Post on 14-Jul-2020
transcript
New MWP Bow Shocks:
To date 196 of the K16 bow shocks have
been rediscovered by MWP, and 93 new
quality candidates were discovered.
The Milky Way Project: A Citizen Science Catalog of Infrared Bow Shock Nebulae
Don M. Dixon, Tharindu K. Jayasinghe, and Matthew S. Povich
Introduction and Motivation
Bow shock nebulae result from
stellar winds interacting with
ambient gas and dust. In the case
of massive, O and B-type stars, the
UV radiation heats dust trapped in
the bow shock, producing bright
mid-infrared emission (Kobulnicky et
al. 2010, Gvaramadze et al. 2011).
The Milky Way Project (MWP) gives
citizens the ability to identify
candidate bow shocks in Spitzer
Space Telescope Galactic plane
survey images (see poster 340.08
by Jayasinghe et al.).
• Enhance bow shock catalog made
by Kobulnicky et al. (2016; K16).
• Evaluate performance of citizen
scientists versus professionals.
• Constrain the mass-loss rates of
massive, O and B type stars.
Bow Shock Tool
MWP volunteers classify bow shocks
by drawing polygons around the arc
of the nebula and placing a reticle on
the likely driving star.
Future Work
• Complete MWP catalog of infrared
bow shock nebulae.
• Spectral classification of
suspected driving stars.
• Infrared photometry of bow shock
nebulae to constrain models of
stellar winds (Kobulnicky et al.
2010 method).
K16 Bow Shocks
A small group of
researchers visually
searched IR survey
images to produce a
catalog of 709 bow
shock candidates. The
large majority were new
identifications, including
six near the famous
Eagle Nebula (Figure 2).
Environment Codes
K16 coded bow shocks by local
environment: FB = Facing Bright-
rimmed cloud; H = inside H II region;
FH = Facing H II region; I = Isolated
(see Figures 2-5 for examples).
Figure 2: Infrared mosaic image of the Eagle Nebula from
the Spitzer GLIMPSE and MIPSGAL surveys (oriented in
Galactic coordinates). Two new candidate bow shocks
found by MWP are shown in “zoom” boxes. Figures 3 & 4
cutout boundaries (colored boxes) contain the six K16 bow
shocks. All example candidate bow shocks in Figures 2–5
are labeled by their environment codes (as defined by K16).
Department of Physics and Astronomy, Cal Poly Pomona
References
Kobulnicky et al. 2010, ApJ, 710, 549
Kobulnicky, H. A., et al. 2016, ApJS,
227, 18 (K16)
Gvaramadze, V. V., et al. 2011, A&A,
535, 29
Acknowledgements
This work is supported by the National
Science Foundation under grants
CAREER-1454334 and AST-1411851.
Special Thanks to Dr. Henry “Chip”
Kobulnicky of the University of
Wyoming and the hard-working
volunteers of the MWP.
Figure 3: Cutout image of
K16 bow shocks in northern
Eagle Nebula, 24 µm
background removed.
Figure 4: K16 bow shocks in southern
Eagle Nebula, at the base of the “Pillars
of Creation.” 24 µm nebular background
removed.
Figure 1: Example bow shock classification
Figure 4
Figure 3
Legend:
SMOG
Cygnus-XGLIMPSE/MIPSGAL
Figure 6: Locations of MWP bow shock classifications in the 1st and 2nd Galactic quadrants. Orange points represent new MWP bow shocks and black points represent the
K16 bow shocks as shown by legend. Survey boundaries are labeled and color coded (half of the GLIMPSE/MIPSGAL survey area searched (295 ≤ l < 360) is omitted).
MWP 2016C
“Cluster” Requirements
A group of driving star classifications
in close proximity constitute a cluster
nominated for inclusion in the bow
shock catalog:
• Both polygon and reticle must be
drawn for a classification.
• ≥ 5 bow reticles within a radius of 7
arcseconds.
Figure 7: Comparing distribution new MWP
bow shock environments to K16 catalog.
Figure 5: 10 of the new MWP bow shock candidates
MIPS 24 µm
IRAC 8.0 µm
IRAC 4.5 µm
FH
I
4 × FHFH
H/
FB?
I H I I I
FB I FB I I
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