Logo (Main page)

Galactic Wind in NGC 4460

Russian version

    A bright extended nebulosity around a lenticular galaxy NGC 4460 was discovered by Igor Karachentsev and Serafim Kaisin (2008, A&A, 479, 603) during the recent H survey of nearby galaxies on the SAO RAS 6-m telescope. An analysis on new observational data taken with the MPFS and SCORPIO spectrographs indicates that we are dealing with the "galactic wind": the gas is blown above the galactic plane with the characteristic velocity of about 130km/s. The gas outflow is caused by a combined action of winds from the supernovae and young massive stars located in the galaxy's circumnuclear region. The current star formation is entirely concentrated in the compact region with the radius of about 1kpc. Total kinetic energy of the gas outflow is several times smaller than that of the known galactic wind in the nearby galaxy NGC 253, which explains a substantially lower total star formation rate in NGC 4460.
    The processes supporting star formation both in NGC 4460 and other known very isolated lenticular galaxies of the Local volume are considered. The most probable hypothesis is that the accretion of intergalactic gas clouds is feeding their star formation. Moreover, gas accretion on the cosmological time-scale is a steady process without any significant variations.
Alexei Moiseev, Igor Karachentsev, Serafim Kaisin
Accepted by MNRAS, arXiv:1001.0234v1 [astro-ph.CO]

Contact - Alexei Moiseev

Fig.1. Results of observations of NGC 4460 with the 6m telescope. Blue colour corresponds to the brightness distribution in the stellar continuum image, red colour is the image in the H line of the ionized gas. The square marks the region observed with the 3D-spectrograph MPFS. For this region we demonstrate the ionized gas velocity field (left) and a map of the emission lines ratio [SII]/H with the H contours superimposed (right).