match was done with Gaia DR1 to identify the known quasars detected by Gaia. This enables one to improve significantly the positioning of these objects, and in parallel to study the astrometric performance of the individual catalogues of the LQAC-4 compilation. Finally, a new method was used to determine absolute magnitudes. Our final catalogue, called LQAC-4, contains 443 725 objects. This is roughly 37.82% more than the number of objects recorded in the LQAC-3. Among them, 249071 were found in common with the Gaia DR1, with a 1" search radius. That corresponds to 56.13% of the whole population in the compilation. The LQAC-4 delivers to the astronomical community a nearly complete catalogue of spectroscopically confirmed quasars (including a small proportion of compact AGNs), with the aim of giving their best equatorial coordinates with respect to the ICRF2 and with exhaustive additional information. For more than 50% of the sample, these coordinates come from the very recent Gaia DR1. Description: The Large Quasar Astrometric Catalogue is a compilation of the large majority of all the quasars recorded so far. Within the catalogue, we record their best coordinates and substansial information concerning their physical properties. The 4th release, LQAC-4, contains 443 725 objects (37.82% larger than LQAC-3) and 56.13% has been cross-matched with Gaia-DR1. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file lqac4.dat 416 443725 4th release of the Large Quasar Astrometric Catalogue
See also: I/284 : The USNO-B1.0 Catalog (Monet+ 2003) I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006) I/323 : International Celestial Reference Frame 2, ICRF2 (Ma+, 2009) I/345 : Gaia DR2 (Gaia Collaboration, 2018) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) II/282 : SDSS Photometric Catalog, DR 7 (Adelman-McCarthy+, 2007) II/294 : The SDSS Photometric Catalog, DR 7 (Adelman-McCarthy+, 2009) VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017) VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004) VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003) VII/158 : Revised and Updated Catalog of QSO (Hewitt+ 1993) VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010) VIII/60 : Interferometer phase calibration sources (Patnaik+ 1998) VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017 J/ApJS/141/13 : First VLBA calibrator survey: VCS1 catalog (Beasley+, 2002) J/AJ/126/2562 : Second VLBA calibrator survey: VCS2 (Fomalont+, 2003) J/AJ/129/1163 : Third VLBA calibrator survey: VCS3 (Petrov+, 2005) J/AJ/131/1872 : Fourth VLBA calibrator survey: VCS4 (Petrov+, 2006) J/AJ/136/580 : Sixth VLBA calibrator survey: VCS6 (Petrov+, 2008) J/MNRAS/372/425 : 2dF-SDSS Luminous Red Galaxy Survey, 2SLAQ (Cannon+, 2006) J/MNRAS/392/19 : The 2dF-SDSS QSO survey (Croom+, 2009) J/AJ/151/154 : Second epoch VLBA Calibrator Survey (VCS-II) (Gordon+, 2016) J/MNRAS/414/2528 : LBA Calibrator Survey (LCS1) (Petrov+, 2011) J/AJ/142/35 : The VLBA Galactic Plane Survey (VGaPS) (Petrov+, 2011) J/AJ/142/89 : Precise astrometry with VLBA (VIPS) (Petrov+, 2011) J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010) J/ApJS/194/25 : VLBA calibrator search for the BeSSeL survey (Immer+, 2011) J/MNRAS/419/1097 : The EVN Galactic Plane Survey - EGaPS (Petrov, 2012) http://www.aoc.nrao.edu/~gtaylor/csource.html : VLA catalog J/A+A/494/799 : Large Quasar Astrometric Catalogue (LQAC) (Souchay+, 2009) J/A+A/537/A99 : Large Quasar Astrometric Catalogue 2 (LQAC-2) (Souchay+, 2012) J/A+A/583/A75 : Large Quasar Astrometric Catalogue 3 (LQAC-3) (Souchay+, 2015) Byte-by-byte Description of file: lqac4.dat
Bytes Format Units Label Explanations
1- 18 A18 --- LQAC LQAC name given for each object based on equatorial coordinates 22 I1 --- Flag [3/4] Flag to recognize already recorded or new sources (1) 23- 49 A27 --- OName Name of the quasar in the original catalog (2) 50- 55 A6 --- Nature Nature of the object (3) 58- 71 F14.10 deg RAOdeg += Right ascension (J2000) in original catalog (4) 74- 87 F14.10 deg DEOdeg Declination (J2000) in original catalog (4) 90- 93 A4 --- Source Source of the following optimized equatorial coordinates (5) 96-109 F14.10 deg RAdeg Optimized Right ascension (J2000) (6) 112-125 F14.10 deg DEdeg Optimized Declination (J2000) (6) 129-134 F6.3 mas e_RAdeg ?=-9.9 Uncertainity in d(alpha)xcos(delta) in Gaia DR1 (7) 138-143 F6.3 mas e_DEdeg ?=-9.9 Uncertainty in d(delta) in Gaia DR1 (7) 146-158 A13 --- Ref Flags indicating the presence of the quasar in the 13 catalogs belonging to the compilation (8) 161-164 A4 --- GAIA Flag to recognize recorded sources in GAIA-DR1 (9) 167-174 F8.5 --- z Redshift 179-184 F6.3 mag umag ?=0 Photometric magnitude in Optical u band between 300 and 400 nm (10) 187-192 F6.3 mag Bmag ?=0 Photometric magnitude in Optical B band between 400 and 500 nm (10) 195-200 F6.3 mag Gmag ?=0 Photometric magnitude in Optical G Gaia band 203-208 F6.3 mag Vmag ?=0 Photometric magnitude in Optical V band between 500 and 600 nm (10) 211-216 F6.3 mag gmag ?=0 Photometric magnitude in Optical g band between 400 and 500 nm (10) 219-224 F6.3 mag rmag ?=0 Photometric magnitude in Optical r band between 600 and 750 nm (10) 227-232 F6.3 mag imag ?=0 Photometric magnitude in Optical i band between 750 and 1000 nm (10) 235-240 F6.3 mag zmag ?=0 Photometric magnitude in Optical z band (10) 243-248 F6.3 mag Jmag ?=0 Photometric magnitude in Infrared J band between 1000 and 1500 nm (11) 251-256 F6.3 mag Kmag ?=0 Photometric magnitude in Infrared K band between 2000 and 3000 nm (11) 259-264 F6.3 Jy S1.4 ?=0 Radio flux between 750 and 1500 MHz (20cm) 267-272 F6.3 Jy S2.3 ?=0 Radio flux between 1500 and 3000 MHz (13cm) 275-280 F6.3 Jy S5.0 ?=0 Radio flux between 3 and 6 GHz (6cm) 283-288 F6.3 Jy S8.4 ?=0 Radio flux between 6 and 12 GHz (3.6cm) 291-296 F6.3 Jy S23 ?=0 Radio flux between 12 and 30 GHz (1.2cm) 303-306 F4.1 --- I1B ?=-9.9 Sharp morphology index in band B 308-311 F4.1 --- I2B ?=-9.9 Sround morphology index in band B 313-316 F4.1 --- I3B ?=-9.9 Ground morphology index in band B 318-321 F4.1 --- I1R ?=-9.9 Sharp morphology index in band R 323-326 F4.1 --- I2R ?=-9.9 Sround morphology index in band R 328-331 F4.1 --- I3R ?=-9.9 Ground morphology index in band R 333-336 F4.1 --- I1I ?=-9.9 Sharp morphology index in band I 338-341 F4.1 --- I2I ?=-9.9 Sround morphology index in band I 343-346 F4.1 --- I3I ?=-9.9 Ground morphology index in band I 350-356 F7.3 mag BMAG ?=-9.9 Absolute magnitude in band B 360-366 F7.3 mag IMAG ?=-9.9 Absolute magnitude in band I 370-376 F7.3 mag uMAG ?=-9.9 Absolute magnitude in band u 380-386 F7.3 mag gMAG ?=-9.9 Absolute magnitude in band g 390-396 F7.3 mag rMAG ?=-9.9 Absolute magnitude in band r 400-406 F7.3 mag iMAG ?=-9.9 Absolute magnitude in band i 410-416 F7.3 mag zMAG ?=-9.9 Absolute magnitude in band z
Note (1): Flag as follows: 3 = sources already recorded in LQAC-3 4 = source is a new entry within LQAC-4 Note (2): This field may contain white spaces. Note (3): The nature of the object is generally a QSO, noted "QUASAR". It is "RADIO" when observed in VLBI. It is "BL LAC" or "AGN" when this terminology is found in Veron-Cetty and Veron (2010, Cat. VII/258) This field may contain white spaces. Note (4): The RA, DE coordinates of the quasar according to the original catalog it has been found. These two coordinates are given in degree, with a precision of 1x10^-10 (i.e. 36 microarcseconds). Note that no quasar, even belonging to the ICRF2 or GAIA-DR1, guarantees this level of accuracy. This justifies that in many cases, final digits have a zero value. Note (5): "ORIG" means the optimized coordinates are taken from the original catalogue with the best astrometric precision ; "GAIA" means they are taken from Gaia-DR1 (Gaia Collaboration, 2016A&A...595A...1G, Cat. I/337, 2016yCat.1337....0G) ; "ICRF" means they are taken from the ICRF2 catalogue (Ma+, 2009ITN....35....1M, Cat. I/323) ; "LQRF" means they are recalculated in the LQRF (Andrei et al., 2009A&A...505..385A, Cat. I/313) Note (6): These two coordinates are given in degree, with a precision of 1x10^-10 (i.e. 36 microarcseconds). Note that no quasar, even belonging to the ICRF2 or GAIA-DR1, guarantees this level of accuracy. This justifies that in many cases, final digits have a zero value. Note (7): Numerous original catalogues do not provide uncertainties on the quasar equatorial coordinates. The uncertainties taken from the Gaia-DR1 catalogue are then a precious information about the position accuracy, when available. Note (8): The catalogs flags are the following ones : A = ICRF2 (Ma et al., 2009, IERS, Technical Note No. 35) B = RFC (Petrov http://astrogeo.org/rfc/ version 2016) C = VLA (Cat. J/ApJS/141/13, J/AJ/126/2562, J/AJ/129/1163, J/AJ/131/1872) D = JVAS (Patnaik et al., Cat. VIII/60) E = SDSS (combination DR7Q-DR12Q, https://www.sdss.org/dr7/ - https://www.sdss3.org/dr12/, Paris+, 2017A&A...597A..79P, Cat. VII/279, 2017yCat.7278....0P) F = 2QZ (Croom et al., Cat. VII/241) G = 2df-SDSS (2df-SDSS LRG and QSO survey (2009)); da Angela et al., 2008MNRAS.383..565D; LRG: Cannon et al., Cat. J/MNRAS/372/425; QOS: Croom et al., Cat. J/MNRAS/392/19 H = FIRST (Becker et al., Cat. VIII/71) I = Hewitt and Burbridge, Cat. VII/158 J = 2MASS (only for magnitude information) (Cutri et al., Cat. II/246) K = GSC2.3 (only for magnitude information) (Lasker et al., Cat. I/305) L = B1.0 (only for magnitude information) (Monet et al., Cat. I/284) M = Veron-Cetty and Veron (2010, Cat. VII/258) m = object is a SDSS quasar found only in Veron-Cetty and Veron (2010, Cat. VII/258) catalog, but no more in the new SDSS releases Note (9): "GAIA" indicates the record of the source in GAIA-DR1, the blank field indicates the opposite. Note (10): For each bandwidth the photometric systems in which the magnitudes have been measured are not homogeneous, the priority being indicated by the catalog flag letter in decreasing alphabetic order. Note (11): Coming from 2MASS (Cutri et al., Cat. II/246)
Acknowledgements: Jean Sourchay, jean.souchay(at)obspm.fr Christophe Barache, christophe.barache(at)obspm.fr Cesar Gattano, cesar.gattano(at)obspm.fr SYRTE/Observatoire Paris/PSL/CNRS/Sorbonne Universite/LNE 61 avenue de l'Observatoire, 75014 Paris
(End) Cesar Gattano [SYRTE-Paris Obs.], Patricia Vannier [CDS] 12-Mar-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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