J/ApJ/654/186 VI photometry of Cepheids in NGC 5128 (Ferrarese+, 2007)
The discovery of Cepheids and a distance to NGC 5128.
Ferrarese L., Mould J.R., Stetson P.B., Tonry J.L., Blakeslee J.P.,
Ajhar E.A.
<Astrophys. J., 654, 186-218 (2007)>
=2007ApJ...654..186F 2007ApJ...654..186F
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry
Keywords: Cepheids - distance scale - galaxies: distances and redshifts -
galaxies: individual (NGC 5128)
Abstract:
We discuss a new distance to NGC 5128 (Centaurus A) based on Cepheid
variables observed with the Hubble Space Telescope. Twelve F555W (V)
and six F814W (I) epochs of cosmic-ray-split WFPC2 observations were
obtained. A total of 56 bona fide Cepheids were discovered, with
periods ranging from 5 to ∼50 days; five of these are likely Population
II Cepheids of the W Virginis class, associated with the bulge or halo
of NGC 5128.
Description:
NGC 5128 was observed between 2001 July 8 and 2001 August 20 as part
of program GO-9043.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 57 18 Log of Observations
table5.dat 76 56 Cepheid Variable Stars in NGC 5128
table8.dat 37 176 Secondary Standard Stars in NGC 5128
table9.dat 30 672 F555W Photometry for the NGC 5128 Cepheids
table10.dat 30 336 F814W Photometry for the NGC 5128 Cepheids
table11.dat 76 70 Suspected Variable Stars in NGC 5128
notes.dat 80 102 Individual notes on NGC 5128 Cepheids
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See also:
J/A+A/406/75 : JHKs magnitudes of variables in NGC 5128 (Rejkuba+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date Date of Observation
12- 21 F10.2 d HJD Heliocentric Julian date
23- 31 A9 --- Obs1 Rootname for first HST observation
33- 41 A9 --- Obs2 Rootname for second HST observation
43- 47 A5 --- Filter Filter
49- 52 I4 s ExpTime1 Exposure Time for Obs1
53 A1 --- --- [+]
54- 57 I4 s ExpTime2 Exposure Time for Obs2
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Byte-by-byte Description of file: table5.dat table11.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- [FMS2007] CNN (table5) or VNN (table11) designation
5- 9 F5.1 pix Xpos X position
11- 15 F5.1 pix Ypos Y position
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 28 F6.3 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 41 F5.2 arcsec DEs Declination (J2000)
43- 44 A2 --- l_Per [=> ] Limit flag on Per
45- 48 F4.1 d Per Period
50- 54 F5.2 mag Vmagi Intensity-averaged V magnitude
56- 60 F5.2 mag Imagi Intensity-averaged I magnitude
62- 66 F5.2 mag Vmagp Phase-weighted V magnitude assuming the period
68- 72 F5.2 mag Imagp Phase-weighted I magnitude assuming the period
74- 76 A3 --- Chip The WFPC2 chip in which the star is located
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Chip The WFPC2 chip (1)
5- 9 F5.1 pix Xpos The X pixel coordinate (1) (2)
11- 15 F5.1 pix Ypos The Y pixel coordinate (1) (2)
17- 21 F5.2 mag Vmag The V band band magnitude
23- 26 F4.2 mag e_Vmag Uncertainty in Vmag
28- 32 F5.2 mag Imag The B band band magnitude
34- 37 F4.2 mag e_Imag Uncertainty in Imag
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Note (1): Cepheids identified as "[FMS2007] Chip Xpos-Ypos" in Simbad,
i.e. "[FMS2007] PC 673.4-236.3" for "PC 673.4 236.3".
Note (2): In the reference frame defined by the u6dm2101r observations
(see Table 1).
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- [FMS2007] Cepheid Identification number (CNN)
5- 8 F4.1 d Per Period
10- 19 F10.2 d HJD Heliocentric Julian Date of observation
21- 25 F5.2 mag Vmag HST/WFPC2 F555W band magnitude
27- 30 F4.2 mag e_Vmag Error in Vmag
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- [FMS2007] Cepheid Identification number (CNN)
5- 8 F4.1 d Per Period
10- 19 F10.2 d HJD Heliocentric Julian Date of observation
21- 25 F5.2 mag Imag HST/WFPC2 F814W band magnitude
27- 30 F4.2 mag e_Imag Error in Imag
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- [FMS2007] Cepheid Identification number (VNN)
5- 80 A76 --- Note Note
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Nov-2008