{'fraction_non_alphanumeric': 0.01881467544684854, 'fraction_numerical': 0.004703668861712135, 'mean_word_length': 4.878453038674033, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Detecting and Interpreting Statistical Lensing by Absorbers

We propose a method for detecting gravitational magnification of distant sources, such as quasars, due to absorber systems detected in their spectra. We first consider the use of metal absorption lines rather than Lyα lines; then we show how to relate the observed moments of the source magnitude distribution to the mass distribution of absorbers. In order to illustrate the feasibility of the method, we use a simple model to estimate the amplitude of the effect expected for Mg II absorption lines and show that their lensing signal might already be detectable in large surveys like the SDSS. Our model suggests that quasars behind strong Mg II absorbers are, on average, brightened by -0.05 to -0.2 mag due to magnification. One must therefore revisit the claim that, in magnitude-limited surveys, quasars with strong absorbers tend to be missed due to extinction effects. In addition to constraining the mass of absorber systems, applying our method will allow for the quantification of this bias.