GTM/LMT sunset

LMT Early Science observations (2015-ES4)

Following the release of the call for Early Science proposals (2015-ES4), the LMT will begin an extended period of scientific observations lasting 8 months, from November 1st 2015, to June 30th 2016. This Early Science phase will consist of shared-risk observations using the 3 mm wide-band spectrograph (73-111 GHz) Redshift Search Receiver (RSR) and the 1.1 mm (273 GHz) continuum camera AzTEC. This call for proposals (2015-ES4) provides an opportunity to conduct scientific projects during the best winter and spring weather conditions for millimeter-wavelength observations.

LMT Early Science Announcement of Opportunity

All interested applicants for LMT Early Science observations should read the Announcement of Opportunity that contains information regarding guidelines for proposers, including the selection criteria for approved projects, and the composition of Scientific Project Teams.

LMT Early Science Announcement of Opportunity

Schedule for Early Science Proposal Submission & Observing Period

  • August 25th 2015 – LMT Early Science Announcement of Opportunity (2015-ES4) released.
  • September 30th 2015 – Proposal Submission deadline.
  • November 1st 2015 – Observing period 2015-ES4 begins.
  • June 30th 2016 – Observing period 2015-ES4 ends.

Shared Risk Observations

This call for Early Science projects is made with the understanding that all successful proposals and scheduled observations are considered as “shared-risk”. During this period of scientific observations the LMT user-community should be aware that the feasibility of the proposed observations may change due to differences in the instrument sensitivities and the efficiency of the telescope performance compared to those that are advertised in this call. Early Science observations may be rescheduled or cancelled according to the need for additional commissioning and engineering activities.

Instructions for submission of Early Science proposals

The virtual LMT office (vLMT) provides the tools to register, submit and monitor the status of all LMT proposals. The vLMT is available to upload the Early Science proposals. Information regarding the proposal title, abstract, principal investigator and contact details will be entered directly into the online submission form. The co-investigators, list of astronomical targets and selection of instruments, and the scientific and technical justifications (including figures, tables and references) will be uploaded as separate documents.

The Early Science observing proposals must be written in English. The scientific and technical proposal will be formatted on Letter-sized paper with a font size not smaller than 11 points, and all page margins must be at least 2cm. A total of two pages are available to present the combined scientific case and technical justifications. Two additional pages are available for figures and tables including captions. References should be printed separately on a fifth page. A final page will provide a summary of the composition of the Scientific Project Team (see section below), including relevant experience, responsibilities, and the role of external (non-LMT partners) co-investigators. The full scientific and technical proposal (not exceeding a total of 6 pages) will be uploaded as a single PDF document.

Scientific Project Team

Membership of the Scientific Project Teams is open to individuals with affiliation at a Mexican research institution or at the Department of Astronomy at the University of Massachusetts and the Five College Astronomy Department. Scientific collaboration between the partners of the LMT project is strongly encouraged. Inclusion of additional external collaborators should be justified in the proposal and shown to offer an essential capability or unique resource to the project.

Proposals for Early Science must identify the full Scientific Project Team that will carry out the observational program. Each Scientific Project Team must demonstrate that it is self-sufficient, and contain team members that are familiar with the operation of the LMT, the preparation of the observing scripts, the use of the scientific instruments and the analysis of the data. It is strongly suggested that potential leaders of Scientific Project Teams contact the LMT Project Scientists, Miguel Chávez (mchavez@inaoep.mx) and Min Yun (myun@astro.umass.edu), who will facilitate and coordinate the involvement of experienced LMT project personnel, and members of the instrument teams, within the individual Scientific Project Teams.

Depending on the assigned ranking of the proposal, following the scientific and technical peer-review, the Principal Investigator will be contacted before scheduling the scientific program on the LMT to prepare the selection of the target sources and the generation of the required observing scripts, and to organize the logistical support of the observations at the telescope. For safety reasons, it is mandatory that observers should be able and willing to drive the LMT trucks and have a valid driver license.

Instrument Sensitivities and Integration Times

A preliminary value of 85 microns r.m.s. is calculated for the total optical error budget, derived from measured deformations in the optics of the primary and secondary mirrors, plus estimates of the impact of environmental effects (wind loading and temperature gradients in the antenna support structure) on the primary surface. This estimated error of 85 microns r.m.s. is the default value used in the determination of the expected sensitivities of the Redshift Search Receiver and AzTEC during the Early Science opportunity with the LMT. Please note that the AzTEC sensitivity calculators for the Photometry and Small Map Modes have been updated according to the results derived from observations of the last ES3 campaign. Furthermore, a new AzTEC scanning mode (Rastajous) to make 5′ diameter maps is offered. This new map mode was successfully tested during the ES3 season. Integration time and sensitivity calculators for both instruments can be found in the following links:

Given the experience of the previous 8-month long observing season, and taking into consideration the variable weather conditions, the telescope operational efficiency and the observing overheads, we anticipate a total of ~300 hours of AzTEC on-source integration time and ~500 hours of Redshift Search Receiver on-source integration time during the next observing period (November 1st 2015 to June 30th 2016). The exact division of observing time between the instruments will depend on the scientific priority awarded to the individual projects.

Atmospheric Quality Specifications

AzTEC observations are performed with opacities less or equal to 0.1, and RSR observations with 0.1 < tau < 0.3 (tau at 225GHz and measured towards the zenith). If the authors of a proposal that request AzTEC observations consider that the project can be successfully accomplished with higher opacities, this should be specified and justified in the Technical Justifications, including the suggested opacity limit. The same applies for RSR projects that may be successful with opacities > 0.3. If a RSR project requires observations with opacities < 0.1 (e.g. to detect sub-mK lines), this should also be specified and justified in the Technical Justifications. A Technical Evaluation Committee will review these cases. If necessary, the PI will be contacted and asked to update the Technical Justification before the proposal is passed to the Scientific Evaluation Committee. It is important to note that all projects will be observed under the best possible weather conditions and atmospheric quality. This requested information, however, is crucial to allow a flexible scheduling and improve the LMT observing efficiency. Proposals with more relaxed weather and atmospheric quality specifications will always have a higher probability to be completed.

Active Primary Surface & Elevation-dependent Gain Corrections

The primary telescope reflector has recently been set with an active surface control system using 12 GHz holography measurements over a wide elevation range. The active surface control system uses a model to correct the gravitational deformations of the primary reflector surface as the telescope moves in elevation. Over an elevation range of ~20 to 75 degrees the telescope has a measured constant and maximum aperture efficiency or gain.

Additional Information

  • Monthly-averaged values of the expected atmospheric opacity at the LMT site can be found in the Metereological Monitoring page.