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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Studies of 22GHz H2O maser emission from the merging galaxy NGC 6240 withdouble nuclei are presented. Two epochs of Very Large Array (VLA) observationsin the A-configuration in spectral-line mode were carried out at 0.1 arcsecresolution by covering the redshifted velocity range of ~ 300 km/s with respectto the systemic velocity of the galaxy. The purpose of these new observationsis twofold: to detect an H2O maser that an earlier VLA observation pinpointedin the southern nucleus in the northern nucleus as well to clarify thekinematics of the double nuclei, and to understand the origin of the maser inthe galaxy. In the second epoch, one velocity feature peaking at Vlsr=7491.1km/s, redshifted by ~200 km/s relative to the systemic velocity, was detectedonly toward the southern nucleus. The detection of an H2O maser feature at ornear this velocity had never been reported in earlier observations. However,including the known velocity features at redshifted velocities, no othervelocity features were observed toward either nuclei throughout these epochs.The maser remains unresolved at an angular resolution of ~ 0".1, correspondingto a linear size of less than about 45 pc. The two epochs of VLA observationsshow that the maser intensity is variable on timescales of at least threemonths, while the correlation between the maser intensity and the radiocontinuum intensity is not certain from our data. It is plausible that themaser in NGC 6240 is associated with the activity of an active galactic nucleusin the southern nucleus. Alternatively, the maser can be explained bystarforming activity at the site of massive starformation in the galaxy.

Two Epochs of Very Large Array Observations of Water Maser Emission in the active galaxy NGC 6240