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[vsnet-campaign-news 90] News from VSNET 63
*** News from VSNET ***
The prototype of microquasars, GRS 1915+105 experiences an X-ray
outburst detected by RXTE/ASM. V818 Sco (Sco X-1) is now very
active.
For more detail information about these objects,
see below, "VSNET Weekly Campaign Summary" of the last week.
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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
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The following was issued on July 16, 2001, as VSNET campaign circulation 1000!
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
V589 Her (RA = 16h22m07s.19, Dec = +19d22'36".3)
As reported by C. Jones and G. Poyner on July 10, V589 Her
experienced a rare outburst of 14.1-14.3mag. Only two outbursts
in 1999 and 2000 have been reported to VSNET. Both outbursts
reached slightly fainter than mag 15, and apparently faded rather
quickly (vsnet-campaign 992, vsnet-campaign-dn 974, 976, 977).
On July 12, the decline rate seems to be faster (vsnet-campaign-dn 980),
and then, the outburst was terminated (vsnet-campaign-dn 981).
M. Uemura reported that the Kyoto team also confirmed that it was
faint at R~15.8 on July 13, but still brighter than the quiescent
level (vsnet-campaign-dn 282). As reported by T. Vanmunster in
[vsnet-alert 6067], the Kyoto team also confirmed no short-term
variation and rapid fading (vsnet-campaign-dn 985).
SN 2001da (RA = 23h53m32s.78, Dec = +08d07'02".6)
According to IAUC 7658, the KAIT team discovered SN 2001da
on July 9 at mag about 16.5, and confirmed on the next day when
SN was about 0.2 mag brighter. The position is about 9" east
and 3" south of the nucleus of the spiral galaxy NGC 7780.
NGC 7780 is a member of a loose group of galaxies. The recession
velocity of this group is around 5200 km/s, thus the expected
maximum of typical SN Ia is about mag 16.0 or slightly brighter
(vsnet-campaign-sn 211).
1RXS J105010.3-140431 (RA = 10h50m10s.2, Dec = -14d04'30")
According to astro-ph/0107207, Mennickent et al. discovered
that 1RXS J105010.3-140431 is a 17-th mag cataclysmic variable
with a period 88.6 m, which has a spectrum closely resembling
that of WZ Sge. Please monitor this object closely. If any
outburst is detected, the object will be the top-priority target
of the VSNET Collaboration team (vsnet-campaign 993).
V1141 Aql (RA = 19h37m10s.01, Dec = +02d35'59".2)
As reported by M. Reszelski on July 12, the SU UMa-type dwarf
nova V1141 Aql experienced an outburst at 15.3mag. The last
likely superoutburst was reported in 2000 August-September
(vsnet-campaign 994). The Kyoto team found the object was rapidly
faded on July 13 and 14. The outburst seems to be a normal one
(vsnet-campaign-dn 984).
AM Her (RA = 18h16m13s.4, Dec = +49d52'03".1)
AM Her has been brightening since the last week. M. Simonsen
reported 14.2mag on July 13 (vsnet-campaign 995).
HT Cam (RA = 07h57m01s.3, Dec = +63d06'01")
M. Reszelski reported a rare outburst of HT Cam at 13.3mag
on July 13. The object is a system with a short orbital period
(below the period gap). Some authors consider the object as a
candidate of a intermediate polar. The last reported outburst
occurred in 2000 September (Kinnunen) (vsnet-campaign 996).
The outburst was quickly faded as shown by observations on July 14
(vsnet-campaign-dn 986, vsnet-campaign-ip 56). Since all known
outbursts of HT Cam faded quickly, urgent observations are needed.
GRS1915+105 (RA = 19h15m11s.57, Dec = 10d56'44".9)
R. Remillard reported that RXTE/ASM detected an outburst of
the galactic microquasar, GRS1915+105. Its X-ray flux reached
730 mCrab on July 15 07:30 (UT). Previous breakouts from the
low-hard state have been associated with the birth of relativistic
radio jets, so radio and IR measurements are urgently needed as
soon as possible (vsnet-campaign 997).
(continuous targets)
V818 Sco (RA = 16h19m55s.07, Dec = -15d38'24".5)
The activity has become much stronger since the last week
(vsnet-campaign-xray 74,76). E. Kuulkers wrote in
[vsnet-campaign-xray 75] that Sco X-1 is known to be flaring on
timescales of hours and X-rays and optical correlate well
during such flares (vsnet-campaign-xray 75).
V1178 Sco (RA = 17h57m06s.92, Dec = -32d23'05".0)
Observations show oscillations of its brightness. It is
gradually brightening and the current magnitude is about 11.4mag
(vsnet-campaign-nova 391, 393).
VW CrB (RA = 16h00m03s.76, Dec = +33d11'14".4)
M. Uemura reported that combined data sets of the Kyoto team
show about 0.0725 d weak periodicity. The object was faded a little
faster on July 9 (vsnet-campaign-dn 973), and then, finally
entered a rapid decline phase on July 10 (vsnet-campaign-dn 975,
vsnet-campaign-dn 978). The outburst lasts at least for 22 days
(vsnet-campaign-dn 983).
V446 Her (RA = 18h57m21s.51, Dec = +13d14'27".3)
D. Nogami reported that E. Pavlenko detected a new outburst
of V446 Her (vsnet-campaign 998, vsnet-campaign-dn 987).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
M. Villata reported BL Lac was R~12.7 and further brightening
(vsnet-campaign-blazar 211). T. Balonek reported it was R=12.45mag
on July 11 (vsnet-campaign-blazar 213). The brightening continued
until July 14-15 when the object rapidly faded on July 14 and 15
(vsnet-campaign-blazar 212, 214, 215).
IX Dra (RA = 18h12m32s.2, Dec = +67d04'41")
An outburst (15.0mag) of IX Dra was detected by M. Reszelski
on July 10 (vsnet-campaign-dn 979).
V445 Pup (RA = 07h37m56s.88, Dec = -25d56'59".1)
The fading trend still continues. B. Monard reported 11.5mag
on July 11 (vsnet-campaign-nova 392).
delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The object is gradually brightening. The current magnitude
is about 1.8mag (vsnet-campaign-be 137).
*** Future schedule ***
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 ***
BL Lac
WEBT campaign on BL Lac page:
http://vsnet.to.astro.it/Groups/Extragal/webt/bllac_2001.html
[vsnet-campaign-blazar 211]
V818 Sco
RXTE/ASM recent X-ray light curve:
http://heasarc.gsfc.nasa.gov/cgi-bin/xte_weather/xte_lc?source=SCOX1
[vsnet-campaign-xray 75]
(This summary can be cited.)
Regards,
Makoto Uemura
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page