Reddening curve of IRAS 14026+4341

In this paper, we thoroughly characterize the anomalously steep reddening law in quasars via an exceptional example observed in IRAS14026+4341. By comparing the observed spectrum to the quasar composite spectrum, we derive a reddening curve in the rest-frame wavelength range of 1200-10000{AA}.

It has a steep rise at wavelengths shorter than 3000{AA}, but no significant reddening at longer wavelengths. The absence of dust reddening in the optical continuum is confirmed by the normal broad-line Balmer decrement (the H{alpha}/H{beta} ratio) in IRAS14026+4341. The anomalous reddening curve can be satisfactorily reproduced with a dust model containing silicate grains in a power-law size distribution, dn(a)/da{prop.to}a^-1.4^, truncated at a maximum size of a_max_=70nm.