19A TAC Report

by Dana Balser last modified Nov 13, 2018


A total of 46 proposals were submitted to LBO's Very Long Baseline Array (VLBA)/High Sensitivity Array (HSA) in semester 19A.  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 19A semester that have been reviewed by the LBO TAC.

Statistics by Proposal Count
Submitted 46
Approved 22
Filler  7
Rejected 17
Oversubscription 2.1
Statistics by Proposal Hours
Requested 1501.10
Available  669.80
Approved   650.90
Filler   250.50
Rejected   629.60
Pressure      2.2


For the 19A semester, the LBO had agreements with the Hubble Space Telescope (HST), the Swift Gamma-Ray Burst Mission, the Chandra X-ray Observatory, and the XMM-Newton Telescope to submit joint proposals whereby the LBO TAC could allocate time on these external facilities (see the 19A Call for Proposals).  The table below summarizes the results for 19A for the VLBA.  The time available on the external facilities is per year and includes the GBT and VLA.


Joint External Proposals

HST (Orbits)

Swift (ks)Chandra (ks)XMM-Newton (ks)


30.0 300.0 120.0 150.0
Requested   0.0    27.0     0.0 0.0
Approved   0.0    27.0     0.0 0.0


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 enlarge.The black line with squares is 63% of the wall-clock time available (after removing time for maintenance and sponsored time).  The time is divided into low and high frequency that includes the different priorities: A (green), B (yellow), C (red), and N (blue).  The shading within each priority indicates high frequencies (lower on the column) or low frequencies.  Pre-committed time is orange and corresponds to time allocated by a TAC from a previous semester that is being executed in the 19A semester.

 VLBA Pressure Plot 19A



Observation Preparation

Unless otherwise stated in the TAC comments, proposals approved for priority A time will be eligible for scheduling in semesters 19A and 19B, and proposals approved for priority B or C time will be eligible for scheduling only during semester 19A.

IMPORTANT:  Those allocated dynamic time should begin their .key file preparation about two weeks before 2019 February 1,  the start of semester 2019A.  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.