VLA calibrator information for 1642+3948
This page summarizes the information for 1642+3948 as found in
the original VLA
calibrator list and, if found there, a link to search the NRAO VLA Archive Survey
(NVAS) for calibrator data before 2010. Furthermore, a table
with the most recent approximate flux densities, starting from 2017 as
mined from the VLA CASA
pipeline is presented.
If shown at the top, we have
recovered the original, pre-WIDAR ANTSOL flux density solutions from
the period roughly 2000-2007; symbols as explained next.
The
mined data are plotted (gray, on the left hand side) as function of
(log) frequency on the top and as function of time on the bottom. The
frequency band symbols in the bottom panel follow the symbols as
outlined in the top panel:
4-band (~75 MHz) horizontal stripe X-band (~10.0 GHz) cross
P-band (~350 MHz) open triangle U/Ku-band (~15.0 GHz) filled square
L-band (~1.5 GHz) VLA-Y shape K-band (~22.2 GHz) open circle
S-band (~3.0 GHz) filled triangle A/Ka-band (~33.2 GHz) 6-pointed star
C-band (~6.0 GHz) open square Q-band (~45.0 GHz) filled circle
Assume a 10% flux density error on each point, up to 30% for the
higher frequency data points. The dashed lines in the frequency plot
indicate the approximate spectral index in the frequency band
(tied to the measured flux density).
Depending on the spectral
behavior, different receiver observing bands (as indicated with the
log-frequency axis) may have very different typical flux
densities. Note that there can be significant flux density changes for
different array configurations, which start date is indicated at the
top of the time-line figure. Calendar years are separated by vertical
dotted lines.
If shown, a curve depicts a fit to the
(unweighted) average data for each band (if there are more than two
bands with measured flux densities). The fit equation is listed at the
top where the x-coordinate represents the base-10 log of the frequency
(GHz) and the y-coordinate represents the base-10 log of the flux
density (mJy/bm). The fit may use more data than shown and is using
data with different time stamps, which means typically different flux
densitities in a single band for genuine variable sources (and/or
observed in different array configurations).
Depending on the
variability of the source, array configuration and the quality of the
data, this fit may, or may not, be representative for the data!
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(Click on the figure for a larger view in a new tab/window)
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Original (outdated) VLA calibrator list information:
IAU NAME EQUINOX PC RA(hh,mm,ss) DEC(ddd,mm,ss) POS.REF ALT.NAME
===================================================================
1642+398 J2000 A 16h42m58.809951s 39d48'36.993950" Aug01 3C345
1641+399 B1950 A 16h41m17.606200s 39d54'10.815000"
-----------------------------------------------------
BAND A B C D FLUX(Jy) UVMIN(kL) UVMAX(kL)
=====================================================
20cm L X X X S 8.00 5
6cm C P P S S 7.80
3.7cm X S X X X 7.00 200
2cm U S S S S 13.00
0.7cm Q S S S S 11.2
Default NVAS search around this position (in new tab/window)
Results from CASA pipeline flux density mining:
| Observing date (UT) | Flux density (Jy/bm) | Source name used |
| C-band data (open squares) |
| 20171217 | 5.498 | J1642+3948 |
| 20171222 | 5.499 | J1642+3948 |
| 20171223 | 5.483 | J1642+3948 |
| 20180423 | 5.332 | J1642+3948 |
| X-band data (X-crosses) |
| 20171208 | 6.029 | J1642+3948 |
| 20171209 | 6.158 | J1642+3948 |
| 20171217 | 6.009 | J1642+3948 |
| 20171222 | 5.974 | J1642+3948 |
| 20171223 | 5.958 | J1642+3948 |
| U-band data (filled squares) |
| 20171208 | 7.439 | J1642+3948 |
| 20171209 | 7.725 | J1642+3948 |
| 20171217 | 7.149 | J1642+3948 |
| 20171222 | 6.966 | J1642+3948 |
| 20171223 | 7.021 | J1642+3948 |
| K-band data (open circles) |
| 20170802 | 6.209 | J1642+3948 |
| 20180913 | 5.965 | J1642+3948 |
| 20180914 | 6.018 | J1642+3948 |
| 20180916 | 5.929 | J1642+3948 |
| 20180921 | 6.029 | J1642+3948 |
| 20180929 | 5.557 | J1642+3948 |
| 20181108 | 5.969 | J1642+3948 |
| 20181110 | 6.330 | J1642+3948 |
| A-band data (6-pointed stars) |
| 20171208 | 7.571 | J1642+3948 |
| 20171209 | 8.391 | J1642+3948 |
| 20171217 | 7.246 | J1642+3948 |
| 20171222 | 7.384 | J1642+3948 |
| 20171223 | 7.190 | J1642+3948 |
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