Skip to main content Accessibility help

Spectroscopic follow-up of the quadruply lensed quasar WGD2038-4008/GRAL2038-4008

  • Chien-Hsiu Lee (a1)


We present independent optical spectroscopic follow-up of WGD2038-4008/GRAL2038-4008, a background quasar strongly lensed by a foreground elliptical galaxy into four images, recently discovered independently by Agnello et al. [2018, MNRAS, 479, 4345] and Krone-Martins et al. [2018, A&A, 616, L11] thanks to the exquisite spatial resolution of Gaia. The quasar images are bright (i ∼ 19 mag), thus enabling us to reach S/N > 20 for the continuum within 30 min of exposure time with the Andalucia Faint Object Spectrograph and Camera spectrograph mounted on the 2.56-m Nordic Optical Telescope. The flexible scheduling and high sensitivity delivered by Andalucia Faint Object Spectrograph and Camera provide timely redshifts and reveal the nature of the quasar images; both are essential for lensing modelling and cosmography. Our analysis shows a strong emission feature in a data gap in Agnello et al. [2018, MNRAS, 479, 4345], which can be attributed to as an interloper emission line feature from the foreground lensing galaxy, or hinting to a higher redshift of the background quasar. We discuss these two scenarios and outline possible tests to verify these scenarios.


Corresponding author

Author for correspondence: Chien-Hsiu Lee, Email:


Hide All
Agnello, A., et al. 2018, MNRAS, 479, 4345
Arnouts, S., et al. 1999, MNRAS, 310, 540
Bonvin, V., et al. 2017, MNRAS, 465, 4914
Cardelli, J. A., Clayton, G. C., & Mathis, J. S. 1989, ApJ, 345, 245
Chen, G. C.-F., et al. 2018, MNRAS, 481, 1115
Ilbert, O., et al. 2006, A&A, 457, 841
Krone-Martins, A., et al. 2018, A&A, 616, L11
Narayan, R., & Bartelmann, M. 1996, arxiv.9606001
Peng, C. Y., Ho, L. C., Impey, C. D., & Rix, H.-W. 2002, AJ, 124, 266
Peng, C. Y., Ho, L. C., Impey, C. D., & Rix, H.-W. 2010, AJ, 139, 2097
Riess, A. G., et al. 2018, ApJ, 855, 136
Schlafly, E. F., & Finkbeiner, D. P. 2011, ApJ, 737, 103
Shajib, A. J., et al. 2018, MNRAS, 483, 5649
Suyu, S. H., et al. 2017, MNRAS, 468, 2590
Vanden Berk, D. E., et al. 2001, AJ, 122, 549
Tie, S. S., & Kochanek, C. S. 2018, MNRAS, 473, 80



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed