C. L. Gerardy and G. H. Marion, University of Texas at Austin, report that a low-resolution optical spectrogram (resolution 600; range 430-700 nm) of SN 2004H (cf. IAUC 8272), obtained on Jan. 22.35 UT with the 2.7-m Harlan J. Smith Telescope (+ LCS spectrograph) at McDonald Observatory, shows it to be a type-Ia supernova near maximum light; adopting the 9497 km/s redshift of IC 708 from the NASA/IPAC Extragalactic Database, the expansion velocity of the Si II feature (rest wavelength 635.5 nm) is 10600 km/s. The 580-nm Si II absorption feature appears unusually strong relative to the 615-nm feature, indicating that SN 2004H is likely a subluminous type-Ia object.
International Astronomical Union Circular
- Pub Date:
- January 2004