10x faster continuum mapping at 90 GHz
MUSTANG3 is a proposed successor to the MUSTANG2 bolometric camera on the 100-meter NSF Green Bank Telescope (NSF GBT), offering
- an order of magnitude increase in mapping speed,
- a wider, 5.0′ field-of-view,
- polarization sensitivity, and
- dual band (75–90 GHz and 90–105 GHz bands)
MUSTANG3 will retain 9′′ resolution and offers much greater continuum sensitivity and large scale recovery than ALMA Band 3, suitable for a diverse range of scientific goals. MUSTANG3 will become a facility instrument available to the astronomical community.
Left: MUSTANG-2 image of the galaxy cluster MS0735 with SZ contours in white and LOFAR (144 MHz) in heat contours. Right: Galactic center as mapped by MUSTANG-2.
Science Enabled
Galaxy clusters
MUSTANG3 can observe the intracluster medium (ICM) via the Sunyaev-Zel’dovich (SZ) effect. The dominant SZ signal is proportional to the electron pressure integrated along the line of sight and is redshift-independent. Relative to X-ray observations, these properties make SZ observations advantageous for observing clusters out to R500 (and larger radii) and clusters at high redshift (z > 1). The figure below shows how MUSTANG3 will capitalize on these intrinsic advantages.
In conjunction with X-ray observations (whose surface brightness is roughly proportional to ne2), temperature and entropy profiles (or maps) can be derived. SZ observations (alone) can also place constraints on thermal and non-thermal pressure support in X-ray cavities [e.g. Orlowski-Scherer+ 2022]. MUSTANG3 will enable detailed thermodynamic characterization of the ICM and provide insights into the nature of ICM heating, energy transport, and cosmic ray acceleration mechanisms.
Figure 1. Thresholds to achieving 3σ constraints on non-parametric Pe (or ne for AXIS) at R500 within 3 hours of observations for various instruments.
Separating emission mechanisms and polarization
In many spectral energy distributions of ISM regions (from scales of individual star-forming clouds to scales of galaxies), 90 GHz (3mm) is often seen as a local minimum, with contributions from both free-free and thermal (dust) emission.
Figure 2. From Ginsburg+ [2020]. Separated components towards Sgr B2 from ATLASGAL 870 μm, MUSTANG2 3mm, and VLA 20 cm datasets.
MUSTANG3 will vastly improve upon MUSTANG2’s capabilities to separate components owing to both the sensitivity improvement as well as the separated bands. Moreover, the polarization capabilities of MUSTANG3 will enable constraints of magnetic fields, properties of dust grains, and further aid in component separation.
Beyond the ISM, small solar system objects (without atmospheres) observed at radio wavelengths are dominated by thermal emission, where the SED and polarization of such thermal emission can reveal the composition of rocky objects, such as asteroids.
Returning to galaxy clusters, there may also be compact sources, which interferes with the SZ signal. Improved characterization of these sources (whether they are radio sources or dusty star forming galaxies) is of interest both for accurate SZ characterization as well as better understanding the populations of galaxies over a span of redshifts.
| Upgrade Characteristics | MUSTANG 2 | MUSTANG 3 |
|---|---|---|
| FOV | 4.2’ | 5.0’ |
| Resolution | 9” | 9” |
| Polarization | No | Yes |
| Freq. bands | 75-105 GHz | 75-90, 90-105 GHz |
| Sensitivity in 1 hour* | 77 uKRJ (59 uJy/bm) | 29 uKRJ (22 uJy/bm) |
References
- Ginsburg, A., Anderson, L. D., Dicker, S., et al. 2020, ApJS, 248, 24
- Orlowski-Scherer, J., Haridas, S. K., Di Mascolo, L., et al. 2022, A&A, 667, L6
Contact
Have questions? Want to know more about what MUSTANG3 can do for your science?
Email us at: moc.s1746512159puorg1746512159elgoo1746512159g@3gn1746512159atsum1746512159
MUSTANG3 will be designed and assembled in partnership with NSF GBO at the University of Pennsylvania
