Pisgah Forest Inst.
Other  Workshops
Contact Us

Up Link

Hercules A: Radio Galaxy

Type of Object:  Hercules A is a powerful radio galaxy.  At 1420 MHz it looks like a double source and is thought to be an active galaxy.  It’s energy output is equivalent to that of 10 billion Crab Nebula!  The structure consists of two radio lobes and two jets.  Five spherical shells make up the western lobe.  Also, the nucleus appears to be a double nucleus.  Her A could be two galaxies merging or interacting.

Distance: 2000 Million light years
Size: 330,000 lyr diameter components separated by 900,000 lyr
 Coordinates (Epoch J2000):
         Right Ascension:     
16 51 08.0
         Declination:                +4 59 33.8

Other Names: 3C 348

Radio Brightness at 1420 MHz (21 cm): 47 Jy

Some Links

Location on the sky: The active galaxy Her A is located to one side of the constellation Hercules as shown in the figure at the right. The radio galaxy extends several arcminutes across this part of the sky.

Images are shown below, at different wavelengths, cover a
0.5 degree x 0.5 degree area of the sky centered on the nebula.  The images are taken from  the SKYVIEW Virtual Observatory maintained under NASA ADP Grant NAS5-32068 with P.I.
Thomas A. McGlynn under the auspices of the High Energy Astrophysics Science  Archive Research Center (HEASARC) at the GSFC Laboratory for High Energy Astrophysics. SKYVIEW contains catalogs and surveys from x-ray to radio observations. The site is located at http://skyview.gsfc.nasa.gov/

Visible image from the digitized Palomar Sky Survey E plates.  Doesn’t show much visible nebulosity.

Far-Infrared Image at 100 microns taken by the Infrared Astronomical Satellite (IRAS) Survey. Shows the dust component is not obvious near Her A

Image taken at the radio emission of neutral hydrogen at 1420 MHz by the NRAO VLA Sky Survey.  Shows the double gas component of the galaxy.  Looks remarkably similar to Cygnus A

Image taken at the radio emission frequency of 4850 MHz. Image shows the gas component, but not the double structure seen in the 1420 MHz image. Image is from a Green Bank survey from 0° to +75° declination).

[Orion Nebula] [crab_nebula] [W3] [cas_a] [cygnus_a] [her_a] [vir_a] [galactic_center] [sgp] [ngp]