J/ApJ/514/614 VI photometry of new Cepheids in NGC 3198 (Kelson+, 1999)
The Hubble Space Telescope Key Project on the Extragalactic Distance
Scale. XIX. The Discovery of Cepheids in and a New Distance to NGC 3198
Kelson D.D., Illingworth G.D., Saha A., Graham J.A., Stetson P.B.,
Freedman W.L., Kennicutt R.C., Mould J.R., Ferrarese L., Huchra J.P.,
Madore B.F., Prosser C.F. Bresolin F., Ford H.C., Gibson B. K.,
Hoessel J.G., Hughes S.M.G., Macri L.M., Sakai S., Silbermann M.A.
<Astrophys. J. 514, 614 (1999)>
=1999ApJ...514..614K 1999ApJ...514..614K
ADC_Keywords: Stars, variable ; Photometry
Mission_Name: HST
Keywords: Cepheids - galaxies: distances and redshifts -
galaxies: individual (NGC 3198)
Abstract:
We report the detection of Cepheid variable stars and a new distance
to the Sc spiral NGC 3198. NGC 3198 is one of 25 galaxies that have
been observed with the WFPC2 of the Hubble Space Telescope (HST) for
the purpose of measuring Cepheid distances. Eighteen of these galaxies
were targeted by the HST Key Project on the Extragalactic Distance
Scale, whose objective is to calibrate a variety of secondary distant
indicators and determine the Hubble constant to an accuracy of 10%.
NGC 3198 was selected as part of this sample because its type and
orientation make it very suitable as a Tully-Fisher calibrator. The
WFPC2 data are comprised of 13 epochs in F555W (∼V) and five epochs
in F814W (∼I). Two different crowded-field photometry packages
(DAOPHOT/ALLFRAME and DoPHOT) were used. The magnitudes derived from
these two packages agree to within a few percent. We identified 78
Cepheid candidates in the period range from eight to >50 days, of
which 52 were selected for establishing the distance modulus.
Period-luminosity relations were constructed in Johnson V and
Kron-Cousins I by transforming the F555W and F814W to the standard
system. We adopted a distance modulus of µo=18.50±0.10 mag
and mean reddening of E(B-V)=0.10 mag to the Large Magellanic Cloud
Cepheids and found a true distance modulus to NGC 3198 of
µo=30.80±0.16 (random) ±0.12 (systematic) mag. This
modulus corresponds to a distance of 14.5 Mpc, with random and
systematic errors of ±1.2 and ±0.9 Mpc, respectively.
Objects
--------------------------------------------
RA (2000) DE Designation(s)
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10 19 55 +45 33 09 NGC 3198 = UGC 5572
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 60 78 Cepheid positions
table6.dat 96 78 Cepheid mean magnitudes and periods
tablea1.dat 29 2026 Cepheid F555W photometry
tablea2.dat 30 810 Cepheid F814W photometry
--------------------------------------------------------------------------------
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/508/491 : M101 Cepheids (Stetson+, 1998)
J/ApJ/521/155 : Extragalactic distance scale key project. XVIII. (Macri+, 1999)
J/ApJ/529/723 : VI photometry of Cepheids (Gibson+, 2000)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- CName Cepheid name
10 I1 --- Chip WFPC chip Cepheid is located in (1 is
the PC chip)
12- 17 F6.2 --- XPos X position on the chip
19- 24 F6.2 --- YPos Y position on the chip
32- 33 I2 h RAh Right Ascension (J2000)
35- 36 I2 min RAm Right Ascension (J2000)
38- 42 F5.2 s RAs Right Ascension (J2000)
49 A1 --- DE- Declination sign
50- 51 I2 deg DEd Declination (J2000)
53- 54 I2 arcmin DEm Declination (J2000)
56- 60 F5.2 arcsec DEs Declination (J2000)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- CName Cepheid name
8 A1 --- Use [YN] indicates if the Cepheid was used
in the Period-Luminosity analysis
12 A1 --- l_Period limit on Period
13- 17 F5.2 d Period Cepheid period
20- 23 F4.1 d E_Period ? Uncertainty in Period. If e_Period exists
this value is the upper limit
25- 28 F4.1 d e_Period ? Lower limit in Period
31- 35 F5.2 mag I.Vmag Intensity weighted mean V band magnitude
39- 42 F4.2 mag e_I.Vmag Uncertainty in I.Vmag
49- 53 F5.2 mag I.Imag ? Intensity weighted mean I band magnitude
57- 60 F4.2 mag e_I.Imag ? Uncertainty in I.Imag
67- 71 F5.2 mag P.Vmag Phase weighted mean V band magnitude
75- 78 F4.2 mag e_P.Vmag Uncertainty in P.Vmag
85- 89 F5.2 mag P.Imag ? Phase weighted mean I band magnitude
93- 96 F4.2 mag e_P.Imag ? Uncertainty in P.Imag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- CName Cepheid name
6- 13 F8.2 --- JD-2400000 Julian date (-2400000) of observation
16- 20 F5.2 mag Vmag V Band magnitude
24- 27 F4.2 mag e_Vmag Uncertainty in Vmag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- CName Cepheid name
6- 13 F8.2 --- JD-2400000 Julian date (-2400000) of observation
16- 20 F5.2 mag Imag I Band magnitude
24- 27 F4.2 mag e_Imag Uncertainty in Vmag
--------------------------------------------------------------------------------
History:
From ApJ electronic edition
References:
(Paper I) Freedman+ 1994ApJ...427..628F 1994ApJ...427..628F
(Paper II) Hughes+ 1994ApJ...428..143H 1994ApJ...428..143H
(Paper III) Kelson+ 1996ApJ...463...26K 1996ApJ...463...26K, Cat. J/ApJ/463/26
(Paper IV) Ferrarese+ 1996ApJ...464..568F 1996ApJ...464..568F
(Paper VI) Silbermann+ 1996ApJ...470....1S 1996ApJ...470....1S
(Paper VII) Graham+ 1997ApJ...477..535G 1997ApJ...477..535G
(Paper VIII) Rawson+ 1997ApJ...490..517R 1997ApJ...490..517R
(Paper IX) Phelps+ 1998ApJ...500..763P 1998ApJ...500..763P
(Paper X) Hughes+ 1998ApJ...501...32H 1998ApJ...501...32H
(Paper XI) Turner+ 1998ApJ...505..207T 1998ApJ...505..207T
(Paper XII) Ferrarese+ 1998ApJ...507..655F 1998ApJ...507..655F, Cat. J/ApJ/507/655
(Paper XIII) Kennicutt+ 1998ApJ...498..181K 1998ApJ...498..181K
(Paper XIV) Silbermann+ 1999ApJ...515....1S 1999ApJ...515....1S
(Paper XV) Madore+ 1999ApJ...515...29M 1999ApJ...515...29M
(Paper XVI) Stetson+ 1998ApJ...508..491S 1998ApJ...508..491S
(Paper XVII) Gibson+ 1999ApJ...512...48G 1999ApJ...512...48G
(Paper XVIII) Macri+ 1999ApJ...521..155M 1999ApJ...521..155M, Cat. J/ApJ/521/155
(Paper XX) Graham+ 1999ApJ...516..626G 1999ApJ...516..626G
(Paper XXI) Mould+ 2000ApJ...528..655M 2000ApJ...528..655M
(Paper XXII) Prosser+ 1999ApJ...525...80P 1999ApJ...525...80P
(Paper XXIII) Sakai+ 1999ApJ...523..540S 1999ApJ...523..540S
(Paper XXIV) Sakai+ 2000ApJ...529..698S 2000ApJ...529..698S
(Paper XXV) Gibson+ 2000ApJ...529..723G 2000ApJ...529..723G, Cat. J/ApJ/529/723
(Paper XXVI) Ferrarese+ 2000ApJ...529..745F 2000ApJ...529..745F
(Paper XXVII) Kelson+ 2000ApJ...529..768K 2000ApJ...529..768K
(Paper XXVIII) Mould+ 2000ApJ...529..786M 2000ApJ...529..786M
(End) Greg Schwarz (AAS) 16-Feb-2000