Determining systemic QSO redshifts from Mg II in the absence of narrow forbidden lines [PDF]

David Gross, David Tytler, David Kirkman, Jeffrey Lee, Aaron Day, Cameron Liang

Center for Astrophysics and Space Sciences, University of California San Diego, La Jolla, CA, 92093-0424

13 September 2011


However, the research did become part of this project, a22.pdf, page 5 [PDF]:

In his first year as an undergraduate David Gross led a project to measure the difference between the redshift given by the peak of the Mg II emission line (that we can readily observe for most QSOs with z < 2.9) and the narrow emission lines from [O II] and [O III]. These Oxygen lines give the systemic redshifts of the QSOs host galaxy, but they are rarely observed in the QSOs we use for LYAF statistics because they are shifted into the near IR. He found that Mg II is an excellent surrogate for the narrow O lines. The mean velocity of Mg II in the frame of [O II] is –38 ± 20 km/s with a standard deviation of 343 km/s, while the mean Mg II velocity in the frame of [O III] is –4 ± 42 km/s with a standard deviation of 336 km/s. These results show that on average the peak of Mg II is sufficiently close to the systemic velocity for our work, and though the dispersion is larger than ideal this is not enough to justify NIR spectra.

QSO ≡ Quasi stellar object

LYAF ≡ Lyman-alpha forest

ΛCDM ≡ Lambda-Cold dark matter model

Relevant Wikipedia summaries:


Porting SPICE to iOS and Loading Netlists via QR Code

View at the Alexandria Digital Research Library above or Self-Hosted

A Thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Electrical and Computer Engineering by David Scott Gross

Committee in charge: Professor K.T. Tim Cheng, Chair Professor Bob York, Professor Umesh Mishra

Balloon-Sat Project [PDF]

Fall 2008

Our team at UCSD designed, built, flew, and successfully recovered a multi-disciplinary payload on a balloon-sat to near space.