STEPHAN`S QUINTET

STEPHAN'S QUINTET
© Eduard Garcia Ribera, 2012
Stephan's Quintet in the constellation Pegasus is al grouping of five galaxies of which four form the first compact galaxy group ever
discovered. The group was discovered by Édouard Stephan in 1877 at Marseilles Observatory.
These galaxies are of interest because of their violent collisions. Four of the five galaxies in Stephan´s Quintet form a physical association,
Hickson Compact Group 92, and are involved in a cosmic dance that most likely will end with the galaxies merging. Also of interest, NGC
7320 indicates a small redshift (790 km/s) while the other four exhibit large redshifts (near 6600 km/s). Since galactic redshift is
proportional to distance, NGC 7320 is only a foreground projection and is ~39 million ly from Earth versus the 210-340 million ly of the
other five. NGC 7319 has a Seyfert nucleus. A sixth galaxy, NGC 7320C, probably belongs to the association: it has a redshift similar to the
Quintet galaxies, and a tidal tail appears to connect it with NGC 7319. PGC 141041 is visible farther to the left of the image. This galaxy is
not physically bound to the cluster, but lies at about the same Quintet distance.
NEGATIVE VERSION (sharp stretched, showing more structures)
Name
Type
R.A. (J2000)
Dec. (J2000)
Redshift (km/s)
Apparent
Magnitude
Size (mins)
NGC 7317
E4
22h35m51.9s
+33°56′42″
6599
+13.6v
0.8' x 0.7'
NGC 7318a
E2 pec
22h35m56.7s
+33°57′56″
6630
+14.3b
0.8' x 0.6'
SB(s)bc pec
22h35m58.4s
+33°57′57″
5774
+13.9b
1.4' x 0.9'
NGC 7319
SB(s)bc pec
22h36m03.5s
+33°58′33″
6747
+13.1v
1.5' x 1.1'
NGC 7320c
(R)SAB(s)0/a
22h36m20.4s
+33°59′06″
5985
+16.7v
0.6′ × 0.5′
NGC 7320
SA(s)d
22h36m04.1s
+33°56′52″
790
+13.2b
2.3' x 1.1'
PGC 141041
SB ?
22h36m41s
+33°56′56″
6057
+18b
0.5′ × 0.5′
NGC 7318b
BLACK & WHITE VERSION
DETAIL: TIDAL CONNECT NGG 7319 with NGC 7320 C
Given that and its apparent size (NGC 7319) of 1.5x1.1 arcmin, it about 150 thousand light years across, and a long arm of ejected
material extends another 200 thousand light years or so to its southwest.
DETAIL: STAR FORMATION REGION
To the north of NGC 7318B is a concentration of atomic hydrogen gas with on-going star formation
DETAIL: FAINT STRUCTURE
------IMAGE MAGNITUDE LIMIT-----In the general picture, there are small galaxies to magnitude +23 /+24...
DETAIL: example galaxy 21th-magnitude, with faint galaxies around.
Galaxy Name: J223621.54+335748.0
Apparent Magnitude: +21 u band
COLOR VERSION
REFERENCES AND MORE INFORMATION:
–
J.Kanipe, D.Webb, The Arp Atlas Of peculiar Galaxies, 2006, Willmann-Bell,inc.
–
http://www.gemini.edu/node/20
–
http://faculty.etsu.edu/smithbj/research/SQ.html
–
http://arpgalaxy.com
–
Wikipedia
- Used Catalogs: NED, GALEX, LEDA, SDSS-DR8.
- Aknowledgements: Pere Gil: http://observatoriagullo.wordpress.com
© Eduard Garcia Ribera, 2012
www.astroedu.net