Particularly in support of calibration of absolute polarization angle (EVPA) of VLBA observations, the VLA is performing regular monitoring of common polarized radio sources from 1-50 GHz. This page contains a summary of ongoing calibrator monitoring efforts to aid current and future observation proposing and observation planning.
Monitoring programs can be summarized in three categories:
Since May 3rd, 2019, the VLA is performing monthly snapshot observations of a common set of standard calibrators used for flux density and polarization calibration. The list of sources included in this monitoring and observing bands is summarized in the following table:
# | Target | Bands | Intent |
---|---|---|---|
1 | J2355+4950 | L-Q | Gain |
2 | 3C48 | L-Q | Gain |
3 | 3C84 | L-Q | Gain |
4 | 3C147 | L-Q | Gain |
5 | J0713+4349 | L-Q | Gain, PolLeak |
6 | 3C196 | L-Q | Gain |
7 | J0217+7349 | L-Q | Gain |
8 | J1153+8058 | L-Q | Gain |
9 | J1800+7828 | L-Q | Gain |
10 | 3C123 | L-Q | Gain |
11 | 3C138 | L-Q | Gain |
12 | J1419+5423 | L-X | Gain |
13 | 3C295 | L-X | Gain |
14 | J1419+5423 | L-X | Gain |
15 | 3C286 | L-Q | Bandpass, Flux Density Scale, PolAngle |
Since about February 2018, a regular monitoring of secondary polarization angle calibrators was resumed, that is meant to resemble the monitoring performed in the pre-EVLA era. Currently, such observations are performed in two separate scheduling blocks and observed about every 3 months. Recently, additional targets were added to evaluate potential new standard calibrators in the LST range 16-21 hours.
Current list of observed sources:
POLCAL_1_v2.2 8 bit / 5.5h | POLCAL_2_v3.0 8 bit only / 5.5 h |
---|---|
J0854+2006 (L-Q) | J0136+4751 (L-Q) |
J0713+4349 (L-Q) | J2202+4216 (L-Q) |
J0521+1638 (L-Q) | J2136+0041 (L-Q) |
J0555+3948 (L-Q) | J2355+4950 (L-Q) |
J0739+0137 (L-Q) | J2253+1608 (L-Q) |
DA240_North (L-Q) | J0136+4751 (L-Q) |
J0927+3902 (L-Q) | J0137+3309 (L-Q) |
J1310+3220 (L-Q) | J0319+4130 (L-Q) |
J1331+3030 (L-Q) | J0359+5057 (L-Q) |
J1330+2509 (L-C) | J0542+4951 (L-Q) |
J1256-0547 (L-Q) | J0521+1638 (L-Q) |
J1743-0350 (L-Q) | |
J1602+3326 (L-Q) | |
J2025+3343 (L-Q) | |
J2148+0657 (L-Q) | |
J2232+1143 (L-Q) |
Leakage
Angle
Ad-hoc observations are performed primarily for VLBA users, if targets are not covered by the above monitoring programs. A summary of recent requests are collected here. We attempt to capture such observations also under TPOL0003. In some instances they are also observed under the requested project code and not immediately publicly available.