Astronomy and Astrophysics, volume 543A, 112-112 (2012/7-1)
Stripped gas as fuel for newly formed HII regions in the encounter between VCC 1249 and M49: a unified picture from NGVS and GUViCS.
ARRIGONI BATTAIA F., GAVAZZI G., FUMAGALLI M., BOSELLI A., BOISSIER S., CORTESE L., HEINIS S., FERRARESE L., COTE P., MIHOS J.C., CUILLANDRE J.C., DUC P.-A., DURRELL P., GWYN S., JORDAN A., LIU C., PENG E. and MEI S.
Abstract (from CDS):
We study the peculiar interacting galaxy system of VCC1249/M49 located in the core of the Virgo B subcluster. Owing to a recent interaction between the dwarf galaxy VCC1249 and the halo gas of the elliptical galaxy M49, neutral hydrogen has been displaced from the interstellar medium of this dwarf into the Virgo intracluster medium. Observations also reveal multiple compact star-forming regions (aka HII regions) that are embedded in this HI cloud, with a projected separation up to 13kpc from VCC1249 in the northwest direction. Motivated by recent near-ultraviolet imaging from the GALEX Ultraviolet Virgo Cluster Survey (GUViCS) of the VCC1249/M49 system that shows significant ongoing/recent star formation in the compact regions, we aim to constrain the origin of these outlying HII regions with a multi-wavelength approach. Using deep optical (u, g, i, z) imaging from the Next Generation Virgo Cluster Survey (NGVS) and new Hα imaging obtained at the San Pedro Martir observatory together with Keck long-slit spectroscopy, we characterize the star formation rates, ages, and metallicity of VCC1249 and its outlying compact regions. Moreover, we analyze the color and luminosity profile of the galaxy to investigate its recent interaction with M49. Our new observations indicate that VCC1249 underwent a recent interaction with M49 in which both ram-pressure stripping and tidal interaction occured. The joint action of the two mechanisms led to the removal of the HI gas from the interstellar medium of VCC1249, while the gravitational tides triggered the stellar tail and counter-tail of VCC1249. Our stellar population synthesis analysis reveals that the star formation in this galaxy was truncated around 200Myr ago and that the outlying HII regions were born in situ ≃10Myr ago out of pre-enriched gas removed from the dwarf galaxy. These observations also reveal that interactions between central and satellite galaxies similar to those between VCC1249/M49 may be an effective way of dispersing metals into the halos of massive galaxies.
galaxies: clusters: individual: Virgo - galaxies: evolution - galaxies: irregular - galaxies: abundances
Status at CDS:
Table 2 objects [LKG97b] CNN are not in Simbad ; figure 5 are stars not in Simbad.
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