17B TAC Report

by Dana Balser last modified May 12, 2017


A total of 45 proposals were submitted to LBO's Very Long Baseline Array (VLBA)/High Sensitivity Array (HSA) in semester 17B.  Proposals are reviewed on a competitive basis with a panel review system (see Proposal Review System).  Below are the statistics by proposal count and hours.  The oversubscription is the ratio of the number of submitted proposals to the number of approved proposals.  The pressure is the ratio of the requested time to the available time in hours.  Here we only include proposals submitted for the 17B semester that have been reviewed by the LBO TAC.

Statistics by Proposal Count
Submitted 45
Approved  23
Filler   8
Rejected   14
Oversubscription 1.9
Statistics by Proposal Hours
Requested 1268.8
Available 905.5
Approved 666.6
Filler 91.6
Rejected 510.6
Pressure 1.4

For the 17B semester, the LBO had agreements with the Hubble Space Telescope (HST), the Swift Gamma-Ray Burst Mission, and the Chandra X-ray Observatory to submit joint proposals whereby the LBO TAC could allocate time on these external facilities (see the 17B Call for Proposals).   No LBO proposals requested time on these external facilities for semester 2017B. 


Telescope Pressure Plots

Pressure plots show the total hours of allocated time as a function of GST.   Also shown are how the hours are divided with respect to observing priority. Click on the plot to view the source file. The upper black line with squares is 60% of the wall-clock time available (after removing time for maintenance) and the lower black line is half that (i.e. 30% of wall-clock time).  The colors correspond to pre-committed time (green), priority A (dark blue), priority B (light blue), priority C (yellow), and priority N (red). The letters A, B, C, and N correspond to the priorities assigned by the TAC where A and B are approved time, C is filler time, and N is rejected time.  Pre-committed (carryover) time is time allocated by a TAC from a previous semester that is being executed in the 17B semester.


VLBA Pressure Plot 17B


Observation Preparation

In semester 17B, Galactic parallax projects require a significant amount of the VLBA time in inner Galaxy to Orion GSTs (~2100 - 1600 GST) in the parallax "season", which is approximately +/-3 weeks centered on the equinox.  Twenty-four hour blocks are especially very difficult to schedule during that time.  If at all possible, dynamic blocks should avoid those GSTs during that  time of the year.

Unless otherwise stated in the TAC comments, proposals approved for priority A time will be eligible for scheduling in semesters 17B and 18A, and proposals approved for priority B or C time will be eligible for scheduling only during semester 17B.

IMPORTANT:  Those allocated dynamic time should begin their .key file preparation about two weeks before 2017 August 1,  the start of semester 2017B.  Those with fixed-date allocations (e.g. HSA proposals) will be informed of the date/time of observation about one month prior and their schedules will be due two weeks prior to observation.

Any approved time tabulated above may be divided into multiple scheduling blocks as appropriate, considering the scheduling priority, observing frequency, GST range suitable for the target(s), and GST pressure. For advice on preparing your scheduling blocks, please consult the VLBA Observing Guide or use the helpdesk.