We have resolved 450 micrometer and 800 micrometer emission from the W3(Main) star forming region into three major peaks, using 8 inch - 14 inch beams with the James Clerk Maxwell Telescope on the summit of Mauna Kea. One of the submillimeter sources is identified with W3 - IRS5, a well-known candidate protostar. However, to our surprise, we find that none of the submillimeter peaks coincides with any of the prominent compact HII regions in the area. We estimate that the three submillimeter sources together contribute 30-50 percent of the total bolometric luminosity of the region, and speculate that the contribution of luminous radio-quiet sources to the total luminosity of HII region/molecular cloud complexes may be larger than is often assumed

Deane, James R.

Ladd, E. F.

Sanders, D. B.

Wynnwilliams, C. Gareth

English

NASA Technical Reports Server

N95. 21773
/
LUMINOUS RADIO-QUIET SOURCES IN THE W3(MAIN)
CLOUD CORE
C. G. WYNN-WILLIAMS, E. F. LADD, J. R. DEANE, AND D. B.
SANDERS
Institute for Ast_vnomy, University of Hawaii, 2680 Woodlawn Drive,
Honohdu, HI 96822
ABSTRACT We have resolved 450#1n and 800#m enlission from the
W3(Main) star forming region into three major peaks, using 8" - 14"
bealns with the Janms Clerk Maxwell Telescope on the sununit of Mauna
Kea. One of the submillinleter sources is identitied with W3 - IRS5, a
well-known candidate protostar. However, to our suprise, we find that
none of the submillinmter peaks coincides with any of the prominent
compact HII regions in the area. We estimate that the three submilfimeter
sources together contribute 30 - 50% of the total bolonmtric luminosity
of the region, and speculate that the contribution of luininous radio-quiet
sources to the total luminosity of HII region/molecular cloud complexes
may be larger than is often assumed.
INTRODUCTION
The spectral energy distributions of HII region/molecular cloud complexes in-
dicate that the bulk of their luminosity is enfitted in the far infrared and that
this far infrared and submillimeter emission is generated by cool (T = 30-60
K) dust (see e.g. Wynn-Williams & Beckfin 197,1; Chini, Krugel, & Wargau
1987). Because of the large beam sizes typically used for far-infrared and sub-
millimeter continuum observations, it has been ditficult to determine whether the
OB stars ionizing the HII regions are the sources of the luminosity, or whether
this luminosity is generated independently within the nearby molecular nlate-
riM. We present new sul)millimeter continuum observations of the Wa(Main)
region with high spatial resolution (< 0.1 pc). These new ol)servations show
that the distribution of submillimeter flux is not similar to the distribution of
radio continuum elnission, and suggest that the total luminosity generated by
Hll region/molecular cloud complexes is not donfinated by' the O and B stars
which generate the observed 1tli regions.
OBSERVATIONS
Submillimeter observations of the W3(Main) region were made with the 15 m
JCMT in 1992 Novelnber. The continuum maps were obtained using the facility
UKT-I,1 bolometer system with passbands centered at approximately 450 #m
and 800 tim. Our results are shown in Figure l, along with maps of 20 #m
S. 'ferebey emd J. Mazzaa'ella (eds.), Science wRh High-Spatial Re_olution Far hffrared Data, 177-181,
1994, Jet Propldsion Laboratory, Pasadena, CA.
https://ntrs.nasa.gov/search.jsp?R=19950015356 2020-06-16T08:24:04+00:00Z
178 WYNN-WILLIAMS ET AL.
(Wynn-Williams et al. 1972) and a 5 GHz radio continuum emission (Harris &
Wynn-Wilfiams 1976). The submillimeter continuum emission breaks up into
three main emission centers--one in the east, and two in the west. We designate
the sources SMS 1, 2, and 3 from E to W in order of decreasing right ascensiou.
DISCUSSION
SMS 1 is resolved and nearly circular at half power, with low flux level exten-
sions to the east in the direction of IllS 3/W3B and north in the direction of
IRS 1/W3A (see Figure 2a). The 450 #m and 800 #m centroid t)ositions are
consistent with the 20 #m position of IRS 5 (Wynn-Williams et al. 1972), sev-
eral H_O maser groul)ings (Genzel et al. 1987), and the radio continuum source
W3(M) (Colley 1980).
SMS 2 ties close to the 20 #m source IRS 4 (Wynn-Wilfiams et al. 1972),
and near to the compact HII region W3(C) (Wynn-Wilfiams 1971; see Figure
2b). We find that the position of SMS 2 ties 7.5" from the center of W3(C).
The size of the positional discrepancy is sufficiently large that we are confident
that SMS 2 is not associated with W3(C). IRS 4 ties 4" from the centers of
both W3(C) and SMS 2, nearly on a fine between these two sources. Therefore
we conclude that there are are least two distinct major sources of emission in
this area (W3(C) and SMS 2), and quite fikely an additional unrelated infrared
source (Ills ,1).
SMS 3 is more extended than the other two subnfillimeter sources, with
I"WHM size of 30" x 16" ({t x 6). No 20 inn emission was detected in this region
to a point source detection threshold of 150 Jy (Wynn-Wilfiams et M. 1972),
nor was radio continuum emission detected greater than 6 may/2" beam (Harris
& Wynn-Williams 1976).
Combining our data with infi'ared results (Wynn-Williams et al. 1972;
Werner et al. 1980), we have estimated the 20-800 t_m luminosities for these
three sources, as well as for Ills 1 (which was not detected as a distinct source
in our submillimeter maps) and the entire region. The total luminosity for
the region is estimated to be 5.2 x 10 s L(._. Ills 1 and IRS 5 each account
tot about 30% of the total. SMS 1 and SMS 2 account for an additional 6%
each. tlowever, it shouhl be noted that the luminosity of SMS 2 may contain
some additional contribution from either IRS ,1 or the source associated with
W3(C), and therefore this luminosity should be regarded as an upper limit to
the luminosity of SMS 2.
Ills 5 has long been recognized as a candidate high-mass protostar, based
on its high luminosity, infi'ared energy distribution, and relatively weak radio
coiltinuum emission (see e.g. Wynn-Williams et al. 1972; Hackwell et al. 1978;
Werner et al. 1980; Wynn-Williams 1982). We have found two more sources
in the W3(Main) cloud that exhibit behavior similar to that of IRS 5. While
both have luminosities about a factor of 5 lower than that of Ills 5, they are not
associated with detected radio continuum emission. These radio-quiet sources
account for at least 35% (SMS 1/Ills 5 + SMS 3) and up to 50% (SMS I/IRS
5 + SMS 2 + SMS 3) of the total luminosity generated in the W3(Main) core.
With the addition of extended emission probably generated by lower-luminosity,
non-ionizing sources, the luminosity from W3(Main) could be roughly equally
O
t_
V
c-
O
"4::_
l"
a
61 ° 53'
61o52 '
61 ° 53'
61 o 52'
W 3 (Main)
I I I _1 1
- °G, -
I I _'t_ .,_e _
w
m
m
_ m
m
I I I I I
__.-I R S 1/,IRS 5 IRS 3
IRS7
I I I
-I-
I. o I.
D_
O 4-
1800.rol-
l I I I 1 I 1 1 I I
2 h22r" 2 h21 r"40' 2 h22m 2 "21 m40'
Right Ascension (1950)
©
r.ar3
O
N
>
_z
Fig. 1 Submillimeter images of the W3 (Main) region at 450 gm (top left) and 800 gm (bottom left) compared with the 20 lam
map from Wynn-Williams et al. (1972; top right) and the 5 GHz contours from Harris & V_nn-Vvtlliams (1976; bottom right).
The submillimeter beam sizes are shown in the lower left of each relevant panel. Contours for the 450 lain map begin at 15 Jy/8"
beam and increment by 15 Jy / 8" beam. Contours for the 800 grn map begin at 1 Jy / 14" beam and increment by 1 Jy / 14" beam.
k--.
C.D
O0
61" 52' 30"
61' 52' 20"
2h21m54s 2h21m52s
61" 53' 00"
61" 52' 50"
2"21=46 s 2h21=44 s
Fig. 2 a) Contours of the 450 I.tm emission near IRS 5. The 450 lain contours begin at 5 Jy / 8" beam and
increment by 5 Jy / 8" beam. The positions of the 20 lain source, the radio continuum source W3 (M) and the H20
maser centers are indicated by a circle, box and cross respectively, b) Comparison of our 450 I.tm contours with
the 15 GHz emission from Colley (1980) toward the SMS 2 / IRS 4 / W3 (C) region. The 450 lma contours begin at
5 Jy / 8" beam and increment by 5 Jy / 8" beam. The position of the 20 lain and 5 _n sources are indicated by a
circle and a triangle respectively.
i
)....d
t'-
>
E
>
LUMINOUS SOURCES IN W3(MAIN) 181
divided between sources associated with HII regions and sources which have
tittle or no ionized environs.
ACKNOWLEDGMENTS
We thank tile operators of the JCMT for their assistance in obtaining tile sub-
millimeter continuum data. C. G. W.-W. acknowledges support from NSF grant
AST89-19563. E. F. L. was supported by the James Clerk Maxwell Telescope
Fellowship.
REFERENCES
Chini, R., Krugel, E., & Wargau, W. 1987, A&A, 181,378
Colley, D. 1980, MNRAS, 193,495
Genzel, R. Downes, D., Moran, J. M., Johnston, K. J., Spencer, J. H., Walker,
R. C., Haschick, A., Matveyenko, L. I., Kogan, L. R., Kostenko, V. I.,
RSnn_ng, B., Rydbeck, O. E. H., & Moiseev, I. G. 1978, A&A, 66,13
Hackwell, J. A., Gehrz, R. D., Smith, J. R., & Briotta, D. A. 1978, ApJ, 221,797
Harris, S., & Wynn-Williams, C. G. 1976, MNRAS, 174,649
Werner, M. W., Becklin, E. E., Gatley, I., Neugebauer, G., Sellgren, K., Thron-
son, H. A., Harper, D. A., Loewenstein, R., & Moseley, S. H. 1980, ApJ,
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Wynn-Williams, C. G. 1982, ARA&A, 20,587
Wynn-Wiltiams, C. G. 1971, MNRAS, 151,397
Wynn-Wiltiams, C. G., & Becklin, E. E. 1974, PASP, 86,5
Wynn-Williams, C. G., Becklin, E. E., & Neugebauer, G. 1972, MNRAS, 160,1

Science with High Spatial Resolution Far-Infrared Data
LIST OF AUTHORS
183
", i, J
,j ">
y /___'
C.H. Anderson ............................................................. 139
H,H. Aumann ................................................................ 1
Tj.R. Bontekoc ......................................................... 2a, laS
Y. Cao ...................................................................... 55
B. Das ...................................................................... 17
J.R. Dearie ................................................................. 173
N.A. Devcreux ............................................................... 79
P.E. Dewdncy .............................................................. 161
Rh. Evans .................................................................. 117
J.W. Fowler .................................................................. 1
S.K. Ghosh .................................................................. 17
l/.A. Gonsalvcs .............................................................. 47
D.A. Harper ................................................................. 97
B. Hcikkila .................................................................. 91
C.E. Hellos ................................................................. 161
G. Hclou ............................................................... 85, 111
J.P. Kenncaly ............................................................... 47
D.J.M. Nester .......................................................... 23, 133
G.R. Knapp ................................................................. 97
I{.M. Kortc .................................................................. 47
E.F. Ladd .................................................................. 173
W.D. Langcr ............................................................... 1:19
J .F. Lcc.s .................................................................... 97
D. Lestcr .................................................................... 33
C. Loup .................................................................... 1:33
K.A. Marsh ................................................................ 111
A.P. Marston ........................................................... 11, 103
P.G. Martin ................................................................ 161
a .M. Mazzarclla ............................................................. 69
R.K. Pifla ................................................................... 61
S.D. l'ricc ................................................................... 47
T.A. Prince ................................................................. 55
R.C. Pucttcr ................................................................ 61
T.N. I/cngarajan ............................................................ 17
W.T. Reach ................................................................ 161
C. Hogcrs .................................................................. 161
M.P. I{upcn ................................................................. 97
I{.S. Sample ................................................................. 47
D.B. Sanders ............................................................... 173
M.F. Schlapfcr .............................................................. 169
J.A. Suracc ............................................................. 69, 123
S. Tcrcbey ................................................................. 123
I{.P. Vcrma .................................................................. 17
I{.G. Walker ................................................................ 169
Z. Wang .................................................................... 153
pAGE _LII.NI_ NOT F_L,f,_7:?
: J/5! e.,
184
L.B.F.M. Waters ........................................................... 133
W.R. Webber ................................................................ 91
R.W. Wilson ............................................................... 139
C.G. Wynn-WilliaHLs ....................................................... 173
C. Xu ....................................................................... 85
185
Sciencewith High Spatial ResolutionFar-Infrared Data
LIST OF ATTENDEES
George Aumann
California Institute of Technology
Infrared Processing and Analysis Center
MS 100-22
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Jean-Phillipe Bernard
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Yu Cao
California Institute of Technology
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Thomas Chester
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186
NedLadd
Universityof Hawaii
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JetPropulsionLaboratory
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1. Report No. 94-5
2. Government Accession No.
TECHNICAL REPORT STANDARD TITLE PAGE
3. Recipient's Catalog No.
4. Title and Subtitle
Infrared Processing and Analysis Center (IPAC)
Science Wigh High Spatial Resolution Far-Infrared Data
Proceedings of a Workshop Held June 14-16, 1993
7. Author(s) S. Terebey and J. Mazzarella
9. Per_rming Organization Name and Address
JET PROPULSION LABORATORY
California Institute of Technology
4800 Oak Grove Drive
Pasadena, California 91109
12. Sponsoring Agency Name and Addre_
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
Washington, D.C. 20546
5. Report Date
April 1994
6. Performing Organization Code
8. Performing Organization Report No.
94-5
10. Work Unit No.
11. Contract or Grant No.
NAS7-918
13. Type of Report and Period Covered
Proceedings
14. Sponsoring Agency Code
15. Supplementary Notes
16. Abstract l)ata at far-infrared wavelengths are difficult to obtain and usually have much lower
spatial resolution than data which are routinely obtained at other wavelengths. However,
the inany astrophysicM problems that can only be well addressed in the far-infrared haw_
inspired et[orts to extract high spatial resolution information from instruments including
the Infrared Astronc,mical Satellite (IRAS) and the Kuiper Airborne Observat<wy (KAO).
The IRAS data also provide a fundamental archive since It{AS produced a nearly complete
survey of the infrared sky. Although the IRAS survey strateGY was not designed with the
specific purpose of constructing images of the sky, the ingenuity of software developers
has receutly resulted in innovative techniques which are allowing astronomers to push the
limits of these and other far-infrared data.
'l'he goal of this workshop was to discuss new science and techniques relevant to high
spatial resolution processing of far-infrared data, with particular focus on high resolution
processing of IRAS data. Users of the maximum correlation method, maximum entropy,
and other resolution enhancement "algorithms applicable to far-infrared data gathered at
the Infrared Processing and An'alysis Center (1PAG) on the Caltech campus in Pasadena
for two days in June 1993 to compare techniques and discuss new results. During a
special session on the third day, interested astronomers were introduced to IRAS HIRES
processing, which is IPAC's implementation of the maximum correlation method to the
IRAS data. Individuals who desire further information about IRAS or HIRES processing
are encouraged to contact IPAC.
17. Key Wor_ (Selected by Author(s))
Far-infrared data;high spatial resolution
data processing; resolution enhancement;
maximum entropy.
18. Distribution Statement
19. Security Cl_sif. _f this report)
Unclassified
20. Security Clmsif. _f this page)
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21. No. of Pages ' 22. Price
187
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Luminous radio-quiet sources in the W3(MAIN) cloud core

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