2011A&A...527A..91P


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.03CEST21:40:24

2011A&A...527A..91P - Astronomy and Astrophysics, volume 527A, 91-91 (2011/3-1)

Optical atmospheric extinction over Cerro Paranal.

PATAT F., MOEHLER S., O'BRIEN K., POMPEI E., BENSBY T., CARRARO G., DE UGARTE POSTIGO A., FOX A., GAVIGNAUD I., JAMES G., KORHONEN H., LEDOUX C., RANDALL S., SANA H., SMOKER J., STEFL S. and SZEIFERT T.

Abstract (from CDS):

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 0.01mag/airmass. 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. The extinction curve of Paranal was obtained through low-resolution spectroscopy of 8 spectrophotometric standard stars observed with FORS1 mounted at the 8.2m Very Large Telescope, covering a spectral range 3300-8000Å. 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 O2, O3, and H2O, and to estimate their column densities. 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 Chichon eruption is detected below 4000Å. 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 Chichon 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.

Abstract Copyright:

Journal keyword(s): techniques: spectroscopic - Earth - site testing - atmospheric effects

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 WG 2 WD* 00 50 03.6494717240 -52 08 15.515729263 13.354 14.157 14.206 14.31 14.428 DA2.7 75 0
2 CPD-69 177 WD* 03 10 31.0201840720 -68 36 03.381441176 10.757 11.413 11.394 11.47 11.558 DA3.0 234 0
3 GD 50 WD* 03 48 50.1861716368 -00 58 32.290158840 12.596 13.787 14.063 14.210 14.388 DA1.2 234 0
4 GD 71 WD* 05 52 27.6197286025 +15 53 13.228639956 11.675 12.783 13.032 13.169 13.337 DA1.5 334 0
5 GD 108 HS* 10 00 47.2462037648 -07 33 30.777365253 12.406 13.349 13.563 13.662 13.781 sdB 129 1
6 BD+18 2647 HS* 12 41 51.7901702595 +17 31 19.750592670 10.261 11.70 11.63 11.969 12.159 sdOpec 162 1
7 CD-38 10980 WD* 16 23 33.8384178546 -39 13 46.160032569 9.916 10.885 11.029 10.936 10.841 DA2 439 1
8 Feige 110 HS* 23 19 58.3995050606 -05 09 56.170282845 10.360 11.45 11.50 11.970 12.145 sdO8VIIIHe5 552 1

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2020.07.03-21:40:24

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