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[vsnet-campaign-news 8] News from VSNET No. 8
*** News from VSNET ***
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.
Regards,
Taichi Kato
On behalf of the VSNET administrator team
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The following was issued on Jun. 26, 2000, as VSNET campaign circulation 255.
Eclipses in CI Aql = the recurrent nova Aql 1917,2000 have become more
prominent. The object is now apparently in its "plateau" stage, when the
fading of the nova shows a standstill. A similar phenomenon was also observed
in the recurrent nova U Sco, during which eclipses were clearly caught.
For more general information of eclipsing recurrent novae, see
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Novae/usco.html
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Novae/ciaql.html
Several blazars (BL Lac objects and optically violently variable quasars)
are on the present and future target lists. Extensive collaborations
with satellites are being planned, and CCD photometrists are welcomed to
join. The observing techinique is similar to that for cataclysmic variables.
A good (and very successful) example can be seen at
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/BLLAC/bllac.html
which shows the large outburst of BL Lac in the summer of 1997.
Short-term violent variations down to five minutes were observed, whose
time-scale is incredibly short for a galactic nucleus, and this phenomenon
led to a special session in the IAU General Assembly held in that summer.
Such violent variability is believed to originate in the beamed relativistic
jet, as is also proposed for explaining enigmatic gamma-ray bursts (GRBs).
Our first paper on the X-ray transient (halo black hole candidate)
XTE J1118+480 is accepted for publication. Please refer to the relevant
messages for more details. The object is still bright at magnitude 13,
deserving continuous attention until it fades down.
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).
VSNET has initiated a number of special mailing lists, some of which are
sub-lists of vsnet-cmapaign.
vsnet-grb (GRBs)
vsnet-rr (RR Lyr stars and short-period pulsating variables)
vsnet-preprint (paper exchange and on-line publication on variable stars)
vsnet-campaign-sn (supernovae campaign)
vsnet-campaign-nova (novae campaign)
vsnet-campaign-blazar (blazar campaign)
If one wish to subscribe to any of new lists, send a message to
vsnet-adm@kusastro.kyoto-u.ac.jp with a body line (for example)
SUBSCRIBE vsnet-grb your e-mail address
SUBSCRIBE vsnet-campaign-sn your e-mail address
etc.
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VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
LD 317 (RA = 23h44m57.4s, Dec = +43d31m21.9s)
As introduced by Kinnunen in vsnet-chat 3145, LD 317 is a very
good CV candidate. T. Kato recommended this star as the long-term
monitoring program (vsnet-campaign 244). Time-resolved photometry
to look for flickering activity is also welcomed.
W Com (RA = 12h21m31.5s, Dec = +28d13m57.6s)
Mike Simonsen reports the brightening of the blazar W Com
on 23 June at 13.8 mag (vsnet-campaign-blazar 3). S. O'Connor
confirmed the outburst on 24 June at 14.20 mag (vsnet-campaign-blazer 4).
Now it is still in bright state.
RX J1450.5+6403 (RA = 14h50m38.4s, Dec = +64d03m29s)
E. Pavlenko reported this SU UMa star was brightened up to R=14.8
on 25/26 June, and the mean magnitude of 24/25 June was R=16.6
(vsnet-campaign 252). This SU UMa star was discovered by T. Vanmunster
on 2000 May, and at peak, 13.4 mag was recorded on 15 May.
Time-series photometry and other observations are encouraged
to clarify the nature of the current outburst.
Supernova 2000cr (RA = 13h58m38.4s, Dec = +37d26m12.9s)
H. Yamaoka forwarded the contents of IAU Circular 7443.
The SN (currently about 17 mag) is located at about 4" east and 45"
north ot the nucleus of the interacting spiral galaxy NGC 5395 with
NGC 5394. The object is superimposed on the bright H II region.
The spectroscopy by CfA group has revealed that it is of type II in
the early epoch. It is consistent that it appeared in the probable
star forming region (vsnet-campaign-sn 2).
(continuous targets)
V803 Cen (RA = 13h23m44.5s, Dec = -41d44m30.1s)
This helium dwarf nova had shown repetitive strong oscillation
(vsnet-campaign 236). W. S. G. Walker reported the brightening to
13.2 mag during 18 - 19 June with his CCD photometry (vsnet-campaign 235).
The object declined to 14.2 or 14.1 mag during 20 - 21, and then,
showed brightening again on 22 June (13.3 mag, by B. Monard)
(vsnet-campaign 245). The present state resembles that observed
in early April, 2000 (vsnet-campaign 251).
The frequent monitorings and the time-series photometry are
encouraged.
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
The fading of CI Aql has become slower. Short-term light
variations have become less prominent. This may resemble a "plateau"
stage observed in the later stage of recurrent nova outbursts
(vsnet-campaign 237). No apparent fading was observed from 12 June
(vsnet-campaign-nova 2). The June 19 and 20 data observed by S. Kiyota
show the evidence of secondary and primary eclipses, though irregular
variations are also superimposed (vsnet-campaign-nova 4).
Observations of eclipses, full-phase light curve and spectroscopy are
strongly needed.
XTE J1118+480 (RA = 11h18m10.9s, Dec = +48d02m12.9s)
The source keeps the very slowly declining (vsnet-campaign 239).
In the averaged light curve during JD2451710 - 2451720, we can see
some possible feature not ever seen, that is, the smaller amplitude
of the hump and the double peak-like feature around the top of humps,
however we cannot discard the possibility that the features are only
the effect of noise (vsnet-campaign 253).
The hump is still prominent and its profile continues to change.
More observations yields better light curve and detailed analysis.
V893 Sco (RA = 16h14m45.26s, Dec = -28d39m30.3s)
The fading (14.0mag) from the outburst which began on 19 June was
revealed by B. Monard's observation on 21 June (vsnet-campaign 242).
The outburst was again a normal one.
*** Future schedule ***
BL Lac campaign (July 17 - August 11)
Massimo Villata, Gino Tosti, and Enrico Massaro organize an
optical campaign on BL Lac contemporaneous with the high-energy
campaign involving X-ray and TeV observatories such as BeppoSAX,
RXTE, STACEE, CAT, HEGRA. Their goal is high-density and
high-precision coverage, possibly in two optical bands (B and R).
Observers interested in participating to this optical campaign are
invited to contact with M. Villata (villata@to.astro.it).
[vsnet-campaign 204]
*** General information ***
LD 317
more information, see
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg03145.html
vsnet-campaign 244
XTE J1118+480
The accepted paper written by VSNET collaboration team is available at:
http://arXiv.org/abs/astro-ph/0004245
vsnet-campaign 247
The new light curve is available at:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Xray/xtej1118-camp.html
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/Xray/XTEJ1118/jd30-120lc.gif
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/Xray/XTEJ1118/jd110-120ph.gif
Supernova 2000cr
more information, see IAUC 7443
New vsnet-campaign sub-mailing lists were set up.
vsnet-campaign-blazar
vsnet-campaign-data
vsnet-campaign-nova
vsnet-campaign-sn
(This summary is reproduction free.)
Regards,
Makoto Uemura
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page