May 2013 eNews
ALMA Band 2 Science Workshop, May 29-30, 2013
A workshop to develop the science case for development and construction of a receiver for ALMA Band 2 (65-90 GHz) will be held in Charlottesville, Virginia, on 29-30 May 2013.
The aim of the workshop is
to assess the science which a Band 2 receiver on ALMA would enable,
to identify a number of highest priority science cases,
to compare the existing ALMA technical specifications and requirements agains the science
to determine the technological readiness for instrumentation on ALMA.
This workshop is part of an NRAO funded ALMA development study to examine the scientific drivers for ALMA Band 2, and to develop a technical plan for the construction of those receivers. The workshop will be available via video connection or local participation. Further information may be found at WEBSITE.
The 4mm wavelength region (65- 90 GHz), otherwise known as ALMA band 2, is a virtually unexplored region of the electromagnetic spectrum. Until the very recent addition of a 4mm receiver to the GBT, there has been only one telescope with a continuing operational receiver in this frequency region: the 12m on Kitt Peak, run by the Arizona Radio Observatory (ARO). Furthermore, unlike the 7mm (31-45 GHz) band, which is covered by the newly upgraded NRAO Jansky Very Large Array (JVLA), there are no radio interferometers in operation in the band 2 region. However, in contrast to the lack of operational astronomical receivers, the expertise to construct and implement a sensitive and stable receiver in this frequency range currently exists. A nearly quantum-limited band 2 receiver can be built for ALMA with very little technology development.
The fundamental, J = 1→ 0 transitions of the deuterium analogs of common, abundant interstellar molecules are unique to this band, including DCO+, DCN, and N2D
+. Studies of such species are crucial to our understanding of the evolution of cores in molecular clouds, and hence to star formation. Because such cores are often quite cold (T ~ 10 K), the J = 1→ 0 lines of these molecules that lie in band 2 are by far the most sensitive probes. Furthermore, observations of such deuterated species are critical in evaluating chemical fractionation in interstellar material, and elucidating the pathways for ion-molecule chemistry. Recently, Mathews et al. (in press) have demonstrated the utility of ALMA observations of the J=3-2 line of DCO+ for locating the CO 'snow line' in a protoplanetary disk; more suitable lower lying lines are not currently available with ALMA.
Band 2 also contains the fundamental transitions of H2CO
and HCNH+, among other molecules. H2CO
is an excellent tracer of galactic structure and an important pre-biotic molecule. HCNH+ is a cornerstone species in ion-molecule chemistry, and the precursor to both HCN and HNC. Further observations of both molecules would be insightful for astrochemistry, astrobiology, and the structure of molecular clouds. In addition, redshifted CO and HCN emission, critical to understanding galaxy evolution, fall in the 4mm window. These examples highlight what is currently known about band 2; as with most unexplored wavelength regions, new scientific discoveries will likely occur, provided a receiver/detector is available with sufficient sensitivity. In band 2, the transparency of the atmosphere and maturity of required hardware virtually guarantee high sensitivity observations.
ALMA Call for Development Studies
Call for ALMA Development Studies
ALMA Early Science results have been pouring out, and more than 30 papers have now been published on a wide range of topics. Installation and commissioning of the final receiver bands funded for construction has begun. In commissioning and Early Science, ALMA has operated at wavelengths from 3mm to 0.3mm across a decade of nearly complete frequency access as enabled by its broad bandwidth receivers, powerful correlators and spectacular site. Having invested ~$1.3B to realize the biggest historical advance in ground-based astronomy, it is vital to maintain and expand its capabilities.
The ALMA Operations Plan envisages an ongoing program of development and upgrades that may include hardware, software, or data analysis tools. With a modest investment, ALMA will continue to lead astronomical research through the 2011-2020 decade and beyond. Construction of the first post-construction receiver bands, phasing hardware, and new data analysis tools has commenced in North America partially under a program of Development Studies submitted in response to a Call issued in November 2011. In response to that Call, 21 submissions were received involving 77 investigators from 26 institutions. After review by an external panel, eight proposals were funded; these are now reaching the end of their funding periods.
A new Call for Development Studies is being issued on 2013 May 1. To support this new Call, an informational workshop was held on Thursday, 18 April 2013 at NRAO headquarters in Charlottesville, VA. An overview of the current ALMA Development Plan and studies now under way was given and presentations are available on line.
The primary aims of these studies are to:
give groups in North America the opportunity to propose ALMA upgrades that may later be implemented as part of the ALMA Development Plan;
support the development of conceptual and detailed designs for ALMA upgrades; and
encourage relevant long-term research and development in areas important for ALMA.
The completed studies will be used, together with similar studies from the other ALMA partners, to augment and implement the ALMA Development Plan.
A Call for Development Projects will be issued 2013 June 3 and will be announced in the June NRAO eNews.
The release date for the FY2014 Call for Study Proposals is May 01, 2013. The period of performance for funded Studies will run from the award date (August 30, 2013) to no later than September 30, 2014 (approximately one year).
Proposers are requested to submit a Notice of Intent by May 17, 2013.
The closing date is July 12, 2013. Proposals received after the closing date may be rejected,
at NRAOs sole discretion.
Further details are can be found in the Conditions Governing the Call for Study Proposals (available at https://science.nrao.edu/facilities/alma/alma-development-2014/call-for-proposals
; refer to the Proposal Documents table).
Award pool a total of one million U.S. dollars ($1.0M) is available for funding Studies during the FY2014 Development Program cycle (subject to the FY2013 Federal Budget and allocation of funds). As a guideline, the NRAO expects to fund several Studies. No individual Study will be funded in excess of two hundred thousand U.S. dollars ($200K).
An informational meeting will be held in Charlottesville, Virginia on May 10, 2013. Interested parties may attend via telecon, videocon, or in person, and are requested to communicate their intention to participate (preferably by close of business on May 06, 2013) to the North American ALMA Science Center at mailto:email@example.com
These Calls are intended to attract proposals for innovative ideas that address current and future scientific opportunities with ALMA. All interested parties located within the North American ALMA partnership are eligible to participate in these studies.
As announced earlier in the ALMA Science Portal
, ALMA will spend the next few months giving priority to commissioning and improvements to infrastructure and overall system stability. During this time, Early Science observing will proceed at a lower priority. As a consequence, the ALMA Cycle1 observing period will be extended from the originally announced end of October 31, 2013 until at least the end of January 2014. The timescale for ALMA Cycle2 will be announced in the near future.
There are once again 55 antennas at the 5000m elevation Array Operations Site (AOS). Both the AOS and the Operations Support Facility (OSF) are powered by a selection of the three propane turbines located at the OSF. This represents a substantial cost savings over the diesel-fueled generators which have run the antennas at the AOS up until 8 April, when the changeover was effected. The new power system allows antennas to be placed on stations with longer baselines, and at present the antennas are deployed in a configuration resembling C32-3 except that six antennas as of this time are located on baselines of roughly one kilometer or longer. This is the first time an ALMA subarray with such long baselines has been available. It will be used to commission techniques necessary for excellent imaging on those baselines, including band-to-band phase transfer and fast switching.
In early April, the first of the ALMA nutators underwent an aceptance review. Ultimately the total power antennas on the ACA will be outfitted with nutators to improve stability.