English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report on the VLBI follow-up observations using the Japanese VLBI Network(JVN) array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 thatoccurred in mid-February, 2010. The total of five epochs of observations wereperformed at intervals of about 20 days between March 7 and May 31, 2010. Nonew-born component associated with the flare was seen directly in the totalintensity images obtained by our multi-epoch VLBI observations. However, onejet component located at ~1 mas north-west from the core was able to beidentified, and its proper motion can be measured as -1.66+/-0.46 mas yr^-1,which corresponds to an apparent velocity of -3.48+/-0.97 c. Here, thisnegative velocity indicates that the jet component was apparently moving towardthe core. As the most plausible explanation, we discuss that the apparentnegative velocity was possibly caused by the ejection of a new component, whichcould not be resolved with our observations. In this case, the obtained Dopplerfactor of the new component is around 10 to 20, which is consistent with theones typically estimated by model fittings of spectral energy distribution forthis source.

Possible Detection of Apparent Superluminal inward motion in Markarian 421 after the Giant X-ray flare in February, 2010