The Monitor project: data processing and light curve production

Irwin, Jonathan; Irwin, M. J.; Aigrain, S.; Hodgkin, S. T.; Hebb, Leslie; Moraux, E.

doi:10.1111/j.1365-2966.2006.11408.x

Cited by 86 publications

(133 citation statements)

References 20 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…The obvious rise of the lower envelope at faint magnitudes is a combination of the standard deviations (root-mean-squares) from Poisson noise in the targets and from sky noise in the photometric aperture (e.g. Irwin et al 2007). The line used as the selection criterion is the lower envelope shifted to larger σ(V 0 )s by magnitude-dependent amounts (roughly 0.06 mag at V 0 ∼ 8.5-11.5 mag, 0.12 mag at V 0 ∼ 12.5 mag, and 0.18 mag at V 0 ∼ 13.5 mag).…”

Section: Discussionmentioning

confidence: 99%

Finding the most variable stars in the Orion Belt with the All Sky Automated Survey

2010

View full text Add to dashboard Cite

We look for high-amplitude variable young stars in the open clusters and associations of the Orion Belt. We use public data from the ASAS-3 Photometric V -band Catalogue of the All Sky Automated Survey, infrared photometry from the 2MASS and IRAS catalogues, proper motions, and the Aladin sky atlas to obtain a list of the most variable stars in a survey area of side 5 deg centred on the bright star Alnilam (ǫ Ori) in the centre of the Orion Belt. We identify 32 highly-variable stars, of which 16 had not been reported to vary before. They are mostly variable young stars and candidates (16) and background giants (8), but there are also field cataclysmic variables, contact binaries, and eclipsing binary candidates. Of the young stars, which typically are active Herbig Ae/Be and T Tauri stars with Hα emission and infrared flux excess, we discover four new variables and confirm the variability status of another two. Some of them belong to the well known σ Orionis cluster. Besides, six of the eight giants are new variables, and three are new periodic variables.

show abstract

Section: Discussionmentioning

confidence: 99%

Finding the most variable stars in the Orion Belt with the All Sky Automated Survey

2010

View full text Add to dashboard Cite

show abstract

“…Data processing and light curve production were performed for each dataset separately, following the procedure described in Irwin et al (2007a). Briefly, a master frame was created by stacking the images taken in the best seeing conditions before using the source detection software.…”

Section: Light Curve Productionmentioning

confidence: 99%

The Monitor Project: stellar rotation at 13 Myr

Moraux

Artemenko

Bouvier

et al. 2013

A&A

115

View full text Add to dashboard Cite

Aims. We aim at constraining the angular momentum evolution of low-mass stars by measuring their rotation rates when they begin to evolve freely towards the zero-age main sequence (ZAMS), i.e., after the disk accretion phase has stopped. Methods. We conducted a multisite photometric monitoring of the young open cluster h Persei, which has an age of ∼13 Myr. The observations were done in the I-band using four different telescopes, and the variability study is sensitive to periods from less than 0.2 day to 20 days. Results. Rotation periods are derived for 586 candidate cluster members over the mass range 0.4 ≤ M/M ≤ 1.4. The rotation period distribution indicates a slightly higher fraction of fast rotators for the lower mass objects, although the lower and upper envelopes of the rotation period distribution, located respectively at ∼0.2-0.3 d and ∼10 d, are remarkably flat over the whole mass range. We combine this period distribution with previous results obtained in younger and older clusters to model the angular momentum evolution of low mass stars during the pre-main sequence (PMS) phase. Conclusions. The h Per cluster provides the first statistically robust estimate of the rotational period distribution of solar-type and lower mass stars at the end of the PMS accretion phase (≥10 Myr). The results are consistent with models that assume significant core-envelope decoupling during the angular momentum evolution to the ZAMS.

show abstract

“…The J-band images from the WTS are reduced by the image reduction pipeline from the Cambridge Astronomical Survey Unit 3 (CASU), which is used to process all images from the WFCAM. The image reduction pipeline is based on the work developed by Irwin (1985) (Irwin et al 2007). The pipeline includes the following steps: de-biassing and trimming, non-linearity correction, bad pixel replacement, flatfielding, defringing, and sky subtraction.…”

Section: Image Reduction Pipelinementioning

confidence: 99%

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

Dominguez

Koppenhoefer

Saglia

et al. 2013

A&A

View full text Add to dashboard Cite

The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ∼475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.

show abstract

The Monitor project: data processing and light curve production

Cited by 86 publications

References 20 publications

Finding the most variable stars in the Orion Belt with the All Sky Automated Survey

Finding the most variable stars in the Orion Belt with the All Sky Automated Survey

The Monitor Project: stellar rotation at 13 Myr

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

Contact Info

Product

Resources

About