Mapping Hydrogen in the Galaxy, Galactic Halo and Local Group with the Galactic Arecibo LBand Feed A - PowerPoint PPT Presentation

1 / 1
About This Presentation
Title:

Mapping Hydrogen in the Galaxy, Galactic Halo and Local Group with the Galactic Arecibo LBand Feed A

Description:

The GALFA-HI Survey will map the entire Arecibo sky (shown between the red lines ... Magellanic Stream: The HI velocity field of the Magellanic System from the ... – PowerPoint PPT presentation

Number of Views:75
Avg rating:3.0/5.0
Slides: 2
Provided by: lsa
Category:

less

Transcript and Presenter's Notes

Title: Mapping Hydrogen in the Galaxy, Galactic Halo and Local Group with the Galactic Arecibo LBand Feed A


1
Mapping Hydrogen in the Galaxy, Galactic Halo and
Local Group with the Galactic Arecibo L-Band Feed
Array (GALFA)
  • The GALFA-HI Survey starting with TOGS
  • M.E. Putman (U. Michigan), K. Douglas (SSL,
    Berkeley), S.J. Gibson (NAIC), C. Heiles
    (UC-Berkeley), E. Korpela (SSL, Berkeley), J.E.G.
    Peek (UC-Berkeley), S. Stanimirovic (UW-Madison)

The GALFA-HI Survey will map the entire Arecibo
sky (shown between the red lines in Figure 1) at
21-cm over a velocity range of -700 to 700 km/s
with a resolution of 0.2 km/s and 3.4 using the
Arecibo L-Band Feed Array. This poster presents
highlights from the TOGS (Turn on GALFA Survey)
portion of GALFA-HI which covers the largest
portion of the Arecibo sky with commensal drift
scan observing (blue boxes in Figure 1). A peak
brightness temperature map and channel map
showing the sky mapped thus far are shown in
Figure 2. The sharp contrast between previous HI
maps and GALFAs is shown in Figure 3. More
information can be found at http//www.astro.lsa.u
mich.edu/mputman/togs.html and
http//www.naic.edu/alfa/galfa.
Figure 1 The LAB HI survey (0.6 deg resolution
Kalberla et al. 2005) with the area covered by
the GALFA-HI Survey shown between the red lines
and the area covered by TOGS in the blue boxes.
Figure 2 Top Peak brightness temperature map
of the sky mapped thus far by TOGS in the Fall.
Bottom Channel map at 3 km/s showing the area
of sky mapped thus far by TOGS in the Spring.
Figure 3 Comparing LAB Survey data (left 0.6
deg beam) to GALFA data (right 3.4 beam).
Galactic Shells GALFA peak brightness
temperature HI map (left) and IRIS 100 micron
thermal dust emission (right) from the nearby
molecular cloud complex MBM 53-55 (e.g., Yamamoto
et al. 2003), which is thought to be part of an
expanding shell (Chastain et al. 2006). The rich
detail provided by GALFA enable direct
comparisons between the datasets and provide
information on the HI content, environment and
kinematics of the shell. This work to be
published by S.J. Gibson et al.
Very High-Velocity Clouds (VHVCs) GALFA reveals
the detailed structure of VHVCs in the halo and
can be used to probe the diffuse halo medium
through fingers extending off the sides of the
cloud and head-tail clouds (e.g. Peek et al.
2007 Stanimirovic et al. 2006). This work to be
published by J. Peek et al. and J. Grcevich et al.
Needles This image shows bundles of very fine
(5) filamentary features at high galactic
latitude (b 80). These features, discovered by
GALFA, are highly correlated to starlight
polarization(red lines), indicating magnetic
fields along their length. In addition, the angle
of both the magnetic fields and the filament
bundles is coincident with the angle of the local
spiral arm. We find these 'filament bundles'
throughout the diffuse ISM, indicating a new
technique for finding the orientation of magnetic
fields. This work to be published by J. Peek et
al.
Leo Cold Cloud To the right is a GALFA image of
an extremely cold (17 K) and nearby (cloud in our Galaxy's ISM (Meyer et al. 2006).
Color represents LSR velocity and brightness
represents hydrogen column density. Because of
its location within the local hot bubble, this
cloud makes a very interesting laboratory for the
study of the CNM and the CNM/HIM interface. A
program comparing the 21-cm observations to
infrared dust emission and optical and
ultraviolet stellar absorption is underway. This
work to be published by J. Peek et al.
lll
lll
Magellanic Stream The HI velocity field of the
Magellanic System from the Parkes telescope
(left 15.5 resolution Putman et al. 2003) and
the tip of the Magellanic Stream as observed by
GALFA (right). The GALFA data reveal four
coherent 10-15 degree long filaments that differ
in morphology and velocity structure and may have
different origins/ages. Numerous small clouds
with high negative velocities are also evident.
Some of these clouds show evidence for a
multiphase medium and may result from spatial
fragmentation of the Stream due to thermal
instability. This work to be published by S.
Stanimirovic et al.
M33 A Local Group galaxy as revealed by GALFA.
What was traditionally thought to be a quiescent
galaxy shows clear evidence for either tidal/ram
pressure disruption and/or gas cloud accretion.
This work will be published by M. Putman et al.
Write a Comment
User Comments (0)
About PowerShow.com