SN2002by   in  ESO ESO139-34    ( 17h 50mn18.58ss  -5933'51.6" )

offset  24.9" W  13.4" S    magnitude  14.5

Telescope  LX200  12"  f/d 2.7  ST7E   UAI173  Ste Clotilde  REUNION   ISLAND

 

discovery image

2002/03/31.02  unflated    binning 2x  60s

reference image

2002/02/25.02  unflated       limiting mag 18  binning 2x  60s

   

confirmation image 2002/04/02.04  mag 14.5   180s

referenced  image  DSS  UK Schmidt 1975/06/14.6    limiting mag 21

   

SUPERNOVA 2002by IN ESO 139-G34 R. Chassagne, Ste. Clotilde, Ile de Reunion, reports his discovery of an apparent supernova (mag 14.5) on an unfiltered CCD frame taken on Mar. 31.02 UT (and confirmed on frames taken on Apr.2.04) with a 0.30-m automated telescope. SN 2002by is located at R.A. = 17h50m18s.58, Decl. = -59o33'51".6 (equinox 2000.0), which is 24".9 west and 13".4 south of the center of ESO 139-G34. The new object does not appear on unfiltered images taken by Chassagne on Feb. 25 (limiting mag about 18) or on a U.K. Schmidt plate taken on 1975 June 14 (limiting mag 21.0).


SUPERNOVA 2002by IN ESO 139-G34 N. Suntzeff, Cerro Tololo Interamerican Observatory (CTIO),reports that spectra (range 380-540 nm) of SN 2002by (cf. IAUC 7865) were obtained by C. Gronwall and H. Ford (Johns Hopkins University) with the CTIO 1.5-m telescope (+ facility spectrograph) on Apr. 3.4 UT. The reduced spectrophotometry shows that this object is a supernova, but the small wavelength coverage and the weakness of the features do not allow a specific classification. The spectrum is possibly consistent with a type-I supernova, but redder spectra will be needed to give an definitive classification.


SUPERNOVA 2002by IN ESO 139-G34 

M. Salvo and B. Schmidt, Research School of Astronomy and Astrophysics, Australian National University (ANU), and Mt. Stromlo Observatory, report that a spectrum (range 380-920 nm, resolution about 0.4 nm) of SN 2002by (cf. IAUC 7865, 7866), taken with the ANU 2.3-m telescope (+ double-beam spectrograph) at Siding Spring Observatory on May 18.53 UT, shows that this object is a somewhat unusual type-I supernova a few weeks past maximum light. E. Cappellaro, Osservatorio Astronomico di Capodimonte, comments that this spectrum closely resembles that of the type-Ia SN 1997bp about 5 weeks past maximum light. SN 1997bp is a peculiar type-Ia supernova, in that it was polarized near optical maximum (see Wang et al. 1998, Bull. AAS 30, 1325), an uncommon characteristic in type-Ia supernovae that indicates an asphericity in the ejecta. Radio observations of SN 2002by obtained by P. Price, E. Berger, J. Chapman, and J. Harnett at the Australia Telescope Compact Array on May 19 show no source detected at the position of the supernova, down to a 3-sigma limit of 0.2 mJy. Salvo et al. conclude that SN 2002by is a spectroscopically peculiar type-Ia event, approximately 2 months past maximum light.