Download [CII] in the nuclear region of M33: HerM33es

[CII] in the nuclear region of M33:
HerM33es
Bhaswati Mookerjea
Tata Institute of Fundamental Research, Mumbai, India
C+ Workshop, Leiden, 7 February 2013
HerM33es: [CII]
Outer HII region
BCLMP691
BCLMP302
Nucleus
Southern Arm
07/02/2013, Leiden
Hα (color) together with PACS
footprints (green) and HIFI onthe-fly cuts.
[CII] in M33-Nucleus
[CII] Spectra in M33
BCLMP691
Braine et al. (2012)
BCLMP302
Mookerjea et al. (2011)
Compared with
VLA HI & IRAM CO(2-1)
at 12” resolution
Southern Arm
Kramer et al. (in prep)
07/02/2013, Leiden
[CII] in M33 nucleus
600 pc
ISM in the M33 Nucleus
●
Unspectacular nucleus
●
GMCs with HII regions
●
12'' @ 840pc → 50 pc
CO, HI and dust
continuum emitting
clouds match well
●
MIPS 24 μm (Color)
HI (Black)
CO(2-1) (White)
600 pc
07/02/2013,
Leiden
CO(2-1) IRAM/HERA
[CII] in M33
& HI VLA (Gratier
etnucleus
al. 2010)
HIFI [CII] cuts in the nucleus of M33
07/02/2013, Leiden
[CII] in M33-Nucleus
HIFI [CII] cuts in the nucleus of M33
Nikola et al. (in prep)
07/02/2013, Leiden
[CII] in M33-Nucleus
[CII] in M33 nucleus
Fully sampled loadchopped
perpendicular OTF
cuts
●
Extracted spectra
at 30 positions on a
10” grid
●
07/02/2013, Leiden
[CII] in M33-Nucleus
Average spectrum
Average spectrum shows at
least 3 velocity components
●
Velocity components
correspond to the different
HII regions (continuum peaks)
sampled by the cuts
●
Reasonable (but not complete)
agreement with CO(2-1)
●
HI emission seems to have
the components blended
together
●
Average is over too large (and
dynamic) an area
●
07/02/2013, Leiden
[CII] in M33-Nucleus
Position-Velocity Diagram along Minor Axis
●
[CII] & CO match
HI shows shift in velocity & enhanced emission to
the NW
●
07/02/2013, Leiden
[CII] in M33-Nucleus
PV Diagram along Major Axis
Clear & large velocity gradient (~ 50 km/s over
120”)
●
Change in velocities at the HII regions
●
Good correspondence with CO(2-1) & HI with a
slight shift
●
07/02/2013, Leiden
[CII] in M33-Nucleus
[C II] Spectra
[C II] clearly detected in 21 out of
30 positions on a 10” grid on the cuts
●
Lineshapes mostly fitted by one or
two Gaussians
●
At all positions but one HI & CO (21) detected for one of the two
velocity components seen in [C II]
●
HI
CO(2-1)
CII
07/02/2013, Leiden
[CII] in M33-Nucleus
[C II]/CO/HI Comparison
07/02/2013, Leiden
[CII] in M33-Nucleus
Comparison of Velocities
Component 1:
--- [C II] emitting
gas also emits CO
at all positions and
HI at all but
one position
--- Match with Hα
velocities to the
east
●
Component 2:
--- Seen at 12
([CII]), 10 (CO)
and 8 (HI) positions
--- At 10 positions
[C II] but no CO at
the same/similar
velocities …
only 3 show HI
emission
●
07/02/2013, Leiden
[CII] in M33-Nucleus
Velocities of Component 1
Discrepancy between [C II] and CO and HI lines mostly < 3 km/s
07/02/2013, Leiden
[CII] in M33-Nucleus
CNM contribution to [CII] emission (Comp. 1)
07/02/2013, Leiden
[CII] in M33-Nucleus
CNM
contribution <20% for most
positions
CII/CO Ratio (Comp. 1)
Ratio < 20000 at most positions
BCLMP302: 6000-30000
BCLMP691:
07/02/2013, 8000
Leiden
[CII] in M33-Nucleus
Typical low-metallicity galaxies: LMC (23000)
Gas Heating Efficiency in the M33 nucleus
TIR (1 μm to 1mm) luminosity
linearly related to the 160 μm
PACS luminosity --- Boquien et
al. (2011)
●
Derived TIR for the nucleus
region on a 12” grid
●
Both components of CII
where present are used
●
[CII]/TIR ratio of intensities
lies between 0.1 and 1.8%
●
07/02/2013, Leiden
[CII] in M33-Nucleus
Gas Heating Efficiency in the M33 nucleus
TIR (1 μm to 1mm) luminosity
linearly related to the 160 μm
PACS luminosity --- Boquien et
al. (2011)
●
Derived TIR for the nucleus
region on a 12” grid
●
Both components of CII
where present are used
●
[CII]/TIR ratio of intensities
lies between 0.1 and 1.8%
●
07/02/2013, Leiden
[CII] in M33-Nucleus
Summary
Clear large velocity gradients detected in [CII] close to the M33
nucleus
●
[CII], CO(2-1) and HI profiles vary significantly --- need to compare
gas with similar velocities
●
●
Major component of [CII] emitting gas is also detected in CO and HI
●
Evidence for [CII] emission without corresponding CO or HI
●
Matching of Hα velocities with [CII] ---> the ionized gas contribution
●
Estimated contribution of CNM to [CII] emission ~ 15-20%
●
High [CII]/CO ratios typical of low-metallicity environments
● 07/02/2013,
Leiden
[CII]/TIR
between
[CII] incomparable
M33-Nucleus to other regions of M33
0.1 to 1.8%,