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Update on the V404 Cyg multi-wavelength campaign: cancellation of UV observations and continuation of other monitoring

ATel #7773; C. Knigge (Southampton), G. R. Sivakoff (Alberta), E. Kuulkers (ESA/ESAC), D. Altamirano, (Southampton), J. Neilsen (MIT) on behalf of a larger collaboration
on 8 Jul 2015; 11:44 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Christian Knigge (christian@astro.soton.ac.uk)

Subjects: Radio, Millimeter, Infra-Red, Optical, Ultra-Violet, X-ray, Gamma Ray, Black Hole, Transient

Referred to by ATel #: 7788, 7959

We provide a brief update on the coordinated multi-wavelength follow-up of V404 Cygni, a black-hole transient X-ray binary that is currently on the decline from its recent outburst. As described in ATel #7735, three HST observations of the system in the near-UV and far-UV were scheduled between July 10-12. We regret to announce that STScI have decided not to execute these observations in light of the recent fading of the source. However, we stress that other multi-wavelength coverage that has crystallized particularly around the HST plan windows remains in place, including X-ray (Chandra, NuSTAR, INTEGRAL, Swift), near-UV (Swift), optical and radio observations. We therefore recommend that all observations scheduled for the coming days should be carried out as planned. Even without HST's unique capabilities in the far-UV, the remaining planned observations should yield an unprecedented and scientifically invaluable (near-)simultaneous data set.

The mailing list and data based announced in ATel #7735 remain very active, with the former having over 100 subscribers and the latter listing over 70 observations (including many spanning multiple epochs) across all wavebands. In order to maximize the science return from this campaign, we strongly encourage all interested researchers to sign up to the mailing list and include their existing and planned observations of V404 Cyg in the data base. In order to subscribe to the mailing list, please send an email to majordomo@lists.soton.ac.uk and put "subscribe v404-mwc" into the BODY of the message (not the header). In order to submit observations to the online data base, go to http://deneb.astro.warwick.ac.uk/phsaap/v404cyg/obsform.html . In order to see a summary of the existing and planned observations in the data base, go to http://deneb.astro.warwick.ac.uk/phsaap/v404cyg/data/