The Interstellar Medium on Milky
Way scales constrained by THOR
Henrik Beuther
& the THOR team
http://www.mpia.de/thor
VLA
Survey (PI: H. Beuther):
-  90 square degrees from 15 < L < 65 deg
-  15’’ resolution, factor 4 improvement!
-  HI 21cm line, 4 OH lines, recombination lines and cm continuum (1-2 GHz)
- 100 Tbyte of data volume
-  230 hour large program at VLA
1.4GHz continuum
32deg
Galactic Longitude
24deg
19deg
THOR
VGPS 1.4GHz
1.4GHz
VLA
Survey (PI: H. Beuther):
-  90 square degrees from 15 < L < 65 deg
-  15’’ resolution, factor 4 improvement!
-  HI 21cm line, 4 OH lines, recombination lines and cm continuum (1-2 GHz)
- 100 Tbyte of data volume
-  230 hour large program at VLA
1.4GHz continuum
32deg
Galactic Longitude
24deg
19deg
1.4GHz cont.
Goals:
- Molecular cloud formation processes
-  Atomic to molecular gas conversion
- OH molecular emission and absorption
-  OH masers
-  Ionized gas in continuum and RRL emission
-
Polarization continuum to identify supernovae and Faraday rotation
http://www.mpia.de/thor
Cloud formation
200
+00.4
180
+00.2
160
+00.0
140
00.2
120
00.4
Column Density [M pc 2]
Galactic Latitude
Color: HI (new
(old VGPS)
THOR)
+00.6
Contours:
870µm
W43 complex
HI column density
100
10pc @ 5.5kpc
80
00.6
31.0
30.5
30.0
Galactic Longitude
29.5
Bihr et al. 2015
Cloud formation
200
+00.4
180
+00.2
160
+00.0
140
00.2
120
00.4
Column Density [M pc 2]
Galactic Latitude
Color: HI (new
(old VGPS)
THOR)
+00.6
Contours:
870µm
W43 complex
HI column density
100
10pc @ 5.5kpc
80
00.6
31.0
30.5
30.0
Galactic Longitude
29.5
Bihr et al. 2015
Cloud formation
200
+00.4
180
+00.2
160
+00.0
140
00.2
120
00.4
Column Density [M pc 2]
Galactic Latitude
Color: HI (new
(old VGPS)
THOR)
+00.6
Contours:
870µm
W43 complex
HI column density
100
10pc @ 5.5kpc
80
00.6
31.0
30.5
30.0
Galactic Longitude
29.5
Bihr et al. 2015
Atomic versus total column density
Krumholz 2009 model:
Solid: G0=1, Z=1
Dashed: G0=5, Z=1.4
Black and blue: model
evaluated at different r
Dotted: Elliptical fit
à Standard Krumholz (2008, 2009) model does not fit.
à Most likely because of strong radiation field in that region
Bihr et al. 2015
OH study toward W43 pilot
- 103 maser sites over 4 square deg.
- 288 maser spots (133@1612, 74
@1665, 72@1667MHz, 9@1720MHz)
- 46 associated with evolved stars,
31 with star formation
26 with unknown associations
1612
1667
GLIMPSE
3color images
Walsh et al. subm.
1612
Circles: 1612
Square: 1665
Diamond: 1667
Plus:
1720
OH study toward
W43
pilot
- 103 maser sites over 4 square deg.
- 288 maser spots (133@1612, 74
@1665, 72@1667MHz, 9@1720MHz)
- 46 associated with evolved stars,
31 with star formation
26 with unknown associations
Grey: 13CO
1612
1667
GLIMPSE
3color images
Walsh et al. subm.
1612
OH study toward W43 pilot
- 103 maser sites over 4 square deg.
- 288 maser spots (133@1612, 74
@1665, 72@1667MHz, 9@1720MHz)
- 46 associated with evolved stars,
31 with star formation
26 with unknown associations
- Diffuse emission toward only a
a few sources
- Absorption against continuum
sources à molecular versus
atomic gas studies
Walsh et al. subm.
1612
1667
GLIMPSE
3color images
1612
OH absorption in the Milky Way
1.4GHz continuum
Green: HI
Blue: OH
Rugel et al. in prep.
OH absorption in the Milky Way
Blue: OH
FWHM(OH)
Green HI
OH/HI abund. ratio
Rugel et al. in prep.
α=-0.8
1.05GHz
1.3GHz
1.43GHz
Averaged image
1.7GHz
THOR
continuum
1.82GHz
1.95GHz
Bihr et al. in prep.
α=+0.14
1.05GHz
1.3GHz
1.43GHz
Averaged image
1.7GHz
THOR
continuum
1.82GHz
1.95GHz
Bihr et al. in prep.
Source properties
Bihr et al. in prep.
http://www.mpia.de/thor
Goals and summary:
-  Study of the molecular, atomic and ionized gas over large fraction of
northern Milky Way
-  Diverse applications from cloud formation, HI to H2 conversion, masers
from early to late evolutionary stages, HII regions, supernovae,
magnetic fields … etc.
-  Pilot study data public this year. The rest later with time.
-  Kind of open team. If people are interested to join, please contact me.