Intrinsic U-B from spectra of HST 11?

From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Fri Apr 11 2003 - 09:01:40 PDT

  • Next message: Robert A. Knop Jr.: "Re: U-band and U-B"

    Calling all SN spectroscopy experts!

    Can the restframe U-band spectra of the five z > 0.6 of the "HST 11"
    SNe be used to even partly discriminate between SNe Ia whose U-B colors
    are intrinsically different? We are using U-B to correct for
    extinction, and then also worrying that the intrinsic U-B color of the
    SN may be different. From the photometry we can't tell the difference,
    but maybe from the spectroscopy we can make a crude distinction using
    spectral features that are not degenerate with dust extinction. Perhaps
    the drop blueward of CaII, or some aspect of the Fe blends could be
    used?

    For Peter in particular, can the spectra rule-out (or rule-in) SNe with
    intrinsic U-B that deviates from the Jha U-B vs. stretch relation?

    Finally, this would be valuable for the Malmquist bias calculation - are
    we in fact picking up any unusually blue SNe at high redshift?

    - Greg

    This archive was generated by hypermail 2.1.4 : Fri Apr 11 2003 - 09:02:09 PDT