J/ApJ/712/797 YSOs in Vul OB1 association (Billot+, 2010)
Young stellar objects and triggered star formation in the Vulpecula OB
association.
Billot N., Noriega-Crespo A., Carey S., Guieu S., Shenoy S., Paladini R.,
Latter W.
<Astrophys. J., 712, 797-812 (2010)>
=2010ApJ...712..797B 2010ApJ...712..797B
ADC_Keywords: Associations, stellar ; Photometry, infrared ; YSOs ; H II regions
Keywords: H II regions - infrared: ISM - infrared: stars - stars: formation -
stars: pre-main sequence
Abstract:
The Vulpecula OB association, Vul OB1, is a region of active star
formation located in the Galactic plane at 2.3kpc from the Sun.
Previous studies suggest that sequential star formation is propagating
along this 100pc long molecular complex. In this paper, we use Spitzer
MIPSGAL and GLIMPSE data to reconstruct the star formation history of
Vul OB1, and search for signatures of past triggering events. We make
a census of young stellar objects (YSOs) in Vul OB1 based on IR color
and magnitude criteria, and we rely on the properties and nature of
these YSOs to trace recent episodes of massive star formation. We find
856 YSO candidates, and show that the evolutionary stage of the YSO
population in Vul OB1 is rather homogeneous -ruling out the scenario
of propagating star formation. We estimate the current star formation
efficiency to be ∼8%. We also report the discovery of a dozen
pillar-like structures, which are confirmed to be sites of small scale
triggered star formation.
Description:
The Spitzer Space Telescope observed over 270deg2 of the inner
Galactic plane in six wavelength bands as part of two legacy programs:
the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE;
PI: E. Churchwell; Benjamin et al. 2003PASP..115..953B 2003PASP..115..953B) and the MIPS
GALactic plane survey (MIPSGAL; S. Carey PI; Carey et al.
2009PASP..121...76C 2009PASP..121...76C). The Vulpecula region was covered by GLIMPSE I
(PID 188) and MIPSGAL I (PID 20597). It was imaged with the Infrared
Array Camera (IRAC) at 3.6, 4.5, 5.8, and 8.0um, and with the MIPS
camera at 24 and 70um. The angular resolution of Spitzer is 2", 6",
and 18" at 8, 24, and 70um, respectively.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 105 856 List of YSO candidates and their 2MASS, IRAC and
MIPS photometry
table3.dat 48 14 Pillars identification, coordinates, and
approximate size
table5.dat 108 14 List of point sources excluded from the YSO
catalog and identified as probable contaminants
based on their IRAC fluxes
--------------------------------------------------------------------------------
See also:
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
J/A+A/537/A1 : Infrared fluxes of HII regions and PNe (Anderson+, 2012)
J/A+A/498/147 : High mass protostellar objects physical parameters (Grave+,
2009)
J/ApJ/658/1264 : IR-excess sources in GLIMPSE and MSX (Uzpen+, 2007)
Byte-by-byte Description of file: table[25].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- --- [SSTGLMC]
9- 25 A17 --- SSTGLMC GLIMPSE source name (GLLL.llll+BB.bbbb)
27- 33 F7.4 deg GLON Galactic Longitude
35- 41 F7.4 deg GLAT Galactic Latitude
43- 47 F5.2 mag Jmag ? 2MASS J band magnitude
49- 53 F5.2 mag Hmag ? 2MASS H band magnitude
55- 59 F5.2 mag Ksmag ? 2MASS Ks band magnitude
61- 65 F5.2 mag [3.6] ? Spitzer/IRAC 3.6 micron band magnitude
67- 71 F5.2 mag [4.5] ? Spitzer/IRAC 4.5 micron band magnitude
73- 77 F5.2 mag [5.8] ? Spitzer/IRAC 5.8 micron band magnitude
79- 83 F5.2 mag [8.0] ? Spitzer/IRAC 8.0 micron band magnitude
85- 89 F5.2 mag [24] ? Spitzer/MIPS 24 micron band magnitude
91- 95 F5.2 mag [70] ? Spitzer/MIPS 70 micron band magnitude
97-101 F5.2 --- SpIndex ? Infrared spectral index (1)
103-108 A6 --- Class Source classification (2)
--------------------------------------------------------------------------------
Note (1): Slope of SED measured from 3.6 to 8.0 microns.
Note (2): Class as follows:
0/I = likely protostars with infalling envelops
II = disk-bearing stars
III = Class III objects with very little circumstellar material
Galaxy = contaminant (in table5)
Shock = contaminant (in table5)
See section 4.3 for further details.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- [BNC2010] Pillar identification (VulPNN)
8- 12 F5.2 deg GLON Galactic longitude
14- 18 F5.2 deg GLAT Galactic latitude
20- 25 F6.2 deg RAdeg Right ascension in decimal degrees (J2000)
27- 31 F5.2 deg DEdeg Declination in decimal degrees (J2000)
33- 34 I2 arcmin amaj1 Size for the long axis
35 A1 --- --- [-]
36 I1 arcmin amaj2 ? Size range
38 A1 --- --- [x]
40- 42 F3.1 arcmin bmin1 Size for the shorter axis
43 A1 --- --- [-]
44 I1 arcmin bmin2 ? Size range
46- 48 I3 deg PA Position angle (given between the long axis of
the pillar and the west axis, positive values
are toward the north)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Apr-2012