Introduction to AST3-II data release 1st. The major part of this data release includes 18729 catalogs and 26578 lightcurves which have been divided into subdirectories labelled by their field names. A table of variables found within our data is also presented. The details on data reduction processes are presented in Huizhang et al. 2018a and Huizhang et al. 2018b. ============================================================================================================================== I. Structure and content of directories catalog/ Calibrated catalogs catalog/Tess004/ ... catalog/Tess013/ ------------------------------------------------------------------------------------------------------------------------------ lightcurve/ lightcurve/raw/ Raw lightcurves lightcurve/raw/Tess004/ ... lightcurve/raw/Tess013/ ------------------------------------------------------------------------------------------------------------------------------ lightcurve/detrended/ Detrended lightcurves lightcurve/detrended/Tess004/ ... lightcurve/detrended/Tess013/ ------------------------------------------------------------------------------------------------------------------------------ AST3II_dr1_catalog.tar.gz A compressed file contains all catalogs AST3II_dr1_lightcurve.tar.gz A compressed file contains all lightcurves variable_table_submitted.txt.gz Table of variables found within this data release AST3II_48_fields.txt Information of all target fields of AST3-II Readme.txt This file ============================================================================================================================== II. Catalog 1. Format of catalog name: The name of each catalog contains the name of the target fields and the number of records in this catalog. "Project Name"-"Field Name"_"sequential number"_"number of stars".cat e.g. AST3II-Tess004_000001_000957.cat NOTE1: The field name start with "Tess", but it is NOT related to the Field No. of TESS. ------------------------------------------------------------------------------------------------------------------------------ 2. The header of each catalog contains following information: a. Observation information: # obs. start time(UT) yyyy-mm-ddThh:mm:ss.ss e.g. 2016-05-16T16:18:40.69 # exposure time(s) i2 e.g. 50 # CCD temperature(K) f6.2 e.g. 218.87 # airmass : f4.2 e.g. 1.07 # solar altitude (degree) f6.2 e.g. -26.84 # moon distance (degree) f5.2 e.g. 90.86 # zero-point mag f5.2 e.g. 24.62 b. Column information (produced by Sextractor (Bertin & Arnouts 1996)) # 1 XWIN_IMAGE : image position in x axis f11.60 [pixel] # 2 YWIN_IMAGE : image position in y axis f11.60 [pixel] # 3 X2WIN_IMAGE : position variance in x axis f9.60 [pixel**2] # 4 Y2WIN_IMAGE : position variance in y axis f9.60 [pixel**2] # 5 XYWIN_IMAGE : position covariance between x and y axis f9.60 [pixel**2] # 6 ERRX2WIN_IMAGE : error of position variance in x axis f9.60 [pixel**2] # 7 ERRY2WIN_IMAGE : error of position variance in x axis f9.60 [pixel**2] # 8 ERRXYWIN_IMAGE : error of position covariance between x axis and y axis f9.60 [pixel**2] # 9 CXXWIN_IMAGE : the first ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] # 10 CYYWIN_IMAGE : the second ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] # 11 CXYWIN_IMAGE : the third ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] # 12 XWIN_WORLD : Right Ascension (Ra) in J2000 f10.60 [deg] # 13 YWIN_WORLD : Declination (Dec) in J2000 f10.60 [deg] # 14 ERRX2WIN_WORLD : error of position variance in Ra f10.60 [deg**2] # 15 ERRY2WIN_WORLD : error of position variance in Dec f10.60 [deg**2] # 16 ERRXYWIN_WORLD : error of position covariance between Ra and Dec f10.60 [deg**2] # 17 MAG_AUTO : Kron-like elliptical aperture magnitude f9.60 [mag] # 18 MAGERR_AUTO : RMS error for AUTO magnitude f9.60 [mag] # 19 FLUX_AUTO : flux within a Kron-like elliptical aperture f16.60 [count] # 20 FLUXERR_AUTO : RMS error for AUTO flux f14.60 [count] # 21-23 MAG_APER : fixed aperture magnitude vector f9.60 [mag] # 24-26 MAGERR_APER : RMS error vector for fixed aperture mag. f9.60 [mag] # 27-29 FLUX_APER : flux vector within fixed circular aperture(s) f16.60 [count] # 30 FLUXERR_APER : RMS error vector for aperture flux(es) f14.60 [count] # 33 FWHM_IMAGE : FWHM assuming a Gaussian core f8.60 [pixel] # 34 ELONGATION : ellipticity of object's isophotal shape f8.60 # 35 BACKGROUND : background at centroid position f10.60 [count] # 36 THRESHOLD : detection threshold above background f10.60 [count] # 37 FLUX_RADIUS : fraction-of-light radius f10.60 [pixel] # 38 FLAGS : extraction flags f10.60 NOTE 1: The magnitudes are in sloan-i band. NOTE 2: The world coordinates are in J2000 equatorial coordinate system. NOTE 3: Aperture sizes of the fixed aperture magnitude are 8, 10, 12 pixels. NOTE 4: Explainations for FLAGS (from the manual of Sextractor): 1 The object has neighbours, bright and close enough to significantly bias the MAG_AUTO photometry, or bad pixels (more than 10% of the integrated area affected). 2 The object was originally blended with another one. 4 At least one pixel of the object is saturated (or very close to). 8 The object is truncated (too close to an image boundary). 16 Object¡¯s aperture data are incomplete or corrupted. 32 Object¡¯s isophotal data are incomplete or corrupted. FLAGS contains, coded in decimal, all the extraction flags as a sum of powers of 2.For example, an object close to an image border may have FLAGS = 16, and perhaps FLAGS = 8+16+32 = 56. The flags are combined such that a unique number will result as the flag entry in the catalogs. ============================================================================================================================== III. Lightcurve Lightcurves are divided into two categories: raw and detrended. 1. Raw lightcurve Raw lightcurves are generated directly from the corresponding catalogs and contain all the information of these catalogs. For each lightcurve we also present a list of reference stars used to detrend this lightcurve. a. Format of lightcurve name lightcurve: "Project Name"-"Field Name"_"i-band magnitude in APASS database"_"Ra/degrees""Dec/degress"_"Number of measurements".dat e.g. AST3II_Tess004_07.68_094.7145-73.3608_001854.dat trend list: "Name of lightcurve""trendlist" e.g. AST3II_Tess004_07.68_094.7145-73.3608_001854trendlist b. Column information of raw lightcurve A raw lightcurve contains 37 columns: #1 time/day: : AST3 observation time in UT (JD --2456000) f11.60 [JD] #2 XWIN_IMAGE : image position in x axis f11.60 [pixel] #3 YWIN_IMAGE : image position in y axis f11.60 [pixel] #4 X2WIN_IMAGE : position variance in x axis f9.60 [pixel**2] #5 Y2WIN_IMAGE : position variance in y axis f9.60 [pixel**2] #6 XYWIN_IMAGE : position covariance between x and y axis f9.60 [pixel**2] #7 ERRX2WIN_IMAGE : error of position variance in x axis f9.60 [pixel**2] #8 ERRY2WIN_IMAGE : error of position variance in x axis f9.60 [pixel**2] #9 ERRXYWIN_IMAGE : error of position covariance between x axis and y axis f9.60 [pixel**2] #10 CXXWIN_IMAGE : the first ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] #11 CYYWIN_IMAGE : the second ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] #12 CXYWIN_IMAGE : the third ellipse parameter of object's isophotal shape f9.60 [pixel**(-2)] #13 XWIN_WORLD : Right Ascension (Ra) in J2000 f10.60 [deg] #14 YWIN_WORLD : Declination (Dec) in J2000 f10.60 [deg] #15 ERRX2WIN_WORLD : error of position variance in Ra f10.60 [deg**2] #16 ERRY2WIN_WORLD : error of position variance in Dec f10.60 [deg**2] #17 ERRXYWIN_WORLD : error of position covariance between Ra and Dec f10.60 [deg**2] #18 MAG_AUTO : Kron-like elliptical aperture magnitude f9.60 [mag] #19 MAGERR_AUTO : RMS error for AUTO magnitude f9.60 [mag] #20 FLUX_AUTO : flux within a Kron-like elliptical aperture f16.60 [count] #21 FLUXERR_AUTO : RMS error for AUTO flux f14.60 [count] #22-24 MAG_APER : fixed aperture magnitude vector f9.60 [mag] #25-27 MAGERR_APER : RMS error vector for fixed aperture mag. f9.60 [mag] #28-30 FLUX_APER : flux vector within fixed circular aperture(s) f16.60 [count] #31-33 FLUXERR_APER : RMS error vector for aperture flux(es) f14.60 [count] #34 FWHM_IMAGE : FWHM assuming a Gaussian core f8.60 [pixel] #35 ELONGATION : ellipticity of object's isophotal shape f8.60 #36 BACKGROUND : background at centroid position f10.60 [count] #37 THRESHOLD : detection threshold above background f10.60 [count] #38 FLUX_RADIUS : fraction-of-light radius f10.60 [pixel] #39 FLAGS : extraction flags f10.60 #40 exposure time : exposure time f10.60 [s] #41 CCD temperature : temperature of CCD chip f10.60 [K] #42 airmass : airmass f10.60 #43 solar altitude : altitude of the Sun f10.60 [degree] #44 moon distance : angular distance to the Moon f10.60 [degree] #45 zero-point mag : zero-point magnitude f10.60 [mag] : NOTE 1: the unit of observation time is in JD and has subtracted a constant of 2456000. NOTE 2: Aperture sizes of the fixed aperture magnitude are 8, 10, 12 pixels. c. Column information of trendlist file #1 Name of reference lightcurve #2 J2000 Ra of this reference star f8.4 [degree] #3 J2000 Dec of this reference star f8.4 [degree] #4 Pearson correlation coefficient between this reference lightcurve and target lightcurve before detrending f4.2 #5 Pearson correlation coefficient between this reference lightcurve and target lightcurve after detrending f4.2 NOTE1: Records in a trendlist file is sorted descendly according to column #4. ------------------------------------------------------------------------------------------------------------------------------ 2. Detrended lightcurve Detrended lightcurves are generated from the raw lightcurves by performing a series of detrending processes. a. Format of lightcurve name It's the same as the name of raw lightcurve: "Project Name"-"Field Name"_"i-band magnitude in APASS database"_"Ra/degrees""Dec/degress"_"Number of measurements".dat e.g. AST3II_Tess004_07.68_094.7145-73.3608_001854.dat b. Colunm information of detrended lightcurve #1 Observation time in JD. A constant of 2456000 has been subtracted. f11.60 [JD] #2 Detrended magnitude in sloan-i band f9.60 [mag] #3 Error of detrended magnitude f9.60 [mag]