J/ApJ/779/113 IR photometry of YSOs in the W40 region (Mallick+, 2013)
The W40 region in the Gould belt: an embedded cluster and H II region at the
junction of filaments.
Mallick K.K., Kumar M.S.N., Ojha D.K., Bachiller R., Samal M.R., Pirogov L.
<Astrophys. J., 779, 113 (2013)>
=2013ApJ...779..113M 2013ApJ...779..113M
ADC_Keywords: YSOs ; Photometry, infrared ; H II regions
Keywords: H II regions; infrared: ISM; ISM: bubbles; ISM: individual: W40;
radio continuum: ISM; stars: formation
Abstract:
We present a multiwavelength study of the W40 star-forming region
using infrared (IR) observations in the UKIRT JHK bands, Spitzer
Infrared Array Camera bands, and Herschel PACS bands, 2.12µm H2
narrowband imaging, and radio continuum observations from GMRT (610
and 1280MHz), in a field of view (FoV) of ∼34'x40'. Archival Spitzer
observations in conjunction with near-IR observations are used to
identify 1162 Class II/III and 40 Class I sources in the FoV. The
nearest-neighbor stellar surface density analysis shows that the
majority of these young stellar objects (YSOs) constitute the embedded
cluster centered on the high-mass source IRS 1A South. Some YSOs,
predominantly the younger population, are distributed along and trace
the filamentary structures at lower stellar surface density. The
cluster radius is measured to be 0.44pc -- matching well with the
extent of radio emission -- with a peak density of 650/pc2. The JHK
data are used to map the extinction in the region, which is
subsequently used to compute the cloud mass -- 126M☉ and
71M☉ for the central cluster and the northern IRS 5 region,
respectively. H2 narrowband imaging shows significant emission,
which prominently resembles fluorescent emission arising at the
borders of dense regions. Radio continuum analysis shows that this
region has a blister morphology, with the radio peak coinciding with a
protostellar source. Free-free emission spectral energy distribution
analysis is used to obtain physical parameters of the overall
photoionized region and the IRS 5 sub-region.
Description:
NIR photometric imaging observations were carried out using the Wide
Field Camera (WFCAM) mounted on the 3.8m United Kingdom Infrared
Telescope (UKIRT). JHK-band data were obtained in the service mode
during the period 2009 December 15-17.
The Spitzer archival data for the Gould belt survey of Allen et al.
(2006sptz.prop30574A) in all four Infrared Array Camera (IRAC) bands
3.6 (Ch1), 4.5 (Ch2), 5.8 (Ch3), and 8.0 (Ch4) µm were obtained
using the Spitzer Heritage Archive.
Narrowband imaging in the 2.12um H2 (v=1-0) S(1) filter and broad
band imaging in the K' for continuum subtraction was obtained for a
19'x14' region centered on the W40 embedded cluster. These data were
obtained with the Calar-Alto 3.5m telescope during the night of 2001
June 13 using the Omega Prime camera.
We obtained the publicly available archival data for the Herchel/PACS
100um and 160um bands --obtained as part of Proposal ID:KGBTpandre1.
New radio continuum observations are obtained using the Giant
Metre-wave Radio Telescope (GMRT) in two bands centered at 1280MHz and
610MHz. The data were obtained on 2011 November 15 and 2011 November
18 (Project ID 21_015), respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 118 1202 YSOs identified in the field of view (FoV)
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See also:
VI/139 : Herschel Observation Log (Herschel Science Centre, 2013)
II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)
VII/244 : Atlas and Catalog of Dark Clouds (Dobashi+, 2005)
II/332 : c2d Spitzer final data release (DR4) (Evans+, 2003)
VIII/64 : Westerhout's Catalogue of 82 Discrete Sources (Westerhout 1958)
J/ApJS/209/29 : MYStIX: Mid-IR observations and catalogs (Kuhn+, 2013)
J/A+A/527/A62 : HK photometry in an UCHII region near Sh2-217 (Brand+, 2011)
J/ApJ/725/2485 : X-rays from the star-forming complex W40 (Kuhn+, 2010)
J/AJ/140/968 : A cluster of compact radio sources in W40 (Rodriguez+, 2010)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/MNRAS/396/964 : T Tauri in and around bright-rimmed clouds (Chauhan+, 2009)
J/ApJ/682/445 : Spitzer observations of S254-S258 (Chavarria+, 2008)
J/A+A/463/1029 : DCld303-14.8 + Thumbprint Nebula JHKs (Kainulainen+, 2007)
J/ApJ/653/1226 : Physical properties of galactic HII regions (Quireza+, 2006)
J/MNRAS/362/689 : AAO/UKST SuperCOSMOS Hα survey (Parker+, 2005)
J/ApJS/155/123 : JHKs photometry of ultracompact HII regions (Alvarez+, 2004)
J/other/AuJPA/14.133 : Galactic radio sources. III. (shaver+ 1970)
J/other/AuJPA/14.1 : 5000MHz galactic radio sources (Goss+, 1970)
http://irsa.ipac.caltech.edu/data/SPITZER/C2D/ : C2D Spitzer NASA/IPAC archive
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 20 F9.6 deg DEdeg Declination in decimal degrees (J2000)
22- 27 F6.3 mag Jmag [7.1/20]? UKIRT/WFCAM J band magnitude in
MKO system
29- 33 F5.3 mag e_Jmag [0.001/0.09]? Uncertainty in Jmag
35- 40 F6.3 mag Hmag ? UKIRT/WFCAM H band magnitude
in MKO system (1)
42- 46 F5.3 mag e_Hmag ? Uncertainty in Hmag
48- 53 F6.3 mag Kmag [4.8/16.4]? UKIRT/WFCAM K band magnitude
in MKO system (1)
55- 59 F5.3 mag e_Kmag [0.001/0.2]? Uncertainty in Kmag
61- 66 F6.3 mag [3.6] [4.9/15.4]? Spitzer/IRAC 3.6um band magnitude
68- 72 F5.3 mag e_[3.6] [0.001/0.5]? Uncertainty in [3.6]
74- 79 F6.3 mag [4.5] ? Spitzer/IRAC 4.5 micron band magnitude
81- 85 F5.3 mag e_[4.5] ? Uncertainty in [4.5]
87- 92 F6.3 mag [5.8] ? Spitzer/IRAC 5.8 micron band magnitude
94- 98 F5.3 mag e_[5.8] ? Uncertainty in [5.8]
100-105 F6.3 mag [8.0] [3.8/12.5]? Spitzer/IRAC 8.0um band magnitude
107-111 F5.3 mag e_[8.0] [0.001/0.6]? Uncertainty in [8.0]
113-117 A5 --- --- [Class]
118 A1 --- Class YSO classification ("1" for Class-I, and
"2" for Class II/III sources)
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Note (1): Instrumental magnitudes are in the WFCAM native system
(the Mauna Kea Consortium Filter System or the MKO system).
See section 2.1.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-May-2015