NGC 3998

Basic data :
NGC 3998 -- Seyfert 2 Galaxy 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: LIN (), X (2012ApJS,1AXG,...), Rad (BWE,6C,...), G (2015ApJS,LEDA,...), AGN (2008ApJS,CGRaBS,...), Sy1 (2012ApJ), QSO (QSO,[WTW94]), Sy2 (2022ApJS), SyG (2009ApJ), Bz? ([SRM2005]), GiP ([T76]), GiG ([CHM2007]), AG? (2020MNRAS), * (Gaia), gam (INTREF), NIR (2MASS), MIR (WISE), IR (IRAS), 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) : 11 57 56.1334044408 +55 27 12.922443432 (Optical) [ 0.0710 0.0744 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) : 11 55 20.9516094958 +55 43 54.767883798 [ 0.0710 0.0744 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) : 138.1723349878691 +60.0633488382720 [ 0.0710 0.0744 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 : 0.049 0.136 [0.093 0.101 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) 1070 [150] / z(emission) 0.00357417 [0.0005] / cz 1071.5092 [150]    (Opt) C 2022ApJS..261....2K 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): 0.0799 [0.1014] A 2020yCat.1350....0G Syntax of morphological type is : mtype quality bibcode mtype : Hubble morphological class (spirals, ellipticals, etc) quality : flag of quality (A=best quality -> E=worst quality, {� } =unknown quality) bibcode : bibcode of the morphological type reference Morphological type: SA C 2019MNRAS.488..590B 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): 1.987 1.629 130 (NIR) C 2006AJ....131.1163S 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 11.64 [0.02] C 2016MNRAS.460..689R V 12.10 [~] D 2010A&A...518A..10V R 10.09 [0.02] C 2016MNRAS.460..689R G 15.549679 [0.004629] C 2020yCat.1350....0G J 8.327 [0.007] C 2006AJ....131.1163S H 7.584 [0.008] C 2006AJ....131.1163S K 7.365 [0.010] C 2006AJ....131.1163S u (AB) 15.09 [0.01] D 2009ApJS..182..543A g (AB) 14.121 [0.007] C 2009ApJS..182..543A r (AB) 10.632 [0.006] C 2009ApJS..182..543A i (AB) 13.604 [0.007] C 2009ApJS..182..543A z (AB) 12.308 [0.007] C 2009ApJS..182..543A	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 NAME NGC 3998 GROUP See also Specfind radio flux densities.

NGC 3998	IVS B1155+557	TIC 55684273	[R97] NGC 3998 9
1AXG J115757+5527	LEDA 37642	UGC 6946	[RW2000] NGC 3998 X-2
BWE 1155+5543	2MASS J11575612+5527128	UZC J115756.2+552713	[SMM2006b] J115756.13+552713.0
6C 115520+554340	2MASX J11575616+5527128	WB 1155+5543	[SRM2005] J115756.13+552712.9
7C 115520.50+554349.00	MCG+09-20-046	WISE J115756.15+552713.0	[T76] 47B
CGRaBS J1157+5527	NVSS J115756+552712	WN B1155.3+5543	[VV2000c] J115756.1+552713
2E 2561	PBC J1158.1+5527	2XMM J115756.1+552714	[VV2003c] J115756.1+552713
2E 1155.3+5543	QSO B1155+557	XSS J11570+5514	[VV2006c] J115756.1+552713
1ES 1155+55.7	RBS 1053	Z 269-25	[VV2010c] J115756.1+552713
FIRST J115756.1+552713	RGB J1157+554	Z 1155.3+5543	[VV98c] J115756.1+552713
GB6 B1155+5543	RX J1157.9+5527	[BAG2012] 179.5145+55.4250	[WTW94] 1155+557
87GB 115521.8+554353	1RXS J115756.1+552717	[CAB95] IRAS F11553+5543	[ZEH2003] RX J1157.9+5527 1
ILT J115755.83+552710.8	SDSS J115756.13+552713.0	[CHM2007] LDC 867 J115756.16+5527128	EQ 1155+557
INTREF 470	SWIFT J1157.8+5529	[CHM2007] HDC 706 J115756.16+5527128	Gaia DR3 841020502831092352
IRAS 11553+5543	SWIFT J1158.0+5526	[LB2005] NGC 3998 X1	Gaia DR2 841020502831092352
IRAS F11553+5543	SWIFT J1158.1+5526	[M98c] 115521.4+554357

References (643 between 1850 and 2024) (Total 643) 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 : NGC 3998

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