4C 18.61

Basic data :
4C 18.61 -- Quasar Origin of the objects types : (Ref) Object type as listed in the reference "Ref" (acronym) Object type linked to the acronym according to the original reference () Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases Other object types: Rad (4C,BWE,...), QSO (2010A&A,[VV2000],...), G (LEDA), * (Gaia) Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" : ra dec : right ascension and declination (unit and frame defined according to your Output Options) Grey values are increasing the original precision due to the computation of frame transformations (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam) [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue), position angle (in degrees North celestial pole to East) quality : flag of quality E ≥ 10" D : 1-10" (and some old data) C : 0.1-1" B : 0.01-0.1" + 2MASS, Tyc A : VLBI, Hipparcos bibcode : bibcode of the coordinates reference ICRS coord. (ep=J2000) : 20 41 24.0684960432 +18 55 01.715960064 (Optical) [ 0.1799 0.1514 90 ] A 2020yCat.1350....0G Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" : ra dec : right ascension and declination (unit and frame defined according to your Output Options) Grey values are increasing the original precision due to the computation of frame transformations (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam) [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue), position angle (in degrees North celestial pole to East) quality : flag of quality E ≥ 10" D : 1-10" (and some old data) C : 0.1-1" B : 0.01-0.1" + 2MASS, Tyc A : VLBI, Hipparcos bibcode : bibcode of the coordinates reference FK4 coord. (ep=B1950 eq=1950) : 20 39 07.7253859312 +18 44 16.651065037 [ 0.1799 0.1514 90 ] Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" : ra dec : right ascension and declination (unit and frame defined according to your Output Options) Grey values are increasing the original precision due to the computation of frame transformations (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam) [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue), position angle (in degrees North celestial pole to East) quality : flag of quality E ≥ 10" D : 1-10" (and some old data) C : 0.1-1" B : 0.01-0.1" + 2MASS, Tyc A : VLBI, Hipparcos bibcode : bibcode of the coordinates reference Gal coord. (ep=J2000) : 063.0932078526443 -13.9340367249640 [ 0.1799 0.1514 90 ] Syntax of proper motions is : "pm-ra pm-dec [error ellipse] quality bibcode" pm-ra : mu-ra*cos(dec) (expressed in the ICRS system in mas/yr) pm-dec : mu-dec (expressed in the ICRS system in mas/yr) [error ellipse] : error major axis and minor axis (in mas), orientation angle (in deg) quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality) bibcode : bibcode of the proper motion reference Proper motions mas/yr : -0.426 -0.374 [0.259 0.236 90] A 2020yCat.1350....0G Syntax of radial velocity (or/and redshift) is : "value [error] (wavelength) quality bibcode" value : radial velocity or/and redshift (Heliocentric frame) according to your Output Options (redshift may be not displayed if the data value is <0 and the database inside value is a radial velocity) [error] : error of the corresponding value displayed before (wavelength) : wavelength range of the measurement : Rad, mm, IR, Opt, UV, Xray, Gam or  '∼'(unknown) quality : flag of quality ( A=best quality -> E=worst quality, ∼=unknown quality) bibcode : bibcode of the value's origin Radial velocity / Redshift / cz : V(km/s) 265435 [~] / z(~) 3.056 [~] / cz 916166 [~]    D 1999AJ....117.1122S Syntax of parallax is : 'value quality [error] bibcode' value : parallax value quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality) [error] : mean error bibcode : bibcode of the parallax reference Parallaxes (mas): 0.1799 [0.2584] A 2020yCat.1350....0G Syntax of fluxes (or magnitudes) is : "filter-name (System) flux-value [error] quality MultVarFlags bibcode" filter-name : U, B, V, R, I, G, J, H, K, u, g, r, i, z (System) : may be AB (default is Vega) flux-value : value of flux or magnitude [error] : error value quality : flag of quality of the flux value ( A=best quality -> E=worst quality, {� } =unknown quality) MultVarFlags : Mult is zero or one char (J) for joined photometry ; Var can be zero or two chars (V[0-4]) bibcode : bibcode of the flux reference Fluxes (2) : V 20.00 [~] E ~ G 19.142790 [0.005345] C 2020yCat.1350....0G	SIMBAD within arcmin ', {sourceSize:12, color:'#30a090'})); aladin.on('objectClicked', function(object) { var objName=object.data.MAIN_ID; aladin.showPopup(object.ra,object.dec,'',''+ objName+''); });" title="Show Simbad objects"> Overlay points in this preview 2MASS DSS SDSSXMMIRACIRISGALEX All (CDSPortal) Send to within arcsec The VizieR photometry tool allows for easy visualization of photometry points extracted around the Simbad position from photometry-enabled catalogues in VizieR. The search radius has to be specified by the user. It is currently limited to a maximum of 30 arcsec. It depends mostly on the precision or quality of the coordinates (SIMBAD and VizieR catalogs), the resolution of the images from which the sources were extracted, source extent, and source crowding. Suggestions are: crowded field: 0.5 to 1.5 arcsec, 3 arcsec otherwise; uncertain coordinates (SIMBAD quality E or coordinates without reference): 5 to 30 arsec (risky!).
Some important notes on this object about identifications and objects associations. notes: See also Specfind radio flux densities.

4C 18.61	MITG J204122+1854	TGSSADR J204124.0+185500	[VV2000] J204124.1+185501
BWE 2039+1844	MITG J204126+1854	TXS 2039+187	[VV2003] J204124.1+185501
GB6 B2039+1844	MITG J204125+1854	UT 2039+187	[VV2006] J204124.1+185501
87GB 203907.5+184431	NVSS J204124+185502	VLSSr J204123.7+185503	[VV2010] J204124.1+185501
GLEAM J204124+185502	OHIO W 165	VLSS J2041.4+1855	Gaia DR2 1813922950061994624
LEDA 2819536	PKS 2039+187	WB 2039+1844	Gaia DR3 1813922950061994624
MITG J2041+1854	PKS J2041+1854	[LBH86] 2039+187

References (18 between 1850 and 2024) (Total 18) Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system). Follow new references on this object

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Data at NED - NASA/IPAC Extragalactic Database : 4C 18.61

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