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Monster Black Hole Awakens After 26 Years

On 15 June 2015, a long-time acquaintance of X-ray and gamma ray astronomers made its comeback to the cosmic stage: V404 Cygni, a system comprising a black hole and a star orbiting one another. It is located in our Milky Way galaxy, almost 8000 light-years away in the constellation Cygnus, the Swan.

In this type of binary system, material flows from the star towards the black hole and gathers in a disc, where it is heated up, shining brightly at optical, ultraviolet and X-ray wavelengths before spiralling into the black hole.

Read the full story at ESA News

Newly discovered nova shells around cataclysmic variables!

Evidence of nova shells found around the NL, V1315 Aql, the dwarf nova, V1363 Cyg and evidence of a light echo around the nova V2275 Cyg, which could indicate it is a recurrent nova.

By authors: D. I. Sahman, V. S. Dhillon, C. Knigge, T. R. Marsh

It’s all about the  standstills, those episodes where the star gets stuck at a mid-point between maximum and minimum. If it doesn’t exhibit standstills it isn’t a Z Cam star.

AM Her stars in need of further investigation

Data from Catalina Real Time Survey 
Drake et al. 2009, ApJ, 696, 87

Northern CVs brighter than 17th magnitude here.

Southern CV's brighter than 17th magnitude here.


New outbursts and unusual activity reported in the last 72 hours

Last updated 14:57 UT July 03, 2015


V452 Cas
EX Dra
V416 Dra
AH Her
AY Lyr
RU Peg
QW Ser

# indicates a noteworthy or unusual outburst
'Activity At A Glance' is gleaned from observations reported to AAVSO MyNewsFlash, BAAVSS-Alert, CVnet-Outburst, VSObs-share and VSNET-outburst. We sincerely thank all the observers who contribute timely observations and reports of activity to these email lists.


For new papers on CV's see astro-ph

Authors: M. J. Darnley, M. Henze, I. A. Steele, M. F. Bode, V. A. R. M. Ribeiro, P. Rodríguez-Gil, A. W. Shafter, S. C. Williams, D. Baer, I. Hachisu, M. Hernanz, K. Hornoch, R. Hounsell, M. Kato, S. Kiyota, H. Kučáková, H. Maehara, J.-U. Ness, A. S. Piascik, G. Sala, I. Skillen, R. J. Smith, M. Wolf

Authors: Deanne L. Coppejans, Elmar G. Koerding, James C.A. Miller-Jones, Michael P. Rupen, Christian Knigge, Gregory R. Sivakoff, Paul J. Groot

Authors: D. I. Sahman, V. S. Dhillon, C. Knigge, T. R. Marsh

Authors: J. Shears, B. Gaensicke, P. Rodriguez-Gil, D. Boyd, G. Darlington, I. Miller

Authors: S. G. Parsons, C. Agurto-Gangas, B. T. Gaensicke, A. Rebassa-Mansergas, M. R. Schreiber, T. R. Marsh, V. S. Dhillon, S. P. Littlefair, A. J. Drake, M. C. P. Bours, E. Breedt, C. M. Copperwheat, L. K. Hardy, C. Buisset, P. Prasit, J. J. Ren

Authors: Linda Schmidtobreick, Michael Shara, Claus Tappert, Amelia Bayo, Alessandro Ederoclite

Authors: Tim O'Brien, Michael Rupen, Laura Chomiuk, Valerio Ribeiro, Michael Bode, Jennifer Sokoloski, Patrick Woudt