J/ApJ/679/71 Mid-IR period-luminosity relations (Freedman+, 2008)
The Cepheid period-luminosity relation at mid-infrared wavelengths.
I. First-epoch LMC data.
Freedman W.L., Madore B.F., Rigby J., Persson S.E., Sturch L.
<Astrophys. J., 679, 71-75 (2008)>
=2008ApJ...679...71F 2008ApJ...679...71F
ADC_Keywords: Stars, variable ; Magellanic Clouds ; Photometry, infrared
Keywords: Cepheids - distance scale - infrared: stars - Magellanic Clouds
Abstract:
We present the first mid-infrared period-luminosity (PL) relations for
Large Magellanic Cloud (LMC) Cepheids. Single-epoch observations of 70
Cepheids were extracted from Spitzer IRAC observations at 3.6, 4.5,
5.8 and 8.0um, serendipitously obtained during the SAGE (Surveying
the Agents of a Galaxy's Evolution) imaging survey of the LMC. All
four mid-infrared PL relations have nearly identical slopes over the
period range 6-88 days, with a small scatter of only ±0.16mag
independent of period for all four of these wavelengths. We emphasize
that differential reddening is not contributing significantly to the
observed scatter, given the nearly 2 orders of magnitude reduced
sensitivity of the mid-IR to extinction compared to the optical.
Future observations, filling in the light curves for these Cepheids,
should noticeably reduce the residual scatter. These attributes alone
suggest that mid-infrared PL relations will provide a practical means
of significantly improving the accuracy of Cepheid distances to nearby
galaxies.
Description:
We report here on single-epoch, mid-infrared data for a subset of the
Persson et al. (2004, Cat. J/AJ/128/2239) LMC sample, which were
observed with Spitzer at 3.6, 4.5, 5.8, and 8.0um. Data for 70 of the
92 Persson et al. Cepheids were serendipitously obtained in the course
of the SAGE project (Meixner et al., 2006, Cat. J/AJ/132/2268).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 58 70 Mid-infrared Cepheid photometry
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See also:
J/A+A/303/137 : EROS Variables: Cepheids in the bar of LMC (Beaulieu+ 1995)
J/AJ/128/2239 : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)
J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)
J/A+A/462/599 : JHKs photometry of LMC cluster Cepheids (Testa+, 2007)
J/A+A/476/73 : Calibration of Cepheid Period/Luminosity relation (Fouque+,
2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Cepheid name (HV NNNNN)
10- 14 F5.3 [d] LogP Log of the period
16- 20 F5.2 mag 3.6mag Spitzer/IRAC 3.6 micron band magnitude
22- 25 F4.2 mag e_3.6mag Error in 3.6mag
27- 31 F5.2 mag 4.5mag Spitzer/IRAC 4.5 micron band magnitude
33- 36 F4.2 mag e_4.5mag Error in 4.5mag
38- 42 F5.2 mag 5.8mag Spitzer/IRAC 5.8 micron band magnitude
44- 47 F4.2 mag e_5.8mag Error in 5.8mag
49- 53 F5.2 mag 8.0mag Spitzer/IRAC 8.0 micron band magnitude
55- 58 F4.2 mag e_8.0mag Error in 8.0mag
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Sep-2010