Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-02-25
Astronomy and Astrophysics
Astrophysics
18 pages, including 5 Postscript figures. Accepted for publication in ApJ Letters
Scientific paper
10.1086/310643
We present the first interferometer map of the water maser emission in the active nucleus of NGC 4945. Although the declination of the galaxy is about -49 degrees, we were able to make the observations with the southernmost antennas of the Very Long Baseline Array. Strong maser emission is present in three velocity ranges, one near the systemic velocity and two shifted roughly symmetrically by +/-(100-150) km/s. This is the first detection of highly blue-shifted water emission in NGC 4945. We determined the position of the maser to be RA(B1950)= 13 02 32.28 +/- 0.02 ; Dec(B1950)= -49 12 01.9 +/- 0.1. The uncertainties in earlier estimates are at least several arcseconds. The maser lies within 2'' (36 pc at a distance of 3.7 Mpc) of the peaks in 1.4 GHz continuum and 1.6 micron emission from the nucleus. The mappable maser emission is distributed roughly linearly over about 40 milliarcseconds (0.7 pc) at a position angle of about 45 degrees, which is close to the 43 +/- 2 degree position angle of the galactic disk. The red and blue-shifted emission symmetrically stradle the systemic emission on the sky, which suggests material in edge-on circular motion around a central object. The position-velocity structure indicates a binding mass of about one million Suns, within a volume of radius about 0.3 pc. This implies that the central engine radiates on the order of 10% of its Eddington luminosity.
Greenhill Lincoln J.
Herrnstein James Rezso
Moran James Michael
No associations
LandOfFree
The Distribution of H2O Maser Emission in the Nucleus of NGC 4945 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Distribution of H2O Maser Emission in the Nucleus of NGC 4945, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Distribution of H2O Maser Emission in the Nucleus of NGC 4945 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-116862