Our assistance has been requested by Dr. Markus Boettcher, Ohio University,
in a study he and colleagues are making of several blazars. The targets are
being intermittently monitored by VERITAS (the Very Energetic Radiation
Imaging Telescope Array System), a four-telescope collection designed to
detect astrophysical sources of very high energy (VHE) gamma-rays that is
located at the Fred Lawrence Whipple Observatory in Arizona. If a VHE
gamma-ray outburst is detected by VERITAS, target-of-opportunity observations
with the Newton X-ray Multi-Mirror (XMM) telescope will be triggered. Since
VERITAS is not regularly monitoring the targets, optical monitoring is crucial
to alert the VERITAS collaboration to a high state of any one of the blazars
on the list in order to initiate VERITAS observations.
The XMM observing season has begun, so AAVSO observers are requested to
monitor the target blazars from now through at least May 2008, when the
current XMM observing cycle ends. Dr. Boettcher and colleagues have
submitted a Chandra proposal along the same lines that, if funded, would
extend the study throughout most of 2008.
The target list is given below. Finder charts for nine of the ten targets
are available through VSP (http://www.aavso.org/observing/charts/vsp), but
two of these do not have sequences. Also, the sequences for three targets are
not completely available in VSP right now but are available through
pre-existing AAVSO charts, so please follow the URLs given for these stars.
The tenth target does not have either a finder chart or a sequence available
right now.
NAME DESIG AAVSO NAME RA (2000.0) DEC (2000.0) MAG
Sequence available in VSP:
1. 1ES0033+595 0030+59 1ES0033+59 00:35:52.63 +59:50:04.6 19.5V
2. 1ES0806+524 0802+52 1ES0806+52 08:09:49.19 +52:18:58.4 14.84V
3. MRK 1218 0832+25 MRK 1218 08:38:10.95 +24:53:42.92 16.3V
4. 1ES1627+402 1625+40 1ES1627+40 16:29:01.31 +40:07:59.9 19V
Comp star coordinates in VSP and values plotted on chart, but magnitudes
not in VSP photometry table yet (sequence photometry available at URLs given
after each star):
5. 3C 66A 0216+42 3C 66A 02:22:39.61 +43:02:07.80 ~13.7-15.7V
ftp://ftp.aavso.org/public/calib/sumner/3c66a.seq
6. BL LAC 2158+41 BL LAC 22:02:43.29 +42:16:39.98 ~13.0-15.5V
use 'f' scale chart at
http://www.aavso.org/cgi-bin/shrinkwrap.pl?path=/charts/LAC/BL_LAC/BLLAC-F.GIF
Sequence temporarily not in VSP; please go to URL below for chart and sequence:
7. W COM 1216+28 W COM 12:21:31.69 +28:13:58.50 ~12.9-15.8V
http://www.aavso.org/cgi-bin/shrinkwrap.pl?path=/charts/COM/W_COM/WCOM-F.JPG
No sequence available in VSP:
8. 1ES0120+340 0117+33 1ES0120+34 01:23:08.9 +34:20:50 15.2V
9. 1ES0647+250 0644+25 1ES0647+25 06:50:46.6 +25:03:00 15.8V
No chart or sequence available (to be announced when added to VSP):
10.1H 0323+342 0318+33 1H0323+342 03:24:41.16 +34:10:45.86 15.72V
Dr. Boettcher has requested the following hierarchy of observations:
Cousins R nightly or multiple times per night; add B if possible; one UBVRI
set per night if possible; signal-to-noise ratio of 50 or better.
VERITAS uses R-band threshold magnitudes to trigger observations. The table
below contains the threshold R magnitude for each target as well as an
approximate V-magnitude trigger value. If you observe a target at or brighter
than the threshold, please notify AAVSO Headquarters immediately by submitting
your observation via WebObs. If the target is below the threshold, please try
to submit your observation within 24 hours. The astronomers need to be alerted
within one to two days, and we have to allow time for confirmation, so please
do not delay in reducing your data and submitting your observations.
Object |AAVSO Name | R_{trigger} | ~ V_{trigger}
=============================================================
1. 1ES 0033+595 |1ES0033+59 | 14.5 | 14.9
2. 1ES 0806+524 |1ES0806+52 | 14.5 | 14.9
3. MRK 1218 |MRK 1218 | 12.5 | 12.9
4. 1ES 1627+402 |1ES1627+40 | 16.5 | 16.9
5. 3C 66A |3C 66A | 13.7 | 14.1
6. BL LAC |BL LAC | 12.8 | 13.2
7. W COM |W COM | 13.7 | 14.1
8. 1ES 0120+340 |1ES0120+34 | 14.4 | 14.8
9. 1ES 0647+250 |1ES0647+25 | 14.0 | 14.4
10. 1H 0323+342 |1H0323+342 | 15.0 | 15.4
The campaign will be coordinated at the AAVSO by Dr. Matthew Templeton, AAVSO
staff astronomer (by Elizabeth Waagen July 14-19).
Your observations will be crucial to the success of this exciting campaign.
Many thanks for your observing efforts and valuable contributions. Good
observing!
Elizabeth O. Waagen, Senior Technical Assistant
-------------------------------------------
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