Correcting for the Effects of Interstellar Extinction

By E. Fitzpatrick. 1998

This paper addresses the issue of how best to correct astronomical data for the wavelength‐dependent effects of Galactic interstellar extinction. The main general features of extinction from the IR through the UV are reviewed, along with the nature of observed spatial variations. The enormous range of extinction properties found in the Galaxy, particularly in the UV spectral region, is illustrated. Fortunately, there are some tight constraints on the wavelength dependence of extinction and some general correlations between extinction curve shape and interstellar environment. These relationships provide some guidance for correcting data for the effects of extinction. Several strategies for dereddening are discussed along with estimates of the uncertainties inherent in each method. In the Appendix, a new derivation of the wavelength dependence of an average Galactic extinction curve from the IR through the UV is presented, along with a new estimate of how this extinction law varies with the parameter R≡A(V)/E(B−V). These curves represent the true monochromatic wavelength dependence of extinction and, as such, are suitable for dereddening IR–UV spectrophotometric data of any resolution and can be used to derive extinction relations for any photometry system.

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

Citations in the corpus

STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 17 PLANETS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION (2015, methodology): “In each step of our fitting process, we draw a value for AV, calculate the expected extinction in all bandpasses AX assuming the RV = 3.1 reddening law of (Fitzpatrick 1999), and then measure the likelihood of our model stellar fit to the observed apparent magnitudes.”
On the massive stellar population of the super star cluster Westerlund 1 (2005, methodology): “…of Rieke & Lebofsky (1985) and Savage & Mathis (1979), which have subsequently been confirmed by other studies (e.g., Cardelli et al. 1989; and Fitzpatrick 1999). core+halo structure with radii of ∼36′′ and ∼72′′ respectively, with a radial light profile that diverges from that expected for a…”
The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 μm Using GLIMPSE Data (2004, methodology): “In contrast to NIR extinction, optical extinction (k < 1 m) is known to vary significantly among sight lines (Cardelli et al. 1989; Fitzpatrick 1999); the variation is well characterized by a single parameter, RV ¼ AV=EB V .”
Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit (2008, methodology): “The absolute flux distribution of WR 22 (from IR to UV) is closely reproduced with a luminosity of 106.3 L⊙ for an adopted distance modulus of 12.1 mag (Lundström & Stenholm 1984), and an interstellar extinction law according to Fitzpatrick (1999)with EB−V = 0.42 andR = 3.6 (see Fig.”
The identification of the optical/IR counterpart of the 29.5-s transient X-ray pulsar GS 1843+009 (2001, background): “Since the observed (V −R) is ∼ 1.7 → 2.1 the reddening should amount to EV−R ∼ 1.8 → 2.3, and assuming a standard reddening law (Fitzpatrick 1999) this converts to AR ∼ 5.6 → 7, AV ∼ 7 → 9 and EB−V ∼ 2.3 → 2.9 (regardless of whether the reddening medium is uniformly distributed along the line of…”
The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3 (2015, methodology): “…spectrum normalized to unity at λ = 1450 Å. Recently, Peek & Schiminovich (2013) have found that UV colours at high latitudes are best fitted with a Fitzpatrick (1999) extinction curve with RV 2.2, while Schlafly & Finkbeiner (2011) found that SFD overestimates reddening by 14 per cent…”
A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition (2019, methodology): “We have utilized a combination of optical–NIR photometry and Gaia astrometry to produce a uniform catalog of accurate distances to local molecular clouds.”
Na-O Anticorrelation and HB. VII. The chemical composition of first and second-generation stars in 15 globular clusters from GIRAFFE spectra (2009, unknown): “We checked that the use of more recent relations between monochromatic absorption and reddening, like those of Fitzpatrick (1999), including dependence of reddening corrections on stellar colours, has negligible impact in our analysis, with differences in the temperatures 10 K.”
Inclination- and dust-corrected galaxy parameters: bulge-to-disc ratios and size–luminosity relations (2008, background): “Although equations to correct the Sérsic parameters pertaining to the bulge are not yet available, we note that the influence of dust at wavelengths around 2 microns is noticeably less than in the optical bands (e.g. Whitford 1958; Cardelli, Clayton & Mathis 1989; Fitzpatrick 1999).”
ESTIMATING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE Mg ii λ2800 EMISSION LINE (2009, methodology): “The spectra are first corrected for Galactic extinction using the extinction map of Schlegel et al. (1998) and the reddening curve of Fitzpatrick (1999).”
On Determining Extinction from Reddening (2004, methodology): “Like the reddening law of Cardelli et al. (1989), that of Fitzpatrick (1999) is parameterized in terms of a parameter r to account for the fact that the shape of the law depends upon environment.”
The Galactic WC stars Stellar parameters from spectral analyses indicate a new evolutionary sequence (2012, methodology): “If this turned out to be insufficient in reproducing the SED, we used the laws of Cardelli et al. (1989) or Fitzpatrick (1999), which treatRV as a free parameter, and adjusted the latter to optimize the SED fit.”
A multiwavelength view on the dusty Wolf-Rayet star WR 48a ★ (2014, methodology): “In the spectral fits, the interstellar (ISM) extinction was also taken into account by making use of the standard ISM extinction curve of Fitzpatrick (1999).”
A Far Ultraviolet Spectroscopic Explorer Survey of Interstellar Molecular Hydrogen in Translucent Clouds (2002, methodology): “The relationship derived by Fitzpatrick (1999) is c2 ¼ 0:824þ 4:717R 1V : ð4Þ The typical scatter about this relationship is a few hundredths in R 1V , or 0.2 in RV for small values and 0.5 for large values.”