English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report detections of 39 2175-{\AA} dust extinction bump candidatesassociated with strong Mg II absorption lines at z$\sim$ 1--1.8 on quasarspectra in Sloan Digital Sky Survey (SDSS) DR3. These strong Mg II absorptionline systems are detected among 2,951 strong Mg II absorbers with the restequivalent width $W_r\lambda2796 >$ 1.0{\AA} at $1.0 < z < 1.86$, which is partof a full sample of 7,421 strong Mg II absorbers compiled by Prochter et al.(2006). The redshift range of the absorbers is chosen to allow the 2175-{\AA}extinction features to be completely covered within the SDSS spectrographoperation wavelength range. An upper limit of the background quasar emissionredshift at z$=$2.1 is set to prevent the Ly$\alpha$ forest lines fromcontaminating the sensitive spectral region for the 2175-{\AA} bumpmeasurements. The FM90 (Fitzpatrick & Massa 1990) parameterization is appliedto model the Optical/UV extinction curve in the rest frame of Mg II absorbersof the 2175-{\AA} bump candidates. The simulation technique developed by Jianget al. (2010a, b) is used to derive the statistical significance of thecandidate 2175-{\AA} bumps. A total of 12 absorbers are detected with2175-{\AA} bumps at a 5$\sigma$ level of statistical significance, 10 aredetected at a 4$\sigma$ level and 17 are detected at a 3$\sigma$ level. Most ofthe candidate bumps in this work are similar to the relatively weak 2175-{\AA}bumps observed in the Large Magellanic Clouds (LMC) LMC2 supershell rather thanthe strong ones observed in the Milky Way (MW). This sample has greatlyincreased the total number of 2175-{\AA} extinction bumps measured on SDSSquasar spectra. Follow-up observations may rule out some of possible falsedetections and reveal the physical and chemical natures of 2175-{\AA} quasarabsorbers.

Towards Detecting The 2175-{\AA} Dust Feature Associated With Strong High Redshift Mg {\ss}II Absorption Lines