J/ApJ/940/64 HST obs. of NGC4258 Cepheids and HII regions (Yuan+, 2022)
Absolute calibration of Cepheid period-luminosity relations in NGC 4258.
Yuan W., Macri L.M., Riess A.G., Brink T.G., Casertano S.,
Filippenko A.V., Hoffmann S.L., Huang C.D., Scolnic D.
<Astrophys. J., 940, 64 (2022)>
=2022ApJ...940...64Y 2022ApJ...940...64Y
ADC_Keywords: Photometry, HST; Stars, variable; H II regions; Abundances;
Optical
Keywords: Cepheid variable stars ; Cepheid distance
Abstract:
Owing to its accurate distance measured from water-maser motions,
NGC4258 is one of the most important anchors for calibrating the
Cepheid period-luminosity relations (PLRs). We expand on previous
efforts and carry out a new Cepheid search in this system using the
Hubble Space Telescope. We discover and measure a sample of
669 Cepheids in four new and two archival NGC 4258 fields, doubling
the number of known Cepheids in this galaxy and obtaining an absolute
calibration of their optical PLRs. We determine a Wesenheit
(WVIHST) PLR of -2.574(±0.034)-3.294(±0.042)logP, consistent
with an independent Large Magellanic Cloud (LMC) calibration at the
level of 0.032±0.044mag in its zero-point, after accounting for a
metallicity dependence of -0.20±0.05mag/dex. Our determination of
the PLR slope also agrees with the LMC-based value within their
uncertainties. We attempt to characterize the metallicity effect of
Cepheid PLRs using only the NGC 4258 sample, but a relatively narrow
span of abundances limits our sensitivity and yields a WVIHST
zero-point dependence of -0.07±0.21mag/dex. The Cepheid measurements
presented in this study have been used as part of the data to derive
the Hubble constant in a companion paper by the SH0ES team.
Description:
In 2003-2004, two NGC 4258 fields were observed with 12 epochs using
the HST Advanced Camera for Surveys (ACS; GO-9810, PI: Greenhill) in
three bands: F435W, F555W, and F814W (HST equivalent to B, V, and I,
respectively). Random-phased WFC3 observations, including NIR imaging,
were also acquired in programs GO-11570 and 15640 (PI: Riess).
We recently designed and acquired new HST time-series observations
(GO-16198, PI: Riess) in four additional fields to search for and
measure more Cepheids in NGC 4258 to better constrain the absolute
calibration of Cepheid period-luminosity relations (PLRs). From
2020 December to 2021 February, we acquired time-series observations:
two partially overlapping fields (F3 and F4) were imaged with ACS,
while the other two fields (F5 and F6, also partially overlapping)
were simultaneously imaged with WFC3. We obtained between 10 and 13
epochs of F555W or F350LP data that span a baseline of 68 days,
depending on the field.
In this study, we analyzed both the archival observations and these
new data at optical wavelengths only. The NIR data reduction and
results are presented by Riess+ 2022ApJ...934L...7R 2022ApJ...934L...7R
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 42 122 Observation log
table2.dat 98 669 Cepheid properties
table4.dat 57 52 H II region metallicity measurements
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See also:
J/ApJ/627/579 : Photometry of variables in NGC 3370 (Riess+, 2005)
J/ApJ/652/1133 : BVI photometry of NGC 4258 Cepheids (Macri+, 2006)
J/A+A/504/959 : Amplitudes of single-mode Cepheids (Klagyivik+, 2009)
J/ApJ/699/539 : Cepheids in SN-Ia host galaxies (Riess+, 2009)
J/ApJ/730/119 : HST/WFC3 obs. of Cepheids in SN Ia hosts (Riess+, 2011)
J/AJ/149/183 : gri photometry of variables in NGC 4258 (Hoffmann+, 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/ApJ/859/101 : The supernovae Ia Pantheon sample (Scolnic+, 2018)
J/ApJ/876/85 : HST observations for LMC Cepheids (Riess+, 2019)
J/ApJ/902/26 : HST opt. & H-band obs. of Cepheids in NGC4151 (Yuan+, 2020)
J/ApJ/913/38 : Compilation of Cepheids in the MW and MCs (Breuval+, 2021)
J/MNRAS/508/4047 : Classical Cepheids HARPSN@TNG spectroscopy (Ripepi+, 2021)
J/A+A/659/A167 : Cepheid Period-Wesenheit-Metallicities (Ripepi+, 2022)
J/A+A/658/A29 : LMC classical Cepheids Fe and O content (Romaniello+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Field Field
4- 5 I2 --- Epoch [1/13] Epoch
7- 16 A10 "Y/M/D" Date Date (UT)
18- 26 A9 --- Dataset MAST dataset identifier (1)
28- 33 A6 --- Filt Filter ("F350LP" for WFC3 fields and "F555W"
or "F814W" for ACS)
35- 40 F6.1 s ExpTime [400/1600] Exposure time
42 I1 --- Ndit [1/2] Dither number
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Note (1): The specific observations analyzed can be accessed on MAST via the
DOI: 10.17909/e5sn-yr35
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- ID Position based identifier (JHHMMSS.ss+DDMMSS.s)
21- 26 F6.3 d Per [5/75.5] Period
28- 37 F10.6 deg RAdeg [184.6/184.9] Right Ascension (J2000)
39- 47 F9.6 deg DEdeg [47.1/47.4] Declination (J2000)
49- 54 F6.3 mag F555W [22.89/27.4] HST/ACS F555W Vega magnitude (1)
56- 60 F5.3 mag e_F555W [0.04/0.7] Uncertainty in F555W
62- 67 F6.3 mag F814W [21.8/26.4] HST/ACS F814W Vega magnitude (1)
69- 73 F5.3 mag e_F814W [0.02/0.8] Uncertainty in F814W
75- 80 F6.3 mag F350LP [23.99/27.6]?=99.999 HST/WFC3 F350LP Vega
magnitude (1)
82- 86 F5.3 mag e_F350LP [0.02/0.3]?=9.999 Uncertainty in F350LP
88- 92 F5.3 mag AmpV [0.13/0.65] F555W or F350LP amplitude
94- 98 F5.3 mag AmpI [0.09/0.5] F814W amplitude
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Note (1): Fully calibrated Vega magnitudes, including background corrections
and their uncertainties.
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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 A3 --- ID HII Region ID ({b/n}NN) (1)
5- 13 F9.5 deg RAdeg [184.6/184.9] Right Ascension (J2000)
15- 22 F8.5 deg DEdeg [47.1/47.4] Declination (J2000)
24- 28 F5.2 kpc Rad [1.4/25.2] Deprojected radius
30- 33 F4.2 --- R23 [2.7/8.6] R23 index, Oxygen-to-H_beta line
flux ratio
35- 38 F4.2 --- ZZ94 [8.37/9.1] Oxygen abundance Z on the
Zaritsky+ 1994ApJ...420...87Z 1994ApJ...420...87Z scale
40- 43 F4.2 --- ZPP04 [8.2/8.9] Oxygen abundance Z transformed to the
Pettini & Pagel 2004MNRAS.348L..59P 2004MNRAS.348L..59P scale
45- 48 F4.2 --- sigma [0.03/0.08] Uncertainty in oxygen abundance Z
50- 57 A8 --- Source Source(s) (2)
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Note (1): If the IDs start with "b", the regions come from
Bresolin 2011ApJ...729...56B 2011ApJ...729...56B and are named <[B2011] NN> in Simbad.
Note (2): Source as follows:
B11 = Bresolin (2011ApJ...729...56B 2011ApJ...729...56B)
new = this study
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Oct-2024