An empirical relation between sodium absorption and dust extinction

By Dovi Poznanski, J. Xavier Prochaska, Joshua S. Bloom. 2012

349 citations recorded by the source corpus.

Dust extinction and reddening are ubiquitous in astronomical observations and are often a major source of systematic uncertainty. We present here a study of the correlation between extinction in the Milky Way and the equivalent width of the Na i D absorption doublet. Our sample includes more than 100 high-resolution spectra from the Keck telescopes and nearly a million low-resolution spectra from the Sloan Digital Sky Survey (SDSS). We measure the correlation to unprecedented precision, constrain its shape and derive an empirical relation between these quantities with a dispersion of the order of 0.15 mag in E(B − V). From the shape of the curve of growth we further show that a typical sight line through the Galaxy, as seen within the SDSS footprint, crosses about three dust clouds. We provide a brief guide on how to best estimate extinction to extragalactic sources such as supernovae, using the Na i D absorption feature, under a variety of circumstances.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b4149666536bfdee5ef5a6fa8f56cc05cbaa7b80

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In Astronomy and Astrophysics

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Citations in the corpus

• PTF12os and iPTF13bvn. Two stripped-envelope supernovae from low-mass progenitors in NGC 5806 (2016, methodology): “This method is not very reliable since it is based on low-resolution spectra, and the Na i D feature is not resolved (see, e.g., Poznanski et al. 2011, 2012), but the presence of significant Na i D absorption confirms that the host extinction is not negligible.”
• ON THE SOURCE OF THE DUST EXTINCTION IN TYPE Ia SUPERNOVAE AND THE DISCOVERY OF ANOMALOUSLY STRONG Na i ABSORPTION (2013, methodology): “The dispersion in AV with respect to this latter relation is 0.30 dex, corresponding to a 68% error in AV for any single object rather than the ∼20% error implied by Poznanski et al. (2012).”
• THE AFTERGLOW OF GRB 130427A FROM 1 TO 1016 GHz (2013, methodology): “Using the empirical relation between sodium absorption strength and dust extinction as derived by Poznanski et al. 2012 (their Equation 9), this implies EB−V = 0.024 mag.”
• CHARACTERIZING THE V-BAND LIGHT-CURVES OF HYDROGEN-RICH TYPE II SUPERNOVAE (2014, methodology): “The use of the Poznanski et al. (2012) relation for the current sample is complicated as it has been shown (e.g. Munari & Zwitter 1997) to saturate for NaD EWs approaching and surpassing 1Å.”
• DISCOVERY, PROGENITOR AND EARLY EVOLUTION OF A STRIPPED ENVELOPE SUPERNOVA iPTF13bvn (2013, background): “We find local extinction of E(B − V ) = 0.0437 and foreground extinction of 0.0278 (Poznanski et al. 2012).”
• Early-time light curves of Type Ib/c supernovae from the SDSS-II Supernova Survey (2014, methodology): “Lacking high resolution spectra for our objects, we can not use the relations between extinction and Na I D equivalent width (EW) suggested in the literature (e.g., Poznanski et al. 2012).”
• Spectrophotometric time series of SN 2011fe from the Nearby Supernova Factory (2013, result): “Using the empirical relation proposed by Poznanski et al. (2012) to derive the dust extinction from the D1 + D2 Na D lines, we obtain E(B−V)host = 0.014± 0.003 mag, in accord with our photometrically derived value.”