J/ApJ/834/185 IR-bright MSX sources in the SMC with Spitzer/IRS (Kraemer+, 2017)
Characterizing the population of bright infrared sources in the
Small Magellanic Cloud.
Kraemer K.E., Sloan G.C., Wood P.R., Jones O.C., Egan M.P.
<Astrophys. J., 834, 185-185 (2017)>
=2017ApJ...834..185K 2017ApJ...834..185K (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Spectra, infrared ; Stars, giant ;
Spectral types ; Photometry, infrared ; Photometry, UBV
Keywords: circumstellar matter; infrared: stars; Magellanic Clouds
Abstract:
We have used the Infrared Spectrograph (IRS) on the Spitzer Space
Telescope to observe stars in the Small Magellanic Cloud (SMC)
selected from the Point Source Catalog of the Midcourse Space
Experiment (MSX). We concentrate on the dust properties of the
oxygen-rich evolved stars. The dust composition has smaller
contributions from alumina compared to the Galaxy. This difference may
arise from the lower metallicity in the SMC, but it could be a
selection effect, as the SMC sample includes more stars that are
brighter and thus more massive. The distribution of the SMC stars
along the silicate sequence looks more like the Galactic sample of red
supergiants than asymptotic giant branch stars (AGBs). While many of
the SMC stars are definitively on the AGB, several also show evidence
of hot bottom burning. Three of the supergiants show PAH emission at
11.3µm. Two other sources show mixed chemistry, with both
carbon-rich and oxygen-rich spectral features. One, MSX SMC 134, may
be the first confirmed silicate/carbon star in the SMC. The other, MSX
SMC 049, is a candidate post-AGB star. MSX SMC 145, previously
considered a candidate OH/IR star, is actually an AGB star with a
background galaxy at z=0.16 along the same line of sight. We consider
the overall characteristics of all the MSX sources, the most
infrared-bright objects in the SMC, in light of the higher sensitivity
and resolution of Spitzer, and compare them with the object types
expected from the original selection criteria. This population
represents what will be seen in more distant galaxies by the upcoming
James Webb Space Telescope (JWST). Color-color diagrams generated from
the IRS spectra and the mid-infrared filters on JWST show how one can
separate evolved stars from young stellar objects (YSOs) and
distinguish among different classes of YSOs.
Description:
Our original set of infrared spectra of MSX SMC sources was obtained
in Spitzer Cycle 1 (Program ID 3277, P.I. M. Egan). This program
included 35 targets from the MSX SMC catalog. 24 targets were
discussed in previous papers; this paper examines the remaining 11
sources in the sample. We also selected 4 objects in the MSX SMC
catalog with similar photometric characteristics in an effort to
uncover additional sources with crystalline dust. We observed these
targets in Spitzer Cycle 3 (Program ID 30355, P.I. J. Houck).
See tables 1 and 2 for observation data and basic properties of the
targets.
Table 3 lists 20 additional MSX SMC sources that were observed by
other Spitzer IRS programs. Overall, 59 MSX SMC sources were observed
with the IRS.
The spectra were observed using the low-resolution modules of the IRS,
Short-Low (SL) and Long-Low (LL), which provided spectra in the 5-14
and 14-37um ranges, respectively, at a resolution between ∼60 and 120.
For 10 evolved stars with oxygen-rich dust in our Cycle 1 program, we
obtained spectra from 0.45 to 1.03um with the Double-Beam Spectrograph
at the 2.3m telescope of the Australian National University at Siding
Spring Observatory. A 0.45-0.89um spectrum for one of the stars in
program 30355 was also observed. These spectra have a resolution of
10Å.
Tables 5-7: catalog based on the 243 sources detected in the MSX
survey of the SMC, updated with positions and photometry from more
recent space-based missions and ground-based surveys. See the Appendix
section for more details. The SMC catalog from MSX consists of the 243
sources in the main MSX catalog (Egan+ 2003, see V/114) that lie
within the region 7°<RAJ2000<18.7° and
-74.4°<DEJ2000←71.5l°.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 65 15 Spitzer/IRS observing log
table2.dat 99 15 Observed program sources
table3.dat 80 20 MSX SMC targets observed in other programs
table4.dat 63 14 Oxygen-rich dust analysis
table5.dat 101 247 MSX SMC source positions
table6.dat 101 247 MSX SMC source photometry: mid-IR
table7.dat 101 247 MSX SMC source photometry: optical and near-IR
--------------------------------------------------------------------------------
See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
II/228 : DENIS Catalogue toward Magellanic Clouds (DCMC) (Cioni+ 2000)
V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
II/288 : IRSF Magellanic Clouds Point Source Catalog (Kato+ 2007)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+AS/97/603 : C stars in SMC (Rebeirot+ 1993)
J/ApJS/119/141 : Oxygen-rich dust shells IR spectral classif. (Sloan+ 1998)
J/AJ/122/1844 : MSX and 2MASS cross-correlation in LMC (Egan+, 2001)
J/AJ/124/2990 : MSX galaxy observations (Kraemer+, 2002)
J/AJ/123/855 : Magellanic Clouds Photometric Survey: SMC (Zaritsky+, 2002)
J/AJ/126/1423 : MSX 8.3um fluxes of star-forming regions (Kraemer+, 2003)
J/AJ/126/2867 : Red supergiants in Magellanic Clouds (Massey+, 2003)
J/A+A/425/595 : OGLE+2MASS+DENIS LPV in Magellanic Clouds (Groenewegen, 2004)
J/A+A/438/521 : SMC C stars B and R light curves (Raimondo+, 2005)
J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)
J/ApJ/655/212 : S3MC IRAC and MIPS photometry (Bolatto+, 2007)
J/A+A/469/799 : Torun catalog of post-AGB & related objects (Szczerba+, 2007)
J/A+A/506/1277 : Modelisation of MCs C/O stars (Groenewegen+, 2009)
J/AJ/142/103 : Cool evolved stars in SAGE-SMC and SAGE-LMC (Boyer+, 2011)
J/AcA/61/217 : VI LCs of SMC long-period variables (Soszynski+, 2011)
J/MNRAS/411/1597 : LMC point source classification in SAGE-Spec (Woods+, 2011)
J/MNRAS/427/3209 : Galactic and MC O-AGBs and RSGs stars (Jones+, 2012)
J/other/Ser/184.93 : 6cm and 3cm sources in SMC (Wong+, 2012)
J/MNRAS/440/631 : IR photometry of LMC O-rich evolved stars (Jones+, 2014)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)
J/A+A/578/A3 : New survey of supergiants in MCs (Gonzalez-Fernandez+, 2015)
J/ApJ/811/145 : LMC & SMC evolved stars detected with Herschel (Jones+, 2015)
J/AJ/149/78 : Candidate IR variables from SAGE-SMC survey (Polsdofer+, 2015)
J/MNRAS/449/639 : VMC survey. XIV. SFR in SMC (Rubele+, 2015)
J/MNRAS/451/3504 : Classification of IRS sources in the SMC (Ruffle+, 2015)
J/AJ/149/11 : Spectra of candidate standard stars in mid-IR (Sloan+, 2015)
J/ApJ/826/44 : Spitzer/IRS obs. of Magellanic carbon stars (Sloan+, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [0/181] MSX SMC Designation (G1)
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 33 F4.1 arcsec DEs Arcsecond of Declination (J2000)
35- 39 I5 --- PID Spitzer Program ID
41- 48 I8 --- AOR Spitzer AOR ID
50- 52 I3 s exp1 Total exposure time, IRS Short-Low
54- 57 I4 s exp2 Total exposure time, IRS Long-Low
59- 65 F7.1 d MJD Observation Date, JD-2400000.5
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [0/181] MSX SMC Designation (G1)
11- 26 A16 --- AltName Alternative Name
28- 31 I4 d Per [141/1859]? Period from literature
33- 35 A3 --- r_Per Reference for Per (1)
37- 50 A14 --- SpT Optical MK Spectral Type
52- 64 A13 --- r_SpT Reference for SpT (2)
66- 76 A11 --- IR Infrared Spectral Class
78- 82 F5.2 mag Mbol [-8.5/-5] Bolometric magnitude (G2)
84- 93 A10 --- R15 Ruffle+ (2015, J/MNRAS/451/3504) class
95- 95 A1 --- f_R15 [c] c: R15 class changed in this manuscript
97- 99 A3 --- Var Variable class, GCVS (Samus et al. Cat. B/gcvs)
--------------------------------------------------------------------------------
Note (1): Period references as follows:
P97 = Pojmanski (1997AcA....47..467P 1997AcA....47..467P, 2014CoSka..43..523P 2014CoSka..43..523P);
G09 = Groenewegen et al. (2009, J/A+A/506/1277);
S11 = Soszynski et al. (2011, J/AcA/61/217).
Note (2): Optical spectral type references as follows:
B80 = Blanco et al. (1980ApJ...242..938B 1980ApJ...242..938B);
E80 = Elias et al. (1980ApJ...242L..13E 1980ApJ...242L..13E);
P83 = Prevot et al. (1983, J/A+AS/53/255);
W83 = Wood et al. (1983ApJ...272...99W 1983ApJ...272...99W);
R93 = Rebeirot et al. (1993, J/A+AS/97/603);
R05 = Raimondo et al. (2005, J/A+A/438/521);
G98 = Groenewegen & Blommaert (1998A&A...332...25G 1998A&A...332...25G);
G15 = Gonzalez-Fernandez et al. (2015, J/A+A/578/A3);
K16 = this work;
Multiple = in five or more of the references.
Additional, multiply-used references: Sanduleak (1989AJ.....98..825S 1989AJ.....98..825S);
Elias et al. (1985ApJS...57...91E 1985ApJS...57...91E);
Massey & Olsen (2003, J/AJ/126/2867);
Levesque et al. (2006ApJ...645.1102L 2006ApJ...645.1102L).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [27/234] MSX SMC Designation
11- 25 A15 --- AltName Alternative Name
27- 31 I5 --- PID Spitzer Program ID
33- 40 I8 --- AOR Spitzer AOR ID
42- 48 A7 --- IR Infrared Spectral Class
50- 58 A9 --- R15 Ruffle+ (2015, J/MNRAS/451/3504) class
60- 64 F5.2 mag Mbol Bolometric magnitude (G2)
66- 80 A15 --- Ref References (1)
--------------------------------------------------------------------------------
Note (1): References as follows:
L07 = Lagadec et al. (2007MNRAS.376.1270L 2007MNRAS.376.1270L);
J12 = Jones et al. (2012, J/MNRAS/427/3209);
BS08 = Bernard-Salas et al. (2008ApJ...672..274B 2008ApJ...672..274B)
BS09 = Bernard-Salas et al. (2009ApJ...699.1541B 2009ApJ...699.1541B);
S14 = Sloan et al. (2014ApJ...791...28S 2014ApJ...791...28S);
O13 = Oliveira et al. (2013MNRAS.428.3001O 2013MNRAS.428.3001O);
S08 = Sloan et al. (2008ApJ...686.1056S 2008ApJ...686.1056S);
LK16 = Keller et al. in prep.;
R15 = Ruffle et al. (2015, J/MNRAS/451/3504)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [0/181] MSX SMC Designation (G1)
11- 14 F4.2 mag [7]-[15] [0.2/2.1] The [7]-[15] color index
16- 19 F4.2 mag e_[7]-[15] [0/0.02] Uncertainty in [7]-[15]
21- 24 F4.2 --- DEC [0.02/3] Dust emission contrast (3)
26- 29 F4.2 --- e_DEC [0/0.03] Uncertainty in DEC
31- 34 F4.2 --- F10/F11 [0.7/1.4] Flux ratio, F10um/F11um
36- 39 F4.2 --- e_F10/F11 [0.01/0.2] Uncertainty in F10/F11
41- 44 F4.2 --- F10/F12 [0.5/2.4] Flux ratio, F10um/F12um
46- 49 F4.2 --- e_F10/F12 [0.02/0.2] Uncertainty in F10/F12
51- 54 F4.2 --- F11/F12 [0.9/1.7] Flux ratio, F11um/F12um, corrected
56- 59 F4.2 --- e_F11/F12 [0.02/0.3] Uncertainty in F11/F12
61- 63 A3 --- SEi SE Index (4)
--------------------------------------------------------------------------------
Note (3): Dust emission contrast is the ratio of stellar continuum to dust
excess from 7.67 to 14.03um.
Note (4): SE index = floor(corrected 10*F11/F12-7.5).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [1/243] MSX SMC Designation
10 A1 --- m_MSXSMC [AB] Component on MSXSMC
12- 41 A30 --- AltName Alternative Name (1)
43- 51 F9.6 deg RAdeg Right Ascension (J2000)
53- 62 F10.6 deg DEdeg Declination (J2000)
64- 68 A5 --- r_Pos Position Reference (2)
70 A1 --- Q Morphological Grade (3)
72- 77 F6.3 mag Mbol [-8.5/-4.5]?=0 Bolometric Magnitude (G2)
78- 89 A12 --- IRSType IRS-based Source Type
91- 98 A8 --- r_IRSType Source Type Reference (4)
100-101 A2 --- Notes Comments (FG= probable foreground star; or
CL = probable star in a cluster)
--------------------------------------------------------------------------------
Note (1): OGLE SMC-LPV-10622 is very likely a misprint for OGLE SMC-LPV-10662;
Note added by CDS.
Note (2): Position references as follows:
2MASS = Cutri et al. (2003, Cat. II/281)
IRAC = Gordon et al. (2011AJ....142..102G 2011AJ....142..102G, Cat. II/305)
MIPS = Gordon et al. (2011AJ....142..102G 2011AJ....142..102G)
MSX = Egan et al. (2003, Cat. V/114)
Note (3): Morphological grade as follows:
A = isolated point sources with little or no extended emission around them.
B = an IRAC point source within 20" or extended emission which contaminates
the MSX beam.
C = complex and crowded fields
D = more complex or crowded fields
E = even more complex or crowded
F = MSX SMC 032, with no point-like object in its vicinity at any wavelength.
Note (4): Source Type References as follows:
BS09 = Bernard-Salas et al. (2009ApJ...699.1541B 2009ApJ...699.1541B)
J12 = Jones et al. (2012, J/MNRAS/427/3209)
K05 = Kraemer et al. (2005ApJ...631L.147K 2005ApJ...631L.147K)
K06 = Kraemer et al. (2006ApJ...652L..25K 2006ApJ...652L..25K)
K16 = This work
L07 = Lagadec et al. (2007MNRAS.376.1270L 2007MNRAS.376.1270L)
O13 = Oliveira et al. (2013MNRAS.428.3001O 2013MNRAS.428.3001O)
R15 = Ruffle et al. (2015, J/MNRAS/451/3504)
S06 = Sloan et al. (2006ApJ...645.1118S 2006ApJ...645.1118S)
S08 = Sloan et al. (2008ApJ...686.1056S 2008ApJ...686.1056S)
S14 = Sloan et al. (2014ApJ...791...28S 2014ApJ...791...28S)
S16 = Sloan et al. (2016ApJ...826...44S 2016ApJ...826...44S)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [1/243] MSX SMC Designation
10 A1 --- m_MSXSMC [AB] Component on MSXSMC
12- 17 F6.3 mag 3.6mag [2.7/13.5]?=99.999 Mean 3.6um band magnitude (4)
19- 23 F5.3 mag e_3.6mag [0.01/0.9]?=9.999 Uncertainty in 3.6mag
25- 30 F6.3 mag 4.5mag [2/13.8]?=99.999 Mean 4.5um band magnitude (4)
32- 36 F5.3 mag e_4.5mag [0/0.7]?=9.999 Uncertainty in 4.5mag
38- 43 F6.3 mag 5.8mag [3/11.6]?=99.999 Mean Spitzer/IRAC 5.8um band
magnitude
45- 49 F5.3 mag e_5.8mag [0.001/0.6]?=9.999 Uncertainty in 5.8mag
51- 56 F6.3 mag 8.0mag [3/9.8]?=99.999 Mean Spitzer/IRAC 8.0um band
magnitude
58- 62 F5.3 mag e_8.0mag [0/0.5]?=9.999 Uncertainty in 8.0mag
64- 69 F6.3 mag 12mag [2.8/8.7]?=99.999 Mean WISE 12um band magnitude
71- 75 F5.3 mag e_12mag [0.01/0.2]?=9.999 Uncertainty in 12mag
77- 82 F6.3 mag 22mag [0.2/7.8]?=99.999 Mean WISE 22um band magnitude
84- 88 F5.3 mag e_22mag [0.01/0.3]?=9.999 Uncertainty in 22mag
90- 95 F6.3 mag 24mag [1/8.6]?=99.999 Mean Spitzer/MIPS 24um band
magnitude
97-101 F5.3 mag e_24mag [0.001/0.6]?=9.999 Uncertainty in 24mag
--------------------------------------------------------------------------------
Note (4): Mean photometry from multi-epoch, multi-instrument observations --
3.6mag: combined Spitzer/IRAC 3.6um and WISE 3.4um data without color
corrections;
4.5mag: combined Spitzer/IRAC 4.5um and WISE 4.6um data without color
corrections;
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [MSXSMC]
7- 9 I03 --- MSXSMC [1/243] MSX SMC Designation
10 A1 --- m_MSXSMC [AB] Component on MSXSMC
12- 17 F6.3 mag Umag [12.2/20.8]?=99.999 U band magnitude (5)
19- 23 F5.3 mag e_Umag [0.02/0.3]?=9.999 Uncertainty in Umag
25- 30 F6.3 mag Bmag [9.6/22.6]?=99.999 B band magnitude (5)
32- 36 F5.3 mag e_Bmag [0.01/0.4]?=9.999 Uncertainty in Bmag
38- 43 F6.3 mag Vmag [9.7/23]?=99.999 V band magnitude (5)
45- 49 F5.3 mag e_Vmag [0/3]?=9.999 Uncertainty in Vmag
51- 56 F6.3 mag Imag [8.3/21]?=99.999 I band magnitude (5)
58- 62 F5.3 mag e_Imag [0.002/1.3]?=9.999 Uncertainty in Imag
64- 69 F6.3 mag Jmag [4.7/19]?=99.999 J band magnitude (6)
71- 75 F5.3 mag e_Jmag [0.007/2]?=9.999 Uncertainty in Jmag
77- 82 F6.3 mag Hmag [3.7/17.2]?=99.999 H band magnitude (6)
84- 88 F5.3 mag e_Hmag [0/2]?=9.999 Uncertainty in Hmag
90- 95 F6.3 mag Kmag [3.4/16.2]?=99.999 K band magnitude (6)
97-101 F5.3 mag e_Kmag [0.005/1]?=9.999 Uncertainty in Kmag
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Note (5): The MCPS (Magellanic Clouds Photometric Survey; Zaritsky+ 2002,
J/AJ/123/855) provides mean magnitudes at U, B, V and I. When mean
magnitudes at V and I are available from the LPV catalogs
from OGLE-III (Soszynski+ 2011, J/AcA/61/217), we substituted these
for the MCPS values.
Note (6): Several epochs are available in the near-IR. The 2MASS maps at
J, H, and Ks were obtained in 1998 August and followed up with a
deeper survey, known as 2MASS 6X, in 2000 December. DENIS adds epochs
at I, J, and Ks from 1996 to 1999, and the IRSF adds more at
J, H, and Ks from 2002 to 2006. We have not attempted to account for
subtle differences between the filter sets from the different
telescopes.
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Global notes:
Note (G1): MSXSMC000 ≡ HV 12122, was below the SNR threshold for inclusion
in the MSXSMC catalog.
Note (G2): Bolometric magnitudes calculated integrating MSX Catalog photometry,
IRS spectra, a 3600K blackbody for the blue end of SED, a Rayleigh-Jeans
tail for the red end of the SED, and an average distance modulus of
18.9 (Rubele et al. 2015, J/MNRAS/449/639)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jul-2017