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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