NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-25 T09:51:07 PDT
Help | Comment | NED Home

Diameter data point(s) for object NGC 4918

Diameter Data --- Published and Homogenized (arcsec) Units

  Published UnitsHomogenized Units
No.Observed Passband
REFCODE
Major Axis
(2a)
Major Axis UnitsMinor Axis
(2b)
Minor Axis UnitsAxis Ratio (b/a)Major Axis Unc.Ellipticity
(1 - b/a)
Eccentricity
[(a/b)2-1]/
[(a/b)2+1]
Position Angle
(deg)
[published]
Reference LevelFrequency (Hz)Major Axis
(2a)
(arcsec)
Major Axis Unc.Axis Ratio (b/a)Ellipticity
(1 - b/a)
Eccentricity
[(a/b)2-1]/
[(a/b)2+1]
cos-1(b/a)
(deg)
Position Angle
(deg)
[J2000]
1 K_s (2MASS isophotal)
20032MASX.C.......:
16.1 (a) arcsec ... ... 0.500 (b/a) ... ... ... 85
[J2000]
20.0 K-mag arcsec^-2^ 1.38E+14 32.20 ... 0.50 0.50 0.60 60 85
[J2000]
2 K_s (2MASS "total")
20032MASX.C.......:
27.5 (a) arcsec ... ... 0.500 (b/a) ... ... ... 85
[J2000]
Diameter for "total" magnitude 1.38E+14 55.00 ... 0.50 0.50 0.60 60 85
[J2000]
3 RC3 D_25, R_25 (blue)
1991RC3.9.C...0000d
1.00 log(2a) + 1 ... ... 0.34
log(a/b)
0.10 ... ... ... 25.0 B-mag arcsec^-2^ 6.81E+14 60.00 15.50 0.46 0.54 0.65 63 ...
4 RC3 D_0 (blue)
1991RC3.9.C...0000d
0.96 log(2a) + 1 ... ... ... ... ... ... ... 25.0 B-mag arcsec^-2^ 6.81E+14 54.70 ... ... ... ... ... ...


Detailed Information for Each Entry

 No. 1
                                Published Units:                    Homogenized Units:

Reference Code                : 20032MASX.C.......:
Published Object Name         : 2MASX J13015062-0430020       
Frequency Targeted            : K_s (2MASS isophotal)         
Major Axis (2a)               : a = 16.1       arcsec               2a = 32.20 arcsec
Uncertainty                   : ...                                 ... 
Minor Axis (2b)               : ...                                 2b = 16.10 arcsec
Uncertainty                   : ...                                 ...
Axis Ratio                    : b/a = 0.500                         b/a = 0.50
Uncertainty                   : ...                                 ...
Ellipticity                   : ...                                 1 - b/a = 0.50
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 [(a/b)2-1]/[(a/b)2+1] = 0.60
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 60 deg
Position Angle [Equinox]      :   85   deg [J2000]                  85 deg [J2000]
Uncertainty                   : ...                                 ...
Significance                  : No uncertainty reported
Diameter Reference Level      : 20.0 K-mag arcsec^-2^         
Frequency                     : 2.17         microns                1.38E+14 Hz
Frequency Mode                : Broad-band detector (e.g. photographic plate)

Measurement Mode               
    Detector Type             : Maps (e.g., 2MASS, VLA, Sloan)
    Fitting Technique         : Ellipse fitting to image
    Measured Quantity         : Isophotal diameter
    Qualifiers                : A radius is given in DIA_MAJ, not a diameter
Coordinates Targeted          : 195.460907      -4.500543    (J2000)
Qualifiers                    : From new, raw data
NED Comment                   :                                         

No. 2 Published Units: Homogenized Units: Reference Code : 20032MASX.C.......: Published Object Name : 2MASX J13015062-0430020 Frequency Targeted : K_s (2MASS "total") Major Axis (2a) : a = 27.5 arcsec 2a = 55.00 arcsec Uncertainty : ... ... Minor Axis (2b) : ... 2b = 27.50 arcsec Uncertainty : ... ... Axis Ratio : b/a = 0.500 b/a = 0.50 Uncertainty : ... ... Ellipticity : ... 1 - b/a = 0.50 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.60 Uncertainty : ... ... Cos-1(b/a) : ... 60 deg Position Angle [Equinox] : 85 deg [J2000] 85 deg [J2000] Uncertainty : ... ... Significance : No uncertainty reported Diameter Reference Level : Diameter for "total" magnitude Frequency : 2.17 microns 1.38E+14 Hz Frequency Mode : Broad-band detector (e.g. photographic plate) Measurement Mode Detector Type : Maps (e.g., 2MASS, VLA, Sloan) Fitting Technique : Ellipse fitting to image Measured Quantity : Isophotal diameter Qualifiers : A radius is given in DIA_MAJ, not a diameter Coordinates Targeted : 195.460907 -4.500543 (J2000) Qualifiers : From new, raw data NED Comment :
No. 3 Published Units: Homogenized Units: Reference Code : 1991RC3.9.C...0000d Published Object Name : NGC 4918 Frequency Targeted : RC3 D_25, R_25 (blue) Major Axis (2a) : log(2a) + 1 = 1.00 2a = 60.00 arcsec Uncertainty : 0.10 15.50 arcsec Minor Axis (2b) : ... 2b = 27.42 arcsec Uncertainty : ... ... Axis Ratio : log(a/b) = 0.34 b/a = 0.46 Uncertainty : 0.08 0.09 Ellipticity : ... 1 - b/a = 0.54 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.65 Uncertainty : ... ... Cos-1(b/a) : ... 63 deg Position Angle [Equinox] : ... ... Uncertainty : ... ... Significance : Mean error Diameter Reference Level : 25.0 B-mag arcsec^-2^ Frequency : 4400 A 6.81E+14 Hz Frequency Mode : Broad-band detector (e.g. photographic plate) Measurement Mode Detector Type : Photographic plate, print, or film Fitting Technique : Eye estimate Measured Quantity : Isophotal diameter Coordinates Targeted : 130150.8 -043004. (J2000) Qualifiers : Homogenized from previously published data NED Comment :
No. 4 Published Units: Homogenized Units: Reference Code : 1991RC3.9.C...0000d Published Object Name : NGC 4918 Frequency Targeted : RC3 D_0 (blue) Major Axis (2a) : log(2a) + 1 = 0.96 2a = 54.70 arcsec Uncertainty : ... ... Minor Axis (2b) : ... ... Uncertainty : ... ... Axis Ratio : ... ... Uncertainty : ... ... Ellipticity : ... ... Uncertainty : ... ... Eccentricity : ... ... Uncertainty : ... ... Cos-1(b/a) : ... ... Position Angle [Equinox] : ... ... Uncertainty : ... ... Significance : No uncertainty reported Diameter Reference Level : 25.0 B-mag arcsec^-2^ Frequency : 4400 A 6.81E+14 Hz Frequency Mode : Broad-band detector (e.g. photographic plate) Measurement Mode Detector Type : Photographic plate, print, or film Fitting Technique : Eye estimate Measured Quantity : Isophotal diameter Coordinates Targeted : 130150.8 -043004. (J2000) Qualifiers : Homogenized from previously published data NED Comment : Extinction and inclination corrected.

Back to NED Home