*** News from VSNET *** The historical outburst of WZ Sge is ongoing. Large amplitude (~0.5mag) early superhumps were detected. For more detail information about these objects, see below, "VSNET Weekly Campaign Summary" of the last week. --------------------------------------------------------------------------- VSNET (Variable Star Network) is an international variable star observing network, covering various areas of novae, supernovae, cataclysmic variables (CVs), X-ray transients, and other classical eruptive, pulsating, and eclipsing variables. VSNET is one of invited contributing organizations to the SkyPub AstroAlert system. The "News from VSNET", mainly focusing on recent remarkable activities of CVs and related systems, is issued on a weekly basis, except on occasions of extremely urgent or transient events. Please refer to the VSNET Home Page for more details of events and objects listed. VSNET Home Page: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/ VSNET provides a number of mailing lists, on which various news and topics are discussed. Subscriptions to the VSNET mailing lists are free of charge; please refer to the instruction on the above page if a reader needs more information of the list structure. CCD observations of such targets are a relatively easy task for a 20-40cm telescope; simply take as many CCD frames (with exposure times 10-30 sec) as possible, spanning several hours per night. The only requirements are the weather and your patience! If you need more help on the observing technique, please feel free to ask on the vsnet-campaign list. We would sincerely appreciate volunteers who would join the VSNET Collaboration team to study the wonders of these exotic variable stars. To join the VSNET campaign collaborative list, send an e-mail to vsnet-adm@kusastro.kyoto-u.ac.jp (VSNET administrator) with a line "SUBSCRIBE vsnet-campaign." (VSNET campaign members are strongly recommended to subscribe to vsnet-alert at the same time). Regards, Taichi Kato On behalf of the VSNET administrator team ---------------------------------------------------------------------------- The following was issued on July 30, 2001, as VSNET campaign circulation 1048 [Note a large part of detailed information is posted to vsnet-campaign sub-lists]. VSNET Weekly Campaign Summary *** Last week news *** (new targets) CI UMa (RA = 10h18m13s.01, Dec = +71d55'42".8) The SU UMa-type dwarf nova CI UMa experienced an outburst at 13.8mag as reported on July 26 by M. Reszelski. The last superoutburst occurred in 2000 September (vsnet-campaign 1041). The outburst was rapidly faded (vsnet-campaign-dn 1039). SN 2001dh (RA = 20h17m24s.16, Dec = -38d40'37".4) IAUC 7670 informed that R. Chassagne discovered a new SN 2001dh on July 22. The brightness of the new object was 15.5 at the discovery. The position is about 39" east and 11" south of the nucleus of the edge-on and warped dim galaxy MCG-6-44-26. It was not detected on June 26.1. The recession velocity of MCG-6-44-26 is around 2600 km/s, which suggests that the typical SN Ia on this galaxy can reach mag 14 (vsnet-campaign-sn 212). V503 Cyg (RA = 20h27m15s.61, Dec = +43d41'45".5) An outburst (13.3mag) was reported by H. McGee on July 23. The outburst seems to be too early for a superoutburst (vsnet-campaign-dn 999). XZ Eri (RA = 04h11m25s.76, Dec = -15d23'24".3) According to astro-ph/0107505, P. Woudt and B. Warner found that XZ Eri is an eclipsing dwarf nova with a period of 88.1m. Outbursts of XZ Eri have been observed roughly once a year (vsnet-campaign 1045). HO Del (RA = 20h36m55s.49, Dec = +14d03'09".4) P. A. Dubovsky reported a possible outburst of HO Del (14.5:mag on July 28). Confirmations are encouraged (vsnet-campaign-dn 1048). IP Peg (RA = 23h23m08s.7, Dec = +18d24'59".1) It is now in outburst. The current magnitude is about 13.3mag (vsnet-campaign-dn 1050). (continuous targets) WZ Sge (RA = 20h07m36s.53, Dec = +17d42'15".3) The historical outburst of WZ Sge is still ongoing (vsnet-campaign-dn 996, vsnet-campaign 1024, vsnet-campaign-dn 1000, 1001, 1002, 1008, 1013, 1017, 1038, 1049). The previous outbursts were observed in 1913, 1946, and 1978 (vsnet-campaign 1015). On July 23, T. Ohshima discovered the outburst (vsnet-campaign 1016). Confirmations of the outburst were reported to vsnet-campaign lists by G. Masi (vsnet-campaign 1014) and P. Schmeer (vsnet-campaign 1015, vsnet-campaign 1020). K. Ayani promptly performed spectroscopy and revealed that Balmer lines were in generally absorption (vsnet-campaign 1022). The light curve obtained by the Kyoto team shows rapid brightening with a rate of 5 mag/d and birth of short-term modulations (vsnet-campaign 1025). The light curve provided by G. Masi after the Kyoto run shows clear humps with a large amplitude, and furthermore, it had a longer periodicity compared with its orbital period (vsnet-campaign 1030). On July 24, A. Good, J. Pietz, G. Masi and the Kyoto team detected early superhumps with a large amplitude of about 0.5mag (vsnet-alert 6115, vsnet-campaign 1026, vsnet-campaign 1034). The period of early superhumps was reported to be 0.05662 day (vsnet-campaign-dn 1004, vsnet-campaign 1030). The decline rate was somewhat fast (0.4mag/d) during in the first half of this day (vsnet-campaign 1026), but then became more gradual (0.23mag/d) (vsnet-campaign 1030). H. Baba reported that optical spectra taken by K. Sadakane using 1.88m Okayama telescope show double peak emission lines of He II and C III/N III which are not seen in spectra on July 23. Balmer lines had both absorption and emission components which varied with time (vsnet-campaign 1028, 1031, 1035). G. Masi noticed the presence of another modulations (secondary maximum) with an amplitude of 0.15mag (vsnet-campaign-dn 1005). On July 25, the spectra taken by K. Ayani also show He II and C III/N III emissions (vsnet-campaign 1033). The Kyoto team reported that the early superhumps were similar to those on July 24 during the early July 25 (vsnet-campaign-dn 1007), however their profiles changed from "V"-shaped to "U"-shaped one (vsnet-campaign-dn 1009). The hump period was calculated to be 0.05664 d (vsnet-campaign 1037). G. Masi reported that amplitudes of humps became smaller and the profiles were changing (vsnet-campaign-dn 1006, 1010, 1012, vsnet-campaign 1032). M. Richmond reported that they performed time-series photometry on July 25 (vsnet-campaign 1038). On July 26, G. Masi and F. Mallia reported that the profile of humps, particularly secondary maximum, varies with time as observed on July 25 (vsnet-campaign 1042). The decrease of hump amplitudes was confirmed in the light curve presented by the Nyrola team. Their data also show possible feature like QPOs (vsnet-campaign 1043). K. Ayani and M. Ioroi (Bisei Observatory) performed spectroscopy covering two entire orbital cycles (vsnet-campaign 1044). M. Richmond performed 7.5 hours run (vsnet-campaign-dn 1021). On July 27, G. Masi reported that the hump profile became complex. He also reported that the short-term fluctuations became dominant (vsnet-campaign-dn 1019, 1024, 1029). T. Kato also reported similar characteristics from the Kyoto observation (vsnet-campaign-dn 1025). R. Novak and L. Cook informed us that they performed time-series photometry (vsnet-campaign-dn 1020, 1031). On July 28, contrary to the last tendency, G. Masi reported that the profile became more regular and the period seems to be longer, which may imply that normal superhumps appeared (vsnet-campaign-dn 1030, 1032). T. Kato confirmed this longer periodicity, but noticed that such phenomenon was observed in the first night of the current outburst (vsnet-campaign-dn 1035). R. Novak also performed time-series photometry (vsnet-campaign-dn 1036). On July 29, T. Kato performed period analysis using the data set taken by G. Masi, R. Novak, J. Pietz, L. Cook, and Kyoto team during July 28.8 to 29.7. It yielded a period of 0.05669 d, which is in agreement not with superhump period, but with the orbital period (vsnet-campaign-dn 1043). Time-series observations by S. Kiyota are available in [vsnet-campaign-data 67]. The hump profile is now more irregular (vsnet-campaign-dn 1052). G. Masi reported a revised coordinate as shown above (vsnet-campaign 1014). The outburst cycle of the current outburst is quite shorter than that previously reported (vsnet-campaign 1023). M. Watanabe reported a new prediscovery observation by T. Inoue (mag. 10.5p on July 23.525) (vsnet-campaign 1036). T. Kato wondered about the reality of the 7.0 mag maximum documented in the literature since the maxima of the past two outbursts of WZ Sge have been around 8.0 or even fainter (vsnet-campaign-dn 1026). E. Kuulkers reported that it may be because of the photographic observations taken during the 1913 outburst which was brighter than the 1946/1978 outbursts (vsnet-campaign-dn 1041). Nova Cyg 2001 (RA = 20h07m17s.94, Dec = +36d04'37".2) (= V2274 Cyg) Some multi-color observations taken by L. Brat and P. Hajek are available in [vsnet-campaign-nova 415, 416, 417, 419]. They reported that this nova is very rapidly fading since around July 28 (vsnet-campaign-nova 419, 420). V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1) Observations show oscillations of the magnitude of this object (vsnet-campaign-dn 997). V818 Sco (RA = 16h19m55s.07, Dec = -15d38'24".5) This X-ray binary again shows strong activity (vsnet-campaign-xray 77). V1504 Cyg (RA = 19h28m55.87s, Dec = +43d05'39".9) The superoutburst is still ongoing (vsnet-campaign-dn 998, 1040). V1141 Aql (RA = 19h37m10s.01, Dec = +02d35'59".2) The superoutburst still continues (vsnet-campaign-dn 1014). AM Her (RA = 18h16m13s.4, Dec = +49d52'03".1) The object is now very bright at about 12.9mag (vsnet-campaign 1047). BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6") The object is now fading. The current magnitude is about 14.7mag (vsnet-campaign-blazar 218). V1548 Aql (RA = 19h07m28s.42, Dec = +11d44'45".8) This nova brightened to 13.0mag on July 25 as reported b y H. McGee (vsnet-campaign-nova 418). *** Future schedule *** WZ Sge campaign D. Steeghs wrote: "Several of us are organizing a campaign on the current outburst of WZ Sge, using a large variety of ground based facilities as well as space observatories. A web-page has been setup listing the scheduled observations so far which we intend to keep up to date at: http://vsnet.astro.soton.ac.uk/~ds/wzsge.html " For more information, see [vsnet-campaign 1039] EM Cyg campaign with HST on 23 - 29 July (most likely 12:22-13:10 UT on July 29) conducted by T. Marsh For more detailed information, see [vsnet-campaign 999] V446 Her campaign until September conducted by Matthias Schreiber, Boris Gaensicke, and Daisaku Nogami For more detailed information, see [vsnet-campaign-dn 918], [vsnet-campaign-nova 349], or [vsnet-campaign 983] CV conference at Goettingen, 5-10 August 2001 [vsnet-announce 15, 20] Two Years of Science with Chandra * * This meeting will also be the 12th Annual Maryland Astrophysics Conference September 5-7, 2001 For more information, see [vsnet-campaign-xray 66] *** General information *** WZ Sge For observations, Please make sure that WZ Sge (and comparison) do not saturate on your images (vsnet-campaign 1017). Eclipse ephemeris, see [vsnet-campaign 1018] CCD image during the outburst presented by G. Masi: http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/WZ_Sge/masi0723.jpg [vsnet-campaign 1019] Spectrum presented by K. Ayani: http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/WZ_Sge/bisei0723.jpg Comparison of light curves of all previous outbursts: http://saturn.sron.nl/~erikk/wzsge/wzsge_2001.gif http://saturn.sron.nl/~erikk/wzsge/wzsge_1913_1946_1978.gif [vsnet-campaign-dn 1003] VSNET web pare: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/wzsge01.html [vsnet-campaign 1027, 1029, vsnet-campaign-dn 1011, 1040, 1015, 1023, 1027, 1028, 1033, 1034, 1037, 1044, 1045, 1046] WZ Sge page by G. Masi: http://vsnet.eurolink.it/comets/wzsge.htm [vsnet-campaign-dn 1005] Photometry by M. Richmond: http://spiff.rit.edu/richmond/ritobs/jul25_2001/jul25_2001.html http://spiff.rit.edu/richmond/ritobs/jul25_2001/wzsge_jul25ut.dat [vsnet-campaign 1038] http://spiff.rit.edu/richmond/ritobs/jul27_2001/jul27_2001.html [vsnet-campaign-dn 1021] Photometry by L. Cook http://vsnet.geocities.com/lcoo/wzsge.htm [vsnet-campaign-dn 1031, 1042] WZ Sge light curves presented by R. Novak http://ada.astronomy.cz [vsnet-campaign-dn 1054] V893 Sco eclipse ephemeris, see [vsnet-campaign-dn 1016] IP Peg eclipse ephemeris, see [vsnet-campaign-dn 1047] (This summary can be cited.) Regards, Makoto Uemura