[IAUC] CBET 2012: 20091112 : SUPERNOVAE 2009ks-2009kz; PSN K0905-1, PSN K0910-1, PSN K0910-2, PSN K0910-3

Jue Nov 12 13:39:34 ART 2009

                                                  Electronic Telegram No. 2012
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2009ks-2009kz; PSN K0905-1, PSN K0910-1, PSN K0910-2, PSN K0910-3
     Further to CBET 1988, on behalf of the PS1 Science Consortium, A. Rest,
G. Narayan, E. Berger, and R. J. Foley, Harvard-Smithsonian Center for
Astrophysics (CfA); M. Huber, Johns Hopkins University (JHU); C. Stubbs, CfA;
J. Tonry and P. A. Price, Institute for Astronomy, University of Hawaii; A.
Riess, JHU; W. M. Wood-Vasey, University of Pittsburgh; R. P. Kirshner, P.
Challis, and A. Soderberg, CfA; S. Smartt, S. Valenti, A. Pastorello, and C.
Trundle, Queen's University, Belfast; and S. Mattila and E. Kankare,
University of Turku, report the discovery of eight confirmed type-Ia
supernovae and four additional possible supernovae via the Pan-STARRS
Telescope 1 (PS1) sky survey.  Images from PS1 Medium-Deep-Fields 1, 2, and
9 were processed by the PS1 "Image Processing Pipeline", and detections were
filtered with a prototype module of the Transient Science Server at Harvard.
Each object was detected on three or more nights in multiple (two to ten),
dithered, 240-s g-, r-, i-, and z-band exposures on any one night, spanning
10-20 days.  Images taken in the first half of Sept. 2009 were used as
templates in the subtractions.  Since the time between template and images is
in some cases less than three weeks, some of the templates might contain some
supernova light.

SN      2009 UT       R.A. (2000.0)  Decl.      Mag.   z       Offset
2009ks  Sep. 22.46   22 15 48.06  + 1 11 05.4   21.1  0.28   0".29 E, 1".11 N
2009kt  Sep. 30.75    2 28 28.37  - 4 04 44.1   21.5  0.27   0".33 W, 0".08 S
2009ku  Oct.  4.83    3 29 53.23  -28 05 12.2   19.9  0.08   0".12 W, 0".09 S
2009kv  Oct. 18.75    2 21 06.60  - 5 01 23.8   21.2  0.32     --
2009kw  Oct. 18.76    3 38 23.39  -28 15 11.8   21.3  0.24     --
2009kx  Oct. 18.78    2 21 13.75  - 3 54 35.8   21.0  0.23   0".47 E, 0".14 N
2009ky  Oct. 18.78    3 34 28.80  -27 54 30.3   20.8  0.26   0".15 E, 0".23 N
2009kz  Oct. 18.79    2 22 40.07  - 4 01 38.3   21.0  0.27   0".09 W, 1".14 S

No clear host galaxies are visible for 2009kv and 2009kw.  Spectra of 2009ks
were taken with the GMOS spectrograph on the 8-m Gemini-North telescope
(Principal Investigator Berger) on Sept. 24, indicating that it is a type-Ia
supernova at z = 0.28, about 1-2 months after maximum light, using the
"SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666,
1024) for cross-correlation against a library of template spectra.  The
spectra of 2009kt, also taken with Gemini-North, reveals a type-Ia supernova
at z = 0.27, about 3-8 days after maximum light (via SNID).  Spectra of
2009ku were taken with the 8-m Gemini-South telescope (+ GMOS) on Oct. 12,
the 2.5-m Nordic Optical Telescope (+ ALFOSC) on Oct. 13, and the 6.5-m
Magellan Clay telescope (+ MagE) on Oct. 17, showing it to be a peculiar
type-Ia supernova similar to SN 2002cx (Li et al. 2003, PASP 115, 453).
Spectra of 2009kw and 2009ky were obtained with the 8-m Gemini-North
telescope (+ GMOS) on Oct. 20 and 21, respectively; spectra of 2009kx,
2009kv, and 2009kz were obtained with the 8-m Gemini-South telescope (+ GMOS)
on Oct. 21.  The spectra of the other five objects tabulated above indicate
that all are of type-Ia supernovae; using SNID, these spectra are found to
have the following phases in days past maximum brightness:  2009kv, 9;
2009kw, 7; 2009kx, 8; 2009ky, 17; 2009kz, 8.

The four transients that have not been confirmed as supernovae are listed
below:

PSN      2009 UT       R.A. (2000.0)  Decl.      Mag.     Offset
K0909-1  Sep. 22.47   22 19 45.87  + 0 50 12.6   21.4   0".17 E, 0".24 N
K0910-1  Oct. 18.78   22 13 13.92  + 0 02 57.5   21.2   0".15 W, 0".32 N
K0910-2  Oct. 18.79    2 22 19.17  - 3 46 45.8   21.6   0".81 E, 0".33 S
K0910-3  Oct. 19.20    3 30 49.84  -28 47 37.6   20.5   0".26 W, 0".01 N

A spectrum of PSN K0909-1 taken with Gemini-North (+ GMOS) on Oct. 13 revealed
only host-galaxy light with a redshift of z = 0.32 from the O III 495.9- and
500.7-nm and the H-alpha emission lines.  Spectroscopy was not attempted for
the other three possible supernovae tabulated above.  During the following
dates, images were taken that did not show the four confirmed supernovae, to
limiting mag about 22.5:  PSN K0909-1, 2009 June 3 to July 17; PSN K0910-1,
2009 June 3 to Sept. 9; PSN K0910-2, 2009 Aug. 29 to Sept. 1; PSN K0910-3,
2009 Aug. 29.  All these discoveries were made with the PS1 System
(http://ps1sc.org/PS1_System_IAU.htm).

NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 November 12                 (CBET 2012)              Daniel W. E. Green