J/AJ/122/2055 UBVRIJHK photometry of AGN field stars (Gonzalez-Perez+, 2001)
Optical and near-infrared calibration of AGN field stars:
an all-sky network of faint stars calibrated on the Landolt system.
Gonzalez-Perez J.N., Kidger M.R., Martin-Luis F.
<Astron. J. 122, 2055 (2001)>
=2001AJ....122.2055G 2001AJ....122.2055G
ADC_Keywords: Photometry, UBVRI ; Photometry, infrared
Keywords: quasars: general - stars: fundamental parameters -
techniques: photometric
Abstract:
We present a total of 12,436 photometric measures of 371 field stars
of 26 quasars in the visible (UBVRI) and 22,276 photometric measures
of 122 field stars of 13 quasars in the near-infrared (JHK), giving a
total of 34,712 measures. Of these, 115 stars in 12 fields are
calibrated in both ranges. One further field, Mrk 421, was calibrated,
but on close examination all sources were found to be probably
nonstellar; thus these results are not included here. The stars
observed cover the range from V=11 to V=20 and from K=9 to K=17 and
are well distributed around the sky north of declination -30°.
This represents the initial sample of an extensive catalog of
calibrated fields that will cover the northern sky down to declination
-30° and that will cover a wide range of Galactic latitudes. These
fields will be useful both for photometry of AGNs in the range from B
to K and also as faint calibration standards for large telescopes. The
median absolute total error on the photometry, including all known
error sources, ranges from 0.008mag in J to 0.034mag in B. These
errors will be greatly reduced with the addition of further data in
the future, although the final precision is fundamentally limited by
the photometric errors in the existing lists of calibration stars used
to calibrate these data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 27 *Objects observed
table2.dat 22 60 Nights used to calibrate in the optical and
infrared bands
bands.dat 30 23 Details of the filter set used
table8.dat 142 430 UBVRI comparison stars in the fields of AGNs
table9.dat 107 122 JHK comparison stars in the fields of AGNs
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Note on table1.dat: Note that all the objects in the field of Mrk 421
were subsequently found to be nonstellar, and thus data for them is
not presented in the tables of results. Some source information is
given that will be of particular interest to quasar observers.
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See also:
II/118 : UBVRI standards around Celestial Equator (Landolt 1983)
II/183 : UBVRI Photometric Standards (Landolt 1992)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- QSO QSO name
22- 23 I2 h RAh Right ascension (J2000.0)
25- 26 I2 min RAm Right ascension (J2000.0)
28- 31 F4.1 s RAs Right ascension (J2000.0)
33 A1 --- DE- Declination sign (J2000.0)
34- 35 I2 deg DEd Declination (J2000.0)
37- 38 I2 arcmin DEm Declination (J2000.0)
40- 41 I2 arcsec DEs Declination (J2000.0)
43- 47 F5.3 --- z ? Redshift
49- 53 A5 --- Type Type of object (1)
55- 62 A8 --- Bands Bands in which the object has been observed
for this paper
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Note (1): Type of object as follows:
Sy1 = Seyfert 1
QSO = radio quiet quasar
LPQ = low polarisation quasar
OVV = optically violent variable
HPQ = high polarisation quasar
BLLac = BL Lac object
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date Observation date
12- 17 A6 --- Tel Telescope used for observations (G1)
20- 22 A3 --- Band Infrared (IR) or visual (Vis) photometry
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Byte-by-byte Description of file: bands.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Tel Telescope or reference code (G1)
9- 17 A9 --- Band Band
20- 24 I5 0.1nm lambda Central lambda
26- 29 I4 0.1nm Bandwith ? Bandwith
30 A1 --- n_Bandwith [n] n: no Bandwith value
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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- 23 A23 --- [GKM2001] Stellar designation (including field name)
25- 26 I2 h RAh The USNO A2.0 Right Ascension (J2000)
28- 29 I2 min RAm The USNO A2.0 Right Ascension (J2000)
31- 35 F5.2 s RAs The USNO A2.0 Right Ascension (J2000)
37 A1 --- DE- Sign of the Declination (J2000)
38- 39 I2 deg DEd The USNO A2.0 Declination (J2000)
41- 42 I2 arcmin DEm The USNO A2.0 Declination (J2000)
44- 47 F4.1 arcsec DEs The USNO A2.0 Declination (J2000)
49- 54 F6.3 mag Umag ? The mean U band magnitude
56- 60 F5.3 mag e_Umag ? The error on the mean in Umag
62- 63 I2 --- n_Umag ? Number of measures used in Umag
65- 66 I2 --- o_Umag ? Number of night on which Umag were taken
68- 73 F6.3 mag Bmag ? The mean B band magnitude
75- 79 F5.3 mag e_Bmag ? The error on the mean in Bmag
81- 82 I2 --- n_Bmag ? Number of measures used in Bmag
84- 85 I2 --- o_Bmag ? Number of night on which Bmag were taken
87- 92 F6.3 mag Vmag ? The mean V band magnitude
94- 98 F5.3 mag e_Vmag ? The error on the mean in Vmag
100-101 I2 --- n_Vmag ? Number of measures used in Vmag
103-104 I2 --- o_Vmag ? Number of night on which Vmag were taken
106-111 F6.3 mag Rmag ? The mean R band magnitude
113-117 F5.3 mag e_Rmag ? The error on the mean in Rmag
119-120 I2 --- n_Rmag ? Number of measures used in Rmag
122-123 I2 --- o_Rmag ? Number of night on which Rmag were taken
125-130 F6.3 mag Imag ? The mean I band magnitude
132-136 F5.3 mag e_Imag ? The error on the mean in Imag
138-139 I2 --- n_Imag ? Number of measures used in Imag
141-142 I2 --- o_Imag ? Number of night on which Imag were taken
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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- 23 A23 --- [GKM2001] Stellar designation (including field name)
25- 26 I2 h RAh The USNO A2.0 Right Ascension (J2000)
28- 29 I2 min RAm The USNO A2.0 Right Ascension (J2000)
31- 35 F5.2 s RAs The USNO A2.0 Right Ascension (J2000)
37 A1 --- DE- Sign of the Declination (J2000)
38- 39 I2 deg DEd The USNO A2.0 Declination (J2000)
41- 42 I2 arcmin DEm The USNO A2.0 Declination (J2000)
44- 47 F4.1 arcsec DEs The USNO A2.0 Declination (J2000)
49- 54 F6.3 mag Jmag ? The mean J band magnitude
56- 60 F5.3 mag e_Jmag ? The error on the mean in Jmag
62- 64 I3 --- n_Jmag ? Number of measures used in Jmag
66- 67 I2 --- o_Jmag ? Number of night on which Jmag were taken
69- 74 F6.3 mag Hmag ? The mean H band magnitude
76- 80 F5.3 mag e_Hmag ? The error on the mean in Hmag
82- 84 I3 --- n_Hmag ? Number of measures used in Hmag
86- 87 I2 --- o_Hmag ? Number of night on which Hmag were taken
89- 94 F6.3 mag Kmag ? The mean K band magnitude
96-100 F5.3 mag e_Kmag ? The error on the mean in Kmag
102-104 I3 --- n_Kmag ? Number of measures used in Kmag
106-107 I2 --- o_Kmag ? Number of night on which Kmag were taken
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Global notes:
Note (G1): Telescope or reference code as follows:
IAC-80 = Most visible data were taken at Teide Observatory on Tenerife,
Canary Islands, Spain, using the 82 cm IAC-80 Telescope (IAC-80).
JKT = Other visible data were taken at the Roque de los Muchachos
Observatory (RMO), on La Palma, Canary Islands, Spain,
using the 1m Jacobus Kapteyn Telescope (JKT).
OAN = Data was taken with the 1.52 m reflector at the Observatorio
Astronsmico Nacional on two nights in 2000 March. The telescope
is sited in the Centro Astronomico Hispano Aleman (CAHA),
within the Estacion de Observacion de Calar Alto of the OAN.
Landolt = published by Landolt, 1983 Cat. II/118, 1992 Cat. II/183
CST = All infrared data were taken with the Carlos Sanchez
Telescope (CST) at Teide Observatory, Tenerife.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 31-Jan-2002