Chandra

Special Notice #428: YZ Cnc Chandra observing window delayed

January 25, 2017: The beginning of the observing window for the Chandra TOO observations of the SU
UMa-type dwarf nova YZ Cnc that are the focus of AAVSO Alert Notice 565 and AAVSO Special Notice #427 has been delayed.

Principal Investigator Dr. Christian Knigge (University of Southampton) informs us that Chandra Mission Planning has informed him that the beginning of the Chandra-observable window for YZ Cnc has been delayed until 2017 February 5.

Special Notice #427: Please continue YZ Cnc coverage for Chandra TOO observations

January 23, 2017: The observing campaign is continuing for the SU UMa-type dwarf nova YZ Cnc. In AAVSO Alert Notice 565, Dr. Christian Knigge (University of Southampton) and colleagues requested AAVSO coverage in support of Chandra X-ray observations to be carried out via a Target of Opportunity (TOO) triggering when the system was in a suitable outburst.

Alert Notice 565: YZ Cnc Chandra observing campaign

December 19, 2016: Dr. Christian Knigge (University of Southampton) and colleagues have requested AAVSO coverage of the SU UMa-type dwarf nova YZ Cnc in support of Chandra X-ray observations to be carried out via a Target of Opportunity (TOO) triggering when the system is in a suitable outburst.

YZ Cnc has normal outbursts about every 7-10 days, and superoutbursts about every 100-110 days. The astronomers are planning to use a superoutburst to trigger the TOO observations.

Special Notice #423: RX And observations needed urgently now

October 11, 2016: Further to AAVSO Alert Notice 549, observations of the dwarf nova RX And are urgently requested immediately. The system *may* be going into outburst, and confirmation is essential in order to know whether to trigger ToO observations with Chandra and other instrumentation.

Alert Notice 549: RX And Chandra observing campaign

September 1, 2016: Dr. Christian Knigge (University of Southampton) and colleagues have requested AAVSO coverage of the Z Cam dwarf nova RX And in support of Chandra X-ray observations to be carried out via a Target of Opportunity (TOO) triggering when the system is in a suitable outburst.

Special Notice #31: Corrected text of AAVSO Special Notice #29 - Observations requested of 2001+32 V550 Cyg

January 19, 2007

In AAVSO Special Notice #29, the wrong satellite was named as the source of observations being analyzed by Dr. Jeno Sokoloski. A correction published in Special Notice #30 was ambiguous. To clarify matters, below is the corrected full text of the AAVSO Special Notice #29. Please disregard Special Notice #30. We apologize for the error and confusion! -- Elizabeth Waagen

Alert Notice 538: Observations of V694 Mon (MWC 560) requested for Chandra campaign

February 26, 2016: Dr. Jeno Sokoloski (Columbia University) and Mx. Adrian Lucy (graduate student, Columbia University) have requested AAVSO observations of the jet-driving symbiotic star V694 Mon (MWC 560), which is in outburst, in support of upcoming Chandra observations to investigate the state of the inner accretion disk during this outburst.

The Chandra observations are scheduled (preliminary schedule) for 2016 March 8 (7:17-14:13 UTC) and March 9 (2:20-9:17 UTC).

Special Notice #411: RT Cru observations need to be continued

December 15, 2015: Further to AAVSO Alert Notice 503 and AAVSO Special Notice #409, Dr. Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) urgently requests that multicolor and visual AAVSO observations of the symbiotic variable RT Cru continue.