G. Folatelli, Las Campanas Observatory, La Serena, reports the confirmation of 2007aa (cf. CBET 848), which was detected in a series of dithered Y-, J-, and H-band images obtained by S. Gonzalez on Feb. 19.26-19.28 UT with the 1-m Swope telescope (+ RetroCam) at Las Campanas Observatory. The supernova is located at R.A. = 12h00m27s.67, Decl. = -1o04'51".5 (equinox 2000.0), as measured on the mosaic of Y-band images; the offset is 60".8 east and 68".5 north of the nucleus of NGC 4030. An approximate J-band magnitude of 15.1 was computed for 2007aa by comparison with a nearby star in the 2-MASS catalogue. A spectrogram was obtained by N. Morrell on Feb. 19.24 with the 2.5-m du Pont telescope (+ WFCCD spectrograph) at Las Campanas Observatory, revealing 2007aa to be a type-II supernova. The spectrogram resembles that of SN 1999em obtained 20 days after explosion. Strong Balmer, Ca II, and Fe II lines are present with P-Cyg profiles. Adopting the NED recession velocity of 1465 km/s for the host galaxy (Koribalski et al. 2004, A.J. 128, 16), the following expansion velocities are derived from the absorption minima of different spectral lines: H-beta, 6000 km/s; Fe II 5169, 5300 km/s; Ca II H and K (blend), 6800 km/s.
Central Bureau Electronic Telegrams
- Pub Date:
- February 2007