J/ApJ/799/153 Yellowballs in Milky Way project (Kerton+, 2015)
The Milky Way project: what are yellowballs?
Kerton C.R., Wolf-Chase G., Arvidsson K., Lintott C.J., Simpson R.J.
<Astrophys. J., 799, 153 (2015)>
=2015ApJ...799..153K 2015ApJ...799..153K
ADC_Keywords: Milky Way ; Infrared sources
Keywords: ISM: bubbles - stars: formation - stars: massive -
stars: pre-main sequence - stars: protostars
Abstract:
Yellowballs are a collection of approximately 900 compact, infrared
sources identified and named by volunteers participating in the Milky
Way Project (MWP), a citizen science project that uses GLIMPSE/MIPSGAL
images from Spitzer to explore topics related to Galactic star
formation. In this paper, through a combination of catalog
cross-matching and infrared color analysis, we show that yellowballs
are a mix of compact star-forming regions, including ultra-compact and
compact HII regions, as well as analogous regions for less massive
B-type stars. The resulting MWP yellowball catalog provides a useful
complement to the Red MSX Source survey. It similarly highlights
regions of massive star formation, but the selection of objects purely
on the basis of their infrared morphology and color in Spitzer images
identifies a signature of compact star-forming regions shared across a
broad range of luminosities and, by inference, masses. We discuss the
origin of their striking mid-infrared appearance and suggest that
future studies of the yellowball sample will improve our understanding
of how massive and intermediate-mass star-forming regions transition
from compact to more extended bubble-like structures.
Description:
We use the spatial distribution of yellowballs, cross-matches with
existing catalogs of star formation tracers, and mid- and far-infrared
photometry to show that the yellowballs identified in the MWP are a
collection of objects tracing a compact, dense phase of massive (O and
B type) star formation. This includes a mix of compact and
ultra-compact HII regions as well as analogous regions for less
massive B stars.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 54 928 Yellowballs identified by MWP participants
table2.dat 79 928 Yellowball catalog matches and MIPSGAL 24µm
saturation
table3.dat 77 183 Yellowball photometry
--------------------------------------------------------------------------------
See also:
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
J/ApJ/721/137 : The Bolocam Galactic Plane Survey (BGPS) (Bally+, 2010)
J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010)
J/ApJS/195/14 : The Bolocam Galactic Plane Survey. V. (Schlingman+, 2014)
J/A+A/549/A45 : ATLASGAL Compact Source Catalog: 330<l<21 (Contreras+, 2013)
J/A+A/487/253 : The RMS survey: 13CO observations of YSOs (Urquhart+ 2008)
J/A+A/501/539 : RMS survey. 6cm observations of YSOs (Urquhart+, 2009)
J/ApJS/208/11 : The Red MSX Source Survey: massive protostars (Lumsden+, 2013)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number
5- 8 A4 --- --- [MWP1]
9- 22 A14 --- MWP1 Milky Way Project identifier, MWP1 GLLLlll+BBbbbY
24- 30 F7.3 deg GLON Galactic longitude
32- 37 F6.3 deg GLAT [-1/1] Galactic latitude
39- 43 F5.3 arcmin dLON [0/6.1] Dimension along galactic longitude (1)
45- 49 F5.3 arcmin dLAT [0/6.2] Dimension along galactic latitude (1)
51- 54 F4.2 --- Hit [0.1/1] Hit rate (2)
--------------------------------------------------------------------------------
Note (1): Average size of user-drawn rectangle enclosing the yellowball.
Note (2): The ratio of number of times the yellowball was identified to number
of times the yellowball was viewed.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/928] Sequential number
5- 19 A15 --- BGPS2 Bolocam Galactic Plane Survey version 2
identifier (J/ApJ/731/90)
20 A1 --- f_BGPS2 [N] N when no cross-match was found,
blank for sources not in the BGPS survey
22- 37 A16 --- ATLASGAL The ATLASGAL survey identifier (J/A+A/568/A41)
38 A1 --- f_ATLASGAL [N] N when no cross-match was found
40- 57 A18 --- RMS Red-MSX Source identifier (J/ApJS/208/11)
58 A1 --- f_RMS [N] N when no cross-match was found
60- 74 A15 --- WISE WISE catalog identifier (II/328)
75 A1 --- f_WISE [N] N when no cross-match was found
77 A1 --- Cl [KGCQ] WISE catalog classification (G1)
79 A1 --- Sat [Y/N] 24µm saturated image? (1)
--------------------------------------------------------------------------------
Note (1): Indicates if any portion of the source was saturated (Y) or
not (N) in MIPSGAL 24µm images.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 28 A28 --- Match Match description
30- 32 I3 --- Seq [1/928] Sequential number
34- 38 F5.3 Jy F8 Average 8µm flux density
40- 44 F5.3 Jy e_F8 Uncertainty in F8
46- 50 F5.3 Jy F12 Average 12µm flux density
52- 56 F5.3 Jy e_F12 Uncertainty in F12
58- 63 F6.3 Jy F24 Average 24µm flux density
65- 69 F5.3 Jy e_F24 Uncertainty in F24
71 A1 --- BGPS [Y/N] Bolocam Galactic Plane Survey match? (1)
73 A1 --- ATLASGAL [Y/N] ATLASGAL survey match? (1)
75 A1 --- WISE [Y/N] WISE catalog match? (1)
77 A1 --- Cl [KGCQ] WISE catalog classification (G1)
--------------------------------------------------------------------------------
Note (1): See Table 2 for match source ID.
Y = Catalog match
N = No catalog match
blank = source not in survey area
--------------------------------------------------------------------------------
Global notes:
Note (G1): WISE catalog classification as follows:
K = known HII regions, which have measured radio recombination line (RRL)
or Hα spectroscopic emission
G = candidate HII regions, which have characteristic HII region mid-infrared
morphology spatially coincident with detected radio continuum emission
but lack RRL or Hα observations
C = follow-up observations by Anderson and colleagues suggest that essentially
all objects in group C are bona fide HII regions
Q = radio quiet objects, which may contain only intermediate-mass stars or be
HII regions in either early or late stages of evolution
--------------------------------------------------------------------------------
Acknowledgements:
Charles Kerton, kerton(at)iastate.edu
(End) Patricia Vannier [CDS] 28-May-2015