
Electronic Telegram No. 2656
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge,
MA 02138,
U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html
SUPERNOVAE
2011X, 2011Y, AND 2011Z
[Note: this text replaces that on CBET 2652] G. Pignata
and M. Cifuentes, Universidad Andres Bello; J. Maza,
M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster,
S. Silva, F. Carrasco, P. Sanchez, and C. Hervias, Universidad
de Chile; P. Gonzalez, Pontificia Universidad Catolica
de Chile (for SN 2011X only); B. Conuel, Wesleyan University;
G. Folatelli, IPMU, University of Tokyo; and D. Reichart,
K. Ivarsen, J. Haislip, A. Crain, D. Foster, M. Nysewander,
and A. LaCluyze, University of North Carolina at Chapel
Hill, on behalf of the CHASE project, report the discovery
of three supernovae on unfiltered CCD images obtained
with the 0.41-m 'PROMPT' telescopes located at Cerro
Tololo; SN 2011X was found with the 'PROMPT 5' telescope,
and the other two supernovae were found with the 'PROMPT
3' telescope. The discovery observations are tabulated
below (positional uncertainty in the range +/- 0".2
to 0".3 in each coordinate):
SN |
2011
UT |
R.A.
(2000.0) |
Decl. |
Mag. |
Offset |
2011X
|
Jan.
15.25 |
13
50 21.36 |
-52
39 58.5 |
17.3 |
63"
W, 20" S |
2011Y |
Jan.
27.07 |
8
12 58.25 |
-27
34 15.7 |
17.3 |
|
2011Z |
Jan.
29.25 |
13
30 43.04 |
-20
57 14.0 |
16.1 |
1".0
W, 8".3 S |
Additional approximate unfiltered CHASE magnitudes
for 2011X (designated PSN J13502136-5239585 on the
Central Bureau's TOCP webpage), which is thought to
be connected with the galaxy ESO 221-7 = PGC 49121:
2009 June 4.06-2010 Aug. 14.07 UT, [21.0 (thirty 40-s
archival images taken over this time span); 2011 Jan.
16.29, 17.2.
Additional approximate unfiltered CHASE magnitudes
for 2011Y (designated PSN J08125825-2734157 on the
Central Bureau's TOCP webpage), for which the faintness
of the presumed host galaxy does not allow the measurement
of reliable offsets between the supernova's position
and the center of the galaxy: 2010 Dec. 31.23, [18.0;
2011 Jan. 8.18, [18.0; 28.05, 17.3.
Additional approximate unfiltered CHASE magnitudes
for 2011Z (designated PSN J13304304-2057140 on the
Central Bureau's TOCP webpage), which is thought to
be connected with the galaxy ESO 576-77 = PGC 47494:
2010 Feb. 11.29, [18.5; June 27.02, [17.0; 2011 Feb.
2.28, (visible, but no mag provided).
M. Stritzinger,
Oskar Klein Centre, Stockholm University; N. Morrell,
Las Campanas Observatory; J. Anderson, F. Foerster,
and M. Hamuy, Universidad de Chile; G. Pignata, Universidad
Andres Bello; and G. Folatelli, University of Tokyo;
on behalf of the Millennium Center for Supernova Science,
report that they have obtained spectra (range 432.5-965.9
nm) of these three supernovae on Mar. 5.1 UT with
the Magellan I Baade 6.5-m telescope (+ IMACS) at
Las Campanas Observatory. The spectrum of SN 2011X
indicates that it is an evolved type-IIP supernova;
best matches with the "Supernova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) suggest
that 2011X is at least 3-4 months old. SN 2011Y is
a normal type-Ia supernova around maximum light; adopting
for the host galaxy a recession velocity of 20385
km/s (as derived by the SNID code, based on the spectral
features of the supernova), an expansion velocity
of 11000 km/s is computed from the absorption minima
of the Si II 635.5-nm line.
SN 2011Z is a type-Ia supernova before maximum light.
Cross-correlation with a library of supernova spectra
using SNID provides a close match to the sub-luminous
supernova 1986G (Phillips et al. 1987, PASP 99, 592).
Adopting a SNID-derived host recession velocity of
6595 km/s, expansion velocities of 10500 km/s and
11000 km/s are derived from the absorption minima
of the Si II 597.1- and 635.5-nm lines, respectively.
NOTE: These 'Central Bureau Electronic
Telegrams' are sometimes superseded by text appearing
later in the printed IAU Circulars.
|
2011
Febrary 15 |
(C)
Copyright 2010 CBAT
(CBET 2656) |
Daniel
W. E. Green |
Volver
|
|