150 likes | 260 Views
COROT planet field observations at INT La Palma. H.J. Deeg 1 , M. Deleuil 2 , C. Moutou 2 1 IAC, Tenerife; 2 LAM Marseille. - Observations taken at 2.5m INT, Obsv. Roque Muchachos of the IAC - Wide Field Camera (WFC), with 4 CCDs, 33x33 arcmin total f.o.v.
E N D
COROT planet field observations at INT La Palma H.J. Deeg1, M. Deleuil2, C. Moutou2 1IAC, Tenerife; 2LAM Marseille - Observations taken at 2.5m INT, Obsv. Roque Muchachos of the IAC - Wide Field Camera (WFC), with 4 CCDs, 33x33 arcmin total f.o.v. - all fields observed complete in 4 filters: B,V, r’, i’. U filter added for some pointings in latest observations (6-9 June 2003) - reduction performed in collaboration Cambridge - LAM - IAC - aim: creation of photometric catalog that aids to: - select prime target fields (in conjuction with AS, of course...) - select pointing within target field - select stars to be included in observed sample
Schematics of the pointings COROT AS-target star
The CCD mosaic of the WFC exposure times: 10-120 sec Overlap of ‘A’ and ‘B’ pointings 'A' and 'B' pointings are taken in all 4 filters
The reduction pipeline -at Univ of Cambridge, with Wide FieldsSurvey (WFS) pipeline: - identification of stars on images - extraction of photometry in several aperture sizes - generation of average nightly photometric coefficients - production of files with stellar ADU values, one for each colors and pointings -at LAM: - first quality check (evaluation of seeing, selection of basic aperture size) - application of photometric calibration from WFS, - cross-identification of stars in different colors - merging into one file per pointing -at IAC: - final photometric calibration (Feb03 data only) - cross-identification of stars in adjacent or multiple pointings - merging of pointings into single catalog - second quality check (magnitude offsets across pointings) - submission to ExoDat
mosaicing for a field (HD174866 field shown) Number of 4-color observations per star vary from 1 to 4 dark-red Nobs=1 red Nobs=2 white Nobs ≥3
The Status of COROT field observations Galactic center: (June 2002, photometric) HD171834 - N6633 field : 19deg2, 2.16 x 106 stars , in exodat HD174866: 8deg2, 1.48 x 106 stars, in exodat Galactic anticenter: (Feb. 2003, seeing/extinction very variable) HD49933: 20deg2, 0.48 x 106 stars, in exodat HD57006: 1.5deg2, in exodat Galactic center: (June 2003, photometric, currently reduced at Cambridge), included some (time-consuming) U band observations HD171834: 6deg2 additional (1.5 deg2 in U) HD177552: 5.5deg2 (all in U too) HD175726: 7.5deg2 (with few pointings in U) Galactic anticenter: 9 nights allocated Dec - Jan 03/04 Galactic center: Summer 04, 6 nights conceded
i < 16 AND V-i >1.0 Giants i < 16 AND V-i < 1.0 V-i MS MS i The HD174866 field is fairly homogenous For a descripion of spectral classification method, see Moutou et al.
high extinction, somewhat lower density in total very few background giants, dwarfs are redder i < 16 AND V-i >1.5 (red) NGC6633- HD17834 field strong inhomogeneities, clear extinction gradient i < 16, all colors i < 16 AND V-i <1.0 (blue)
zone 1 zone 1 zone 3 zone 2 zone 3 zone 2 idea: we need to define a floating V-i (as a fct of V) segregation value to separate dwarf vs giant pops. could be defined as 15% line +0.3 in V-I. Or search for minimum in histogram V-I at different mags. -> program to create maps of densities dwarfs and giants NGC6633 - HD171834 field; HR diagrams i < 16 AND V-I < 1.0
i < 16 HD49933 field Observations taken in feb 03 with strongly varying extinction and seeing up to 5” Photometry based on nightly zero-points (from WFS pipeline) is shown. Some pointings are clearly suffering strong extinction Re-calibration based on observed Landolt fields was performed
Photometric calibration of Feb 03 data Based on average offset magWFS-magcat[+color terms] of 30 Landolt-stars in L98 -> linear interpolation of zero-pt offsets applied to COROT field pointings magWFS -magcat relatively good conditions in short windows in 3rd night: |magWFS-magcat| <~ 0.02mag -> WFS calibration should be fine at photometric conditions? needs verification lastly: Re-assembly of merged catalog: verifiy that each pointing added does not have offset >0.1mag in any color of overlapping stars
before and after final phot. calibration HD49933 fld, mag i < 16
Nstar histograms against Vmag HD174866/N6633 19°2, 2.15M * HD174866, 8°2, 1,48M * HD49933 after calibr, 20°2, 0,43M *
Summary Galactic center: Fields HD174866, HD171834 +NGC6633 are nearly complete and calibrated photometry has been inserted into COROT source catalogue. In four photometric nights (June 6-9, 2003) large parts of the new target fields HD175726 and HD177552 were observed, with reduction in progress. Six nights at INT/WFC conceded for summer 04. Galactic anticenter: Field HD49933 is mostly complete HD57006 only started. 10 nights at INT/WFC conceded for Dec 03/Jan 04.