Radio Jet Collimation Region of M87

https://www.nrao.edu/archives/plugins/Dropbox/files/m87_jetcollimation_hi.jpg

Description

The elliptical galaxy M87 hosts a radio galaxy whose main jet is especially well-studied on arcsec and milliarcsec scales. Prior Global VLBI observations at 43 GHz offered sub-milliarcsec resolution and indicated that the initial jet collimation region extended to at least 0.5 milliarcsec, corresponding to 0.04 pc or 140 times the Schwarzschild radius, Rs, of the massive black hole energizing the radio galaxy. The figure shows the VLBA image of M87 at 43 GHz, with a resolution of 390 microarcsec times 170 microarcsec, which independently confirms the Global VLBI result of collimation over the inner 1 milliarcsec. Moreover, jet emission is detected out to about 3 milliarcsec (0.2 pc or 820 times Rs) along the direction of the larger-scale jet indicated by the arrow in the figure. One difference between the VLBA image in the figure and the Global VLBI image is the presence of a weak counterjet in the VLBA image. Detection of a counterjet would be very interesting, if real. But such structures are also a natural consequence of amplitude calibration errors. Despite considerable testing, the counterjet detection in the VLBA image can only be considered suggestive, not reliable. Student C. Ly acknowledges support at the NRAO by the REU program of the U.S. NSF.

Creator

Legacy Astronomical Images

Rights

NRAO/AUI/NSF does not hold full copyright for this image. Contact the archivist for details.

Type

Legacy Astronomical Image

Object Name

M87

Investigators

C. Ly, R.C. Walker, J.M. Wrobel

Telescope

Very Long Baseline Array (VLBA)

Observation Date

2001-10-12

Type of Observation

continuum

Band

Q

Wavelength

7 mm

Frequency

45 GHz

Center of Image

RA 12:30:49.420, Dec: 12:23:28.000 (J2000)

Field of View

0.000019 x 0.000014 degrees

Notes

Contact the archivist for a high resolution tif of this image.

Series

Active Galactic Nuclei Series

Unit

Radio Galaxies Unit

Citation

Legacy Astronomical Images, “Radio Jet Collimation Region of M87,” NRAO Archives, accessed December 3, 2021, https://www.nrao.edu/archives/items/show/33358.