J/ApJ/678/200 YSOs in N63 and N180 (Caulet+, 2008)
Young stellar objects in the Large Magellanic Cloud: N63 and N180 HII regions.
Caulet A., Gruendl R.A., Chu Y.-H.
<Astrophys. J., 678, 200-218 (2008)>
=2008ApJ...678..200C 2008ApJ...678..200C
ADC_Keywords: YSOs ; Photometry, infrared ; Magellanic Clouds ; H II regions
Mission_Name: Spitzer
Keywords: H II regions - Magellanic Clouds - stars: formation
Abstract:
We used Spitzer infrared observations to find the young stars of two
HII regions in the Large Magellanic Cloud, N63 and N180. The young
stellar object (YSO) candidates were identified in each nebula by
means of color-color, color-magnitude diagrams, and the shapes of
their spectral energy distributions (SEDs). The most luminous YSOs are
found near the ionization fronts within strong 8um emission clumps.
Most YSOs, less luminous, are seen in projection inside the HII
regions. HST images show several Class I stars that have emerged along
the borders of the HII regions; other YSOs are embedded in cometary
clouds. The most luminous YSO of N63 is connected to a string of
pointlike sources. Its SED can be modeled by a central source of
stellar mass M* between 7 and 11M☉, with a circumstellar disk
of outer radius Rd of ∼55AU, and an envelope of moderate accretion
rate, Menv of ∼2x10-5M☉/yr. N180 is experiencing a phase of
star formation more intense than N63, attested by the properties of
its most luminous YSO: M* of 25M☉, Rd of ∼200AU, and Menv
of ∼1.5x10-3M☉/yr. The modes of triggered star formation in
N63 and N180 appear similar to those seen in Galactic HII regions.
Description:
The deep Spitzer observations of N63 and N180 are part of program
ID 3565 "Massive Star Forming Regions in the LMC". They were obtained
on 2004 December 16 with the Infrared Array Camera (IRAC) and on 2005
March 7 with the Multiband Imaging Photometer (MIPS).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 141 18 Galaxies and AGB stars
table5.dat 141 29 Properties of the YSOs of N63
table6.dat 141 38 Properties of the YSOs of N180
notes.dat 76 42 Notes on YSOs
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See also:
J/A+A/405/111 : LMC Survey of Young Stellar Systems (Gouliermis+, 2003)
J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)
J/ApJ/699/150 : Spectral classifications of Massive YSOs in LMC (Seale+,
2009)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Field Field of view
10 A1 --- f_Field [cd] Flag on Field (1)
12- 14 A3 --- cl AGB or Galaxy type (2)
15 A1 --- f_cl [e] superimposed sources (3)
17 I1 h RAh Hour of right ascension (J2000)
19- 20 I2 min RAm Minute of right ascension (J2000)
22- 26 F5.2 s RAs Second of right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Degree of declination (J2000)
32- 33 I2 arcmin DEm Arcminute of declination (J2000)
35- 38 F4.1 arcsec DEs Arcsecond of declination (J2000)
40- 45 F6.3 mag Jmag ? 2MASS J-band magnitude
47- 51 F5.3 mag e_Jmag ? Jmag uncertainty
53- 58 F6.3 mag Hmag ? 2MASS H-band magnitude
60- 64 F5.3 mag e_Hmag ? Hmag uncertainty
66- 71 F6.3 mag Ksmag ? 2MASS Ks-band magnitude
73- 77 F5.3 mag e_Ksmag ? Ksmag uncertainty
79- 84 F6.3 mag 3.6mag Spitzer/IRAC 3.6um magnitude (G1)
86- 90 F5.3 mag e_3.6mag 3.6mag uncertainty (G1)
92- 97 F6.3 mag 4.5mag Spitzer/IRAC 4.5um magnitude (G1)
99-103 F5.3 mag e_4.5mag 4.5mag uncertainty (G1)
105-110 F6.3 mag 5.8mag Spitzer/IRAC 5.8um magnitude (G1)
112-116 F5.3 mag e_5.8mag 5.8mag uncertainty (G1)
118-123 F6.3 mag 8.0mag Spitzer/IRAC 8.0um magnitude (G1)
125-129 F5.3 mag e_8.0mag 8.0mag uncertainty (G1)
131-135 F5.3 mag 24mag ? Spitzer/MIPS 24.0um magnitude (G1)
137-141 F5.3 mag e_24mag ? 24mag uncertainty (G1)
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Note (1): Note on Field of view (FOV) as follows:
c = FOV of 40'x40' shown in Figs. 4 and 8 for N63 and N180, respectively.
Two AGB stars are located within the boundaries of Fig. 9.
d = FOV of 10'x10' of ISPI images for N63 and N180; the galaxies are shown
in Figs. 5, 6, and 9.
Note (2): These objects were removed from our lists of classified YSOs.
They are evolved stars (AGB) identified in the CMD diagrams or
background galaxies (G) identified on ISPI images (see text).
Note (3):
e = There are two 2MASS superimposed sources at this position; the
magnitudes of the other source are [J]=13.858±0.026,
[H]=12.864±0.034, and [Ks]=11.841±0.271 .
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Byte-by-byte Description of file: table5.dat table6.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Name YSO name (see Nomenclature notes) (1)
5- 6 A2 --- cl [1/2/fs ] YSO class (2)
8 I1 h RAh Hour of right ascension (J2000)
10- 11 I2 min RAm Minute of right ascension (J2000)
13- 17 F5.2 s RAs Second of right ascension (J2000)
19 A1 --- DE- Declination sign (J2000)
20- 21 I2 deg DEd Degree of declination (J2000)
23- 24 I2 arcmin DEm Arcminute of declination (J2000)
26- 29 F4.1 arcsec DEs Arcsecond of declination (J2000)
31 A1 --- f_Jmag [*] This paper ISPI Jmag; 2MASS otherwise
32- 37 F6.3 mag Jmag ? 2MASS J-band magnitude
39- 43 F5.3 mag e_Jmag ? Jmag uncertainty
45- 50 F6.3 mag Hmag ? 2MASS H-band magnitude
52- 56 F5.3 mag e_Hmag ? Hmag uncertainty
58 A1 --- f_Ksmag [*] This paper ISPI Ksmag; 2MASS otherwise
59- 64 F6.3 mag Ksmag ? 2MASS Ks-band magnitude
66- 70 F5.3 mag e_Ksmag ? Ksmag uncertainty
72- 77 F6.3 mag 3.6mag Spitzer/IRAC 3.6um magnitude (G1)
79- 83 F5.3 mag e_3.6mag 3.6mag uncertainty (G1)
85- 90 F6.3 mag 4.5mag Spitzer/IRAC 4.5um magnitude (G1)
92- 96 F5.3 mag e_4.5mag 4.5mag uncertainty (G1)
98-103 F6.3 mag 5.8mag Spitzer/IRAC 5.8um magnitude (G1)
105-109 F5.3 mag e_5.8mag 5.8mag uncertainty (G1)
111-116 F6.3 mag 8.0mag Spitzer/IRAC 8.0um magnitude (G1)
118-122 F5.3 mag e_8.0mag 8.0mag uncertainty (G1)
124-128 F5.3 mag 24mag ? Spitzer/MIPS 24.0um magnitude (G1) (3)
130-134 F5.3 mag e_24mag ? 24mag uncertainty (G1) (3)
136-138 I3 arcsec Sep YSO separation from center of HII region (4)
139 A1 --- --- [/]
140 A1 --- m [1-3m-] Multiplicity (5)
141 A1 --- n_Name [f-mF-W] Note on YSOs. See notes.dat file (6)
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Note (1): YSOs without 24um photometry have a "C" appended to their number in
these tables, including N63 YSOs 8C, 16C, and 31C, which have 24um
manual photometry.
Note (2): The class "flat spectrum" is designated by "fs".
Note (3): The 24um magnitudes listed here used the SSC aperture corrections,
which likely underestimate fluxes by a factor of ∼20% (see Sect. 2.2).
Note (4): separation of YSOs from the approximate center of
* NGC 2030 (=LHA 120-N 63) at 05:35:32.3-66:02:38 (J2000.0),
i.e., on star 2 (Fig. 6) in table5;
* the brightest ionizing star of NGC 2122 at 05:48:49.6-70:03:58 (J2000.0)
(=HD 270145), i.e. star 118 (Fig. 9) in table6
Note (5): Number of stars seen on J, Ks ISPI images within 3" of the YSO;
"m" is for several stars.
Note (6): Lower case letter flag for table 5, upper case letter for table 6.
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1 A1 --- Flag Note designation
3- 76 A74 --- Note Text of note
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Global note:
Note (G1): The IRAC bands and the MIPS 24um magnitude errors are those
resulting from the aperture photometry. There are additional errors
of ∼0.11mag from the flux calibration uncertainties (Fazio et al.,
2004ApJS..154...39F 2004ApJS..154...39F; Rieke et al., 2004ApJS..154...25R 2004ApJS..154...25R).
Nomenclature notes:
In table3, objects are <[CGC2008] JHHMMSS.ss+DDMMSS.s> in Simbad;
In table5, YSOs are <[CGC2008] N63 NN> or <[CGC2008] N63 NNC> in Simbad;
In table6, YSOs are <[CGC2008] N180 NN> or <[CGC2008] N180 NNC> in Simbad.
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 16-Sep-2010