J/ApJS/184/172 High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)
High- and intermediate-mass young stellar objects in the Large Magellanic Cloud.
Gruendl R.A., Chu Y.-H.
<Astrophys. J. Suppl. Ser., 184, 172-197 (2009)>
=2009ApJS..184..172G 2009ApJS..184..172G
ADC_Keywords: Photometry, infrared ; Magellanic Clouds ; YSOs ;
Cross identifications
Keywords: infrared: general - Magellanic Clouds - stars: formation - surveys
Abstract:
Archival Spitzer Infrared Array Camera (IRAC) and MIPS observations of
the Large Magellanic Cloud (LMC) have been used to search for young
stellar objects (YSOs). We have carried out independent aperture
photometry of these data and merged the results from different
passbands to produce a photometric catalog. To verify our methodology
we have also analyzed the data from the SAGE and SWIRE Legacy
programs; our photometric measurements are in general agreement with
the photometry released by these programs. Using our mid-infrared
photometric catalogs and two simple selection criteria,
[4.5]-[8.0]>2.0 to exclude normal and evolved stars and
[8.0]>14-([4.5]-[8.0]) to exclude background galaxies, we have
identified a sample of 2910 sources in the LMC that could potentially
be YSOs. We then used the Spitzer observations complemented by optical
and near-infrared data to carefully assess the nature of each source.
From the examination of the initial sample, we suggest that 1172
sources are most likely YSOs. Spitzer IRS observations of 269 of the
brightest YSOs from our sample have confirmed that ≳95% are indeed
YSOs.
Description:
The LMC has been observed by the Spitzer Space Telescope using the
Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for
Spitzer (MIPS). We have obtained complementary optical and near-IR
imaging observations using the Blanco 4m telescope at the Cerro Tololo
Inter-American Observatory for selected regions throughout the LMC.
The MOSAICII camera was used to obtain I-band observations on 2006
February 2-8. The IR Side Port Imager (ISPI) was used to obtain J- and
Ks-band observations during three observing runs in 2005 November,
2006 November, and 2007 February.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 142 117 LMC evolved stars
table5.dat 142 56 LMC planetary nebulae
table6.dat 140 949 Background galaxies
table7.dat 140 126 Probable background galaxies
table8.dat 140 159 Diffuse non-sources
table9.dat 140 855 Definite LMC Young Stellar Objects
table10.dat 140 317 Probable LMC Young Stellar Objects
table11.dat 140 213 Possible LMC Young Stellar Objects
table12.dat 140 291 Stellar sources
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See also:
II/255 : SWIRE ELAIS N1 Source Catalogs (Surace+, 2004)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/405/111 : LMC Survey of Young Stellar Systems (Gouliermis+, 2003)
J/AJ/122/1844 : MSX and 2MASS cross-correlation in LMC (Egan+, 2001)
J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)
Byte-by-byte Description of file: table*.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Source Source name (HHMMSS.ss+DDMMSS.s) (J2000) (1)
20- 24 F5.2 mag Jmag ? 2MASS J band magnitude
26- 28 F3.2 mag e_Jmag ? Uncertainty in Jmag
30- 34 F5.2 mag Hmag ? 2MASS H band magnitude
36- 38 F3.2 mag e_Hmag ? Uncertainty in Hmag
40- 44 F5.2 mag Ksmag ? 2MASS Ks band magnitude
46- 48 F3.2 mag e_Ksmag ? Uncertainty in Kmag
50- 54 F5.2 mag 3.6mag ? Spitzer/IRAC 3.6um band magnitude
56- 58 F3.2 mag e_3.6mag ? Uncertainty in 3.6mag
60- 64 F5.2 mag 4.5mag Spitzer/IRAC 3.6um band magnitude
66- 68 F3.2 mag e_4.5mag Uncertainty in 4.5mag
70- 74 F5.2 mag 5.8mag ? Spitzer/IRAC 3.6um band magnitude
76- 78 F3.2 mag e_5.8mag ? Uncertainty in 5.8mag
80- 84 F5.2 mag 8.0mag Spitzer/IRAC 3.6um band magnitude
86- 88 F3.2 mag e_8.0mag Uncertainty in 8.0mag
90- 94 F5.2 mag 24mag ? Spitzer/MIPS 24.0um band magnitude
96- 98 F3.2 mag e_24mag ? Uncertainty in 24.0mag
100 A1 --- f_24mag [s] saturated or amid saturated
diffuse emission.
102 A1 --- l_70mag Limit flag on 70.0mag
103-107 F5.2 mag 70mag ? Spitzer/MIPS 70.0um band magnitude
108-111 F4.2 mag e_70mag ? Uncertainty in 70.0mag
113-115 A3 --- Class Source classification (3)
117-140 A24 --- Simbad Cross identification from SIMBAD
142 A1 --- u_Simbad [?] Uncertainty flag on cross-identification
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Note (1): [GC2009] JHHMMSS.ss+DDMMSS.s in Simbad.
Note (3): Up to 3 classes can be found in this column.
When a single class is listed, the classification has a high
confidence; when several classes are listed in the column, the first
classification should be considered as "probable", the following
classifications giving possible alternatives.
A = AGB stars or post-AGB stars
D = Diffuse source: moderate contamination among our initial sample
by "sources" that are local enhancements within filamentary dust
emission most notably either at intersections between filaments
or at sharp bends in filaments.
E = Extremely Red Objects (EROs)
G = Background galaxy
P = Planetary Nebulae
S = "normal" stars (objects exhibiting normal stellar photospheric
emission and excess mid-IR emission due to circumstellar dust).
May be followed by a second class, e.g. 'SD' for stars with
photometric contamination from diffuse emission, or 'SC' for
stars with an IR excess that could possibly be YSOs.
C = Young Stellar Objects (YSO). A 'C' alone means that the object
can be considered as a "definite YSOs". When 'C' is followed
by another classification, the object can be considered as a
"probable YSOs". When 'C' appears as 2nd or 3rd choice, the
object is likely not an YSO, but this classification cannot
be ruled out: such objects are "possible YSOs".
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Feb-2010