[Physics-grads-open] PASS talk on Observational Astronomy

[Pooyan Goodarzi]

Reminder: Happening in ~45 mins.
The talk will also be available over Zoom with the following link.

https://ucr.zoom.us/j/91513752509?pwd=Ko32wny5WmyG0fAL54ppL5MIDK8hxY.1
Meeting ID: 915 1375 2509 Passcode: 408447



On Sun, Nov 24, 2024 at 14:42 Pooyan Goodarzi <pooyan.goodarzi at email.ucr.edu>
wrote:

> Hi all,
>
> We will have our next PASS talk on Monday with al talk by Issac. Please
> join us on *November 25th (Monday)* at *noon* (from 12:00 pm to 1:00 pm)
> in the *Nebula Room* (PHYS 3027).
>
>
> *Issac Ye Lin*
> *, PhD Student *
>
> Monday, 12:00 pm, Nebula Room (PHYS 3027)
> *KBSS-Lyα: Metallicity of Lyman-α Emitters at z~2.5*
>
> We present a Keck/MOSFIRE composite spectrum for a sample of faint
> KBSS-Lyα emitters (z~2.5) in the Keck Baryonic Structure Survey. With the
> new stacked measurement of [OII] λλ3727,3729Å doublet, we combine
> rest-optical measurements of O, H, and N lines to infer for 12+log(O/H)
> oxygen abundance with photoionization modeling. In our 4-parameter MCMC
> inference (Z_neb, Z_star, N/O, and log(U)), the input emission line ratios
> produce a bimodal metallicity posterior (Z_neb=0.2 Z_sun}, Z_neb=0.9Z_sun).
> Characterized by high O32 ratio (log([OIII]/[OII] = 0.78), high ionization
> (log(U) = -2.2), and low dust attenuation (E(B-V) = 0.12), we reconcile the
> lower metallicity peak with other common metrics such as z~2-3 MZR,
>  log(U)-M_sun relation, and electron temperature metallicity inference. The
> elevated O32 hints at density-bounded star forming regions in contrast to
> the more commonly assumed ionization-bounded case in photoionization
> models. Therefore, additional parameters are needed to break the degeneracy
> observed in the extreme physical environment of faint LAEs.
>
>
> If you’re interested in sharing your work as a speaker, please feel free
> to add your name to the spreadsheet [Google Sheet
> <https://docs.google.com/spreadsheets/d/1N3ncf43jdB6aHYHhyWmyHMycxDg4_phHZXLkQvviO0o/edit?usp=sharing>].
>
>
> Best,
> Pooyan
> Physics and Astronomy Student Seminar (PASS)
>
>
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