J/ApJ/905/61 YSO candidates in the HII region SH 2-112 (Panwar+, 2020)
Star formation and evolution of blister-type HII region SH2-112.
Panwar N., Sharma S., Ojha D.K., Baug T., Dewangan L.K., Bhatt B.C.,
Pandey R.
<Astrophys. J., 905, 61 (2020)>
=2020ApJ...905...61P 2020ApJ...905...61P
ADC_Keywords: YSOs; Photometry, infrared; H II regions
Keywords: Star formation ; H II regions ; Young stellar objects
Abstract:
We report the observational findings of the Sh2-112 HII region by
using the multiwavelength data analysis ranging from optical to radio
wavelengths. This region is powered by the massive O8V-type star
BD+45°3216. The surface density distribution and minimum spanning
tree analyses of the young stellar object (YSO) candidates in the
region reveal their groupings toward the western periphery of the HII
region. A GMRT radio continuum emission peak is found toward the
northwest boundary of the HII region and is investigated as a
compact/ultracompact HII region candidate powered by a B0-B0.5-type
star. Toward the southwest direction, a prominent curved rim-like
structure is found in the Hα image and GMRT radio continuum
maps, where the H2 and 13CO emission is also observed. These
results suggest the existence of the ionized boundary layer (IBL) on
the surface of the molecular cloud. This IBL is found to be
overpressured with respect to the internal pressure of the surrounding
molecular cloud. This implies that the shocks are
propagating/propagated into the molecular cloud, and the young stars
identified within it are likely triggered due to the massive star. It
is also found that this region is ionization-bounded toward the west
and density-bounded toward the east. Based on the distribution of the
ionized gas, molecular material, and YSO candidates, we propose that
the Sh2-112 HII region is a good candidate for the blister-type HII
region that has been evolved on the surface of a cylindrical molecular
cloud.
Description:
Optical [SII](6724Å), Hα(6563Å), and [OIII](5007Å)
narrowband filter observations of the central region of the Sh2-112
HII region were carried out on 2010 October 12 using the Himalaya
Faint Object Spectrograph and Camera (HFOSC) mounted on the 2m
Himalayan Chandra Telescope (HCT). With an integration time of 300s in
each filter, the HCT observations cover a field of view (FOV) of
∼10'x10'.
We carried out the short-exposure optical (UBVI) observations of the
Sh2-112 region (FOV ∼18'x18') on 2018 October 5 using the 2kx2k CCD
camera mounted on the f/4 Cassegrain focus of the 1.3m Devasthal Fast
Optical Telescope (DFOT) of the Aryabhatta Research Institute of
Observational Sciences (ARIES), Nainital, India (for details, see
Panwar+ 2017, J/MNRAS/468/2684).
See Section 2.1.
We performed Hα slitless spectroscopic observations of Sh2-112
using the HFOSC on the 2m HCT on 2010 October 12. The spectra were
obtained with the combination of a wide Hα filter
(6300-6740Å) and grism 5 (5200-10300Å) with a spectral
resolution of 870Å. See Section 2.2.
Radio continuum observations of the Sh2-112 region at the 610 and
1280MHz bands were carried out using the Giant Metrewave Radio
Telescope (GMRT) on 2010 October 22 (project code 19_026;
PI: S. S. Borgaonkar) and 2012 November 9 (project code 23_019;
PI: K. K. Mallick), respectively. Total observing time at the 610 and
1280MHz bands was 5.4 and 4.5hr, respectively. See Section 2.4.
We retrieved only reliable near-IR sources (photometric uncertainty
<0.1mag) in the Sh2-112 region from UKIDSS GPS DR6 (II/316). We also
used the NIR data from the Two Micron All Sky Survey (2MASS).
We used the WISE catalog from Cutri+ (2014, II/328) to identify YSO
candidates in the Sh2-112 region.
We retrieved 21cm radio continuum data from the Canadian Galactic
Plane Survey (CGPS; Taylor+ 2003, VI/128) to trace the extension of
ionized gas around Sh2-112.
The 13CO (J=3-2) (330.588GHz; beam ∼14") data were retrieved from
the James Clerk Maxwell Telescope (JCMT) archive (ID: M08AU19;
PI: Stuart Lumsden).
We utilized the wide-field Hα-, I- and B-band images from the
National Optical Astronomical Observatory (NOAO) archive to trace the
extension of the ionized hydrogen and optical morphology of the
region.
We also accessed the processed H2- and K-band images from the
Canada-France-Hawaii Telescope archive observed with the Camera
Panoramique Proche InfraRouge (CPAPIR) imager attached to the
Observatoire du Mont-Megantic 1.6m telescope operated by the
Universite de Montreal, Universite Laval.
See Section 2.5.
Using various NIR/MIR color-color diagrams and CMDs, we identified a
total of 138 YSO candidates in the region. Out of these, eight are
class I objects, 59 are class II objects, and the remaining 71 are
sources with IR excess (H-K>0.9) which could be candidate
classII/classI YSO candidates. The H/(H-K) CMD analysis shows that the
majority of YSO candidates have masses less than 3M☉.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
20 33 49 +45 38.0 SH 2-112 = GAL 083.8+03.3
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 126 138 YSO candidates from 2MASS/UKIDSS and WISE data
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See also:
B/cfht : Log of CFHT Exposures (CADC, 1979-)
III/92 : A Library of Stellar Spectra (Jacoby+ 1984)
III/195 : Atlas of Optical Spectral Classification OB Stars (Walborn+ 1990)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VI/128 : Log of CGPS exposures (Taylor+, 2003-)
VII/20 : Catalogue of HII Regions (Sharpless 1959)
J/A+AS/103/97 : Grids of stellar models V. (Meynet+ 1994)
J/AJ/129/856 : Herbig Ae/Be stars in nearby OB assoc. (Hernandez+, 2005)
J/MNRAS/379/1237 : VIcJHK phot. of NGC 1893 Halpha sources (Maheswar+, 2007)
J/MNRAS/396/964 : T Tauri in and around bright-rimmed clouds (Chauhan+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/A+A/501/539 : RMS survey. 6cm observations of YSOs (Urquhart+, 2009)
J/MNRAS/418/1689 : Red MSX water maser and ammonia emissions (Urquhart+, 2011)
J/ApJ/759/48 : YSOs in the Galactic HII region Sh2-297 (Mallick+, 2012)
J/ApJ/755/40 : HII regions in the MCs from MCELS (Pellegrini+, 2012)
J/MNRAS/430/1125 : RMS survey: NIR spectroscopy of massive YSOs (Cooper+, 2013)
J/ApJ/779/113 : IR photometry of YSOs in the W40 region (Mallick+, 2013)
J/MNRAS/439/3719 : Embedded clusters infrared photometry (Chavarria+, 2014)
J/MNRAS/443/1614 : YSOs in BRC 5, 7 and 39 (Panwar+, 2014)
J/MNRAS/454/4335 : Multiwavelenght photometry of Sh 2-138 YSOs (Baug+, 2015)
J/MNRAS/452/637 : Distance-limited sample of MYSOs (Maud+, 2015)
J/MNRAS/453/645 : Massive mol. outflows distance-limited sample (Maud+, 2015)
J/AJ/151/126 : Phot. of YSOs in eight bright-rimmed clouds (Sharma+, 2016)
J/MNRAS/468/2684 : IC1805 YSOs (Panwar+, 2017)
J/MNRAS/467/2943 : NGC 7538 region YSOs (Sharma+, 2017)
J/AJ/157/112 : IR phot. of YSOs in the W4 cloud complex (Panwar+, 2019)
J/ApJ/891/81 : Deep opt. and infrared photometry of Sh2-305 (Pandey+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/138] Running sequence number
5- 14 F10.6 deg RAdeg [308.28/308.64] Right Ascension (J2000)
16- 24 F9.6 deg DEdeg [45.46/45.76] Declination (J2000)
26- 31 F6.3 mag Jmag [8.48/20.96] 2MASS/UKIDSS J band magnitude (1)
33- 38 F6.3 mag e_Jmag [0.002/0.5]?=99.999 Uncertainty in Jmag
40- 45 F6.3 mag Hmag [7/18.53] 2MASS/UKIDSS H band magnitude (1)
47- 52 F6.3 mag e_Hmag [0.001/0.14]?=99.999 Uncertainty in Hmag
54- 59 F6.3 mag Kmag [6.2/17.5] 2MASS/UKIDSS K band magnitude (1)
61- 65 F5.3 mag e_Kmag [0.001/0.14] Uncertanity in Kmag
67- 72 F6.3 mag W1mag [5.73/13]?=99.999 WISE band 1 [3.4um] magnitude
74- 78 F5.3 mag e_W1mag [0.02/0.14]?=9.99 Uncertainty in W1mag
80- 85 F6.3 mag W2mag [5.17/12.5]?=99.999 WISE band 2 [4.6um] magnitude
87- 91 F5.3 mag e_W2mag [0.019/0.13]?=9.99 Uncertainty in W2mag
93- 98 F6.3 mag W3mag [4.52/9.41]?=99.999 WISE band 3 [12um] magnitude
100-104 F5.3 mag e_W3mag [0.014/0.2]?=9.99 Uncertainty in W3mag
106-111 F6.3 mag W4mag [0.96/9.18]?=99.999 WISE band 4 [22um] magnitude
113-117 F5.3 mag e_W4mag [0.02/0.51]?=9.99 Uncertainty in W4mag
119-126 A8 --- Flag Selection flag -- Color-Color/Color-Magnitude
diagram used ("NIR", "WISE", "WISE/NIR")
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Note (1): 2MASS/UKIDSS magnitudes represent primarily United Kingdom
Infrared Deep Sky Survey (UKIDSS) photometry, shifted to the 2MASS
photometric system for J>14, and 2MASS magnitudes for sources brighter
than this limit.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Jul-2022