[Edited 2011 July 12 to indicate that the apertures and annuli are radii rather than diameters. -- M. Templeton, AAVSO]
July 8, 2011: Dr. Misty Bentz of Georgia State University requests observations of four active galactic nuclei (AGN) for a study of variability in these sources by the STARE Collaboration. She requests BVRcIc filtered photometry of NGC 6814, NGC 7213, NGC 7469, and NGC 1566 from July 10, 2011 to November 1, 2011 in support of a spectroscopic monitoring campaign to run concurrently using the SMARTS 1.5-meter telescope at CTIO in Chile. Although the nuclei are bright, the background galaxian light will be significant, and observers are asked to use the photometric apertures and background annuli as described below for consistency.
Dr. Bentz has set up a website for this project, and observers should use it as the primary resource for this project:
http://www.chara.gsu.edu/STARE
The targets to be observed are given in the following table. For each target, use the Aperture ("Ap.") radius specified to photometer the central source, and use the specified annulus ("Sky ann.") radius for sky background. This will maximize the detection of the AGN emission while minimizing the contribution from the underlying galaxy.
Galaxy RA(J2000) Dec(J2000) V(mag) Ap. Sky ann.
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NGC 6814 19 42 40.60 -10 19 25.3 14.0 5" 120"-135"
NGC 7213 22 09 16.24 -47 10 00.4 15.0 4" 120"-135"
NGC 7469 23 03 15.75 +08 52 25.8 14.5 4" 120"-135"
NGC 1566 04 20 00.40 -54 56 16.0 14.5 5" 120"-135"
If you are unable to perform photometry using the recommended aperture/annulus combination, please clearly indicate what you used in the comments for each observation. Note that NGC 7213 and NGC 1566 are both southern sources, and are not appropriate for most northern hemisphere observers. Also, due to the color dependence of the variability, unfiltered observations are not appropriate for this project. Participating observers are asked to obtain 1-2 sets of BVRcIc or any subset thereof; B and V filtered data are most strongly desired.
Observers can visit the STARE website for observing information and images of each galaxy. You may also plot charts for each field using VSP; the galaxies will not appear in VSX, but you may plot charts and submit data using the NGC names (be sure to include a space between "NGC" and the catalog number). You will find it useful to select the "Plot DSS" option when creating charts in VSP. CCD comparison stars within 30' have been provided and are available via VSP.
Observers are asked to report their observations to the AAVSO via WebObs. For technical assistance please contact aavso@aavso.org. For more information on this project, please contact Dr. Bentz directly (bentz@chara.gsu.edu).
This AAVSO Alert Notice was prepared by Dr. Matthew Templeton.