J/ApJ/836/98 YSOs search in Stock 8 with opt. to IR photom. (Jose+, 2017)
The low-mass population in the young cluster Stock 8: stellar properties and
initial mass function.
Jose J., Herczeg G.J., Samal M.R., Fang Q., Panwar N.
<Astrophys. J., 836, 98-98 (2017)>
=2017ApJ...836...98J 2017ApJ...836...98J (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; YSOs ; Photometry, VRI ; Photometry, infrared
Keywords: stars: formation; stars: luminosity function, mass function
Abstract:
The evolution of H II regions/supershells can trigger a new generation
of stars/clusters at their peripheries, with environmental conditions
that may affect the initial mass function, disk evolution, and star
formation efficiency. In this paper we study the stellar content and
star formation processes in the young cluster Stock 8, which itself is
thought to be formed during the expansion of a supershell. We present
deep optical photometry along with JHK and 3.6 and 4.5µm photometry
from UKIDSS and Spitzer-IRAC. We use multicolor criteria to identify
the candidate young stellar objects in the region. Using evolutionary
models, we obtain a median log(age) of ∼6.5 (∼3.0Myr) with an observed
age spread of ∼0.25dex for the cluster. Monte Carlo simulations of the
population of Stock 8, based on estimates for the photometric
uncertainty, differential reddening, binarity, and variability,
indicate that these uncertainties introduce an age spread of ∼0.15dex.
The intrinsic age spread in the cluster is ∼0.2dex. The fraction of
young stellar objects surrounded by disks is ∼35%. The K-band
luminosity function of Stock 8 is similar to that of the Trapezium
cluster. The initial mass function (IMF) of Stock 8 has a
Salpeter-like slope at >0.5M☉ and flattens and peaks at
∼0.4M☉, below which it declines into the substellar regime.
Although Stock 8 is surrounded by several massive stars, there seems
to be no severe environmental effect in the form of the IMF due to the
proximity of massive stars around the cluster.
Description:
Optical imaging of Stock 8 was obtained on 2014 December 13 with the
Supernova Integral Field Spectrogap (SNIFS) instrument on the UH 2.2m
telescope at Maunakea, Hawaii. Two exposures were obtained in V and I
bands, with integration times of 150 and 100s, respectively. Average
seeing during observations was ∼0.7" (see Figure 1).
NIR photometry was obtained from the UKIDSS 6th archival data release
of the Galactic Plane Survey (GPS). UKIDSS observations were performed
using the UKIRT Wide Field Camera (WFCAM). Typical UKIDSS PSFs have
0.8"-1" FWHM with 0.4" pixels. 2MASS photometry is used to calibrate
the final fluxes.
The Spitzer data in the two bands of IRAC centered at 3.6 and 4.5um
were obtained from the Spitzer archive. These observations were taken
on 2010 May 05 (Program ID: 61070; PI: Barbara Whitney).
Objects:
------------------------------------------------------------------------
RA (ICRS) DE Designation(s) (Dist) (Age)
------------------------------------------------------------------------
05 28 07.5 +34 25 42 Stock 8 = Cl Stock 8 (2.1kpc) (∼1-5Myr)
------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 72 1326 Photometric data of all point sources
within 3' radius of Stock 8
--------------------------------------------------------------------------------
See also:
VI/128 : Log of CGPS exposures (Taylor+, 2003-)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)
J/ApJ/540/1016 : K-band & NICMOS photom. of Trapezium Cluster (Luhman+, 2000)
J/ApJ/573/366 : Infrared photometry of Trapezium cluster (Muench+, 2002)
J/ApJ/593/1093 : IC 348 membership (Luhman+, 2003)
J/MNRAS/379/289 : The outer Galaxy at 1420 and 408MHz. II. (Kerton+, 2007)
J/ApJ/672/914 : HST photometry in NGC 346 (Hennekemper+, 2008)
J/ApJ/686/1195 : IR photometry in the γ Vel cluster (Hernandez+, 2008)
J/MNRAS/384/1675 : BVRIc photometry of Stock 8 (Jose+, 2008)
J/ApJ/688/377 : Low-mass objects in Upper Scorpius. II. (Slesnick+, 2008)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/MNRAS/392/1034 : IZJHKL' photometry of NGC 6611 (Oliveira+, 2009)
J/A+A/539/A119 : Pismis 24 stars with X-ray emission (Fang+, 2012)
J/ApJ/755/20 : YSOs population of Sh2-294 with Spitzer/IRAC (Samal+, 2012)
J/ApJS/207/5 : YSOs in LDN 1641 with Hectochelle spectra (Fang+, 2013)
J/A+A/558/A53 : MW global survey of star clusters. II. (Kharchenko+, 2013)
J/ApJ/764/172 : UBVRI photometry of stars toward NGC 1931 (Pandey+, 2013)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/A+A/569/A125 : Spiral structure of the Milky Way (Hou+, 2014)
J/ApJ/787/107 : Spatial structure of young clusters. I. (Kuhn+, 2014)
J/MNRAS/443/1614 : YSOs in BRC 5, 7 and 39 (Panwar+, 2014)
J/A+A/566/A122 : JHK and IRAC photometry of Sh2-90 YSOs (Samal+, 2014)
J/AJ/150/147 : Galactic HII regions. I. Stellar distances (Foster+, 2015)
J/A+A/581/A66 : UV variability and accretion in NGC 2264 (Venuti+, 2015)
J/ApJ/822/49 : Candidate YSOs in AFGL 333 (Jose+, 2016)
J/MNRAS/459/880 : Open clusters in Auriga OB2 (Marco+, 2016)
J/AJ/151/126 : Photom. of YSOs in 8 bright-rimmed clouds (Sharma+, 2016)
J/A+A/585/A49 : VCNS II. The IR-excess-selected population (Zeidler+, 2016)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.4 deg RAdeg Right Ascension in decimal degrees (J2000)
9- 15 F7.4 deg DEdeg Declination in decimal degrees (J2000)
17- 21 F5.2 mag Vmag [8.9/24.1]? SNIFS V band magnitude
23- 27 F5.2 mag Imag [8.6/22.3]? SNIFS I band magnitude
29- 33 F5.2 mag Jmag [8.3/20.1]? UKIDSS J band magnitude
35- 39 F5.2 mag Hmag [8.3/19.2]? UKIDSS H band magnitude
41- 45 F5.2 mag Kmag [8.3/18.4]? UKIDSS K band magnitude
47- 51 F5.2 mag 3.6mag [8.2/17.2]? Spitzer/IRAC 3.6um band magnitude
53- 57 F5.2 mag 4.5mag [8.2/17.1]? Spitzer/IRAC 4.5um band magnitude
59- 63 A5 --- --- [class]
64- 72 A9 --- Class Class ("I": 15 occurrences; "II": 146 occurrences
or "III/field")
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Jose et al. Paper I. 2008MNRAS.384.1675J 2008MNRAS.384.1675J Cat. J/MNRAS/384/1675
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Sep-2017