J/MNRAS/466/4540 SUMaC I (Hagen+, 2017)
Swift Ultraviolet Survey of the Magellanic Clouds (SUMaC).
I. Shape of the ultraviolet dust extinction law and recent star formation
history of the Small Magellanic Cloud.
Hagen L.M.Z., Siegel M.H., Hoversten E.A., Gronwall C., Immler S., Hagen A.
<Mon. Not. R. Astron. Soc., 466, 4540-4557 (2017)>
=2017MNRAS.466.4540H 2017MNRAS.466.4540H (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Galaxies, photometry ; Extinction
Keywords: dust, extinction - galaxies: individual: SMC - Magellanic Clouds
Abstract:
We present the first results from the Swift Ultraviolet Survey of the
Magellanic Clouds, the highest resolution ultraviolet (UV) survey of
the Magellanic Clouds yet completed. In this paper, we focus on the
Small Magellanic Cloud (SMC). When combined with multiwavelength
optical and infrared observations, the three near-UV filters on the
Swift Ultraviolet/Optical Telescope are conducive to measuring the
shape of the dust extinction curve and the strength of the 2175Å
dust bump. We divide the SMC into UV-detected star-forming regions and
large 200-arcsec (58pc) pixels and then model the spectral energy
distributions using a Markov-chain Monte Carlo method to constrain the
ages, masses, and dust curve properties. We find that the majority of
the SMC has a 2175Å dust bump, which is larger to the north-east
and smaller to the south-west, and that the extinction curve is
predominantly steeper than the Galactic curve. We also derive a star
formation history and find evidence for peaks in the star formation
rate at 6-10, 30-80, and 400Myr, the latter two of which are
consistent with previous work.
Description:
The SUMaC (Swift Ultraviolet survey of the Magellanic Clouds)
programme is the first comprehensive multifilter near-ultraviolet
(NUV) survey covering the inner Magellanic Clouds.
The SMC was observed in a staggered pattern of 50 tiles, each
17x17-arcmin, with a few previous observations used to patch the
coverage. All observations were taken in 2x2 binned mode with a pixel
scale of 1.0-arcsec. Observations began on 2010 September 26 and ended
on 2013 November 6, with the majority of the observations made between
2011 May 2011 and December. Typical exposure times were 1 ks per
filter in the uvw2, uvm2 and uvw1 filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 107 338 Photometry of SMC star-forming regions
table4.dat 107 775 Photometry of SMC large pixels
table5.dat 98 338 Physical properties of SMC star-forming regions
table6.dat 108 775 Physical properties of SMC large pixels
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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- 3 I3 --- Region [1/338] Region number
5- 10 F6.3 mag W2mag Swift/UVOT uvw2 magnitude (AB)
12- 16 F5.3 mag e_W2mag Swift/UVOT uvw2 magnitude uncertainty (1)
18- 23 F6.3 mag M2mag Swift/UVOT uvm2 magnitude (AB)
25- 29 F5.3 mag e_M2mag Swift/UVOT uvm2 magnitude uncertainty (1)
31- 36 F6.3 mag W1mag Swift/UVOT uvw1 magnitude (AB)
38- 42 F5.3 mag e_W1mag Swift/UVOT uvw1 magnitude uncertainty (1)
44- 49 F6.3 mag Bmag Harris B magnitude (AB)
51- 55 F5.3 mag e_Bmag Harris B magnitude uncertainty (1)
57- 62 F6.3 mag Vmag Harris V magnitude (AB)
64- 68 F5.3 mag e_Vmag ?=- Harris V magnitude uncertainty (1)
70- 75 F6.3 mag Rmag Harris R magnitude (AB)
77- 81 F5.3 mag e_Rmag Harris R magnitude uncertainty (1)
83- 88 F6.3 mag Jmag 2MASS J magnitude (AB)
90- 94 F5.3 mag e_Jmag 2MASS J magnitude uncertainty (1)
96-101 F6.3 mag 3.6mag IRAC 3.6 micron magnitude (AB)
103-107 F5.3 mag e_3.6mag ?=- IRAC 3.6 micron magnitude uncertainty (1)
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Note (1): The minimum uncertainty is 0.05 mag.
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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- 3 I3 --- Pixel [1/775] Pixel number
5- 10 F6.3 mag W2mag Swift/UVOT uvw2 magnitude (AB)
12- 16 F5.3 mag e_W2mag Swift/UVOT uvw2 magnitude uncertainty (1)
18- 23 F6.3 mag M2mag Swift/UVOT uvm2 magnitude (AB)
25- 29 F5.3 mag e_M2mag Swift/UVOT uvm2 magnitude uncertainty (1)
31- 36 F6.3 mag W1mag Swift/UVOT uvw1 magnitude (AB)
38- 42 F5.3 mag e_W1mag Swift/UVOT uvw1 magnitude uncertainty (1)
44- 49 F6.3 mag Bmag Harris B magnitude (AB)
51- 55 F5.3 mag e_Bmag Harris B magnitude uncertainty (1)
57- 62 F6.3 mag Vmag ?=- Harris V magnitude (AB)
64- 68 F5.3 mag e_Vmag ?=- Harris V magnitude uncertainty (1)
70- 75 F6.3 mag Rmag Harris R magnitude (AB)
77- 81 F5.3 mag e_Rmag Harris R magnitude uncertainty (1)
83- 88 F6.3 mag 3.6mag IRAC 3.6 micron magnitude (AB)
90- 94 F5.3 mag e_3.6mag IRAC 3.6 micron magnitude uncertainty (1)
96-101 F6.3 mag 8.0mag IRAC 8.0 micron magnitude (AB)
103-107 F5.3 mag e_8.0mag IRAC 8.0 micron magnitude uncertainty (1)
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Note (1): The minimum uncertainty is 0.05 mag.
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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- 3 I3 --- Region [1/338] Region number
5- 8 F4.1 pc Rad Radius
10- 13 F4.2 mag AV Best-fit total extinction in V band, A_V
15- 18 F4.2 mag E_AV Upper uncertainty on A_V
20- 23 F4.2 mag e_AV Lower uncertainty on A_V
25- 28 F4.2 --- RV Best-fit ratio of selective to total
extinction, R_V
30- 33 F4.2 --- E_RV Upper uncertainty on R_V
35- 38 F4.2 --- e_RV Lower uncertainty on R_V
40- 43 F4.2 --- Bump Best-fit 2175A bump strength
45- 48 F4.2 --- E_Bump Upper uncertainty on Bump
50- 53 F4.2 --- e_Bump Lower uncertainty on Bump
55- 58 F4.2 [Myr] logAge Best-fit log10 of the age
60- 63 F4.2 [Myr] E_logAge Upper uncertainty on log.age
65- 68 F4.2 [Myr] e_logAge Lower uncertainty on log.age
70- 73 F4.2 [Msun] logMass Best-fit log10 of the mass (1)
75- 78 F4.2 [Msun] E_logMass Upper uncertainty on log.mass
80- 83 F4.2 [Msun] e_logMass Lower uncertainty on log.mass
85- 88 F4.2 [Msun] logMstel Best-fit log10 of the stellar mass
90- 93 F4.2 [Msun] E_logMstel Upper uncertainty on log.stel
95- 98 F4.2 [Msun] e_logMstel Lower uncertainty on log.stel
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Note (1): The mass includes the contributions of both the current stars
and stellar remnants.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Pixel [1/775] Pixel number
5- 8 F4.2 mag AV ?=9.99 Best-fit total extinction in V band,
10- 13 F4.2 mag E_AV ?=9.99 Upper uncertainty on A_V
15- 18 F4.2 mag e_AV ?=9.99 Lower uncertainty on A_V
20- 23 F4.2 --- RV ?=9.99 Best-fit ratio of selective to total
extinction, R_V
25- 28 F4.2 --- E_RV ?=9.99 Upper uncertainty on R_V
30- 33 F4.2 --- e_RV ?=9.99 Lower uncertainty on R_V
35- 38 F4.2 --- Bump ?=9.99 Best-fit 2175A bump strength
40- 43 F4.2 --- E_Bump ?=9.99 Upper uncertainty on bump
45- 48 F4.2 --- e_Bump ?=9.99 Lower uncertainty on bump
50- 53 F4.2 [Myr] logAge ?=9.99 Best-fit log10 of the age
55- 58 F4.2 [Myr] E_logAge ?=9.99 Upper uncertainty on log.age
60- 63 F4.2 [Myr] e_logAge ?=9.99 Lower uncertainty on log.age
65- 68 I4 Myr tau ?=9999 Best-fit for the age, SFH time-scale
tau
70- 73 I4 Myr E_tau ?=9999 Upper uncertainty on tau
75- 78 I4 Myr e_tau ?=9999 Lower uncertainty on tau
80- 83 F4.2 [Msun] logMass ?=9.99 Best-fit log10 of the mass (1)
85- 88 F4.2 [Msun] E_logMass ?=9.99 Upper uncertainty on log.mass
90- 93 F4.2 [Msun] e_logMass ?=9.99 Lower uncertainty on log.mass
95- 98 F4.2 [Msun] logMstel ?=9.99 Best-fit log10 of the stellar mass
100-103 F4.2 [Msun] E_logMstel ?=9.99 Upper uncertainty on log.stel
105-108 F4.2 [Msun] e_logMstel ?=9.99 Lower uncertainty on log.stel
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Note (1): The mass includes the contributions of both the current stars
and stellar remnants.
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History:
From electronic version of the journal
(End) Lea M. Z. Hagen [Penn State Univ.], Patricia Vannier [CDS] 14-Nov-2019