4C -02.81

Basic data :
4C -02.81 -- BL Lac 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 (2010AJ,4C,...), QSO (2009ApJS,QSO,...), gam (1FGL,2FGL,...), Bla (2016ApJS,[DGT2001],...), AGN (2011ApJ,CGRaBS), BLL (2009A&A,[VV98b]), G (2022ApJS,LEDA), X (2009A&A,2E), MIR (WISEA,WISE), BL? (2021MNRAS), Bz? (2022ApJS), Q? (FBQS), * (Gaia), cm (AT20G), NIR (2MASS), Opt (SDSS) 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) : 21 34 10.30958988 -01 53 17.2389056 (Radio) [ 0.0331499 0.0366 0 ] A 2020A&A...644A.159C 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) : 21 31 35.13887381 -02 06 39.9945338 [ 0.0331499 0.0366 0 ] 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) : 052.38970930404 -36.50364829707 [ 0.0331499 0.0366 0 ] 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 : -0.634 -0.235 [0.217 0.167 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) 203060 [~] / z(spectroscopic) 1.28 [~] / cz 383734 [~]    (Opt) D 2017ApJS..233....3T Syntax of angular size is : "maj-axis min-axis angle (wtype) quality bibcode" maj-axis : major axis size (arc minutes) min-axis : minor axis size (arc minutes) angle : orientation angle (in degrees) (wtype) : wavelength class for the origin of the angular size (Rad, mm, IR, Opt, UV, Xray, Gam) quality : flag of quality of the angular size values ( A=best quality -> E=worst quality, {� } =unknown quality) bibcode : bibcode of the angular size reference Angular size (arcmin): 0.0000132 0.0000060 -1 (Rad) D 2010AJ....139.1713C 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 (12) : B 18.6 [~] E ~ V 19.00 [~] D 2010ApJ...710..764K R 18.87 [~] D 2008ApJS..175...97H G 18.254074 [0.010961] C 2020yCat.1350....0G J 17.095 [0.209] D 2003yCat.2246....0C H 16.229 [0.276] D 2003yCat.2246....0C K 15.723 [0.233] D 2003yCat.2246....0C u (AB) 18.8343 [0.0256] C 2020ApJS..250....8L g (AB) 18.1896 [0.0140] C 2020ApJS..250....8L r (AB) 17.6657 [0.0172] C 2020ApJS..250....8L i (AB) 17.2585 [0.0148] C 2020ApJS..250....8L z (AB) 16.8943 [0.0224] C 2020ApJS..250....8L	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 -02.81	IVS B2131-021	SDSS J213410.31-015317.2	[GR92] 2131-021
AT20G J213410-015316	1Jy 2131-021	TGSSADR J213410.3-015318	[HB93] 2131-021
BWE 2131-0207	LEDA 2818139	TIC 269024255	[MGL2009] BZU J2134-0153
CGRaBS J2134-0153	2MASS J21341033-0153168	TXS 2131-021	[MGL2009] BZB J2134-0153
CRATES J213410-015325	MRC 2131-021	UT 2131-021	[MML2015] 5BZB J2134-0153
Cul 2131-021	MSH 21-0-11	VLSSr J213410.5-015316	[P82] 2131-021
2E 4488	NEWPS5 J2134-0153	VLSS J2134.1-0153	[VV2000] J213410.3-015317
2E 2131.5-0206	NVSS J213410-015317	VSOP J2134-0153	[VV2003] J213410.3-015317
FBQS J2134-0153	OHIO X -053	WB 2131-0207	[VV2006] J213410.3-015317
1FGL J2134.0-0203	PCCS2 143 G052.40-36.49	WISEA J213410.31-015317.3	[VV2010] J213410.3-015317
2FGL J2133.8-0154	PKS 2131-021	WISE J213410.30-015317.1	[VV98b] J213410.3-015317
3FGL J2134.1-0152	PKS J2134-0153	WISE J213410.31-015317.3	[WCO2009] J213415-015935
4FGL J2134.2-0154	PMN J2134-0153	WMAP 20	[WPW2003] J2134-0153
3FHL J2134.2-0152	QSO B2131-021	WMAP J2134-0154	EQ 2131-02
FIRST J213410.3-015317	QSO B2131-0206	WMAP J2134-0153	Gaia DR3 2686427654815559808
GLEAM J213410-015313	QSO J2134-0153	9Y-MST J2134-0151	Gaia DR2 2686427654815559808
ICRF J213410.3-015317	RFC J2134-0153	[DGT2001] B2131-021
IERS B2131-021	RORF 2131-021	[DSJ85] 2131-021

References (382 between 1850 and 2024) (Total 382) 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

Collections of Measurements

External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Data at NED - NASA/IPAC Extragalactic Database : 4C -02.81

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