Special Notice #77: Update on Alert Notice 353 -- blazar monitoring campaign

October 30, 2007: The campaign to monitor blazars as described in Alert Notice 353 is ongoing, and the triggering thresholds for VERITAS observations have recently been updated by the PI, Dr. Markus Boettcher.

The blazar 1ES 0120+340 (1ES0120+34, AAVSO Designation 0117+33) has recently been seen just above the new triggering threshold of Rc = 17.0, and observations of this source are requested over the next several weeks. 1ES 0120+340 is located at coordinates

RA: 01:23:08.6 , Dec: +34:20:48 (J2000)

and is currently hovering around Rc = 17.3. Please obtain photometry accurate to 0.1 magnitudes or better, preferably in either Rc or V. We do not currently have a sequence for this object loaded into VSP, but for CCD photometry, observers may use the following stars for comparisons and checks:

Comparison stars:

Comp 1: RA 01:23:16.78 , Dec +34:20:50.5 , V = 15.65 , Rc = 15.38

Comp 2: RA 01:22:57.26 , Dec +34:22:56.7 , V = 15.20 , Rc = 14.90

Check stars:

RA 01:23:15.88 , Dec +34:21:12.4 , V= 16.75 , Rc = 16.37

RA 01:23:06.03 , Dec +34:21:10.2 , V= 17.19 , Rc = 16.69

RA 01:23:05.06 , Dec +34:22:40.4 , V= 16.15 , Rc = 15.74

RA 01:23:18.44 , Dec +34:19:26.5 , V= 14.43 , Rc = 13.98

Photometry for these stars is from A. Henden; the magnitudes have errors on the order of 0.03 magnitudes. Complete sequences will be added to VSP shortly after the AAVSO Annual Meeting.

Ongoing observations of all ten blazars in the list are requested through mid-2008 to catch these objects in outburst. Because blazars vary on timescales of hours to a few days, please observe these objects nightly as your observing schedule permits. If the object is brighter than the threshold magnitude, please submit your data as quickly as possible. Time-series observations are not required but please obtain 0.1-magnitude photometry or better. Observations in Rc are preferred, but V-band observations are also useful, as are visual observations.

The new triggering thresholds for VERITAS are as follows:

Object        | AAVSO Name      | Rc trigger | V trigger

========================================================

1ES 0033+595  | 1ES0033+59      |    16.6    |   17.0

1ES 0120+340  | 1ES0120+34      |    17.0    |   17.4

3C 66A        | 3C 66A          |    13.7    |   14.1

1H 0323+342   | 1H0323+342      |    15.0    |   15.4

1ES 0647+250  | 1ES0647+25      |    15.4    |   15.8

1ES 0806+526  | 1ES0806+52      |    14.8    |   15.2

Mrk 1218      | MRK 1218        |    12.5    |   12.9

W Comae       | W COM           |    13.7    |   14.1

1ES 1627+402  | 1ES1627+40      |    16.5    |   16.9

BL Lacertae   | BL LAC          |    13.0    |   13.4

For more information on this campaign in support of VERITAS and the XMM-Newton satellite, please see 
AAVSO Alert Notice 353: http://www.aavso.org/publications/alerts/alert353.shtml
The Alert Notice contains links to charts when available. 

This AAVSO Special Notice was prepared by Matthew Templeton.
---------------------------------------------------