J/MNRAS/500/817 Mid-infrared catalogue for LMC and SMC Cepheids (Chown+, 2021)
The mid-infrared Leavitt law for classical Cepheids in the Magellanic Clouds.
Chown A.H., Scowcroft V., Wuyts S.
<Mon. Not. R. Astron. Soc., 500, 817-837 (2021)>
=2021MNRAS.500..817C 2021MNRAS.500..817C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Magellanic Clouds ; Photometry, infrared
Keywords: stars: variables: Cepheids - Magellanic Clouds - infrared: stars
Abstract:
The Cepheid Leavitt Law (LL), also known as the Period-Luminosity
relation, is a crucial tool for assembling the cosmic distance ladder.
By combining data from the OGLE-IV catalogue with mid-infrared
photometry from the Spitzer Space Telescope, we have determined the
3.6 and 4.5µm LLs for the Magellanic Clouds using ∼5000
fundamental-mode classical Cepheids. Mean magnitudes were determined
using a Monte Carlo Markov Chain (MCMC) template fitting procedure,
with template light curves constructed from a subsample of these
Cepheids with fully phased, well-sampled light curves. The dependence
of the Large Magellanic Cloud LL coefficients on various period cuts
was tested, in addition to the linearity of the relationship. The
zero-point of the LL was calibrated using the parallaxes of Milky Way
Cepheids from the Hubble Space Telescope and Gaia Data Release 2. Our
final calibrated relations are
M[3.6]=-3.246(±0.008)(log(P)-1.0)-5.784(±0.030) and
M[4.5]=-3.162(±0.008)(log(P)-1.0)-5.751(±0.030).
Description:
The data used in this work are from Spitzer, which launched in 2003
and recently ceased operations in January 2020. Onboard Spitzer was
the Infrared Array Camera (IRAC; Fazio et al. 2004ApJS..154...10F 2004ApJS..154...10F),
which initially operated simultaneously at four mid-infrared
wavelengths (3.6, 4.5, 5.8, and 8.0µm) during its 'cold' mission.
Once its cryogenic fuel was exhausted in 2009, Spitzer entered its
'warm mission' phase, operating only at the two shorter wavelengths,
3.6 and 4.5µm. We combine data from both the cold and warm
missions, using only the data at 3.6 and 4.5µm.
We use data from both the CHP sample (Scowcroft et al.
2011ApJ...743...76S 2011ApJ...743...76S, Cat. J/ApJ/743/76; Monson et al.
2012ApJ...759..146M 2012ApJ...759..146M, Cat. J/ApJ/759/146; Scowcroft et al.
2016ApJ...816...49S 2016ApJ...816...49S, Cat. J/ApJ/816/49) of Cepheids and the Spitzer
SAGE survey (Meixner et al. 2006AJ....132.2268M 2006AJ....132.2268M, Cat. J/AJ/132/2268;
Gordon et al. 2011AJ....142..102G 2011AJ....142..102G; Riebel et al. 2015ApJ...807....1R 2015ApJ...807....1R).
While the CHP sample has fully phased well-sampled observations for
every Cepheid (number of observations Nobs=24 for the LMC and 12 for
the SMC), the SAGE data only provides a few observations (median
number of observations are 3 and 4 for the LMC and SMC, respectively)
that do not uniformly sample the light curve. Therefore, in order to
obtain precise mean magnitudes of the Cepheids with sparsely sampled
light curves, we have developed and applied a template light curve
fitting procedure. The templates are constructed from the CHP
Cepheids, hereafter referred to as the 'calibrating sample'. These
templates are then fit to the sample of all known fundamental mode
Cepheids in the Magellanic Clouds, hereafter referred to as the
'complete sample'.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7.dat 77 5024 Final mid-IR catalogue for 2352 LMC and 2672 SMC
fundamental mode Classical Cepheids in the
Magellanic Clouds
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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- 3 A3 --- Galaxy [LMC/SMC] Host galaxy
5- 21 A17 --- Name OGLE identifier
(OGLE-LMC-CEP-NNNN or OGLE-SMC-CEP-NNNN)
23- 29 F7.3 d Period Period from the OGLE-IV catalogue (1)
31- 36 F6.3 mag 3.6mag Mean Spitzer/IRAC 3.6um band magnitude (2)
38- 42 F5.3 mag e_3.6mag Error on 3.6mag
44- 49 F6.3 mag 4.5mag Mean Spitzer/IRAC 4.5um band magnitude (2)
51- 55 F5.3 mag e_4.5mag Error on 4.5mag
57- 61 F5.3 mag E(B-V) Colour excess (3)
63- 67 F5.3 mag e_E(B-V) Error on E (B-V)
69 A1 --- Rejected [Y/N] Flag indicating whether a Cepheid is
rejected from further analysis due to poor
SAGE data
71- 77 A7 --- OName Alternative name
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Note (1): The periods given here have uncertainties of the order of 10-5s
Note (2): The magnitudes provided here have not been corrected for reddening
but can be corrected using E(B-V) and equations A[3.6]=0.203E(B-V)
and A[4.5]=0.156E(B-V) respectively
Note (3): Colour excess values computed from the application of the Cardelli,
Clayton & Mathis (1989ApJ...345..245C 1989ApJ...345..245C) and Indebetouw et al.
(2005ApJ...619..931I 2005ApJ...619..931I) reddening laws, assuming RV=3.1
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 28-Sep-2023