J/ApJ/876/85 HST observations for LMC Cepheids (Riess+, 2019)
Large Magellanic Cloud Cepheid standards provide a 1% foundation for the
determination of the Hubble constant and stronger evidence for physics beyond
ΛCDM.
Riess A.G., Casertano S., Yuan W., Macri L.M., Scolnic D.
<Astrophys. J., 876, 85 (2019)>
=2019ApJ...876...85R 2019ApJ...876...85R
ADC_Keywords: Magellanic Clouds; Stars, variable; Photometry, HST; Optical;
Infrared sources
Keywords: cosmological parameters; distance scale; stars: variables: Cepheids;
supernovae: general
Abstract:
We present an improved determination of the Hubble constant from
Hubble Space Telescope (HST) observations of 70 long-period Cepheids
in the Large Magellanic Cloud (LMC). These were obtained with the same
WFC3 photometric system used to measure extragalactic Cepheids in the
hosts of SNe Ia. Gyroscopic control of HST was employed to reduce
overheads while collecting a large sample of widely separated
Cepheids. The Cepheid period-luminosity relation provides a
zero-point-independent link with 0.4% precision between the new 1.2%
geometric distance to the LMC from detached eclipsing binaries (DEBs)
measured by Pietrzynski+ (2019Natur.567..200P 2019Natur.567..200P) and the luminosity of
SNe Ia. Measurements and analysis of the LMC Cepheids were completed
prior to knowledge of the new DEB LMC distance. Combined with a
refined calibration of the count-rate linearity of WFC3-IR with 0.1%
precision, these three improved elements together reduce the overall
uncertainty in the geometric calibration of the Cepheid distance
ladder based on the LMC from 2.5% to 1.3%. Using only the LMC DEBs to
calibrate the ladder, we find H0=74.22±1.82km/s/Mpc including
systematic uncertainties, 3% higher than before for this particular
anchor. Combining the LMC DEBs, masers in NGC 4258, and Milky Way
parallaxes yields our best estimate: H0=74.03±1.42km/s/Mpc,
including systematics, an uncertainty of 1.91%-15% lower than our best
previous result. Removing any one of these anchors changes H0 by less
than 0.7%. The difference between H0 measured locally and the value
inferred from Planck CMB and ΛCDM is 6.6±1.5km/s/Mpc or
4.4σ (P=99.999% for Gaussian errors) in significance, raising
the discrepancy beyond a plausible level of chance. We summarize
independent tests showing that this discrepancy is not attributable to
an error in any one source or measurement, increasing the odds that it
results from a cosmological feature beyond ΛCDM.
Description:
The 70 LMC Cepheids presented here were imaged in three HST bands, two
in the optical with WFC3-UVIS (F555W and F814W) and one in the NIR
with WFC3-IR (F160W), in two HST programs: GO-14648 and GO-15146
(PI: Riess). All data frames are available in MAST. The observations
were taken between 2017 January 9 and 2018 December 16 and are
identified and described in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 66 230 Observations of LMC Cepheids
table2.dat 93 70 Photometric results LMC Cepheids
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/AJ/128/2239 : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)
J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)
J/ApJ/700/1097 : Light curve parameters of SN Ia (Hicken+, 2009)
J/ApJ/722/566 : Host galaxies of SNIa in SDSS-II SN survey (Lampeitl+, 2010)
J/MNRAS/406/782 : Type Ia supernovae luminosities (Sullivan+, 2010)
J/ApJ/730/119 : HST/WFC3 obs. of Cepheids in SN Ia hosts (Riess+, 2011)
J/ApJ/746/85 : THe HST Cluster Supernova Survey. V. (Suzuki+, 2012)
J/A+A/568/A22 : Joint analysis of the SDSS-II & SNLS SNe Ia (Betoule+, 2014)
J/ApJ/795/44 : PS1 SNe Ia (0.02<z<0.7) griz light curves (Rest+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/MNRAS/448/732 : Type Ia SN environment within host galaxies (Anderson+, 2015)
J/ApJ/799/144 : M31 Cepheids in near-IR (Kodric+, 2015)
J/AJ/149/117 : LMC infrared survey. I. Photometry of Cepheids (Macri+, 2015)
J/ApJ/830/10 : HST obs. of Cepheids in SNIa host gal. (Hoffmann+, 2016)
J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SN Ia host gal. (Riess+, 2016)
J/AJ/154/149 : LMC NIR synoptic survey. V. NIR phot. of Miras (Yuan+, 2017)
J/ApJ/869/56 : Updated calibration of the CSP-I SNe Ia sample (Burns+, 2018)
J/A+A/620/A99 : SMC Cepheids K-band and RV curves (Gieren+, 2018)
J/ApJ/857/67 : HST obs. of Mira candidates in NGC 4258 (Huang+, 2018)
J/ApJ/857/51 : Measuring dark energy data with PS1 SNe. II. (Jones+, 2018)
J/A+A/615/A68 : Type Ia supernova luminosities (Roman+, 2018)
J/ApJ/872/199 : Cand. spectrophotometric standard DA WDs (Calamida+, 2019)
J/ApJ/874/32 : Environment and hosts of Type Ia supernovae (Rose+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [OGL]
4- 7 I4 --- OGLE Cepheid identifier ( in Simbad)
9- 17 A9 --- Frame HST frame identifier
19- 23 A5 --- Filter Filter used
25- 33 F9.4 d MJD [754.34/1468.23] Modified Julian Date; MJD-57000
35- 40 F6.2 s Exp [0.8/4] Exposure time
42- 56 A15 --- Array Array used
58- 61 I4 pix Xpix [3/1295] X pixel coordinate on Array
63- 66 I4 pix Ypix [60/1605] Y pixel coordinate on Array
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [OGL]
4- 7 I4 --- OGLE Cepheid identifier
( in Simbad)
9- 17 F9.6 deg RAdeg [74.11/81.85] Right Ascension (J2000)
19- 28 F10.6 deg DEdeg [-70.35/-68.29] Declination (J2000)
30- 35 F6.3 --- Geo [-0.004/0.04] Correction for geometry of LMC
37- 41 F5.3 [d] logP [0.78/1.73] log period
43- 48 F6.3 mag F555Wmag [12.3/16.66] HST/WFC3 F555W band magnitude
50- 54 F5.3 mag e_F555Wmag [0.008/0.06] Uncertainty in F555Wmag
56- 61 F6.3 mag F814Wmag [11.29/15.06] HST/WFC3 F814W band magnitude
63- 67 F5.3 mag e_F814Wmag [0.008/0.021] Uncertainty in F814Wmag
69- 74 F6.3 mag F160Wmag [10.43/13.72] HST/WFC3 (IR) F160W band
magnitude (1)
76- 80 F5.3 mag e_F160Wmag [0.017/0.08] Uncertainty in F160Wmag
82- 87 F6.3 mag mWH [10/13.4] Reddening-free Wesenheit index (2)
89- 93 F5.3 mag e_mWH [0.019/0.08] Uncertainty in mWH
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Note (1): Does not include addition of 0.0300±0.0024mag to
correct CRNL 4dex between MW and extragalactic Cepheids.
Note (2): Includes subtraction of geometric correction to LMC line of nodes
and addition of 0.0300±0.0024mag to correct CRNL 4dex
between MW and extragalactic Cepheids.
mHW=mF160W-0.386(mF555W-mF814W); see Section 2.2.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Nov-2020