Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI

Details Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI

2009-10-20

arxiv.org/abs/0910.3893v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

11 pages, accepted for publication in ApJ

Scientific paper

Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to <10 Schwarzschild radii of the presumed 4 million solar mass black hole. In previous work, we demonstrated the potential for total-intensity (sub)millimeter-wavelength VLBI to detect time-variable -- and periodic -- source structure changes in the Sgr A* black hole system using nonimaging analyses. Here we extend this work to include full polarimetric VLBI observations. We simulate full-polarization (sub)millimeter VLBI data of Sgr A* using a hot-spot model that is embedded within an accretion disk, with emphasis on nonimaging polarimetric data products that are robust against calibration errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)mm-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

Affiliated with

Also associated with

No associations

Rating

Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI 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 Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-144857