• Yang Chen

      Articles written in Journal of Astrophysics and Astronomy

    • Star Formation Rate Indicators in Wide-Field Infrared Survey Preliminary Release

      Fei Shi Xu Kong James Wicker Yang Chen Zi-Qiang Gong Dong-Xin Fan

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      With the goal of investigating the degree at which the MIR luminosity in the Wide-field Infrared Survey Explorer (WISE) traces the SFR, we analyse 3.4, 4.6, 12 and 22 𝜇m data in a sample of ∼ 140,000 star-forming galaxies or star-forming regions covering a wide range in metallicity 7.66 < 12 + \log (O/H) < 9.46, with redshift 𝑧 < 0.4. These star-forming galaxies or star-forming regions are selected by matching the WISE Preliminary Release Catalog with the star-forming galaxy Catalog in SDSS DR8 provided by JHU/MPA. We study the relationship between the luminosity at 3.4, 4.6, 12 and 22 𝜇m from WISE and H𝛼 luminosity in SDSS DR8. From these comparisons, we derive reference SFR indicators for use in our analysis. Linear correlations between SFR and the 3.4, 4.6, 12 and 22 𝜇m luminosity are found, and calibrations of SFRs based on L(3.4), L(4.6), L(12) and L(22) are proposed. The calibrations hold for galaxies with verified spectral observations. The dispersion in the relation between 3.4, 4.6, 12 and 22 𝜇m luminosity and SFR relates to the galaxy’s properties, such as 4000 Å break and galaxy color.

    • Observations of the Ca ${\rm\tiny II}$ IR Triplet in High Luminosity Quasars: Exploring the Sample

      Mary Loli Martínez-Aldama Paola Marziani Deborah Dultzin Jack W. Sulentic Alessandro Bressan Yang Chen Giovanna M. Stirpe

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      We present a new spectroscopic sample of 11 quasars at intermediate redshift observed with the Infrared Spectrometer and Array Camera (ISAAC) on the ESO Very Large Telescope (VLT), covering O ${\rm\tiny I}$ 𝜆8446 and the Ca ${\rm\tiny II}$ triplet 8498, 8542, 8662. The new observations – that supplement the sample presented by Martínez-Aldama et al. (2015) – allow us to confirm the constraints on physical conditions and location of the region emitting the low ionization lines, as well as the relation between Ca ${\rm\tiny II}$ and Fe ${\rm\tiny II}$.

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    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

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      Posted on July 25, 2019

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