What does AmmoniaWhat does Ammonia trace in Egg Nebulatrace in Egg Nebula

Pao-Jan ChiuPao-Jan ChiuWith With Jeremy LimJeremy Lim

2003 8.272003 8.27

OutlineOutline

Optical Structure of the Egg Nebula 12CO Molecular Outflows Structure of NH3(1,1) Observations with VLA Results and Discussion Summary

CRL2688 - Egg CRL2688 - Egg NebulaNebula

Proto-Planetary nebula (PPN) Distance ~ 1 kpc Optical features

• bipolar lobes• twin searchlight beams• quasi-spherical AGB wind• shocked molecular hydrogen• “dust lane”

Multiple Outflows in Egg Multiple Outflows in Egg nebulanebula

12CO trace multiple outflows. Shocked molecular hydrogen traces lobes of

polar outflow, tips of “equatorial” outflows.

Arrow – axis of Arrow – axis of 1212CO outflows contour – CO outflows contour – 1212CO CO color – optical image + shocked Hcolor – optical image + shocked H2 2

NHNH33(1,1) in Egg nebula(1,1) in Egg nebulaEquatorial disk or central toru?Equatorial disk or central toru?

Nguyen-Q-Rieu, A. Winnberg, V. Bujarrabal ,1986Nguyen-Q-Rieu, A. Winnberg, V. Bujarrabal ,1986VLA D array, beamsize 4”.3 × 3”.4VLA D array, beamsize 4”.3 × 3”.4Redial velocites from -63.5 to -23.9 km/sRedial velocites from -63.5 to -23.9 km/s

NH3(1,1) aligned with the dust lane Kinematics suggest expansion: Expanding Disk Spur to north?

Bipolar lobes

NH3(1,1)

-75~ 5km/s

-63.5~-23.9km/s

ObservationsObservations

observerobserver VLA D-arrayVLA D-array

objectiveobjective NHNH33(3,3) in Egg(3,3) in Egg

frequencyfrequency 23.874 GHz23.874 GHz

wavelengthwavelength 1.3 cm1.3 cm

bandwidthbandwidth 12.5 MHz12.5 MHz

velocity rangevelocity range -110.4 -110.4 ~ ~ 46.4 46.4 km/skm/s

bandwidth pre bandwidth pre channelchannel

195.3 Hz195.3 Hz

( 2.454 km/s )( 2.454 km/s )

beam size beam size 3.19”×2.51”3.19”×2.51”

Results and Results and DiscussionDiscussion

•At higher angular resolution, structure of NH3(3,3) does not resemble disk

Beamsize 4”.3 Beamsize 4”.3 ×× 3”.4 3”.4 Beamsize 3”.19 × 2”.51Beamsize 3”.19 × 2”.51

NH3(1,1)

Comparison of NH3(3,3) andNH3(1,1)

NH3(3,3)

Compare with optical lobes Compare with optical lobes and shocked Hand shocked H22

•NH3(3,3) traces higher density (~105-106) and higher temperature (~120K) than 12CO (2-1)

•The four NH3(3,3) peaks are at/close to tips of 12CO outflows.

•NH3(3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) color – optical image + shocked H2 color – optical image + shocked H2

contour – NHcontour – NH33(3,3) contour – (3,3) contour – 1212COCO

outflowsoutflows

1212CO CO

1212CO CO

Shock Shock regionregion

Shock Shock regionregion

Shock Shock regionregion

cooling regioncooling region

ShockShocked ed HH22

NHNH33(3,(3,3) 3)

1212CO CO

1212CO CO

1212CO CO

1212CO CO

1212CO CO

1212CO CO

cooling regioncooling region

ShockShocked ed HH22

NHNH33(3,(3,3) 3)

ShockShocked ed HH22

Compare with optical lobes Compare with optical lobes and shocked Hand shocked H22

•NH3(3,3) traces higher density (~105-106) and higher temperature (~120K) than 12CO (2-1)

•The four NH3(3,3) peaks are at/close to tips of 12CO outflows.

•NH3(3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) color – optical image + shocked H2 color – optical image + shocked H2

contour – NHcontour – NH33(3,3) contour – (3,3) contour – 1212COCO

Velocity distribution in NHVelocity distribution in NH3 3

•North and east NH3(3,3) peaks are blueshifted•South and west NH3(3,3) peaks are redshifted •Kinematics of NH3(3,3) similar to 12CO outflow

NHNH33(3,3)(3,3)

Contour -Contour - 12 12COCOColor arrow - Color arrow - 1212CO outflowsCO outflows

SummarySummary Observed NH3(3,3) in Egg Nebula with VLA NHObserved NH3(3,3) in Egg Nebula with VLA NH33(3,3) trac(3,3) trac

e the higher density and temperature e the higher density and temperature moleculemolecule gas gas NHNH33(3,3) (3,3) not consistentnot consistent with expanding disk with expanding disk NHNH33(3,3) located at/close to tips of (3,3) located at/close to tips of 1212CO outflows and behiCO outflows and behi

nd the shocked molecular hydrogen gas nd the shocked molecular hydrogen gas Kinematics of NH3(3,3) similar to Kinematics of NH3(3,3) similar to 1212CO outflowsCO outflows NH3(3,3) traces NH3(3,3) traces shocked molecular gasshocked molecular gas behind the shoc behind the shoc

k front (traced by shocked molecular hydrogen)k front (traced by shocked molecular hydrogen) Does the “equatorial” outflows lie in the same plane; i.e., dDoes the “equatorial” outflows lie in the same plane; i.e., d

isk that is aligned with the dust laneisk that is aligned with the dust lane

Orientation of the Multiple Orientation of the Multiple “Equatorial” Outflows“Equatorial” Outflows

Two models: Model 1. Oriented in different directions, with no

common plane

Model 2. “Equatorial” Outflows lie in the plane of a “disk” aligned with the dust lane

Orientation of the Multiple Orientation of the Multiple “Equatorial” Outflows“Equatorial” Outflows

Two models: Model 1. Oriented in different directions, with no

common plane

Model 2. “Equatorial” Outflows lie in the plane of a “disk” aligned with the dust lane

Model 2 requires the “disk” to be (rapidly)

rotating

Thank Thank you !!you !!