Colloquia

2021 CoolSci at JHU/STScI

Wed 20 Jan 2021
Location:

This colloquium is hosted by STScI and will be held as a fully virtual event.

Time:

3:00 PM - 4:00 PM

Contact Information:

Have questions? Please contact STScI.

Description:

Featuring Mireia Montes (STScI) on Hidden in the Darkness: The Faint Universe and Ramona Augustin (STScI) on Simulations and Observations of the Circumgalactic Medium.

Notes:

All 2021 CoolSci at JHU/STScI Colloquium virtual talks are held on Wednesdays at 3:00 PM.

Please direct questions or comments to contact above.  The 2021 committee members are Ramona Augustin, Andres del Pino Molina, and Raymond Simons (STScI).

Name: Ramona Augustin
Title: Simulations and Observations of the Circumgalactic Medium
Abstract: Understanding the processes of gas flows in and out of galaxies is crucial in galaxy evolution studies. Yet, observations of the faint and diffuse Circum-Galactic Medium (CGM), where these processes take place, remain challenging.

The most efficient approach to detect this faint and diffuse gas is in absorption towards bright background quasars. However, to investigate the CGM we need to also identify the galaxy counterpart and connect it to the absorption feature. In this context we characterized counterparts to Damped Lyman-alpha Absorbers (DLAs) at z~1 using HST broad-band images. We measured their stellar masses and find them to be generally less massive than the average galaxy population. We also discovered their complex morphology and environments, challenging the interpretation of CGM studies in absorption.

Quasar absorbers are typically limited to a single sightline and hold no information on the spatial structure of the absorber. To overcome this limitation and gain information on the spatial structure and the nature of CGM absorbers, we combine IFU data with high-resolution cosmological FOGGIE simulations. We detect and analyze two MgII absorption systems at z~1 that show significant differences in their equivalent width variations towards the different sightlines. We find that these variations are consistent with expectations from inflow/outflow regions simulations.

Beyond absorption, prospects to map the CGM in emission will offer new information on its extent and clumpiness. To optimize observing strategies of the CGM in emission, we have made predictions from dedicated cosmological zoom-in RAMSES simulations. We post-processed galaxy halos with an emission model to create mock integral field observations. Using the instrument model, our results indicate that ELT/HARMONI will enter a regime of low surface brightness typical of the CGM which is not attainable with current facilities.

Name: Mireia Montes
Title: Hidden in the Darkness: The Faint Universe
Abstract: A vast amount of astrophysical phenomena is still buried in the noise. This is the realm of the faintest structures that, although difficult to explore, promise to deliver transformative insights into a wide range of issues from understanding the assembly of galaxies to the very nature of dark matter. In this talk I will present how the recent developments in ultra deep imaging have speed up our capacity to discover new objects and structures in the sky.