I/331 Absolute Proper motions Outside the Plane (APOP) (Qi+, 2015)
Absolute Proper motions Outside the Plane - APOP.
A step towards the GSC2.4.
Qi Z.X., Yu Y., Bucciasrelli B., Lattanzi M.G., Smart R.L., Spagna A.,
McLean B.J., Tang Z.H., Jones H.R.A., Morbidelli R., Nicastro L.,
Vacchiato A.
<Astron. J., 150, 137 (2015)>
=2015AJ....150..137Q 2015AJ....150..137Q
=2015yCat.1331....0Q 2015yCat.1331....0Q
ADC_Keywords: Positional data ; Surveys ; Proper motions
Keywords: astrometry - astronomical databases: miscellaneous - catalogs -
proper motions - reference systems
Abstract:
We present a new catalog of absolute proper motions and updated
positions derived from the same Space Telescope Science Institute
digitized Schmidt survey plates utilized for the construction of the
Guide Star Catalog II. As special attention was devoted to the
absolutization process and removal of position, magnitude and color
dependent systematic errors through the use of both stars and
galaxies, this release is solely based on plate data outside the
galactic plane, i.e. |b|≥27°. The resulting global zero point
error is less than 0.6 mas/yr, and the precision better than 4.0mas/yr
for objects brighter than RF=18.5, rising to 9.0mas/yr for objects
with magnitude in the range 18.5<RF<20.0. The catalog covers 22,525
square degrees and lists 100,774,153 objects to the limiting magnitude
of RF∼20.8. Alignment with the International Celestial Reference
System (ICRS) was made using 1288 objects common to the second
realization of the International Celestial Reference Frame (ICRF2) at
radio wavelengths. As a result, the coordinate axes realized by our
astrometric data are believed to be aligned with the extragalactic
radio frame to within ±0.2mas at the reference epoch J2000.0. This
makes our compilation one of the deepest and densest ICRF-registered
astrometric catalogs outside the galactic plane. Although the Gaia
mission is poised to set the new standard in catalog astronomy and
will in many ways supersede this catalog, the methods and procedures
reported here will prove useful to remove astrometric magnitude- and
color-dependent systematic errors from the next generation of
ground-based surveys reaching significantly deeper than the Gaia
catalog.
Description:
The APOP is a absolute proper motion catalog achieved on the Digitized
Sky Survey Schmidt plates data established by GSC-II project that
outside the galactic plane (|b|>27°). The sky cover of this
catalog is 22,525 square degree, the mean density is
4473 objects/sq.deg. and the magnitude limit is around R=20.8mag. The
systematic errors of absolute proper motions related to the position,
magnitude and color are practically all removed by using the
extragalactic objects. The zero point error of absolute proper motions
is less than 0.6mas/yr, and the accuracy is better than 4.0mas/yr for
objects bright than R=18.5, and rises to 9.0mas/yr for objects with
magnitude 18.5<R<20.0.
We believe the catalog is reliable for operational applications and
will be also fine for astrophysical research. But the user should use
this catalog with that in mind, the accuracy condition is good for
objects with Declination>-30 degree and is not very well for others,
the reason is that the epoch difference is large for
Declination>-30° (45 years) but South than that is only around 12
years. It is fine for statistical studies for objects with
Declination←30° that people could find and remove obviously
incorrect entries.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
apop.sam 156 100 *Absolute Proper motions Outside the Plane
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Note on apop.sam: The reading format when using Fortran is
'(A13,1X,I3,1X,2F12.7,1X,2F7.1,1X,2F8.1, 1X,2F6.1,1X,I3,1X,F7.3,1X,7F8.3)'.
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See also:
http://gsss.stsci.edu/catalogs/gsc/gsc2/gsc2.htm : the GSC-II Home Page
I/254 : The HST Guide Star Catalog, Version 1.2 (Lasker+ 1996)
I/271 : The Guide Star Catalog, Version 2.2 (GSC2.2) (STScI, 2001)
I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)
Byte-by-byte Description of file: apop.sam
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Bytes Format Units Label Explanations
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1- 13 A13 --- ID Source identifier (1)
17 A1 --- Type Classification of the source (2)
20- 30 F11.7 deg RAdeg Right ascension
(ICRS, position epoch=J2000.0, TDB)
32- 42 F11.7 deg DEdeg Declination
(ICRS, position epoch=J2000.0, TDB)
45- 51 F7.2 mas e_RAdeg Error in right ascension at Epoch
52- 58 F7.2 mas e_DEdeg Error in declination at Epoch
59- 66 F8.1 mas/yr pmRA Absolute proper motion in RA (pmRA*cos(DE))
68- 74 F7.1 mas/yr pmDE Absolute proper motion in Declination
76- 81 F6.1 mas/yr e_pmRA Error in pmRA at Epoch
83- 87 F5.1 mas/yr e_pmDE Error in pmDE at Epoch
89- 91 I3 --- Nobs Number of observations (3)
94- 99 F6.3 yr Dt Maximal time differences (4)
102-108 F7.3 mag Rmag ?=-99 Magnitude in RF photographic
band (red) (5)
110-116 F7.3 mag Bmag ?=-99 Magnitude in BJ photographic
band (blue) (5)
118-124 F7.3 mag Nmag ?=-99 Magnitude in IN photographic band
(near infrared) (5)
126-132 F7.3 mag Vmag ?=-99 Magnitude in V photographic band
(visible) (5)
134-140 F7.3 mag Jmag ?=-99 2MASS J magnitude (6)
142-148 F7.3 mag Hmag ?=-99 2MASS H magnitude (6)
150-156 F7.3 mag Kmag ?=-99 2MASS Ks magnitude(6)
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Note (1): The ID is the source identifier for object in the APOP, which is as
same as the source identifier of that object in GSC2.3 catalog.
Here the APOP ID is the combination of the HTM_ID and the running_number in
GSC2.3, i.e.
32768+0000005 for GSC2.3=S000000005, HTM6=S0000000 source,
32785+0003424 fpr GSC2.3=S00H003424, HTM6=S0000101 source
in GSC2.3 (Cat. I/305).
Note (2): The classification is based on the following codes:
0 = star as defined in the GSC23
1 = stars from the GSC23 used as reference sources
2 = QSOs from the GIQC catalog
3 = Non-stars as defined in the GSC23
4 = Non-stars indicated as extragalactic from Non-stars
Note (3): The Nobs is the number of plates used for deriving the pmRA, pmDE of
that object.
Note (4): The Dt is the maximal time differences between the plates used for
the calculation.
Note (5): The magnitudes data are extracted directly from GSC2.3 catalog.
Users can identify the exact meaning by looking at the 'Table 3' in GSC2.3
paper (Lasker et al., 2008AJ....136..735L 2008AJ....136..735L, Cat. I/305).
The default value is -99.000 if there is no data in that passband.
Note (6): The photometric data are the near-infrared J (1.25um), H (1.65um),
and Ks (2.16um) from the 2MASS catalog (Skrutskie et al., 2006AJ....131.1163S 2006AJ....131.1163S,
Cat. VII/233).
The default value is -99.000 if there is no data in that passband.
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Acknowledgements:
This work is a joint study of the Shanghai Astronomical Observatory (SHAO),
the Osservatorio Astrofisico di Torino (OATo) and the Space Telescope
Science Institute (STScI). We would like to express our thanks to many
former and present members of the GSC project for their support and effort
for this large project. This work is supported by grants from the National
Science Foundation of China (NSFC No. 10903022) and the IPERCOOL FP7
International Research Staff Exchange Scheme (No. 247593). This research
has made use of the MCS database server system, developed by Giorgio
Calderone and Luciano Nicastro, operated at OATo and SHAO.
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Author's address:
Zhaoxiang Qi, kevin(at)shao.ac.cn
(End) Zhaoxiang Qi [SHAO/CAS, China] 09-Sep-2015