Print Page Print Page

ASTRO2020 – Preparations

As you are aware, we are preparing a long-term plan for the scientific program of the Green Bank Observatory and the GBT for the period 2020 – 2030. Over the past four months we have solicited both ideas and interest from the scientific community.

We are now forming a number of scientific working groups to better define the long-term scientific goals for the Green Bank Observatory, with the ultimate aim of these groups to produce one or more white papers. Based on your interest in the Observatory, we would like to invite you to join one (or more!) of the groups and help us as we plan for the future of Green Bank.

If you are interested, please send an email to indicating which of the science discussions you would like to join. If none of the categories adequately describes your interests, please let us know that (and your interests) as well. Finally, of course, if you wish to be removed from these mailings, please let us know.

Scientific Discussion Categories:

  1. Fundamental Physics (e.g. gravitational waves, general relativity, equivalence principle)
  2. The Transient Sky (e.g. FRBs, SETI, Pulsars )
  3. Stars & Star Formation (e.g. turbulence, magnetic fields, multi-scale molecular clouds, diffuse environments, ISM)
  4. Galaxies & Galaxy Clusters (Milky Way and beyond) (e.g. cosmic web, HI extent of galaxies, galaxy structure, galaxy clusters)
  5. Astrobiology & Astrochemistry (also could include comets, SETI)
  6. Planetary Systems (e.g. sun, stars, asteroid, comets, exoplanets, planetary weather/atmosphere)
  7. Cosmology & Large Scale Structure


Transformative Science Workshop

The workshop Big Questions. Large Problems, and New Instruments is now over, but the work is continuing. Presentations from the workshop are available on our archived page.

The Argus receiver highlighting the amplifier modules at top and the 4 x 4-pixel card array.

The Argus+ Project at the GBT

The GBT is now into its second winter season with Argus, the 16-pixel camera for spectroscopy in the molecule-rich 3mm atmospheric window between 74 – 116 GHz. Argus is the brainchild of Sarah Church of Stanford University and collaborators, who received an NSF ATI grant to design a modular receiver system for the GBT that could be replicated and expanded in a straightforward way. With the unique combination of angular resolution (6.5 – 9 arcseconds), sensitivity, and field of view of the GBT, Argus is being used for ground-breaking surveys of dense gas in galaxies and nearby star-forming regions. Recent Argus results were highlighted at the American Astronomical Society 2018 Winter Meeting in Washington D.C.

Left: Filament in DR21 mapped in 13CO. This map took 40 minutes in only moderate weather (τ=0.4). The footprint of the Argus array is shown upper right. Right: part of OMC-1 mapped by Argus in HNC(1-0). This map took 4.5 hours, including pointing, surface setting and calibration. The white circle shows the Argus beam (figure courtesy of Alvaro Hacar)

The Green Bank Observatory and the original Argus team are now collaborating on an Argus+ project, which would take advantage of the technical development afforded by Argus to produce a camera with ten times the mapping speed and includes a new spectrometer. Argus+ has the capability to routinely produce spectral line maps of key species such as CO, HCN, and HCO+ with a spatial dynamic range (map area / pixel size) of 104 to 105.

As part of the Argus+ project the community will be invited to participate in legacy surveys with the new instrument. There will be a spectroscopic survey of the Gould Belt molecular clouds, and a survey of dense gas tracers in nearby star-forming galaxies. The legacy surveys will produce unique data of lasting value. Argus+ data will also be displayed in exhibits at the GBO Science Center, and will be incorporated into a range of programs in STEM education throughout the region.

The project leverages the NSF’s investment in the prototype Argus to produce a uniquely powerful scientific instrument accessible to the U.S. scientific community. A proposal was submitted to the NSF MSIP program in early 2018 and was well reviewed, but ultimately not funded in this round. The Argus+ team has taken the reviewer comments to create an even stronger proposal for the next funding call and discussion during the upcoming Astro2020 Decadal Review.

Below is a quick comparison of the original Argus and Argus+.

Property Argus Argus+ Notes
Pixels 16 144 Single Pol
IF Bandwidth 1.5 GHz 7 GHz

16 pix x 2 win x 23.4 MHz x 4096 ch
16 pix x 1250 MHz x 1024 ch

144 pix x 600 MHz x 131k ch
16 pix x 1250 MHz x 1024 ch

Receiver Tsys

40 – 80K

30 – 60K

Usable 3mm hours/year



TLS metrology
Frequency Range

74 – 116 GHz

74 – 116 GHz

Map time 6’x6′
dv=0.1 km/sec,
σTb=0.1 K

 53 hours

 5 hours

Includes overhead