J/ApJ/835/55 AzTEC/ASTE survey at 1.1mm toward the SMC (Takekoshi+, 2017)
The 1.1mm continuum survey of the Small Magellanic Cloud: physical properties
and evolution of the dust-selected clouds.
Takekoshi T., Minamidani T., Komugi S., Kohno K., Tosaki T., Sorai K.,
Muller E., Mizuno N., Kawamura A., Onishi T., Fukui Y., Ezawa H.,
Oshima T., Scott K.S., Austermann J.E., Matsuo H., Aretxaga I.,
Hughes D.H., Kawabe R., Wilson G.W., Yun M.S.
<Astrophys. J., 835, 55-55 (2017)>
=2017ApJ...835...55T 2017ApJ...835...55T (SIMBAD/NED BibCode)
ADC_Keywords: Millimetric/submm sources ; Magellanic Clouds ; Infrared sources ;
H II regions ; YSOs
Keywords: galaxies: individual: SMC; ISM: clouds; ISM: molecules;
Magellanic Clouds
Abstract:
The first 1.1mm continuum survey toward the Small Magellanic Cloud
(SMC) was performed using the AzTEC instrument installed on the ASTE
10m telescope. This survey covered 4.5deg2 of the SMC with 1σ
noise levels of 5-12mJy/beam, and 44 extended objects were identified.
The 1.1mm extended emission has good spatial correlation with Herschel
160µm, indicating that the origin of the 1.1mm extended emission is
thermal emission from a cold dust component. We estimated physical
properties using the 1.1mm and filtered Herschel data (100, 160, 250,
350, and 500µm). The 1.1mm objects show dust temperatures of 17-45K
and gas masses of 4x103-3x105M☉, assuming single-temperature
thermal emission from the cold dust with an emissivity index, β,
of 1.2 and a gas-to-dust ratio of 1000. These physical properties are
very similar to those of giant molecular clouds (GMCs) in our galaxy
and the Large Magellanic Cloud. The 1.1mm objects also displayed good
spatial correlation with the Spitzer 24µm and CO emission,
suggesting that the 1.1mm objects trace the dense gas regions as sites
of massive star formation. The dust temperature of the 1.1mm objects
also demonstrated good correlation with the 24µm flux connected to
massive star formation. This supports the hypothesis that the heating
source of the cold dust is mainly local star-formation activity in the
1.1mm objects. The classification of the 1.1mm objects based on the
existence of star-formation activity reveals the differences in the
dust temperature, gas mass, and radius, which reflects the evolution
sequence of GMCs.
Description:
Continuum observations at 1.1mm toward the SMC were conducted with the
AzTEC instrument installed on the ASTE telescope in the Atacama
desert, Chile. The angular resolution is 28" at FWHM. The observations
covered a total of a 4.5deg2 field of the SMC by connecting four
patches of scans that are denominated as southwest (SW), northeast
(NE), Wing, and N88, as shown in Figure 1. Observations were performed
from 2008 October 7 to December 26.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 44 AzTEC/ASTE 1.1mm extended source catalog of the SMC
table3.dat 138 44 Total flux densities of the 1.1mm extended objects
table4.dat 62 44 Physical properties of the 1.1mm extended objects
table5.dat 76 44 Association with the signs of star formation
activity and CO emission
table7.dat 101 53 *AzTEC/ASTE 1.1mm PCA source catalog of the SMC
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Note on table7.dat: The correlated noise removal was performed using a
principal component analysis (PCA) cleaning (Laurent+ 2005ApJ...623..742L 2005ApJ...623..742L).
The PCA map is shown in the Appendix.
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See also:
VII/232 : Nebulae in the Magellanic Clouds (Davies+ 1976)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
J/AJ/119/1214 : Census of star clusters in the SMC (Bica+, 2000)
J/A+A/364/455 : ubvy photometry of LMC/SMC B stars (Larsen+, 2000)
J/AJ/127/1632 : UBVR(UIT) photometry of O and OB stars in SMC (Oey+, 2004)
J/ApJ/655/212 : S3MC IRAC and MIPS photometry (Bolatto+, 2007)
J/A+A/471/103 : SIMBA observations of SMC (Bot+, 2007)
J/ApJ/686/948 : CO in extragalactic giant molecular clouds (Bolatto+, 2008)
J/ApJS/178/56 : CO observations of LMC Giant Molecular clouds (Fukui+, 2008)
J/MNRAS/385/2225 : AzTEC millimetre survey of COSMOS field (Scott+, 2008)
J/ApJS/184/1 : Molecular clouds in the LMC by NANTEN. II. (Kawamura+, 2009)
J/MNRAS/417/2651 : AT20G-optical catalogue (Mahony+, 2011)
J/MNRAS/423/529 : AzTEC deep-field observations (Downes+, 2012)
J/ApJ/761/37 : CO observations in giant molecular clouds of M33 (Miura+, 2012)
J/AJ/146/62 : HERschel HERITAGE in Magellanic Clouds (Meixner+, 2013)
J/AJ/148/124 : Herschel key program Heritage (Seale+, 2014)
J/ApJS/217/7 : Orion A dense cores based on 1.1mm & C18O (Shimajiri+, 2015)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reg Region (SW, NE, Wing or N88;
see Figure 1)
6- 7 I2 --- Seq [1/24] Running number in Region
9- 10 I2 h RAh [0/1] Hour of Right Ascension (J2000)
12- 13 I2 min RAm [2/59] Minute of Right Ascension (J2000)
15- 18 F4.1 s RAs Second of Right Ascension (J2000)
20- 20 A1 --- DE- [-] Sign of the Declination (J2000)
21- 22 I2 deg DEd [71/73] Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 28 I2 arcsec DEs Arcsecond of Declination (J2000)
30- 34 F5.1 mJy/beam PkFlux [35/150] Observed Peak Flux
36- 39 F4.1 mJy/beam e_PkFlux [4/12] Map noise level at 1.1mm
41- 44 F4.1 --- SNR [6/29] Signal-to-noise ratio
46- 51 F6.1 mJy TotFlux [23/1683] 1.1mm total flux
53- 57 F5.1 mJy e_TotFlux [5/216] Uncertainty in TotFlux
59- 62 F4.1 pc Rad [5.8/40] Projected source radius
64- 67 F4.1 pc Rad-d [0.3/40] Deconvolved source radius
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reg Region
6- 7 I2 --- Seq Running number in Region
9- 13 F5.1 mJy S4.8GHz [0.5/608] Unfiltered 4.8GHz ATCA+Parkes flux
density (SRaw-4.8GHz)
15- 17 F3.1 mJy e_S4.8GHz [0.1/7] Uncertainty for S4.8GHz
19- 23 F5.1 mJy S8.64GHz [-1.4/590] Unfiltered 8.6GHz ATCA+Parkes flux
density (SRaw-8.64GHz)
25- 27 F3.1 mJy e_S8.64GHz Uncertainty for S8.6GHz
29- 34 F6.1 mJy S1.1mm [23/1683] FRUIT derived AzTEC+ASTE 1.1mm flux
density (SFRUIT-1.1mm) (1)
36- 40 F5.1 mJy e_S1.1mm [5/216] Uncertainty for S1.1mm
42- 46 F5.2 Jy S500um [0.07/16] FRUIT derived Herschel/SPIRE 500um
flux density (SFRUIT-500um) (1)
48- 51 F4.2 Jy e_S500um [0.1/2] Uncertainty for S500um
53- 57 F5.2 Jy S350um [0.1/38] FRUIT derived Herschel/SPIRE 350um
flux density (SFRUIT-350um) (1)
59- 62 F4.2 Jy e_S350um Uncertainty for S350um
64- 68 F5.2 Jy S250um [0.3/79] FRUIT derived Herschel/SPIRE 250um
flux density (SFRUIT-250um) (1)
70- 73 F4.2 Jy e_S250um Uncertainty for S250um
75- 80 F6.2 Jy S160um [0.5/180] FRUIT derived Herschel/PACS 160um
flux density (SFRUIT-160um) (1)
82- 86 F5.2 Jy e_S160um Uncertainty for S160um
88- 93 F6.2 Jy S100um [0.6/257] FRUIT derived Herschel/PACS 100um
flux density (SFRUIT-100um) (1)
95- 99 F5.2 Jy e_S100um Uncertainty for S100um
101-106 F6.2 Jy S70um [0.5/192] Unfiltered Spitzer/MIPS 70um flux
density (SRaw-70um)
108-111 F4.2 Jy e_S70um Uncertainty for S70um
113-119 F7.1 mJy S24um [14/24577] Unfiltered Spitzer/MIPS 24um flux
density (SRaw-24um)
121-125 F5.1 mJy e_S24um Uncertainty for S24um
127-132 F6.1 mJy S8um [9/2734] Unfiltered Spitzer/IRAC 8um flux
density (SRaw-8um)
134-138 F5.1 mJy e_S8um Uncertainty for S8um
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Note (1): FRUIT (Liu+ 2010AJ....139.1190L 2010AJ....139.1190L) is a method to recover extended
components by performing the principal component analysis (PCA)
cleaning iteratively.
The point response function (PRF), after applying FRUIT, gives a
Gaussian FWHM of 40", which corresponds to a physical scale of 12pc
at the distance of the SMC.
See section 2.2 for further explanations.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reg Region
6- 7 I2 --- Seq [1/24] Running number in Region
9- 12 F4.1 K Tdust [16/45] Derived dust temperature
14- 16 F3.1 K e_Tdust [0.7/4] Uncertainty in Tdust
18- 22 F5.1 Msun Mdust [4/337] Total dust mass
24- 27 F4.1 Msun e_Mdust [1/34] Uncertainty in Mass-dust
29- 33 F5.1 10+3Msun Mgas [4/337] Total gas mass (2)
35- 38 F4.1 10+3Msun e_Mgas [1/34] Uncertainty in Mass-gas (2)
40- 44 F5.1 cm-3 nH2 [17/171] Number density, H2, molecules/cm3
46- 49 F4.1 cm-3 e_nH2 [1/81] Uncertainty in nH2
51- 53 F3.1 10+21cm-2 NH2 [1/5] Column density, H2,
1021 molecules/cm2
55- 57 F3.1 10+21cm-2 e_NH2 [0.2/3] Uncertainty in NH2
59- 62 F4.1 % ff1.1mm [0.1/23] 1.1mm Free-Free fractional
contribution
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Note (2): The total gas mass Mgas (including the H2, HI, and He gas components)
was estimated assuming a gas-to-dust mass ratio GDR: Mgas=GDRxMdust
We assumed that the GDR=1000, which is a typical value in the SMC
(Leroy+ 2007ApJ...658.1027L 2007ApJ...658.1027L; Planck Collaboration+ 2011A&A...536A..17P 2011A&A...536A..17P;
Gordon+ 2014ApJ...797...85G 2014ApJ...797...85G), to estimate the total gas mass, though
these studies showed an uncertainty of a factor of two.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reg Region
6- 7 I2 --- Seq Running number in Region
9- 63 A55 --- Cat Catalog or other evidence of star formation (3)
65- 76 A12 --- CO CO Detection survey
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Note (3): Catalog or other evidence of star formation, separated by "/" --
N## = The Henize Catalogue of SMC Emission Nebulae,
Henize (1956ApJS....2..315H 1956ApJS....2..315H);
DEM S### = Magellanic Cloud Emission-line Survey DEM Catalog:
Small Magellanic Cloud, Davies et al. (1976, VII/232);
S3MC ## = S3MC Young Stellar Object Catalog,
Bolatto et al. (2007, J/ApJ/655/212), Table 4.
24um = Spitzer/MPS 24um emission.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reg Region (SW, NE, Wing or N88;
see Figure 12)
6- 7 I2 --- ID [1/28] Running number in Region, PCA map
9- 10 I2 h RAh [0/1] Hour of Right Ascension (J2000)
12- 13 I2 min RAm [2/59] Minute of Right Ascension (J2000)
15- 18 F4.1 s RAs Second of Right Ascension (J2000)
20- 20 A1 --- DE- [-] Sign of the Declination (J2000)
21- 22 I2 deg DEd [71/73] Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 28 I2 arcsec DEs Arcsecond of Declination (J2000)
30- 34 F5.1 mJy/beam PkFlux [25/113] Observed Peak Flux, PCA map
36- 39 F4.1 mJy/beam e_PkFlux [5/13] PCA Map noise level at 1.1mm
41- 44 F4.1 --- SNR [4.5/18] Signal-to-noise ratio, PCA
46- 47 I2 --- Seq [1/20]? AzTEC/ASTE 1.1mm extended source
catalog sequence number within Reg;
as in table 2 (1)
49-101 A53 --- OName Counterparts (2)
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Note (1): Note that the running sequence is different for the two catalogs,
e.g., SW-1 in Table 2 is the counterpart of SW-3 (column "ID")
in this (PCA) catalog.
Note (2): Counterpart catalog, notes include:
N## = The Henize Catalogue of SMC Emission Nebulae,
Henize (1956ApJS....2..315H 1956ApJS....2..315H; in Simbad)
S### = Magellanic Cloud Emission-line Survey DEM Catalog:
Small Magellanic Cloud, Davies et al. (1976, VII/232;
in Simbad);
SMCB-[12] # = Molecular Clouds in the SMC (Rubio+ 1993A&A...271....9R 1993A&A...271....9R;
<[RLB93] SMC-B[12] N> in Simbad);
LIRS 36 1 = Molecular Clouds in the SMC (Bolatto+ 2008, J/ApJ/686/948;
[BLR2008] SMC LIRS36 1 in Simbad);
OGLE-CL SMC 187 = Star clusters in the SMC (Bica & Dutra 2000, J/AJ/119/1214);
identified as OB cluster in Oey et al. (2004, J/AJ/127/1632);
S3MC JHH... = The Spitzer Survey of the SMC Catalog,
Bolatto et al. (2007, J/ApJ/655/212);
KHBG 27 = HST photometry of galaxy clusters behind the SMC,
Krienke & Hodge (2001PASP..113.1115K 2001PASP..113.1115K);
2MASS J00465185-7315248 = 2MASS All Sky Catalog of point sources,
Cutri et al. (2003, II/246);
NGC 346 = The New General Catalogue of Nebulae and Clusters of Stars (NGC);
6dFGS gJ011132.5-730210 = The 6dF Galaxy Survey Catalog,
Jones et al. (2009, VII/259);
MM J01071-7302 = Takekoshi et al. (2013ApJ...774L..30T 2013ApJ...774L..30T).
We searched for the counterparts of the PCA objects using SIMBAD at
the positions of the PCA objects within the beam size (28"), and
corresponding emission nebulae were checked on the PCA images.
See the appendix section for further explanations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Aug-2017