AAVSO Alert Notice 377: REQUEST EXTENDED TO OBSERVE HMXBS IN SUPPORT OF RADIAL VELOCITY OBSERVATIONS

Dr. Gordon Sarty, University of Saskatchewan, Canada, has requested our continuing assistance (see AAVSO Alert Notices 348 and 354) in his ongoing radial velocity observations of four High Mass X-ray Binaries (HMXBs). From Dr. Sarty:

"[Please obtain] BVRI photometry (or any subset thereof, in IVBR order of preference)...for the month of May 2008 to complement the spectroscopic data that will be obtained from May 14 to 27. Spectroscopy of the four (4) HMXBs, for the purpose of measuring their radial velocities, will be done with the Dominion Astrophysical Observatory (DAO) 1.85-m Plaskett telescope, in Victoria, B.C., Canada. The object is to determine the orbital periods of the HMXBs. Optical photometry will also reveal other periods and variation due to mass transfer, pulsations and other effects. The availability of photometry will be very valuable for interpreting the spectroscopic data and has already been very useful for the HMXB RX J0146.9+6121 (which, however, is not visible from DAO for this run). For more information on HMXBs and this project, please see our eJAAVSO article:

http://www.aavso.org/publications/ejaavso/ej56.shtml

"The table below lists the four target HMXBs for this observing campaign:

Desig.  Name            R.A.(2000)  Dec.(2000)   Mag  LPH no.  AUID

1930+53 1936+541        19:32:52.3  +53:52:45.5  9.8  115    000-BDC-070

2027+47 RX J2030.5+4751 20:30:30.9  +47:51:50.7  9.3  123    000-BDC-306 

       (AAVSO name used to be J2030.5+47)

2157+49 2202+501        22:01:38.2  +50:10:04.6  8.8  127    000-BDC-509

2204+54 2206+543        22:07:57.1  +54:31:05.8  9.9  128    000-BDC-531

where the LPH number is a cross-reference to the HMXB listing in the JAAVSO paper and the HMXB chart web page which may be found at:

http://homepage.usask.ca/~ges125/AAVSO_HMXB_Charts.html

"As mentioned in the earlier Alert Notices, please follow the observing instructions given on the chart web page and on the charts and submit your results directly to the AAVSO International Database."

Also, Dr. Sarty asks that any questions about this observing campaign be sent to him at gordon.sarty@usask.ca or to Rick Huziak at rickhuziak@shaw.ca.

Your continued observations of these bright HMXBs are extremely important.
Many thanks for your efforts and your astronomical contributions.

Good observing!

Elizabeth O. Waagen
Senior Technical Assistant

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