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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.

    
ACTIVITY AT A GLANCE

New outbursts and unusual activity reported in the last 72 hours

Last updated 14:57 UT July 03, 2015

YYYYMMDD

20150702
V452 Cas
EX Dra
V416 Dra
AH Her
AY Lyr
RU Peg
QW Ser
ASASSN-14dh 
GALEXJ211312.2-590714


# 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.

RECENT PAPERS ON CVs


For new papers on CV's see arxiv.org 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