<i>UBVRI</i>night sky brightness during sunspot maximum at ESO-Paranal

Patat, F.

doi:10.1051/0004-6361:20030030

Cited by 93 publications

(127 citation statements)

References 32 publications

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“…However, it is known that the main mirrors of the VLT are subject to a reflectivity loss, mainly due to aluminum oxidation. The losses are as large as ∼13% per year in the U band, they decrease at redder wavelengths, and reach ∼5% per year in the I band (Patat 2003). Since the data presented in this paper span over six months, the implied efficiency variation is significantly higher than the measurement errors, and this is expected to increase the noise.…”

Section: Data Reductionmentioning

confidence: 87%

“…Since the data presented in this paper span over six months, the implied efficiency variation is significantly higher than the measurement errors, and this is expected to increase the noise. To account for this effect, at least to a first order, the measured instrumental magnitudes were corrected using the time elapsed from the previous aluminization (May 17, 2008; MJD = 54603.5), and a linear interpolation of the values deduced from broad band photometry (Patat 2003) to the required wavelengths. The application of this correction reduces the rms scatter from the best fit solution by ∼25%.…”

Section: Data Reductionmentioning

confidence: 99%

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Optical atmospheric extinction over Cerro Paranal

Patat

Moehler

O’Brien

et al. 2011

A&A

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120

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Aims. The present study was conducted to determine the optical extinction curve for Cerro Paranal under typical clear-sky observing conditions, with the purpose of providing the community with a function to be used to correct the observed spectra, with an accuracy of 0.01 mag airmass −1 . Additionally, this work was meant to analyze the variability of the various components, to derive the main atmospheric parameters, and to set a term of reference for future studies, especially in view of the construction of the Extremely Large Telescope on the nearby Cerro Armazones. Methods. The extinction curve of Paranal was obtained through low-resolution spectroscopy of 8 spectrophotometric standard stars observed with FORS1 mounted at the 8.2 m Very Large Telescope, covering a spectral range 3300-8000 Å. A total of 600 spectra were collected on more than 40 nights distributed over six months, from October 2008 to March 2009. The average extinction curve was derived using a global fit algorithm, which allowed us to simultaneously combine all the available data. The main atmospheric parameters were retrieved using the LBLRTM radiative transfer code, which was also utilised to study the impact of variability of the main molecular bands of O 2 , O 3 , and H 2 O, and to estimate their column densities. Results. In general, the extinction curve of Paranal appears to conform to those derived for other astronomical sites in the Atacama desert, like La Silla and Cerro Tololo. However, a systematic deficit with respect to the extinction curve derived for Cerro Tololo before the El Chichón eruption is detected below 4000 Å. We attribute this downturn to a non standard aerosol composition, probably revealing the presence of volcanic pollutants above the Atacama desert. An analysis of all spectroscopic extinction curves obtained since 1974 shows that the aerosol composition has been evolving during the last 35 years. The persistence of traces of non meteorologic haze suggests the effect of volcanic eruptions, like those of El Chichón and Pinatubo, lasts several decades. The usage of the standard CTIO and La Silla extinction curves implemented in IRAF and MIDAS produce systematic over/under-estimates of the absolute flux.

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Section: Data Reductionmentioning

confidence: 87%

Section: Data Reductionmentioning

confidence: 99%

Optical atmospheric extinction over Cerro Paranal

Patat

Moehler

O’Brien

et al. 2011

A&A

Self Cite

120

130

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“…Another group of studies consisted of estimations of the night-sky quality at astronomical centres (Benn & Ellison 1998;Massey & Foltz 2000;Patat 2003). There were also measurements of light pollution in large urban centres or in their vicinity, as well as in protected areas, such as national parks or nature reserves (Walker 1970(Walker , 1977Treanor & Salpeter 1972;Bertiau, de Graeve & Treanor 1973;Berry 1976).…”

Section: H I S To Ry O F M E a S U R E M E N T Smentioning

confidence: 99%

Particulate matter as an amplifier for astronomical light pollution

Ściężor¹,

Kubala²

2014

Monthly Notices of the Royal Astronomical Society

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In this paper, we state that the main factor that influences seasonal changes in the brightness of the cloudless, moonless, light-polluted night sky is primarily particulate matter, emitted mainly from low-emission sources, especially in winter. This effect is particularly noticeable in Cracow and its surroundings, one of the places in Europe that is most polluted by particulate matter. Measurements taken over a period of one year have allowed us to show a linear relationship between the concentration of particulate matter and the brightness of the clear, cloudless night sky. We have also found similar correlations in other, industrialized areas of Poland, as well as at the Mount Suhora Astronomical Observatory. We believe that the factor described here should be taken into account when planning the construction of new astronomical observatories, especially those located near large urban areas.

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“…Transformations from instrumental magnitudes to Vega magnitudes were calculated using IRAF-PHOTCAL. The transformation equations from the instrumental to Vega magnitudes included an extinction coefficient appropriate for Paranal (Patat 2003). A potential inclusion of a colour term was consistent with zero to within the uncertainties, so this term was neglected.…”

Section: Photometrymentioning

confidence: 99%

Uncovering strong MgII absorbing galaxies

Christensen

Noterdaeme

Petitjean

et al. 2009

A&A

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Context. The nature of the galaxies that give rise to absorption lines, such as damped Lyman-α systems (DLAs) or strong Mg ii lines, in quasar spectra is difficult to investigate in emission. These galaxies can be very faint and located close to the lines of sight of the much brighter background quasars. Aims. Taking advantage of the total absorption of the QSO light bluewards of the Lyman limit of two DLAs at z > 3.4, we look for the continuum emission from intervening galaxies at z ≈ 2 that are identified via strong metal absorption lines. The Mg ii absorbers have equivalent width large enough to be potential DLA systems. Methods. Deep images are obtained with the FOcal Reducer and Spectrograph (FORS1) on the Very Large Telescope for the fields towards SDSS J110855+120953 and SDSS J140850+020522. These quasars have Mg ii absorption lines at z = 1.87 (W r (Mg ii) = 2.46 Å) and z = 1.98 (W r (Mg ii) = 1.89 Å), respectively, and each QSO has two intervening higher redshift DLAs at z > 3. The U and R bands of FORS1 lie blue and redwards of the Lyman limit of the background DLAs, allowing us to search for emission from the foreground galaxies directly along the lines of sight to the QSOs. Results. No galaxies are found close to the sight line of the QSO to a point source limit of U AB ∼ 28.0. In both fields, the closest objects lie at an impact parameter of ∼5 corresponding to ∼40 kpc in projection at z = 2, and have typical colours of star forming galaxies at that redshift. However, the currently available data do not allow us to confirm if the galaxies lie at the same redshifts as the absorption systems. A more extended structure is visible in the SDSS J14085+020522 field at an impact parameter of 0. 8 or 7 kpc. If these objects are at z ≈ 2 their luminosities are 0.03-0.04 L * in both fields. The star formation rates estimated from the UV flux are 0.5-0.6 M yr −1 , while the SFRs are half these values if the U band flux is due to Lyα emission alone. Conclusions. The non-detection of galaxies near to the line of sight is most likely explained by low metallicities and luminosities of the Mg ii galaxies. Alternatively, the Mg ii clouds are part of extended halos or in outflows from low-metallicity galaxies.

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UBVRInight sky brightness during sunspot maximum at ESO-Paranal

Cited by 93 publications

References 32 publications

Optical atmospheric extinction over Cerro Paranal

Optical atmospheric extinction over Cerro Paranal

Particulate matter as an amplifier for astronomical light pollution

Uncovering strong MgII absorbing galaxies

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