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J/ApJ/446/115                      Gamma ray burst localizations (Vrba+ 1995)

Deep optical counterpart searches of gamma-ray burst localizations Vrba F.J., Hartmann D.H., Jennings M. C. <Astrophys. J. 446, 115 (1995)> =1995ApJ...446..115V
ADC_Keywords: QSOs ; Gamma rays Keywords: gamma rays: bursts - quasars: general - surveys - techniques: photometric Abstract: We report the results of a 5 year CCD imaging program of small gamma-ray burst (GRB) error boxes from the First Interplanetary Network and an optical transient field. The fields include GBS 0010-16, GBS 0552-08, GBS 1028+46, GBS 1205+23, GBS 1412+79, OTS 1809+31, GBS 2006-22, and GBS 2252-03. A total of 274 hours of open shutter time was used to obtain multiple UBVI-filtered frames covering an area approximately twice that of the 99% confidence localizations. For 2070 objects in these fields above the survey detection limit of V∼24, 79,000 calibrated photometric measurements were made. The objectives of the survey were to search for objects of unusual colors, variability, or proper motions. The final census of objects in these fields is consistent with the expected numbers of normal stars, galaxies, and proper motion objects based on statistics of large-scale surveys. While no obvious GRB optical counterparts were found, several potentially interesting objects were discovered, along with marginal evidence for a QSO excess at the rate of one per high Galactic latitude localization. The results and implications are discussed in detail along with suggestions for future work. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 108 2074 Condensed Database table6.dat 99 27 Objects of possible interest
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Field *Field name 13- 16 I4 --- Object *Object identification number 17 A1 --- Gal [g ] Indicates if object is a resolved galaxy 19- 24 F6.3 mag Vmag []?=-9.000 Mean V magnitude 26- 31 F6.3 mag e_Vmag *[]?=-1.000 Uncertainty in Vmag 33- 39 F7.3 mag B-V []?=-9.000 Mean (B-V) color 41- 46 F6.3 mag e_B-V *[]?=-1.000 Uncertainty in B-V 48- 54 F7.3 mag U-B []?=-9.000 Mean (U-B) color 56- 61 F6.3 mag e_U-B *[]?=-1.000 Uncertainty of U-B 63- 69 F7.3 mag V-I []?=-9.000 Mean (V-I) color 71- 76 F6.3 mag e_V-I *[]?=-1.000 Uncertainty in V-I 78- 84 F7.3 mag U-V []?=-9.000 Mean (U-V) color 86- 91 F6.3 mag e_U-V *[]?=-1.000 Uncertainty in U-V 93- 99 F7.2 pix Xpos *? X pixel coordinate 101-108 F8.2 pix Ypos *? Y pixel coordinate
Note on Field: Eight GBS or OTS fields are arranged in increasing order of Galactic latitude. The field name is repeated here for each object. Note on Object: Object identification numbers for each field are arranged in decreasing order of declination. Note on e_Vmag, e_B-V, e_U-B, e_V-I, e_U-V: The uncertainties listed are the larger of i) the weighted standard deviation of the mean, or ii) the minimum error based on the photometric uncertainties of individual observations. Thus, the listed error represents the uncertainty of the value whether primarily due to photometric error or variability. A -9.000 or -1.000 in the color/magnitude and uncertainty columns, respectively, indicates that there are insufficient data to calculate that quantity. A few lines of data are listed to only .01mag precision. These are highly extended objects whose photometric data were obtained by synthetic aperture photometry, rather than the usual point spread function fitting, as described in the text of the printed paper. Note on Xpos, Ypos: The fiducial pixel coordinates (X,Y, with the origin at the northeast corner of each field) for each object to the nearest .01 pixel. Most pixel coordinates are from the Daophot `find' routine and have internal precisions of .01 pixel for the best exposed objects to about 1.0 pixel for the faintest and/or extended objects. Additionally, those objects with all zeros to the right of the decimal point for both X and Y were added to the object list by hand and have internal precisions of only 1.0 pixel. There was no attempt to estimate the internal precisions for each object since, as explained in Section 2.7 of the printed paper, the positional errors are dominated by not knowing the CCD rotation to better than about 0.5 degree. For an object lying 400 pixels from the center of the field this amounts to a 3.5 pixel error. At the telescope scale of 0.4295 arcsec/pixel the combined errors could be as large as 2 arcsec. Thus, the pixel coordinates should be used for identification purposes only and not for high accuracy astrometry. Finally, there are three objects (one each in the fields OTS 1809+31, GBS 2006-22, GBS 1205+23) with blank fields in X and Y. These are due to CCD artifacts which were realized as such only until well after the final object numbering system was finalized.
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Field Field name (Gamma Burst Source) 13- 15 I3 --- No Object number 18 I1 --- o_Umag Number of observation in U filter 20 I1 --- o_Bmag Number of observation in B filter 22- 23 I2 --- o_Vmag Number of observation in V filter 25- 26 I2 --- o_Imag Number of observation in I filter 29- 33 F5.2 mag Vmag V magnitude 35- 37 F3.2 mag e_Vmag rms uncertainty on Vmag 40- 43 F4.2 mag B-V B-V colour index 45- 47 F3.2 mag e_B-V rms uncertainty on B-V 50- 54 F5.2 mag U-B ? U-B colour index 56- 58 F3.2 mag e_U-B ? rms uncertainty on U-B 61- 64 F4.2 mag V-I V-I colour index 66- 68 F3.2 mag e_V-I rms uncertainty on V-I 71- 73 A3 --- GRBBox This column answers whether the object lies within the IPN 99% confidence localization (1) 74- 77 F4.2 arcmin Dist ? Approximate distance to the nearest edge of the localization for objects that lies outside the localization. 80- 99 A20 --- Com Comments (1)
Note (1): NA = not associated; IPN: Cline et al., 1980ApJ...237L...1C
History: * 07-Oct-1995: AAS CD-ROM series, Volume 5, 1995 (Lee Brotzman [ADS]) * 12-Nov-1996: table6 added at CDS.
(End) [CDS] 08-Jan-1997
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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