CFHT’s Skyprobe: True Atmospheric Attenuation Measurement in the Telescope Field

Cuillandre, J. C.; Magnier, E. A.; Isani, Sidik; Sabin, Dan; Knight, Wiley; Kras, Simon; Lai, Kamson

doi:10.1007/1-4020-2527-0_34

Cited by 3 publications

(3 citation statements)

References 9 publications

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“…Each field was observed in dithering mode to effectively compute and remove the sky. Weather conditions on Mauna Kea on 20 June 2007 and 17 April 2004 were photometric, as reported by the CFHT Skyprobe atmospheric attenuation measurements (Cuillandre et al 2004). No data are available for 16 April 2004, but the quality and depth of the images suggests that the weather was similarly good.…”

Section: Subaru Telescope: I and Z Band Archival Datamentioning

confidence: 89%

The low-mass population of theρ Ophiuchi molecular cloud

Oliveira¹,

Moraux²,

Bouvier³

et al. 2010

A&A

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Context. Star formation theories are currently divergent regarding the fundamental physical processes that dominate the substellar regime. Observations of nearby young open clusters allow the brown dwarf (BD) population to be characterised down to the planetary mass regime, which ultimately must be accommodated by a successful theory. Aims. We hope to uncover the low-mass population of the ρ Ophiuchi molecular cloud and investigate the properties of the newly found brown dwarfs. Methods. We used near-IR deep images (reaching completeness limits of approximately 20.5 mag in J and 18.9 mag in H and K s ) taken with the Wide Field IR Camera (WIRCam) at the Canada France Hawaii Telescope (CFHT) to identify candidate members of ρ Oph in the substellar regime. A spectroscopic follow-up of a small sample of the candidates allows us to assess their spectral type and subsequently their temperature and membership. Results. We select 110 candidate members of the ρ Ophiuchi molecular cloud, from which 80 have not previously been associated with the cloud. We observed a small sample of these and spectroscopically confirm six new brown dwarfs with spectral types ranging from M6.5 to M8.25.

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Section: Subaru Telescope: I and Z Band Archival Datamentioning

confidence: 89%

The low-mass population of theρ Ophiuchi molecular cloud

Oliveira¹,

Moraux²,

Bouvier³

et al. 2010

A&A

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“…Photometric nights were selected using the CFHT "Skyprobe" instrument (Cuillandre 2003), which monitors atmospheric transparency in the direction that the telescope is pointing. Only the 50% of nights with the smallest scatter in transparency were considered.…”

Section: Photometric Calibration Of Tertiary Standardsmentioning

confidence: 99%

The Supernova Legacy Survey: measurement of $\Omega_{\mathsf{M}}$, $\Omega_\mathsf{\Lambda}$ andwfrom the first year data set

Astier

Guy

Regnault

et al. 2006

A&A

2,243

1,370

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We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands, as part of the CFHT Legacy Survey (CFHTLS). Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multi-band photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: Ω M = 0.263 ± 0.042 (stat) ± 0.032 (sys) for a flat ΛCDM model; and w = −1.023 ± 0.090 (stat) ± 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.

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“…Cross comparisons can be facilitated by parallel wide-field observations along the line of sight to each image, as in the CFHT skyprobe facility (Cuillandre et al 2004) 1 , or other "context" camera systems. But having multi-filter standards within each digital image offers many simplifying advantages.…”

Section: Introductionmentioning

confidence: 99%

All-Sky Spectrally MatchedUBVRI - ZYandu^′g^′r^′i^′z^′Magnitudes for Stars in the Tycho2 Catalog

Pickles

Depagne

2010

Publications of the Astronomical Society of the Pacific

171

122

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We present fitted UBVRI-ZY and u ′ g ′ r ′ i ′ z ′ magnitudes, spectral types and distances for 2.4 M stars, derived from synthetic photometry of a library spectrum that best matches the Tycho2 B T V T , NOMAD R N and 2MASS JHK 2/S catalog magnitudes. We present similarly synthesized multi-filter magnitudes, types and distances for 4.8 M stars with 2MASS and SDSS photometry to g < 16 within the Sloan survey region, for Landolt and Sloan primary standards, and for Sloan Northern (PT) and Southern secondary standards.The synthetic magnitude zeropoints for B T V T , UBV RI, Z V Y V , JHK 2/S , JHK M KO , Stromgren uvby, Sloan u ′ g ′ r ′ i ′ z ′ and ugriz are calibrated on 20 calspec spectrophotometric standards. The UBV RI and ugriz zeropoints have dispersions of 1-3%, for standards covering a range of color from −0.3 < V − I < 4.6; those for other filters are in the range 2-5%.The spectrally matched fits to Tycho2 stars provide estimated 1σ errors per star of ∼0.2, 0.15, 0.12, 0.10 and 0.08 mags respectively in either UBV RI or u ′ g ′ r ′ i ′ z ′ ; those for at least 70% of the SDSS survey region to g < 16 have estimated 1σ errors per star of ∼0.2, 0.06, 0.04, 0.04, 0.05 inThe density of Tycho2 stars, averaging about 60 stars per square degree, provides sufficient stars to enable automatic flux calibrations for most digital images with fields of view of 0.5 degree or more. Using several such standards per field, automatic flux calibration can be achieved to a few percent in any filter, at any airmass, in most workable observing conditions, to facilitate intercomparison of data from different sites, telescopes and instruments.Internal relative flux calibration of single or repeated data sets are routinely achieved to 0.2% or better, including during non-photometric conditions, by reference to non-variable stars in the observed field. But significant questions arise about effective cross calibration of observations from different epochs. The situation is particularly complicated for time-domain science, where multiple sites, telescope apertures, filters and sets of instrumentation become involved, or when time constraints or observing conditions preclude traditional calibrations. Offsets between otherwise very accurate data sets can be much larger than expected. This can introduce significant uncertainty in multi-observation analysis, or obscure real variations.Cross comparisons can be facilitated by parallel wide-field observations along the line of sight to each image, as in the CFHT skyprobe facility (Cuillandre et al 2004) 1 , or other "context" camera systems. But having multi-filter standards within each digital image offers many simplifying advantages. The ideal scenario for calibration of optical imaging data would be if there were all-sky stars of adequately known brightness on standard photometric systems, and present in sufficient numbers to provide a few in every digital image.Precursors to such standards include i) the Sloan Digital Sky Survey (SDSS) of 360 million objects, observed with a 2.5m telesco...

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CFHT’s Skyprobe: True Atmospheric Attenuation Measurement in the Telescope Field

Cited by 3 publications

References 9 publications

The low-mass population of theρ Ophiuchi molecular cloud

The low-mass population of theρ Ophiuchi molecular cloud

The Supernova Legacy Survey: measurement of $\Omega_{\mathsf{M}}$, $\Omega_\mathsf{\Lambda}$ andwfrom the first year data set

All-Sky Spectrally MatchedUBVRI - ZYandu^′g^′r^′i^′z^′Magnitudes for Stars in the Tycho2 Catalog

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CFHT’s Skyprobe: True Atmospheric Attenuation Measurement in the Telescope Field

Cited by 3 publications

References 9 publications

The low-mass population of theρ Ophiuchi molecular cloud

The low-mass population of theρ Ophiuchi molecular cloud

The Supernova Legacy Survey: measurement of $\Omega_{\mathsf{M}}$, $\Omega_\mathsf{\Lambda}$ andwfrom the first year data set

All-Sky Spectrally MatchedUBVRI - ZYandu′g′r′i′z′Magnitudes for Stars in the Tycho2 Catalog

Contact Info

Product

Resources

About

All-Sky Spectrally MatchedUBVRI - ZYandu^′g^′r^′i^′z^′Magnitudes for Stars in the Tycho2 Catalog