High-Velocity Clouds (HVCs), those assemblies of gas around galaxies that do not follow the galactic rotation, have been enigmatic since their discovery almost 60 years ago. Recent observational and theoretical advances have clarified their properties and importance to galaxy formation and evolution. To explore this topic further, a Green Bank Workshop on “Galactic and Extragalactic High-Velocity Clouds” will be held June 26-29, 2022. It will bring together scientists with diverse interests for lively discussions of the latest observations, computational models, and theoretical considerations.
The Workshop will be held at the Green Bank Observatory, where the great natural beauty and intimate setting produce meetings characterized by a high level of interaction. Because of logistical considerations, attendance will be limited to 45 participants.
Lodging
Lodging will be at the Observatory or nearby locations. All meals will be served in the Observatory Cafeteria. A $550 per participant fee will cover all local expenses, including lodging and meals. It may be possible to waive this cost for some of the participants.
Accommodations for accompanying persons and child care will be available.
Travel Information
The easiest way to get here is to follow the directions on our “Getting Here” page. Please note that some GPS systems do not always give the best route to the Green Bank Observatory, and nothing beats the good old-fashioned paper map for navigation.
We will attempt to coordinate ride-sharing from airports if there is interest.
Workshop Schedule
| Date | Start Time | Duration | Topic/Title |
|---|---|---|---|
| 26-June 2022 Sunday | People arrive throughout the afternoon and evening | ||
| 17:30 | 1:00 | Dinner in the Cafeteria | |
| 18:30 | Informal Reception in the Drake Lounge | ||
| 27-June Monday | 7:45 | 1:00 | Breakfast in the cafeteria |
| Session 1 — Overview | 8:45 | 0:15 | Welcome: Jim Jackson and LOC |
| Chair: Bob Benjamin | 9:00 | 0:45 | M. Putman: High Velocity Clouds |
| 9:45 | 0:45 | J. Werk: HVCs and the Circumgalactic Medium | |
| 10:30 | 0:20 | Coffee | |
| 10:50 | 0:30 | N. Lehner: Discovery and Properties of HVCs Through Absorption Spectroscopy | |
| 11:20 | 0:45 | A. Fox: Magellanic HVCs | |
| 12:05 | 0:20 | Y. Zheng: The Mocky Way: Investigating Biases in Observing HVCs in the Milky Way | |
| End of session 1 | 12:25 | ||
| 12:30 | 0:45 | Lunch in Cafeteria | |
| Session 2 — GBT Tour | 13:15 | 2:15 | GBT Tour |
| 15:30 | 0:00 | ||
| Session 3 — Origins and measurements | 15:30 | 0:30 | F. Fraternali: How to make HVCs via fountain-driven condensation (remote) |
| Chair: Will Armentrout | 16:00 | 0:30 | A. Marasco: Collimated outflows and diffuse inflows traced by ionised HVCs and IVCs at the disc-halo interface |
| 16:30 | 0:15 | Coffee and group photo | |
| 16:45 | 0:25 | E. Di Teodoro: HVCs in the nuclear wind of the Milky Way | |
| 17:10 | 0:25 | B. Wakker: Metalicities of HVCs | |
| 17:35 | 0:25 | T. Tripp: The High-Velocity Clouds Above the Disk of the Outer Milky Way: Misty Precipitating Gas in a Region Roiled by Stellar Streams | |
| 18:00 | 0:00 | ||
| 18:00 | |||
| End of session 3 | 18:00 | ||
| 18:00 | 1:00 | Drinks and Dinner in the Science Center | |
| Session 4: Panel Discussion | 19:00 | 1:30 | Evening Panel in Science Center Auditorium: The Origin of HVCs — Ionized and Neutral |
| Ashley, Howk, Marasco, Tripp | |||
| 20:30 | Retire to the Drake Lounge for continued Discussion | ||
| 28 June Tuesday | 7:45 | 0:45 | Breakfast in the cafeteria |
| Session 5 — The Magellenic Streams | 8:30 | 0:25 | S. Lucchini: A new orbital history for the Magellanic Clouds |
| 8:55 | 0:20 | E. Chwalik: Mapping the Edge of the Magellanic Stream | |
| 9:15 | 0:20 | K. Barger: The LMC’s Galactic Feedback | |
| 9:35 | 0:20 | D. Nidever: Recent Star Formation in the Magellanic Stream Leading Arm | |
| 9:55 | 0:20 | F.J. Lockman: The Smith Cloud | |
| End of session 5 | 10:15 | 0:20 | Coffee Break |
| Session 6 — Theoretical Issues | 10:35 | 0:40 | A. Gronnow: The effect of magnetic fields on High-Velocity Clouds |
| 11:15 | 0:20 | P. Oh: Thermal Instability and Mixing Layers | |
| 11:35 | 0:20 | B. Tan: Radiative Turbulent Mixing Layers in Cold Clouds | |
| 11:55 | 0:20 | G. Bryan: The structure of turbulent radiative mixing layers and the cloud/CGM interaction | |
| 12:15 | 0:15 | ||
| 12:30 | |||
| 12:30 | 0:45 | Lunch in the Cafeteria | |
| 13:15 | 0:20 | L. Armilotta: The impact of cosmic rays on the dynamics of the extra-planar gas | |
| 13:35 | 0:20 | R. Shelton: Simulations of dark-matter Rich HVCs | |
| End of session 6 | 13:55 | 0:20 | F. Heitsch:Metallicity Estimates of HVCs: Insights from Simulations |
| 14:15 | 0:20 | Coffee Break | |
| Session 7 | 14:35 | 0:20 | L. Jung: Search for magnetic field associated with high-velocity clouds using Faraday rotation |
| 14:55 | 0:20 | A. Hill: Polarized radio emission from the anti-centre shell: Interaction between an HVC and the Galactic magnetic field | |
| 15:15 | 0:20 | D. French: A FUSE HI survey of the Galactic Halo | |
| 15:35 | 0:30 | Poster viewing session | |
| 16:05 | 0:20 | B. Benjamin: Complexity in the Outer Galaxy | |
| 16:25 | 0:20 | T. Minter: No OH in the Smith Cloud (remote) | |
| 16:45 | 0:20 | A. Smith: Intermediate Velocity Molecular Clouds | |
| 17:05 | 0:25 | ||
| End of session 7 | 17:30 | ||
| 17:30 | 0:30 | Drinks in the Lounge | |
| 18:00 | 1:00 | Dinner in the cafeteria | |
| Session 8 | 19:00 | 1:30 | Panel in the Jansky Lab — Theoretical issues in HVCs: |
| Armillotta, Byon, Gronnow, Oh | |||
| 20:30 | Discussion continues in the Drake Lounge | ||
| 29-June Wednesday | 7:45 | 1:00 | Breakfast in the Cafeteria |
| Session 9 — HVCs from the nuclear wind | 0:30 | R. Bordoloi: The UV perspective on the nuclear wind | |
| 9:15 | 0:20 | T. Ashley: Metallicities of Outflowing Fermi Bubble Clouds | |
| 9:35 | 0:20 | D. Krishnarao: Anomalous Velocity Gas near Galactic Center | |
| 9:55 | 0:20 | F. Cashman: Molecular Gas within the Milky Way’s Nuclear Wind | |
| Session 10 — Extragalactic HVCs | 10:15 | 0:20 | J.C. Howk: Project AMIGA: H I in a Sea of H II in Andromeda’s Halo |
| 10:35 | 0:20 | Coffee Break | |
| 10:55 | 0:25 | DJ Pisano: The HI Clouds surrounding M31 | |
| 11:20 | 0:25 | H. Gim: Anomalous HI clouds in M100 | |
| Session 11: Panel | 11:45 | 0:45 | HVCs: The Path Forward |
| Workshop End | 12:30 | Lunch in the Cafeteria |
Topics to be considered include:
- The origin of HVCs
- New observations
- Magnetic, ionized, metal, and dark matter components
- The Magellanic Stream
- HVCs in other galaxies
- HVCs effect on our Galaxy and its CGM
- HVCs as probes of their environments
- The fates of HVCs
- The connection between nuclear winds and HVCs
- Intermediate Velocity Clouds and their Connections to HVCs
Scientific Organizing Committee
- Kat Barger (TCU)
- Joss Bland-Hawthorn (Univ. Sydney)
- Andy Fox (STScI)
- Filippo Fraternali (Univ. Groningen)
- Jay Lockman (Green Bank Observatory)
- Naomi McClure-Griffiths (Australian National Univ.)
- Mary Putman (Columbia Univ.)
- Robin Shelton (Univ. Georgia)
Registered Participants
| Will Armentrout | Green Bank Observatory |
| Lucia Armillotta | Princeton University |
| Dr. Trisha Ashley | Space Telescope Science Institute |
| Kat Barger | Texas Christian University |
| Bob Benjamin | University of Wisconsin |
| Rongmon Bordoloi | North Carolina State University |
| Greg Bryan | Columbia University |
| Francie Cashman | Space Telescope Science Institute |
| Erica Chwalik | Montana State University |
| Enrico Di Teodoro | Johns Hopkins University |
| Andy Fox | STScI |
| David M. French | STScI |
| Hansung Gim | Montana State University |
| Eric Goetz | University of Georgia |
| Asger Gronnow | Kapteyn Institute, University of Groningen |
| Fabian Heitsch | UNC Chapel Hill |
| Alex S. Hill | UBC Okanagan / DRAO |
| Chris Howk | University of Notre Dame |
| Jim Jackson | Green Bank Observatory |
| Lyla Jung | Australian National University |
| Dhanesh Krishnarao (DK) | Johns Hopkins University / Colorado College |
| Glen Langston | National Science Foundation |
| Nicolas Lehner | University of Notre Dame |
| Jay Lockman | Green Bank Observatory |
| Scott Lucchini | University of Wisconsin – Madison |
| Antonino Marasco | INAF – Padova Observatory |
| Jennifer Donovan Meyer | NRAO |
| Toney Minter | Green Bank Observatory |
| David Nidever | Montana State University |
| Peng Oh | UCSB |
| D.J. Pisano | UCT/WVU |
| Mary Putman | Columbia University |
| Evan Schneider | University of Pittsburgh |
| Nigel Sharp | National Science Foundation |
| Dr. Robin Shelton | University of Georgia |
| Allison Smith | Arecibo Observatory |
| Brent Tan | UCSB |
| Todd Tripp | University of Massachusetts – Amherst |
| Ananya Tuli | PhD candidate at the University of Notre Dame |
| Jo Vazquez | Texas Christian University |
| Bart Wakker | University of Wisconsin-Madison |
| Chen Wang | University of Georgia |
| Jessica Werk | University of Washington |
| Ellie White | Green Bank Observatory |
| Yong Zheng | UC Berkeley |
Local Organizing Committee
- Brenne Gregory
- Sue Ann Heatherly
- Jay Lockman
- Pedro Salas
- Ellie White