J/ApJ/508/491 M101 Cepheids (Stetson+, 1998)
The extragalactic distance scale key project.
XVI. Cepheid variables in an inner field of M101.
Stetson P.B., Saha A., Ferrarese L., Rawson D.M., Ford H.C.,
Freedman W.L., Gibson B.K., Graham J.A., Harding P., Han M., Hill R.J.,
Hoessel J.G., Huchra J.P., Hughes S.M.G., Illingworth G.D., Kelson D.D.,
Kennicutt R.C.Jr, Madore B.F., Mould J.R., Phelps R.L., Sakai S.,
Silbermann N.A., Turner A.
<Astrophys. J. 508, 491 (1998)>
=1998ApJ...508..491S 1998ApJ...508..491S
ADC_Keywords: Stars, variable ; Photometry
Mission_Name: HST
Keywords: Cepheids - galaxies: distances and redshift -
galaxies: individual (M101) - galaxies: photometry
Abstract:
We report on the identification of 255 candidate variable stars in a
field located some 1.7' from the center of the late-type spiral galaxy
M101 = NGC 5457, based on observations made with the Wide Field and
Planetary Camera 2 on board the Hubble Space Telescope. Photometric
measurements in the F555W and F814W filters - analyzed independently
with the DAOPHOT/ALLFRAME and DoPHOT software suites - have been
transformed to the Johnson V and Kron-Cousins I standard magnitude
systems. Periods and intensity-averaged mean magnitudes for 61
carefully selected candidate Cepheid variables with periods in the
range 10-48 days indicate a reddening-corrected mean distance modulus
(m-M)0=29.05±0.14 (if the true modulus of the Large Magellanic
Cloud is 18.50±0.10, and if there is no dependence of the
period-luminosity relation on metal abundance); results consistent
with this are obtained whether or not the sample is expanded to
include a larger fraction of the candidates. Applying a
metallicity-dependent correction of +0.16±0.10mag would increase
this estimate to (m-M)0= 29.21±0.17mag.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 70 139 Coordinates and mean magnitudes for local standards
table3.dat 76 255 Variable coordinates, periods, and mean magnitudes
table5.dat 48 93 Comparison of ALLFRAME AND DoPHOT for variables
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See also:
J/ApJ/463/26 : Extragalactic Distance Scale Key Project. III (Kelson+ 1996)
J/ApJ/507/655 : VI photometry of new Cepheids in NGC 2541 (Ferrarese+, 1998)
J/ApJ/521/155 : New Cepheids and distance to NGC 4535 (Macri+, 1999)
J/ApJ/523/540 : VI photometry of new Cepheids in NGC 3319 (Sakai+, 1999)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Chip [0/4] WFPC2 chip number
3- 7 I5 --- [SSF98] Identification number ([SSF98] NNNNN in Simbad)
9- 13 F5.1 pix Xpos X position
15- 19 F5.1 pix Ypos Y position
21- 22 I2 h RAh Right ascension (J2000)
24- 25 I2 min RAm Right ascension (J2000)
27- 31 F5.2 s RAs Right ascension (J2000)
33 A1 --- DE- Declination sign (J2000)
34- 35 I2 deg DEd Declination (J2000)
37- 38 I2 arcmin DEm Declination (J2000)
40- 43 F4.1 arcsec DEs Declination (J2000)
45- 49 F5.2 mag Vmag V magnitude (F555W)
51- 54 F4.2 mag e_Vmag rms uncertainty on V magnitude
56- 60 F5.2 mag Imag I magnitude (F814W)
62- 65 F4.2 mag e_Imag rms uncertainty on I magnitude
67- 68 I2 --- o_Vmag Number of observations in Vmag
70 I1 --- o_Imag Number of observations in Imag
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [SSF98] Identification number ([SSF98] VNNN in Simbad)
5 I1 --- Chip [1/4] WFPC2 chip number
7- 11 F5.1 pix Xpos X position
13- 17 F5.1 pix Ypos Y position
19- 20 I2 h RAh Right ascension (J2000)
22- 23 I2 min RAm Right ascension (J2000)
25- 29 F5.2 s RAs Right ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 41 F4.1 arcsec DEs Declination (J2000)
43- 48 F6.2 d Per Period
50- 54 F5.2 d e_Per rms uncertainty on Per
56- 60 F5.2 mag <Vmag> Mean V magnitude (F555W)
62- 65 F4.2 mag e_<Vmag> rms uncertainty on <Vmag>
67- 71 F5.2 mag <Imag> Mean I magnitude (I814W)
73- 76 F4.2 mag e_<Imag> rms uncertainty on <Imag>
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [SSF98] Identification number ([SSF98] VNNN in Simbad)
5- 8 F4.1 d Per DoPHOT period
10- 14 F5.2 mag <Vmag> Mean DoPHOT V magnitude (F555W)
16- 20 F5.2 mag <Imag> Mean DoPHOT V magnitude (I814W)
22- 26 F5.2 [d] DlogPer DoPHOT-ALLFRAME log(Per)
28- 32 F5.2 mag D<Vmag> DoPHOT-ALLFRAME <Vmag>
34- 37 F4.2 mag e_D<Vmag> rms uncertainty on D<Vmag>
39- 43 F5.2 mag D<Imag> DoPHOT-ALLFRAME <Imag>
45- 48 F4.2 mag e_D<Imag> rms uncertainty on D<Imag>
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History: From ApJ electronic version
References:
Freedman et al. Paper I 1994ApJ...427..628F 1994ApJ...427..628F
Hughes et al. Paper II 1994ApJ...428..143H 1994ApJ...428..143H
Kelson et al. Paper III 1996ApJ...463...26K 1996ApJ...463...26K, Cat. J/ApJ/463/26
Ferrarese et al. Paper IV 1996ApJ...464..568F 1996ApJ...464..568F
Hill et al. Paper V 1998ApJ...496..648H 1998ApJ...496..648H
Silbermann et al. Paper VI 1996ApJ...470....1S 1996ApJ...470....1S
Graham et al. Paper VII 1997ApJ...477..535G 1997ApJ...477..535G
Rawson et al. Paper VIII 1997ApJ...490..517R 1997ApJ...490..517R
Phelps et al. Paper IX 1998ApJ...500..763P 1998ApJ...500..763P
Hughes et al. Paper X 1998ApJ...501...32H 1998ApJ...501...32H
Turner et al. Paper XI 1998ApJ...505..207T 1998ApJ...505..207T
Ferrarese et al. Paper XII 1998ApJ...507..655F 1998ApJ...507..655F, Cat. J/ApJ/507/655
Kennicutt et al. Paper XIII 1998ApJ...498..181K 1998ApJ...498..181K
Silbermann et al. Paper XIV 1999ApJ...515....1S 1999ApJ...515....1S
Madore et al. Paper XV 1999ApJ...515...29M 1999ApJ...515...29M
Gibson et al. Paper XVII 1999ApJ...512...48G 1999ApJ...512...48G
Macri et al., Paper XVIII 1999ApJ...521..155M 1999ApJ...521..155M, Cat. J/ApJ/521/155
Kelson et al. Paper XIX 1999ApJ...514..614K 1999ApJ...514..614K
Graham et al. Paper XX 1999ApJ...516..626G 1999ApJ...516..626G
Mould et al., Paper XXI 2000ApJ...528..655M 2000ApJ...528..655M
Prosser et al., Paper XXII 1999ApJ...525...80P 1999ApJ...525...80P
Sakai et al., Paper XXIII 1999ApJ...523..540S 1999ApJ...523..540S, Cat. J/ApJ/523/540
Sakai et al. Paper XXIV 2000ApJ...529..698S 2000ApJ...529..698S
Gibson et al. Paper XXV 2000ApJ...529..723G 2000ApJ...529..723G
Ferrarese et al. Paper XXVI 2000ApJ...529..745F 2000ApJ...529..745F
Kelson et al. Paper XXVII 2000ApJ...529..768K 2000ApJ...529..768K
Mould et al. Paper XXVIII 2000ApJ...529..786M 2000ApJ...529..786M
(End) Patricia Bauer [CDS] 20-Apr-1999