Central Bureau for Astronomical Telegrams
IAUC 7282: 1999eh; XTE J1859+226
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 7283
.dvi or
.ps format.
Circular No. 7282
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVA 1999eh IN NGC 2770
G. M. Hurst, Basingstoke, England, reports the discovery by
Mark Armstrong, Rolvenden, of a supernova (mag about 17.5) on an
unfiltered CCD frame taken on Oct. 12.1375 UT with a 0.30-m
telescope in the course of the U.K. Nova/Supernova Patrol. In
response to an alert, T. Boles, Wellingborough, obtained a
confirmatory image on Oct. 14, and Armstrong also secured a further
image on Oct. 14.157 showing the new object at about the same
brightness. Precise positions measured by Armstrong from his Oct.
12 and 14 images yield R.A. = 9h09m32s.67, Decl. = +33o07'16".9
(equinox 2000.0), which is 20" west and 5" south of the center of
NGC 2770. Armstrong's measurement of Boles' image yields position
end figures 32s.55, 16".3. Research by Hurst indicates that SN
1999eh is absent from the Vickers Deep Space CCD Atlas: North
(1993, p. 96; limiting mag about 19) and from both Palomar Sky
Surveys (limiting mag about 20).
S. Jha, P. Garnavich, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum of SN
1999eh, obtained by M. Calkins on Oct. 15.5 UT with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST spectrograph), shows it
to be a type-Ib supernova. The spectrum exhibits a flat continuum
and broad absorption features with He I (rest 587.6, 706.5, and
492.2 nm) being most prominent. There is also evidence of weak [O
I] emission, indicating that the supernova is about 2 months past
maximum light.
XTE J1859+226
M. L. McCollough, Universities Space Research Association and
Marshall Space Flight Center (MSFC); and C. A. Wilson, MSFC, report
for the BATSE team: "XTE J1859+226 (IAUC 7274) was first detected
with CGRO/BATSE on Oct. 9 at a flux of 0.5 Crab (9.1 x 10**-9 erg
cm**-2 s**-1) and rose to 0.6 Crab (1.0 x 10**-8 erg cm**-2 s**-1)
on Oct. 11, before slowly decreasing to 0.3 Crab (6.1 x 10**-9 erg
cm**-2 s**-1) on Oct. 13. XTE J1859+226 has shown evidence of
spectral softening in the energy band 20-100 keV, from a power-law
photon index of -2.3 +/- 0.1 on Oct. 9 to a photon index of -2.8
+/- 0.1 at its peak (Oct. 11). XTE J1859+226 is clearly being
detected up to 200 keV."
(C) Copyright 1999 CBAT
1999 October 15 (7282) Daniel W. E. Green
Read IAUC 7283
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
