Pulsar Wind Nebulae in EGRET Error Boxes

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Pulsar Wind Nebulae in EGRET Error Boxes
Mallory Roberts McGill University/Eureka
Scientific
Crystal Brogan, Bryan Gaensler, Jason Hessels,
Namir Kassim, Joseph Lazio, C.-Y. Ng, Roger Romani
(see Kaspi, Roberts Harding 2004, Gaensler ad
nauseum)
http//www.physics.mcgill.ca/pulsar/pwncat.html
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(Lamb Macomb 1997)
At least 6 PWN were first discovered by X-ray
imaging of EGRET error boxes
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Stationary PWN

• Around Youngest Pulsars
• Have Toroid Jet Morphologies
• Tend to be in non-variable sources
• Can be used to constrain geometry

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It's the Geometry, Stupid

• The first step is knowing where the acceleration
  occurs
• Pulse profiles can map the magnetospheric
  emission sites
• BUT the viewing and magnetic inclination angles
  can't be free parameters
• The combination of toroidal PWN (Ng Romani
  2004), pulse polarization sweep (Radhakrishnan
  Cooke 1969), and possibly radio pulse profile
  (Gonthier, van Guilder, Harding 2004) can provide
  powerful constraints on the geometry

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An Example The Continuing Saga of PSR J20213651

• Find a good position
• Image at hard X-rays
• Do very deep radio searches

Result Pulsar with spin properties identical to
PSR B1706-44
Roberts et al. 2002
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Torus Fitting Step 1 Obtain (deep) Chandra Image
Note to Ground based observers PSR J20213651
PWN is both much brighter and much larger than
PWN around PSR B1706-44
Hessels et al. 2004
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Torus Fitting Step 2 Single or Double Torus?
For Details See Ng Romani 2004
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Torus Fitting Step 3 If Brave Enough to Infer
Magnetic Inclination Angle from Double Torus
Separation, Sanity Check With Radio Pulse Profile

• How bright is it?
• It it a single or double pulse?
• Is pulse broad or narrow? BEWARE of scattering!
• Try to measure polarization sweep

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How Many Suitable sPWN?

• Not alot! But, maybe enough to decide the
  geometry
• A high fraction (5/14) of low latitude, low
  variability, non-AGN GeV sources coincident with
  sPWN
• Crab, Vela, PSR J1706-44, PSR J20213651, PSR
  J22296114
• Maybe a few more associated with EGRET sources
  will turn out to be useful for torus fitting (eg
  CTA 1,PSR B0540-69) or others now known will be
  GLAST sources (G0.90.1, G54.10.3, G292.01.8,
  3C58)

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Rapidly Moving PWN

• Motion of pulsar greatly affects PWN shape
• Tend to be moderately energetic (3X1035-3X1036
  ergs/s)
• Mouse is New Canonical RPWN (near Galactic
  center)
• Remarkably little is understood about them

Gaensler et al. 2004
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GeV J1809-2327 The Canonical Variable, GeV
Emitting RPWN

• Most prominent source in small error box
• Highest V123.93 (Nolan et al. 2003) of any
  low-latitude, non-AGN source
• Interacting with molecular cloud (Oka et al.
  1999)?

Braje et al. 2002, Roberts et al. in prep
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Is GeV J1809-2327 a Mouse?

• Larger VLA image suggests bright PWN is analagous
  to Mouse head
• EPIC-PN (contours, small window mode) image
  suggests fainter X-rays out to radio edge.
  (Larger image coming soon).

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Is (SNR?) G7.4-1.4 the Birthsite of GeV
J1809-2327?

• Large region of soft X-ray emission Discovered by
  ROSAT (never published?)
• 90cm imaging in progress

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l18o Sources

• Complex region with at least 2 EGRET sources
• Region of bright unidentified, variable Comptel
  source.
• GeV J1825-1310 (3EG J1826-1302) second highest
  V123.22
• 20 and 90cm imaging resolve at least 4 SNR, 2 of
  them new, as well as many molecular clouds and
  some other structures

New SNR
Kes 67
SNR G18.9-1.1
3EG J1823-1314
New SNR
GeV J1825-1310
Brogan et al. in prep.
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GeV J1825-1310
New Nebula
New SNR
PSR B1823-13
Roberts, Romani Kawai 2001
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New X-ray RPWN in GeV J1825-1310
New PWN
stellar cluster
Roberts et al. in prep
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New radio RPWN?
Very suggestively shaped radio nebula, no clear
infrared counterpart
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Other RPWN in Variable EGRET Sources
Kookaburra complex containing PSR J1420-6048 and
the Rabbit PWN V121.59 (Roberts et al.
1999,2001,inprep)
PSR B185301 in W44 V121.57 (Petre et al. 2002)
Lu, Wang, Lang 2003 claim G359.89-0.08 is RPWN
V122.35
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Most Sources Without RPWN Not Well Studied
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Pulsar Wind Nebulae, Not Just Pretty Pictures!

• Galactic Gamma-Ray Sources Point to PWN
• SPWN Are The Key to Pulsar Geometry (Need DEEP
  Chandra Observations for reliable fits)
• RPWN in Overdense Regions Are THE Major Class of
  Variable EGRET Sources in the Galactic Plane NO
  Theory Yet!, Need Deep Images!