J/ApJ/877/49 DUSTiNGS. V. 3.6 and 4.5um light curves (Goldman+, 2019)
An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS).
V. The Period-Luminosity Relation for Dusty Metal-poor AGB Stars.
Goldman S.R., Boyer M.L., McQuinn K.B.W., Whitelock P.A., McDonald I.,
van Loon J.T., Skillman E.D., Gehrz R.D., Javadi A., Sloan G.C.,
Jones O.C., Groenewegen M.A.T., Menzies J.W.
<Astrophys. J. 877, 49 (2019)>
=2019ApJ...877...49G 2019ApJ...877...49G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry, millimetric/submm
Keywords: galaxies: dwarf - galaxies: stellar content - infrared: stars -
Local Group - stars: AGB and post-AGB - stars: carbon
Abstract:
The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS) has
identified hundreds of candidate dust-producing asymptotic giant
branch (AGB) stars in several nearby metal-poor galaxies. We have
obtained multi-epoch follow-up observations for these candidates with
the Spitzer Space Telescope and measured their infrared (IR) light
curves. This has allowed us to confirm their AGB nature and
investigate pulsation behavior at very low metallicity. We have
obtained high-confidence pulsation periods for 88 sources in seven
galaxies. We have confirmed DUSTiNGS variable star candidates with a
20% success rate and determined the pulsation properties of 19 sources
already identified as thermally pulsing AGB stars. We find that the
AGB pulsation properties are similar in all galaxies surveyed here,
with no discernible difference between the DUSTiNGS galaxies (down to
1.4% solar metallicity; [Fe/H]=-1.85) and the far more metal-rich
Magellanic Clouds (up to 50% solar metallicity; [Fe/H]=-0.38).
These results strengthen the link between dust production and
pulsation in AGB stars and establish the IR period-luminosity
relation as a reliable tool (±4%) for determining distances to
galaxies, regardless of metallicity.
Description:
We construct light curves using 3.6 and 4.5um imaging data from the
IRAC on board Spitzer, with a mix of programs from both the cryogenic
and post-cryogenic phases. Data include new and archival observations
from 2003 to 2017.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 139 The archival Spitzer observations
table3.dat 153 261 The results of 3.6 and 4.5 um lightcurve fitting
lc/* . 443 Individual 3.6 and 4.5um fits light curves
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See also:
J/ApJS/216/10 : DUSTiNGS. I. The Good Source Catalog (Boyer+, 2015)
J/ApJ/851/152 : DUSTiNGS. IV. AGB spectral types with HST (Boyer+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Galaxy Galaxy
13- 17 I5 --- PID Spitzer Program Identifiers
19- 26 I8 --- AOR Individual Spitzer AOR
28- 29 I2 h RAh Hour of Right Ascension (J2000)
31- 32 I2 min RAm Minute of Right Ascension (J2000)
34- 38 F5.2 s RAs Second of Right Ascension (J2000)
40 A1 --- DE- Sign of the Declination (J2000)
41- 42 I2 deg DEd Degree of Declination (J2000)
44- 45 I2 arcmin DEm Arcminute of Declination (J2000)
47- 50 F4.1 arcsec DEs Arcsecond of Declination (J2000)
52- 62 A11 "date" Obs.date Observation Start Date, UT
64- 67 F4.2 h texp Exposure time, hours
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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- 9 A9 --- Galaxy Galaxy
10- 11 A2 --- n_Galaxy [_12 ] Multiplicity index on Galaxy
13- 19 I7 --- TID Target ID
21- 32 F12.8 deg RAdeg Right Ascension, decimal degrees (J2000)
34- 45 F12.8 deg DEdeg Declination, decimal degrees (J2000)
47- 51 F5.2 mag <3.6>mag mid-line 3.6um magnitude from best fit
light curve
53- 57 F5.2 mag <4.5>mag ? mid-line 4.5um magnitude from best fit
light curve
59- 62 I4 d Per3.6 Best fit pulsation periods, 3.6um
64- 67 I4 d Per4.5 ? Best fit pulsation periods, 4.5um
69- 72 I4 d Per3.6-2 Second best fit pulsation periods, 3.6um
74- 77 I4 d Per4.5-2 ? Second best fit pulsation periods, 4.5um
79- 82 F4.2 mag Amp Fitted peak-to-peak 3.6um amplitude
84- 88 F5.2 mag Color ? Spitzer [3.6] - [4.5] color
90- 95 F6.2 % s_Color ? standard deviation of Color
97-101 A5 --- Flag Fit quality flag (1)
103-127 A25 --- lc36 Name of the fits 3.6um light curve file
in subdirectory lc
129-153 A25 --- lc45 Name of the fits 4.5um light curve file
in subdirectory lc
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Note (1): Fit quality flags (see also Section 5.4) as follows:
RF = high-confidence reliable fit;
IE = insufficient epochs;
UF = unreliable fit;
S-LPV = LPV 5000+.
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Acknowledgements:
Steve Goldamn, sgoldman(at)stsci.edu
References:
Boyer et al., Paper I 2015ApJS..216...10B 2015ApJS..216...10B, Cat. J/ApJS/216/10
Boyer et al. Paper II 2015ApJ...800...51B 2015ApJ...800...51B, Cat. J/ApJ/800/51
McQuinn et al., Paper III 2017ApJ...834...78M 2017ApJ...834...78M
Boyer et al., Paper IV 2017ApJ...851..152B 2017ApJ...851..152B, Cat. J/ApJ/851/152
(End) Patricia Vannier [CDS] 31-May-2019