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| Paper: |
Galactic Small Scale Structure Revealed by the GALFA-H I Survey |
| Volume: |
438, The Dynamic Interstellar Medium: A Celebration of the Canadian Galactic Plane Survey |
| Page: |
126 |
| Authors: |
Begum, A.; Stanimirović, S.; Peek, J. E. G.; Ballering, N.; Heiles, C.; Douglas, K. A.; Putman, M.; Gibson, S. J.; Grcevich, J.; Korpela, E. J.; Lee, M.; Saul, D.; Gallagher, J. |
| Abstract: |
The Galactic Arecibo L-band Feed Array H I (GALFA-H I) survey
is mapping the entire Arecibo sky at 21 cm, over a
velocity range of –700 to +700 km s-1 (LSR), at a
velocity resolution of 0.18 km s-1 and an angular
resolution of 3.5 arcmin.
The unprecedented resolution and sensitivity of the GALFA-H I survey
have resulted in
the detection of many isolated, very compact H I clouds at low Galactic
velocities which are distinctly separated from the H I disk emission.
In the limited area
of ∼4600 deg2 searched so far, we have detected 96 such compact clouds. The
detected clouds are cold with Tk less than 300 K.
Moreover, they are quite compact and faint,
with median values of 5 arcmin in angular size, 0.75 K in peak brightness
temperature, and 5×1018 cm-2 in H I column density.
From the modeling of spatial and velocity distributions of the whole compact
cloud population, we find that the bulk of clouds are related
to the Galactic disk, and are within a few kpc distance.
We present properties of the compact clouds sample and discuss
various possible scenarios for the origin of this cloud population
and its role in Galactic interstellar medium studies. |
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