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 present a Spitzer Infrared Spectrograph (IRS) map of H2 emission from thenearby galaxy NGC 4258 (Messier 106). The H2 emission comes from 9.4E6 Msun ofwarm molecular hydrogen heated to 240-1040 K in the inner anomalous arms, asignature of jet interaction with the galaxy disk. The spectrum is that of amolecular hydrogen emission galaxy (MOHEG), with a large ratio of H2 over 7.7micron PAH emission (0.37), characteristic of shocked molecular gas. We findclose spatial correspondence between the H2 and CO emission from the anomalousarms. Our estimate of cold molecular gas mass based on CO emission is 10 timesgreater than our estimate of 1.0E8 Msun based on dust emission. We suggest thatthe X(CO) value is 10 times lower than the Milky Way value because of highkinetic temperature and enhanced turbulence. The H2 disk has been overrun andis being shocked by the jet cocoon, and much of the gas originally in the diskhas been ejected into the galaxy halo in an X-ray-hot outflow. We measure amodest star formation rate of 0.08 Msun/yr in the central 3.4 square kpc thatis consistent with the remaining gas surface density.

Jet-Shocked H2 and CO in the Anomalous Arms of Molecular Hydrogen Emission Galaxy NGC 4258