Cs. Kiss1, A. Moór2,
L.V. Tóth1,3, V. Könyves3
The large scale spiral structure of the Galaxy is affected by the complex distribution
of cavities, filaments, arcs, loops and shells, often refered as the "Cosmic
Bubble Bath". First examples of such features were found in radio continuum
measurements, extended to high galactic latitudes (Loop I, II and III).
Later anomalous HI features like worms, chimneys and supershells were identified
and catalogued. Similar morphology has been recognized in some nearby spiral
and irregular galaxies (M31, M33, LMC, SMC).
The most studied galactic shells
are formed by supernova explosions and winds of massive stars. High velocity
clouds may also form large cavities when infalling from the halo, however
observations suggest, that most of the HI shells are related to star-formation,
rather than to the infall of HVCs. Gamma ray bursts may also be responsible for
the formation of the largest supershells and nonlinear development of instabilities
in the interstellar medium may from large cavities without stellar energy injection,
which can be very similar to those created by SN explosions or stellar winds.
These shells/loops may also provide a nest
for the next gerenation of stars via the process of propagating star formation.
The cavities of the interstellar medium contain low density hot gas in its
multiphase model. The hot gas filling factor f is an
important parameter of the ISM, which is poorly constrained observationally.
Reliable estimates of f
In our study we searched the whole sky for loops/arcs
using IRAS based far-infrared data (a detailed description of the data reduction can
be found here). This is the first study which is not restricted
to the galactic midplane. Our catalogue contains the basic properties of
462 loops. Distance estimates are given for 73 of these loops,
based on indicator objects (massive stars, dark clouds, supernova remnants, etc.).
The catalogue and others results have been published in two separate papers
(see the links below); Paper I -- the 2nd Galactic
quadrant and Paper II -- the 1st, 3rd
and 4th Galactic quadrants.
The supershell GIRL134-28, first identified by Heiles (1984)
lies at a distance of ~1.5kpc and has a size of ~0.41x0.31kpc
(dust column density image, Schlegel et al., 1998)
- Könyves, V., Kiss, Cs., Moór, Tóth, L.V., Kiss, Z., 2006,
"Catalouge of far-infrared loops in the Galaxy", A&A, in press (astro-ph/0610465)
- Kiss, Cs., Moór, A., Tóth, L.V., 2003, "Far-infrared loops in the 2nd
Astronomy & Astrophysics, 418, 131
- Könyves, V., Kiss, Cs., Moór, A., 2003, "An All-Sky Survey of Far-Infrared Loops",
Winds, Bubbles, and Explosions: a conference to honor John Dyson, Pa'tzcuaro, Michoacán,
Mexico, September 9-13, 2002 (Eds. S. J. Arthur & W. J.
Henney) Revista Mexicana de
Astronomía y Astrofísica
(Serie de Conferencias) Vol. 15, p. 302
- Moor, A., Kiss, Cs., Toth, L.V., 2001,
Investigation of far infrared loops in the 2nd Galactic Quadrant,
Publications of the Astronomy Department of the Eötvös University No. 11, Proceedings of the
Postgraduate Reunion in Astronomy & Astrophysics, 2000, p. 65
- Toth, L.V., Kiss, Cs., Moor, A., 1996,
Catalogue of IRAS Loops in the IInd Galactic Quadrant, in:
The Role of Dust in the Formation of Stars, Proceedings of the ESO Workshop Held at Garching,
Germany, 11 - 14 September 1995. Edited by Hans U. Kaufl and Ralf Siebenmorgen. Springer-Verlag,