Milli-second optical observations of V 404 Cyg with SiFAP
ATel #7842; F. Ambrosino (INAF-Osservatorio Astronomico di Roma, Monteporzio Catone, Italy) I. Bruni (INAF-Osservatorio Astronomico di Bologna, Stazione Astronomica di Loiano, Italy) P. Cretaro, F. Meddi, C. Rossi (Dpt of Physics, La Sapienza University, Roma, Italy) F. Giovannelli (INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy)
on 25 Jul 2015; 23:06 UT
Credential Certification: Corinne Rossi (email@example.com)
Subjects: Optical, Binary, Black Hole, Transient
Referred to by ATel #: 7959
SiFAP: A simple sub-millisecond astronomical photometer (Ambrosino et al.: 2013, J. Astron. Instrum. Vol. 2 (01), 1350006; Ambrosino et al.: 2014, Proc of the SPIE, 9147, 91478R) has been used at the Cassegrain focus of the G.D. Cassini 152 cm Loiano telescope in order to detect possible short term periodicities and/or QPOs of the black hole X-ray binary V 404 Cyg. The nights were clear and the seeing was about 1 arcsec. A comparison star was observed simultaneously.
The time resolution used was 20 microseconds. Data were acquired on 2015 July 23 from UT 01:22 to UT 02:17 (first run), and 2015 July 24 from UT 01:19 to UT 02:14 (second run). Because of incoming skylight, only the first 1000 seconds for both runs have been used. Data have been rebinned down to 10 ms in order to improve S/N ratio.
Neither periodicities nor QPOs have been detected in both runs. Variations lower than 0.3% of the signal cannot be detected with our instrumentation.