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Alert Notice 404: Supernova 2009ig has brightened

September 21, 2009

Event: Type-Ia Supernova 2009ig in NGC 1015 has brightened

Discovered By: I. Kleiser, S. B. Cenko, W. Li, and A. V. Filippenko, University of California (LOSS discovery on unfiltered KAIT images)

Discovery Date: Aug. 20.48 UT

Discovery Magnitude:
- 17.5 on KAIT images on Aug. 20
- brightened as of Sept. 20.646 UT to 14.0, according to two unfiltered CCD images taken by Yoshiteru Matsuura (Nada-ku, Kobe, Japan) with a 0.23-m f/10 Schmidt Cassegrain reflector

02:38:11.61 -01:18:45.1 (J2000.0); this position is offset 0.6" East, 22.0" North from the nucleus of NGC 1015

Spectra: H. Navasardyan, E. Cappellaro, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, report that a spectrogram obtained on Aug. 21.08 UT with the Asiago 1.82-m telescope indicates that the object is a type-Ia supernova caught soon after explosion. They note some similarity to early spectra of SN 2002bo (Benetti et al. 2004, MNRAS 348, 261), although Si II 597.2-nm and S II 564.0-nm are not yet present.

Charts: The field may be plotted online using VSP:

using the coordinates or (soon) the identifier VSX J023811.6-011845 or the name SN 2009ig. It is advisable to check the "Use DSS Image" option so that NGC 1015 is included on the chart. No comparison star sequence is available at present, but we will attempt to acquire field calibration.

Observing instructions: Visual and CCD observations are encouraged. In accordance with AAVSO policy on Type-Ia supernovae, CCD observers are requested to follow the procedure below:

  • CCD observations in BVIc bands are requested to 0.05 mag precision. We need an observation every 2-3 days until a month after maximum and then once every 4-6 days until it fades below SNR=20. Then we need monitoring once per month for 1-3 years in the Ic band, if possible, to look for rebrightening.
  • In addition to reducing and submitting their data as usual, we also request that observers FTP their flat/dark/biased processed FITS images to this location:

username: ftp
password: your e-mail address
directory: upload/sn/
Filename: Your observer code and supernova (ex:WEO-sn2009ig.fits)

SN 2009ig has been assigned the VSX identifier VSX J023811.6-011845 and the AUID 000-BJQ-201. Please submit data to the AAVSO Interntional Database as SN 2009ig or SN 2009IG.

a. Discovery announced on Central Bureau for Astronomical Telegrams Electronic Telegram (CBET) No. 1918 (Daniel W. E. Green, editor).
b. Brightening to magnitude 14.0 reported by S. Nakano, Sumoto, Japan, in CBET No. 1946 (Daniel W. E. Green, editor).
c. Nothing was visible at KAIT position on Aug. 16.46 down to magnitude 18.7.

Congratulations to the discoverers both of the supernova itself and of the brightening!

Good observing,
Elizabeth O. Waagen, AAVSO



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