Calendar

Apr
25
Thu
ASTR 506 – Stellar Dynamics and Hydrodynamics
Apr 25 @ 12:00 pm – 1:15 pm
Apr
26
Fri
Colloquium: Megan Reiter (Host: Kristian Finlator)
Apr 26 @ 3:15 pm – 4:15 pm
Colloquium: Megan Reiter (Host: Kristian Finlator) @ BX102

The Role of Ecology in Star and Planet Formation

Megan Reiter, Royal Observatory Edinburgh

Understanding how feedback regulates star and planet formation is one of the outstanding unsolved problems in astrophysics. Stellar feedback affects all astrophysical scales: it shapes the interstellar medium and mass function of galaxies, determines the fragmentation and star formation efficiency of molecular clouds, and plays a central role in the geochemical evolution of terrestrial planets. High-mass stars shape the local star-forming environment – the ecology – via radiation pressure, stellar winds, photoionization, and supernovae. Photoionization is the least explored of these; however, recent numerical work suggests that it dominates the destruction of molecular clouds and planet-forming disks around stars born in clusters. These predictions depend critically on the dynamics of newborn stars and feedback-altered gas, but these quantities are poorly unconstrained. I will talk about two on-going surveys using ALMA, MUE/VLT, and M2FS/Magellan to measure gas and stellar kinematics in order to test the role of environment in shaping the outcome of star and planet formation.

Apr
29
Mon
ASTR 616 – Galaxies II
Apr 29 @ 10:30 am – 11:45 am
Apr
30
Tue
ASTR 610 – Radio Astronomy
Apr 30 @ 10:30 am – 11:45 am
ASTR 506 – Stellar Dynamics and Hydrodynamics
Apr 30 @ 12:00 pm – 1:15 pm
May
1
Wed
ASTR 616 – Galaxies II
May 1 @ 10:30 am – 11:45 am
May
2
Thu
ASTR 610 – Radio Astronomy
May 2 @ 10:30 am – 11:45 am
ASTR 506 – Stellar Dynamics and Hydrodynamics
May 2 @ 12:00 pm – 1:15 pm
Sep
6
Fri
Colloquium: Brian Svoboda (Host: Moire Prescott)
Sep 6 @ 3:15 pm – 4:15 pm
Colloquium: Brian Svoboda (Host: Moire Prescott) @ BX102

Starless clumps and the earliest phases of high-mass star formation in the Milky Way

Brian Svoboda, NRAO Jansky Fellow

High-mass stars are key to regulating the interstellar medium, star formation activity, and overall evolution of galaxies, but their formation remains an open problem in astrophysics. In order to understand the physical conditions during the earliest phases of high-mass star formation, I will present observational studies we have carried out on dense starless clump candidates (SCCs) that show no signatures of star formation activity. We identify 2223 SCCs from the 1.1 mm Bolocam Galactic Plane Survey, systematically analyse their physical properties, and show that the starless phase is not represented by a single timescale, but evolves more rapidly with increasing clump mass. To investigate the sub-structure in SCCs at high spatial resolution, we investigate the 12 most high-mass SCCs within 5 kpc using ALMA. We find previously undetected low-luminosity protostars in 11 out of 12 SCCs, fragmentation equal to the thermal Jeans length of the clump, and no starless cores exceeding 30 solar masses. While uncertainties remain concerning the star formation efficiency in this sample, these observational facts are consistent with models where high-mass stars form from initially low- to intermediate-mass protostars that accrete most of their mass from the surrounding clump. I will also present on-going research studying gas inflow signatures with GBT/Argus and ALMA, and the dense core mass function with the JVLA.

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Apr
17
Fri
Remote Colloquium: Fuyan Bian (Host: Kristian Finlator)
Apr 17 @ 3:00 pm – 4:00 pm
Remote Colloquium: Fuyan Bian (Host: Kristian Finlator) @ Online

Evolution of Ionized Interstellar Medium across Cosmic Time

Fuyan Bian, European Southern Observatory

The ionized interstellar medium (ISM) provides essential information on the star-forming environments, metal enrichment, and underlying ionizing radiation field in galaxies. It is crucial to understand how the ionized ISM evolves with Cosmic time. In this talk, I will present a sample of local galaxies that closely resemble the properties of high-redshift galaxies at high redshift. These local analogs of high-redshift galaxies provide a unique local laboratory to study high-redshift galaxies. I will discuss how to use these analogs to improve our understanding of the high-redshift metallicity empirical calibrations and physical mechanism(s) to drive the evolution of optical diagnostics lines from high redshift to low redshift.