J/AJ/136/479 IRAC observations of M83 extended UV disk (Dong+, 2008)
Spitzer observations of star formation in the extreme outer disk
of M83 (NGC5236).
Dong H., Calzetti D., Regan M., Thilker D., Bianchi L., Meurer G.R.,
Walter F.
<Astron. J., 136, 479-497 (2008)>
=2008AJ....136..479D 2008AJ....136..479D
ADC_Keywords: Galaxies, nearby ; Ultraviolet ; Photometry, infrared
Keywords: galaxies: evolution - galaxies: individual (M83) - galaxies: ISM -
galaxies: star clusters - galaxies: stellar content
Abstract:
Spitzer Infrared Array Camera (IRAC) observations of two fields in
the extended UV disk (XUV-disk) of M83 have been recently obtained,
∼3RHII away from the center of the galaxy (RHII=6.6kpc). Galaxy
Evolution Explorer (GALEX) UV images have shown the two fields to host
in situ recent star formation. The IRAC images are used in conjunction
with GALEX data and new HI imaging from The HI Nearby Galaxy Survey
(THINGS) to constrain stellar masses and ages of the UV clumps in the
fields, and to relate the local recent star formation to the reservoir
of available gas. Multi-wavelength photometry in the UV and mid-IR
(MIR) bands of 136 UV clumps (spatial resolution >220pc) identified in
the two target fields, together with model fitting of the stellar
UV-MIR spectral energy distributions (SEDs), suggests that the clumps
cover a range of ages between a few Myr and >1Gyr with a median value
around ≤100Myr, and have masses in the range 103-3x106M☉,
with a peak ∼104.7M_☉.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 109 152 Source list
table3.dat 79 152 Derived ages and masses for the sources
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_Seq [E] E for Sources with unusual high excess
4.5, 5.8 and 8.0um flux
3- 5 I3 --- Seq [1/152] Sequential number,
<[DCR2008] NNN> in Simbad
7- 12 A6 --- Field IRAC field (OuterI or OuterL, see Fig.1)
15- 16 I2 h RAh right ascension (J2000)
18- 19 I2 min RAm right ascension (J2000)
21- 24 F4.1 s RAs right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 39 I2 arcsec Rad Radius of the photometric aperture
41- 47 F7.1 zW/m2/nm FUV GALEX/FUV flux (in 10-21W/m2/nm) (1)
49- 53 F5.1 zW/m2/nm e_FUV rms uncertainty on FUV
55- 60 F6.1 zW/m2/nm NUV GALEX/NUV flux (in 10-21W/m2/nm)(1)
62- 65 F4.1 zW/m2/nm e_NUV rms uncertainty on NUV
67- 71 F5.1 zW/m2/nm F3.6 IRAC 3.6um flux (in 10-21W/m2/nm) (2)
73- 76 F4.2 zW/m2/nm e_F3.6 rms uncertainty on F3.6
78- 82 F5.2 zW/m2/nm F4.5 IRAC 4.5um flux (in 10-21W/m2/nm) (2)
84- 87 F4.2 zW/m2/nm e_F4.5 rms uncertainty on F4.5
89- 93 F5.2 zW/m2/nm F5.8 IRAC 5.8um flux (in 10-21W/m2/nm) (2)
95- 98 F4.2 zW/m2/nm e_F5.8 rms uncertainty on F5.8
100-104 F5.1 zW/m2/nm F8.0 IRAC 8.0um flux (in 10-21W/m2/nm) (2)
106-109 F4.2 zW/m2/nm e_F8.0 rms uncertainty on F8.0
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Note (1): For FUV (120-177nm) and NUV (177-300nm) bands, the flux has been
corrected for the foreground Milky Way extinction, E(B-V)=0.066
[A_{FUV}=8.376E(B-V) and A_{NUV}=8.741E(B-V) (Wyder et al.
2005ApJ...619L..15W 2005ApJ...619L..15W)] after convolving the GALEX spectral response
curve with the Galaxy's extinction curve, using the relation of
Cardelli et al. (1989ApJ...345..245C 1989ApJ...345..245C) with RV=3.1)
Note (2): The flux in the Spitzer IRAC bands is assumed to be extinction free.
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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 A1 --- n_Seq [E] E for Sources with unusual high excess
4.5, 5.8 and 8.0um flux
3- 5 I3 --- Seq Sequential number
7- 10 A4 --- XUV Cross-identification of sources in common
with those of Gil de Paz et al.
(2007ApJ...661..115G 2007ApJ...661..115G),
<[GMB2007] NGC 5236 XUV NN> in Simbad
12- 17 F6.1 Myr Age1 Age for E(B-V)=0.07 (OuterI) or
E(B-V)=0.1 (OuterL) (1)
19- 23 F5.1 Myr E_Age1 Error on Age1 (upper limit)
25- 29 F5.1 Myr e_Age1 Error on Age1 (lower limit)
31- 36 F6.1 Myr Age2 Age for E(B-V)=0.3 (2)
38- 42 F5.1 Myr E_Age2 Error on Age2 (upper limit)
44- 48 F5.1 Myr e_Age2 Error on Age2 (lower limit)
51- 54 F4.2 [Msun] logMass1 Mass for E(B-V)=0.07 (OuterI) or
E(B-V)=0.1 (OuterL) (1)
56- 59 F4.2 [Msun] E_logMass1 Error on logMass1 (upper limit)
61- 64 F4.2 [Msun] e_logMass1 Error on logMass1 (lower limit)
66- 69 F4.2 [Msun] logMass2 Mass for E(B-V)=0.3 (2)
71- 74 F4.2 [Msun] E_logMass2 Error on logMass2 (upper limit)
76- 79 F4.2 [Msun] e_logMass2 Error on logMass2 (lower limit)
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Note (1): SED-fitting results for the 152 sources in the two OuterI and
OuterL fields. The values of the color excess used in the fits are
E(B-V)=0.07 for OuterI and E(B-V)=0.1 for OuterL. These values are
derived from the average HI column densities in each region,
NHI=3.5x1020cm-2 for OuterI and NHI=5x1020cm-2 for OuterL,
and the extinction-to-HI column density ratio of Bohlin et al.
(1978ApJ...224..132B 1978ApJ...224..132B).
Note (2): SED-fitting results, applying a larger value of the extinction,
E(B-V)=0.3, as derived by Gil de Paz et al. (2007ApJ...661..115G 2007ApJ...661..115G)
for a few of the HII regions detected in the M83 outskirts.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 04-Feb-2011