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NASA/IPAC EXTRAGALACTIC DATABASE Date and Time of the Query: 2019-04-21 T05:40:21 PDT Help | Comment | NED Home

You have selected the following parameters to search on:

Velocity(km/s): Unconstrained
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Parameters for Distances and Cosmology: H_o= 73.0; Ω_matter = 0.27; Ω_vacuum = 0.73;
Derived Quantities use a Redshift corrected to a Reference Frame defined by the 3K CMB

Detailed Information for Object No. 1

INDEX for NGC 6921

Essential Data (jump to sub-section of this query report):

Essential Note
Cross-IDs
Coordinates
Basic Data
Quantities Derived from Redshift
Redshift-Independent Distances
Quick-Look Photometry and Luminosities
Quick-Look Angular and Physical Sizes
Classifications
Foreground Galactic Extinction
External Services

Detailed Data (NED queries):

43 Photometric data point(s) and SED

Spectra
Redshift-Independent Distances
71 Reference(s)
13 Position data point(s)
10 Redshift data point(s)
6 Diameter data point(s)
4 Note(s)
UGC data
RC3 data

ESSENTIAL NOTE for NGC 6921 (Back to INDEX)

N/A

CROSS-IDENTIFICATIONS for NGC 6921 (Back to INDEX)

Object Names	Type	Object Names	Type
NGC 6921	G	UZC J202828.8+254324	G
UGC 11570	G	87GB 202621.8+253300	RadioS
MCG +04-48-001	G	NVSS J202828+254325	RadioS
2MASX J20282884+2543241	IrS	IGR J20286+2544:[RTC2009] 2	XrayS
2MASS J20282888+2543244	IrS	IGR J20286+2544(2)	G
PGC 064768	G	SWIFT J2028.5+2543b	XrayS
SSTSL2 J202828.84+254324.6	IrS	[WGB2006] 202624+25330_a	G
USNO-B1.0 1157-0462166	VisS	[WMR2009] 134	G

COORDINATES for NGC 6921 (Back to INDEX)

Position Reference:20032MASX.C.......:

Reference    Frame     Longitude    Latitude        RA           DEC      Uncertainty Ellipse (arcsec)
                       (degrees)   (degrees)                              Semimajor Semiminor  PA(deg)
Equatorial (B1950.0)  306.586418   25.556459  20h26m20.74s  +25d33m23.3s  1.25E+00  1.25E+00    0
Equatorial (J2000.0)  307.120250   25.723417  20h28m28.86s  +25d43m24.3s  1.25E+00  1.25E+00    0
Ecliptic   (B1950.0)  317.487570   43.157551                              1.25E+00  1.25E+00    0
Ecliptic   (J2000.0)  318.181347   43.153550                              1.25E+00  1.25E+00    0
Galactic               66.983282   -7.558412                              1.25E+00  1.25E+00    0
SuperGalactic         324.938305   66.013359                              1.25E+00  1.25E+00    0

Additional detailed measurements with references are also available by clicking below:
13 Position data point(s)

REDSHIFT-INDEPENDENT DISTANCES for NGC 6921 (Back to INDEX)

N/A

CLASSIFICATIONS (TYPES, ATTRIBUTES) for NGC 6921 (Back to INDEX)

Type	As Published	NED Homogenized	Flag	Reference Code
Hierarchy	P	in a pair	...	1976RC2...C...0000d
Kinematics	HI line width	HI line width	...	2003A&A...412...57P
Galaxy Morphology	SA(r)0/a:	SA0/a?(r)	...	1991RC3.9.C...0000d

7 Detailed Classification(s)

FOREGROUND GALACTIC EXTINCTION for NGC 6921 (Back to INDEX)

Galactic Extinction from the Schlafly & Finkbeiner 2011, Appendix; 2011ApJ...737..103S (SF11) recalibration 
of the Schlegel, Finkbeiner & Davis 1998, Appendix B; 1998ApJ...500..525S (SFD98) infrared-based dust map. 
The map is based on dust emission from COBE/DIRBE and IRAS/ISSA; 
the recalibration assumes a Fitzpatrick (1999PASP..111...63F) reddening law with R_v = 3.1 and different source spectrum than SFD98.



     L  a  n  d  o  l  t S  D  S  S U  K  I  R  T
Filter [µm] U (0.35) B (0.43) V (0.54) R (0.64) I (0.80) u (0.36) g (0.47) r (0.62) i (0.75) z (0.89) J (1.25) H (1.66) K (2.19) L' (3.78)
A_λ [mag] 1.918 1.605 1.213 0.960 0.666 1.876 1.462 1.011 0.751 0.559 0.314 0.199 0.134 0.068

  

Show/Hide A_λ magnitudes in all 88 photometric bands based on SF11
 

Bandpass [µm] A_λ [mag]
Landolt U (0.35)  1.918
Landolt B (0.43)  1.605
Landolt V (0.54)  1.213
Landolt R (0.64)  0.960
Landolt I (0.80)  0.666
CTIO U (0.37)  1.817
CTIO B (0.43)  1.611
CTIO V (0.55)  1.187
CTIO R (0.65)  0.938
CTIO I (0.80)  0.671
UKIRT J (1.25)  0.314
UKIRT H (1.66)  0.199
UKIRT K (2.19)  0.134
UKIRT L' (3.78)  0.068
Gunn g (0.52)  1.290
Gunn r (0.66)  0.909
Gunn i (0.79)  0.688
Gunn z (0.91)  0.546
Spinrad R_S (0.69)  0.850
Stromgren u (0.35)  1.905
Stromgren b (0.47)  1.482
Stromgren v (0.41)  1.679
Stromgren beta (0.49)  1.409
Stromgren y (0.55)  1.189
SDSS u (0.36)  1.876
SDSS g (0.47)  1.462
SDSS r (0.62)  1.011
SDSS i (0.75)  0.751
SDSS z (0.89)  0.559
DSS-II g (0.46)  1.496
DSS-II r (0.65)  0.924
DSS-II i (0.81)  0.658
PS1 g (0.49)  1.404
PS1 r (0.62)  1.005
PS1 i (0.75)  0.744
PS1 z (0.87)  0.585
PS1 y (0.97)  0.481
PS1 w (0.62)  1.036
LSST u (0.37)  1.834
LSST g (0.48)  1.432
LSST r (0.62)  1.006
LSST i (0.75)  0.745
LSST z (0.87)  0.585
LSST y (0.97)  0.481
WFPC2 F300W (0.31)  2.169
WFPC2 F450W (0.46)  1.509
WFPC2 F555W (0.54)  1.219
WFPC2 F606W (0.60)  1.069
WFPC2 F702W (0.69)  0.862
WFPC2 F814W (0.79)  0.685
WFC3 F105W (1.04)  0.429
WFC3 F110W (1.12)  0.390
WFC3 F125W (1.23)  0.321
WFC3 F140W (1.37)  0.271
WFC3 F160W (1.53)  0.227
WFC3 F200LP (0.55)  1.309
WFC3 F218W (0.22)  3.434
WFC3 F225W (0.24)  3.093
WFC3 F275W (0.27)  2.428
WFC3 F300X (0.29)  2.314
WFC3 F336W (0.34)  1.971
WFC3 F350LP (0.59)  1.161
WFC3 F390W (0.40)  1.724
WFC3 F438W (0.43)  1.603
WFC3 F475W (0.48)  1.437
WFC3 F475X (0.50)  1.379
WFC3 F555W (0.53)  1.263
WFC3 F600LP (0.74)  0.788
WFC3 F606W (0.59)  1.101
WFC3 F625W (0.62)  1.000
WFC3 F775W (0.76)  0.727
WFC3 F814W (0.80)  0.680
WFC3 F850LP (0.91)  0.535
ACS clear (0.62)  1.078
ACS F435W (0.43)  1.598
ACS F475W (0.48)  1.446
ACS F550M (0.56)  1.159
ACS F555W (0.54)  1.236
ACS F606W (0.59)  1.094
ACS F625W (0.63)  0.982
ACS F775W (0.77)  0.721
ACS F814W (0.80)  0.675
ACS F850LP (0.90)  0.550
DES g (0.48)  1.432
DES r (0.64)  0.963
DES i (0.78)  0.706
DES z (0.91)  0.539
DES Y (0.99)  0.468


For completeness, we include the original SFD98 values:


     L  a  n  d  o  l  t S  D  S  S U  K  I  R  T
Filter [µm] U (0.34) B (0.44) V (0.54) R (0.65) I (0.81) u (0.35) g (0.49) r (0.63) i (0.78) z (0.93) J (1.27) H (1.67) K (2.22) L' (3.81)
A_λ [mag] 2.419 1.921 1.476 1.190 0.864 2.295 1.689 1.225 0.929 0.658 0.402 0.256 0.163 0.068

See Notes on Galactic Extinction for important caveats.

BASIC DATA for NGC 6921 (Back to INDEX)

Helio. Radial Velocity     :      4337 +/-       10 km/s      
Redshift                   :  0.014467 +/- 0.000033        2003A&A...412...57P
Major Diameter (arcmin)    :   0.9
Minor Diameter (arcmin)    :   0.2
Magnitude and Filter       : 14.4 
Classifications            : SA(r)0/a:      Sy2  

NOTE: This information is indicative only. With the exception of the
      redshift they are unreferenced and highly inhomogeneous as to
      their origin. The Radial Velocity (when available) is computed
      from the listed redshift. The remaining values are designed to
      orient the user with a quick-look, overall assessment of the
      general properties of the object in question. They are not
      averages nor are they standardized in any way.

Additional detailed measurements with references are also available by clicking below:
10 Redshift data point(s)      43 photometric data point(s)      6 Diameter data point(s)

QUANTITIES DERIVED FROM REDSHIFT for NGC 6921 (Details)(Back to INDEX)

Calculated and Corrected Velocities
V (Heliocentric)           :    4337 +/-     10 km/s      2003A&A...412...57P
V (Kinematic LSR)          :    4354 +/-     10 km/s      1986MNRAS.221.1023K
V (Galactocentric GSR)     :    4551 +/-     13 km/s      1991RC3.9.C...0000d
V (Local Group)            :    4621 +/-     20 km/s      1996AJ....111..794K
V (3K CMB)                 :    4067 +/-     21 km/s      1996ApJ...473..576F
V (Virgo Infall only)      :    4590 +/-     20 km/s      2000ApJ...529..786M
V (Virgo + GA only)        :    4593 +/-     20 km/s      2000ApJ...529..786M
V (Virgo + GA + Shapley)   :    4604 +/-     20 km/s      2000ApJ...529..786M

Hubble Flow Distance and Distance Modulus (where H_o =   73.0 +/-   5 km/sec/Mpc)
D (Galactocentric GSR)     :    62.3 +/-    4.4 Mpc      (m-M) = 33.97 +/- 0.15 mag
D (Local Group)            :    63.3 +/-    4.4 Mpc      (m-M) = 34.01 +/- 0.15 mag
D (3K CMB)                 :    55.7 +/-    3.9 Mpc      (m-M) = 33.73 +/- 0.15 mag
D (Virgo Infall only)      :    62.9 +/-    4.4 Mpc      (m-M) = 33.99 +/- 0.15 mag
D (Virgo + GA only)        :    62.9 +/-    4.4 Mpc      (m-M) = 33.99 +/- 0.15 mag
D (Virgo + GA + Shapley)   :    63.1 +/-    4.4 Mpc      (m-M) = 34.00 +/- 0.15 mag

Scale at Hubble Flow Distances
Scale (Galactocentric GSR) :     302 pc/arcsec =  0.302 kpc/arcsec =  18.14 kpc/arcmin =   1.09 Mpc/degree
Scale (Local Group)        :     307 pc/arcsec =  0.307 kpc/arcsec =  18.41 kpc/arcmin =   1.10 Mpc/degree
Scale (3K CMB)             :     270 pc/arcsec =  0.270 kpc/arcsec =  16.20 kpc/arcmin =   0.97 Mpc/degree
Scale (Virgo Infall only)  :     305 pc/arcsec =  0.305 kpc/arcsec =  18.29 kpc/arcmin =   1.10 Mpc/degree
Scale (Virgo + GA only)    :     305 pc/arcsec =  0.305 kpc/arcsec =  18.30 kpc/arcmin =   1.10 Mpc/degree
Scale(Virgo + GA + Shapley):     306 pc/arcsec =  0.306 kpc/arcsec =  18.35 kpc/arcmin =   1.10 Mpc/degree











To Search for Nearby Objects (Physical Companions):
Enter Your Preferred Values and click on "Submit Environment Search" button 

Search for Objects within +/-arcmin where 100 kpc =  5.451 arcmin  
and Selected Redshift, defined by the Velocity Range:
from  to km/sec where V(Heliocentric) =   4337 km/sec  






Cosmology-Corrected Quantities [H_o =  73.00 km/sec/Mpc, Ω_matter =   0.27, Ω_vacuum =   0.73]
[Redshift 0.013565 as corrected to the Reference Frame defined by the 3K Microwave Background Radiation]
Luminosity Distance        : 56.3 Mpc      (m-M) = 33.75 mag
Angular-Size Distance      : 54.8 Mpc      (m-M) = 33.69 mag
Co-Moving Radial Distance  : 55.6 Mpc      (m-M) = 33.72 mag
Co-Moving Tangential Dist. : 55.6 Mpc      (m-M) = 33.72 mag
Co-Moving Volume           : 0.000718 Gpc^3
Light Travel-Time          :    0.180 Gyr
Age at Redshift 0.013565   :   13.119 Gyr
Age of Universe            :   13.299 Gyr
Scale (Cosmology Corrected):     266 pc/arcsec =  0.266 kpc/arcsec =  15.94 kpc/arcmin =   0.96 Mpc/degree
Surface Brightness Dimming : Flux Density per Unit Area =  0.94753; Magnitude per Unit Area = 0.05852 mag







To change Cosmological Input Parameters for Derived Quantities:
Enter Your Preferred Values and click on "Submit Changed Hubble Parameters for this object" button 

H_oΩ_matterΩ_vacuum
    


Correct Redshift To the Reference Frame defined by:

as Input for Calculation of the Distances and Cosmology-Corrected Quantities

QUICK-LOOK PHOTOMETRY and LUMINOSITIES for NGC 6921 (Back to INDEX)

The brightest flux in each of the following spectral regions, when available:
Gamma-Ray (ν > 2E19 Hz); X-Ray (2E19 Hz > ν > 2E16 Hz); Ultraviolet (2E16 Hz > ν > 9E14 Hz); Visual (9E14 Hz > ν > 3E14 Hz);
Near-Infrared (3E14 Hz > ν > 6E13 Hz); Mid-Infrared (6E13 Hz > ν > 7.5E12 Hz); Far-Infrared (7.5E12 Hz > ν > 1E12 Hz);
Sub-Millimeter (1E12 Hz > ν > 3E11 Hz); Millimeter (3E11 Hz > ν > 3E10 Hz); Radio (3E10 Hz > ν).

Spectral Region	Band	Apparent Mag or Flux	Refcode	Absolute Mag or νL_ν [W]	νL_ν [L_☉(Bolometric)]
Gamma-Ray	14-195 keV (Swift)	6.1E-11 erg/cm^2^/s	2008ApJ...681..113T	2.31E+36 [W]	6.02E+09
X-Ray	2-10 keV (XMM)	2.53E-12 ergs/cm^2^/s	2008ApJ...674..686W	9.57E+34 [W]	2.49E+08
Visual	V (V_T^0)	11.71 mag	1991RC3.9.C...0000d	-22.04 [mag]	4.03E+10
Near-Infrared	H	9.180 +/- 0.019 mag	20032MASX.C.......:	-24.57 +/- 0.50 [mag]	3.91E+10 +/- 7.86E+09
Mid-Infrared	25 microns (IRAS)	0.62 +/- 0.20 Jy	2004AJ....127.3235S	2.82E+36 +/- 1.07E+36 [W]	7.34E+09 +/- 2.79E+09
Far-Infrared	100 microns (IRAS)	7.48 +/- 2.30 Jy	2004AJ....127.3235S	8.51E+36 +/- 3.12E+36 [W]	2.21E+10 +/- 8.12E+09
Radio	1.4GHz	28.2 +/- 1.2 milliJy	1998AJ....115.1693C	1.50E+31 +/- 3.06E+30 [W]	3.90E+04 +/- 7.97E+03

NOTE: The above quantities are derived using a Distance Modulus of 33.75 mag corresponding to
a Luminosity Distance of 56.3 Mpc [assuming 10%uncertainty] using the Cosmology-Corrected Quantities.
The quantities quoted above have not necessarily been corrected for foreground extinction, and no K-Corrections have been applied.

View details and SED for 43 Photometric data point(s) available in NED.

QUICK-LOOK ANGULAR & PHYSICAL DIAMETERS for NGC 6921 (Back to INDEX)

The largest diameters in the Visual and Near-Infrared spectral regions, when available:

Passband	Apparent Major Axis (2a) [arcsec]	Apparent Minor Axis (2b) [arcsec]	PA [degrees] (J2000.0)	Reference Level	Refcode	Physical Major Axis (2a) [kpc]	Physical Minor Axis (2b) [kpc]
RC3 D_0 (blue)	70.50	...	...	25.0 B-mag arcsec^-2^	1991RC3.9.C...0000d	21.56	...
K_s (2MASS "total")	106.50	44.73	140	Diameter for "total" magnitude 20032MASX.C.......:	20032MASX.C.......:	32.57	13.68

NOTE: At z <= 0.5, physical diameters are derived using a Scale at the Hubble Flow Distance (Virgo + GA + Shapley) of 0.306 kpc/arcsec.
The quantities quoted above have not necessarily been corrected for foreground extinction.

View details for 6 Diameter data point(s) available in NED.

EXTERNAL ARCHIVES AND SERVICES for NGC 6921 Help (Back to INDEX)

Resources for Object Names	Site/Service
Query SIMBAD by primary NED object name -- NGC 6921	SIMBAD (CDS, Strasbourg, France)
Revised New General Catalogue -- NGC 6921	VizieR Catalog Query (U.S. mirror, CfA/Harvard)
Uppsala General Catalog -- UGC 11570	VizieR Catalog Query (U.S. mirror, CfA/Harvard)
Morphological Catalog of Galaxies -- MCG +04-48-001	VizieR Catalog Query (U.S. mirror, CfA/Harvard)
2MASS Extended Source Images (JHKs) -- 2MASX J20282884+2543241	NASA/IPAC Infrared Science Archive (IRSA)
Catalogue of Principal Galaxies -- PGC 064768	VizieR Catalog Query (U.S. mirror, CfA/Harvard)
Retrieve mean data from LEDA -- PGC 064768	The Lyon/Meudon Extragalactic Database (LEDA)
Query UZC Spectral Archive (60 arcsec search radius)	Updated Zwicky Catalog Data (Harvard/SAO)
	NRAO/VLA Sky Survey (NVSS)
Query GALEX (NUV/FUV) Mission Archive (7.2 arcsec search radius) -- NGC 6921	GALEX Mission Data Archive at MAST
Explore IRSA resources with RADAR (10 arcsec search radius) -- NGC 6921	NASA/IPAC Infrared Science Archive (IRSA)
Resources for position 20h28m28.8s, +25d43m24s (J2000)	Site/Service
Query Optical and UV Mission Archives (Default search radius)	Multimission Archive at STScI (MAST)
Query High Energy Mission Archives (Default search radius)	HEASARC (NASA/GSFC)
Query IRSA for WISE images (10 arcmin search radius)	NASA/IPAC Infrared Science Archive (IRSA)
Band(s): Size:	NASA/IPAC Infrared Science Archive (IRSA)
Band(s): Size:	NASA/IPAC Infrared Science Archive (IRSA)
	NASA/IPAC Infrared Science Archive (IRSA)
Size: Contours (PS) JPEG FITS File	NRAO/VLA Sky Survey (NVSS)
	The NRAO Data Archive System

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