J/AJ/116/469 VI photometry of galactic cepheids (Metzger+ 1998)
A search for distant galactic Cepheids toward l = 60°.
Metzger M.R., Schechter P.L.
<Astron. J. 116, 469 (1998)>
=1998AJ....116..469M 1998AJ....116..469M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Photometry, CCD
Keywords: Cepheids - distance scale - Galaxy: fundamental parameters -
Galaxy: stellar content - Galaxy: structure - surveys -
techniques: photometric
Abstract:
We present results of a survey of a 6deg2 region near l=60°,
b=0° to search for distant Milky Way Cepheids. Few such Cepheids
are known at distances ≳ R0, limiting large-scale Milky Way disk
models derived from Cepheid kinematics; this work was designed to find
a sample of distant Cepheids for use in such models. The survey was
conducted in the V and I bands over eight epochs, to a limiting I~=18,
with a total of almost 5 million photometric observations of over 1
million stars. We present a catalog of 578 high-amplitude variables
discovered in this field. Cepheid candidates were selected from this
catalog on the basis of variability and color change and observed
again the following season. We confirm 10 of these candidates as
Cepheids with periods from 4 to 8 days, most at distances greater than
3kpc. Many of the Cepheids are heavily reddened by intervening dust,
some with implied extinction AV>10mag. With a future addition of
infrared photometry and radial velocities, these stars alone can
provide a constraint on R0 to 8% and in conjunction with other known
Cepheids should provide good estimates of the global disk potential
ellipticity.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 35 98 Galactic plane regions, 50°<l<70°
table3.dat 63 579 *High-amplitude variable stars
table4.dat 58 11 New Cepheids
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Note on table3.dat: this table is corrected from the printed version,
see the "Historical Notes" section below
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Region Region identification number
4- 8 F5.2 deg GLON Galactic longitude of field center
10- 14 F5.2 deg GLAT Galactic latitude of field center
16- 17 I2 h RAh Right ascension (J2000.0)
19- 20 I2 min RAm Right ascension (J2000.0)
22- 25 F4.1 s RAs Right ascension (J2000.0)
27 A1 --- DE- Declination sign
28- 29 I2 deg DEd Declination (J2000.0)
31- 32 I2 arcmin DEm Declination (J2000.0)
34- 35 I2 arcsec DEs Declination (J2000.0)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- [MS98] Catalog identification number
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 19 F4.1 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 29 I2 arcsec DEs Declination (J2000.0)
31- 35 F5.2 mag mag Average I magnitude
37- 41 F5.3 mag e_mag rms uncertainty on mag
43- 48 F6.1 --- 2_mag ξ2 value on mag
50- 53 F4.2 mag - ? - colour index
55- 63 A9 --- Notes Notes (1)
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Note (1): the symbols have the following meaning:
1: Cepheid candidate selected for follow-up photometry
2: Less promising Cepheid candidate based on visual inspection
3: Long-period variable
*: The star is also in table4.
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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- 10 A10 --- Star Star name from J2000 position
12- 19 A8 --- [MS98] Catalog identification number
21- 22 I2 h RAh Right ascension (J2000.0)
24- 25 I2 min RAm Right ascension (J2000.0)
27- 30 F4.1 s RAs Right ascension (J2000.0)
32 A1 --- DE- Declination sign
33- 34 I2 deg DEd Declination (J2000.0)
36- 37 I2 arcmin DEm Declination (J2000.0)
39- 40 I2 arcsec DEs Declination (J2000.0)
42- 46 F5.2 mag mag Average I magnitude
48 A1 --- l_- Limit flag on -
49- 51 F3.1 mag - - colour index
53- 58 F6.4 d Per Period
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History:
* 08-Oct-1998: Prepared from AJ electronic version.
* 22-Feb-1999: The page starting with star 22-24908 and ending with 36-03868
was replaced in the original version (electronic + paper) by a duplication
of the previous page (starting by --- and aneding by ---).
Mark Metzger () kindly supplied the missing stars
to CDS in February 1999.
(End) Patricia Bauer [CDS] 22-Feb-1999