X-ray Emission from an Expanding Supergiant Shell in IC 2574

Abstract

We present a multi--wavelength study of a supergiant shell within the violent interstellar medium of the nearby dwarf galaxy IC 2574, a member of the M81 group of galaxies. Neutral hydrogen (HI) observations obtained with the Very Large Array (VLA) reveal a prominent expanding supergiant HI shell which is thought to be produced by the combined effects of stellar winds and supernova explosions. It measures roughly 1000 x 500 pc in size and is expanding at about 25 km/s. The HI data suggest an age of about 1.4 x 10^6 yrs; the energy input must have been of order (2.6\pm 1) x 10^53 ergs. Massive star forming regions, as traced by H$\alpha$ emission, are situated predominantly on the rim of this HI shell. VLA radio continuum observations at 6 cm show that these star-forming regions are the main sources of radio continuum emission in this galaxy. Soft X-ray emission from within the HI hole is detected by a pointed ROSAT PSPC observation. The emission is resolved, coinciding in size and orientation with the HI shell. These spatial properties suggest that the emission is generated by an X-ray emitting plasma located within the HI shell although a contribution from X-ray binaries cannot be completely ruled out. The X-ray data are compatible with emission coming from a Raymond & Smith plasma at a temperature of about log(T[K]) = 6.8 and a density of 0.03 cm^-3.

10 pages LaTeX, 1 PS-figure, accepted by ApJ Letters

References in corpus (3)

• Hot Interstellar Gas in the Irregular Galaxy NGC 4449
• X-Rays from Superbubbles in the Large Magellanic Cloud. V. The H II Complex N11
• The Multi-Phase Medium in the Interstellar Complex N44

Cited by in corpus (29)

• Dark and luminous matter in THINGS dwarf galaxies
• High-resolution mass models of dwarf galaxies from LITTLE THINGS
• High-resolution dark matter density profiles of THINGS dwarf galaxies: Correcting for non-circular motions
• [CII] 158 $\mu$m Emission as a Star Formation Tracer
• Holes and Shells in the Interstellar Medium of the Nearby Dwarf Galaxy IC 2574
• Dynamical Centers and Non-Circular Motions in THINGS Galaxies: Implications for Dark Matter Halos
• Evidence for tidal interaction and a supergiant HI shell in the Local Group dwarf galaxy NGC 6822
• Dust and Atomic Gas in Dwarf Irregular Galaxies of the M81 Group: The SINGS and THINGS view
• Turbulent Gas in Lensed Planck-selected Starbursts at redshifts 1-3.5
• The Westerbork SINGS Survey: I. Overview and Image Atlas
• The stellar population and interstellar medium in NGC 6822
• The Interaction between the ISM and Star Formation in the Dwarf Starburst Galaxy NGC 4214
• Testing Spallation Processes With Beryllium and Boron
• Evolution of the X-ray luminosity and metallicity of starburst blown superbubbles
• Spitzer Observations Of The Supergiant Shell Region In IC 2574
• The evolution of stellar structures in dwarf galaxies
• UV Observations of the Powering Source of the Supergiant Shell in IC2574
• Triggered Star Formation and the Creation of the Supergiant HI Shell in IC 2574
• The supergiant shell with triggered star formation in Irr galaxy IC 2574: neutral and ionized gas kinematics
• DDO 88: A Galaxy-Sized Hole in the Interstellar Medium
• The LBT Panoramic View on the Recent Star-Formation Activity in IC2574
• Self-enrichment of Galactic halo globular clusters: stimulated star formation and consequences for the halo metallicity distribution
• Optical and infrared emission of H II complexes as a clue to the PAH life cycle
• The Violent Interstellar Medium of Nearby Dwarf Galaxies
• ROSAT X-ray observations of the dwarf galaxy Holmberg II
• On the shape of Superbubbles evolving in the Galactic Plane
• X-Ray Emission from the Supergiant Shell in IC 2574
• Bubbles in galactic haloes
• Red Variable Stars in Three M81 Group Dwarf Galaxies