ADC/CDS Standard Document for Catalog:/journal_tables/ApJ/463/26/
ADC/CDS Standard Document for Catalog:| 1. Use the ADC Data Viewer Suite to visualize the data. |
|
| 2. Get the data files via anonymous FTP. (See Note.) |
|
J/ApJ/463/26 Extragalactic Distance Scale Key Project. III (Kelson+ 1996)
================================================================================
The Extragalactic Distance Scale Key Project. III.
The discovery of Cepheids and a new distance to M101 using the
Hubble Space Telescope.
Kelson D.D., Illingworth G.D., Freedman W.F., Graham J.A., Hill R.,
Madore B.F., Saha A., Stetson P.B., Kennicutt Jr.R.C., Mould J.R.,
Hughes S.M., Ferrarese L., Phelps R., Turner A., Cook K.H., Ford H.,
Hoessel J.G., Huchra J.
<Astrophys. J. 463, 26 (1996)>
=1996ApJ...463...26K
================================================================================
ADC_Keywords: Stars, variable ; Photometry
Mission_Name: HST
Keywords: Cepheids - distance scale - galaxies: distances and redshifts -
galaxies: individual (M101)
Abstract:
We report on the discovery of 29 Cepheid variables in the galaxy M101
using the original Wide Field Camera (WFC) and the new Wide Field and
Planetary Camera 2 (WFPC2) on the Hubble Space Telescope. We observed
a field in M101 at 17 independent epochs in V (F555W), five epochs in
I (F785LP/F814W), and one epoch in B (F439W), with a time interval
baseline of 381 days. We have found Cepheids with periods ranging from
10 to 60 days. The data have been calibrated using WFPC2 observations
with zero points derived from Omega Cen, Pal 4, and NGC 2419
observations. This calibration has been verified by using the Medium
Deep Survey (MDS) WFC photometric zero points, and ground-based
secondary standards in V and I. The V calibrations agree to
+/-0.06mag, and the I calibrations agree to +/-0.4mag. We have
constructed V and I period-luminosity (PL) relations and have derived
apparent distance moduli based on a distance modulus for the Large
Magellanic Cloud (LMC) of 18.50mag and a reddening of E(B-V)=0.10mag
to the LMC Cepheids. Period-residual minimization was used to minimize
the effects of Malmquist bias on the period-luminosity relation
fitting process. Using a Galactic extinction law and the apparent V
and I distance moduli, we have found a mean reddening for the M101
sample of E(B-V)=0.03mag and a true distance modulus to M101 of
29.34+/-0.17mag, corresponding to a distance of 7.4+/-0.6Mpc. The
sources of error have been rigorously tracked through an error budget;
systematic and random errors contribute roughly equally to the quoted
error. The mean gas-phase metal abundances in the LMC and in the M101
outer field are similar so we expect metallicity effects to be
minimal. These Cepheids will be used in conjunction with results from
a Key Project search for Cepheids in an inner field, where the
metallicity is larger by a factor of 5, to probe the effects of
abundance on the Cepheid period-luminosity relation.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1 47 660 V photometry
tableb2 47 159 I photometry
--------------------------------------------------------------------------------
See also:
J/ApJ/507/655 : VI photometry of new Cepheids in NGC 2541 (Ferrarese+, 1998)
J/ApJ/508/491 : M101 Cepheids (Stetson+, 1998)
J/ApJ/523/540 : VI photometry of new Cepheids in NGC 3319 (Sakai+, 1999)
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)
J/ApJ/529/723 : VI photometry of Cepheids (Gibson+, 2000)
Byte-by-byte Description of file: tableb1
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Cepheid Cepheid number
4- 7 F4.1 d Per Period
9- 21 E13.4 d JD Julian date, midpoint of individual exposure
22 I1 --- CCD Which CCD the star can be found in
24- 29 F6.2 pix Xpos X position on CCD frame
31- 36 F6.2 pix Ypos Y position on CCD frame
38- 42 F5.2 mag Vmag Calibrated F555W magnitude
44- 47 F4.2 mag e_Vmag ALLFRAME uncertainty in F555W magnitude
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Cepheid Cepheid number
4- 7 F4.1 d Per Period
9- 21 E13.4 d JD Julian date, midpoint of individual exposure
22 I1 --- CCD Which CCD the star can be found in
24- 29 F6.2 pix Xpos X position on CCD frame
31- 36 F6.2 pix Ypos Y position on CCD frame
38- 42 F5.2 mag Imag Calibrated F814W magnitude
44- 47 F4.2 mag e_Imag ALLFRAME uncertainty in F814W magnitude
--------------------------------------------------------------------------------
Origin: AAS CD-ROM series, Volume 7, 1996 Lee Brotzman [ADS] 10-Oct-96
References:
Freedman et al., Paper I 1994ApJ...427..628F
Hughes et al., Paper II 1994ApJ...428..143H
Kelson et al., Paper III 1996ApJ...463...26K, Cat. <J/ApJ/463/26>
Ferrarese et al., Paper IV 1996ApJ...464..568F
Hill et al., Paper V 1998ApJ...496..648H
Silbermann et al., Paper VI 1996ApJ...470....1S
Graham et al., Paper VII 1997ApJ...477..535G
Rawson et al., Paper VIII 1997ApJ...490..517R
Phelps et al., Paper IX 1998ApJ...500..763P
Hughes et al., Paper X 1998ApJ...501...32H
Turner et al., Paper XI 1998ApJ...505..207T
Ferrarese et al., Paper XII 1998ApJ...507..655F, Cat. <J/ApJ/507/655>
Kennicutt et al., Paper XIII 1998ApJ...498..181K
Silbermann et al., Paper XIV 1999ApJ...515....1S
Madore et al., Paper XV 1999ApJ...515...29M
Stetson et al., Paper XVI 1998ApJ...508..491S
Gibson et al., Paper XVII 1999ApJ...512...48G
Macri et al., Paper XVIII 1999ApJ...521..155M, Cat. <J/ApJ/521/155>
Kelson et al., Paper XIX 1999ApJ...514..614K
Graham et al., Paper XX 1999ApJ...516..626G
Mould et al., Paper XXI 2000ApJ...528..655M
Prosser et al., Paper XXII 1999ApJ...525...80P
Sakai et al., Paper XXIII 1999ApJ...523..540S, Cat. <J/ApJ/523/540>
Sakai et al. Paper XXIV 2000ApJ...529..698S
Gibson et al., Paper XXV 2000ApJ...529..723G, Cat. <J/ApJ/529/723>
Ferrarese et al. Paper XXVI 2000ApJ...529..745F
Kelson et al. Paper XXVII 2000ApJ...529..768K
Mould et al. Paper XXVIII 2000ApJ...529..786M
================================================================================
(End) Patricia Bauer, [CDS] 31-Jan-1997