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Colloquia

About Event

Wed 14 Aug 2024

Location

Space Telescope Science Institute (STScI)
3700 San Martin Drive
Baltimore, MD 21218

Time

3:00 PM - 4:00 PM EDT

Contact Information

Have questions? Please contact STScI.

Description

"The Future of HST" featuring Amrita Singh (STScI) on SDSS-V Local Volume Mapper's Lagoon nebula: Addressing the abundance discrepancy problem, Kalina Nedkova (STScI) on UVCANDELS: What drives the differences between UV and optical sizes of disk galaxies?, and Qiushi (Chris) Tian (JHU) on Nebular Properties of Stellar Associations in Nearby Galaxies with PHANGS-HST and JWST.

Notes

All 2024 HotSci talks are held on Wednesdays at 3:00 PM. This series is hosted by STScI and will be held as an in-person and virtual event.

You may join in person at STScI’s John N. Bahcall Auditorium or virtually on STScI's Live Science Events Facebook page.

Please direct questions or comments to contact above. The 2024 HotSci Committee members are: Logan Jones (STScI), Sapna Mishra (STScI), Pallavi Patil (JHU), Adarsh Ranjan (STScI).

Special Talk

Speaker: Amrita Singh (STScI)
Title: SDSS-V Local Volume Mapper's Lagoon nebula: Addressing the abundance discrepancy problem  
Abstract: The Sloan Digital Sky Survey V (SDSS-V) Local Volume Mapper (LVM) is an ultra-wide integral-field spectroscopic survey of the Milky Way and the local volume galaxies. The LVM's spatially resolved spectroscopy covers the full optical range (3600-9800 Å) at medium spectral resolution (R ∼ 4000) and maps the disks of the galaxy at extremely high physical spatial resolution (e.g., < 1 pc in the MW and ∼ 10 pc in the Magellanic Clouds). The LVM covers the entire Lagoon Nebula (M8) in 10 pointings, each with an exposure time of 2*900 secs, at a spatial resolution of ∼ 0.22 pc/spaxel. We have detected good signal-to-noise ratio measurements of (a) more than half a dozen metal Recombination Lines (RLs) of oxygen and carbon, (b) HI and HeI RLs, (c) and nebular and auroral Collisional Excited Lines (CELs). These lines enable us to thoroughly examine the physical conditions, including Te, ne, ionic and elemental abundances of the ionized gas, as well as delve into the intricate internal physics of the gas. We focus on the chemical abundance measurements from metal RL diagnostics and direct method chemical abundance measurements through CEL diagnostics. As a result, the differences in abundances computed from metal RLs and CELs within the internal structures of the nebula can be measured, allowing us to measure the magnitude of the ADF in different parts of the nebula and study whether the ADF depends on location and other properties of the ionized gas, like the electron temperature.

Speaker: Kalina Nedkova (STScI)
Title: UVCANDELS: What drives the differences between UV and optical sizes of disk galaxies?
Abstract: Using high-resolution imaging from UVCANDELS, we show that massive disk galaxies (>10^10 Msun) are typically much larger in the rest-frame UV than optical. To understand if this difference is driven by dust or inside-out growth, we use the VELA simulations. When dust is included, these simulations reproduce observations; however, when the effects of dust are removed, the difference between the rest-frame UV and optical sizes of disk galaxies is consistent with zero. Since dust alone can account for differences between the rest-frame UV and optical sizes of star-forming galaxies, we find that variations in galaxy size with wavelength do not constitute evidence for specific galaxy growth scenarios. With JWST, sizes are now being obtained for large samples of high-redshift galaxies. Understanding the effects of dust will allow us to constrain how the earliest galaxies build up their stellar mass.

Speaker: Qiushi (Chris) Tian (JHU)​​​​​​​
Title: Nebular Properties of Stellar Associations in Nearby Galaxies with PHANGS-HST and JWST
Abstract: Abstract is forthcoming.

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