From: clidman (clidman@eso.org)
Date: Tue Mar 25 2003 - 16:54:57 PST
Dear Andy, Mamoru,
The spectrum of SuF02-026 is rather interesting. It has has two unidentified emission lines
and the morphology of the lines are very different. One is resolved into three components and the
other is unresolved. The continuum is flat. However, from the VLT spectra, there is no evidence of
a SN.
Even if the object is not a SN, it may be worth further study. I would think that the probability of
finding an object with two unidentified emission lines from a sample of 42 (this is the number of
candidates we have observed with the VLT) targets is rather low.
Cheers, Chris.
Andy Howell wrote:
> Mamoru,
> That looks fine to me. The only think I would change is, "have not
> spectral confirmation"
> should be "do not have spectral confirmation."
>
> -Andy
>
> Mamoru Doi wrote:
>
> > Dear Andy and colleagues,
> >
> > Sorry for my slow response. I have been busy for a biannual
> > assembly of the astronomical society of Japan (Mar.23-26),
> > since I am in charge of the program.
> >
> > Let me write down responses to Andy's comments/questions first.
> >
> >> -SuF02-026 was not on the circular. Why is that? Spectra were
> >> indeterminate,
> >> but it has a light curve that looks like a SN. The LC says z=1.46 --
> >> where
> >> did that come from? I have not put it back on the list, but Mamoru may
> >> want to.
> >
> > I put this into not a possible AGN category.
> > We observed this object twice. There are two comments on this according to
> > my note.
> > The photometric redshift is estimated to be z=0.80.
> > 11/6 Keck weak SN signal
> > 11/9 VLT AGN? 1.46[OII]
> > Chris, do you think we should put this to a posible SNe?
> >
> >> -Update on SuF-065: Peter says Gerson's fit is only good because it can
> >> choose the date of max. His data has an additional constraining point.
> >> Plus he has ACS data. However, I believe there is something wrong
> >> with the
> >> photometry, because the spectrum looks like a Ia or Ib/c to both of us.
> >> II doesn't fit at any z. Chris says it is possible that the redshift is
> >
> > >from the big nearby galaxy. In the face of all of this uncertainty,
> >
> >> it remains a "SN".
> >
> > The last ACS photometry is crucial. Other results can be interpreted
> > as a Ia with large stretch factor.
> >
> >> -I still haven't heard back on the Keck spectra for 61, 21, 77, so I am
> >> going to pretend we don't have them and move forward.
> >
> > We won't include these unless we can get new information.
> >
> >> -The "light curves" of the candidates in the second category are not
> >> great.
> >> Since there could be host galaxy light, and I don't believe the limits,
> >> You can see them on a plot that Naoki gave me here:
> >> http://panisse.lbl.gov/collab/observing/schedule2002/2002B/lightcurves/fewpo
> >> ints.ps
> >> I have ordered these SNe in what I believe to be the rough order of
> >> believability that they are SNe (almost every one is a gray area). I left
> >> a break where I believe we should cut the list. This would mean
> >> throwing out:
> >> 61, 83, 21, 34, 81, 51, 05, 59
> >> I don't think we could defend these to Dan Green. I don't even know if
> >> we could defend some of the ones higher up on the list.
> >
> > O.K. These are the ones which don't have enough epochs for follow up
> > (< 4). If spectral information is poor, we should remove these 8.
> >
> > I attached the revised version, though this version still includes
> > comments in the table.
> >
> > Regards,
> >
> > -Mamoru
> >
> >
> > Ver.6
> > -------------------------------------------------------------
> >
> > M. Doi, Univ. of Tokyo, on behalf of the Supernova Cosmology
> > Project(cf. IAUC 7971, plus V. Fadeyev, B. Lee, V. Stanishev,
> > and R. Vogel) and the Subaru high-redshift supernova search
> > group (N. Yasuda, N. Kashikawa, K. Motohara, T. Morokuma,
> > K.Sekiguchi, G. Kosugi, H. Furusawa, Y. Komiyama, T. Takata,
> > M. Ouchi, Y. Ohyama, and Subaru Observatory SXDS Project members),
> > reports the discovery of 13 spectroscopically confirmed supernovae
> > and 9 probable supernovae found with Subaru telescope + Suprime-Cam
> > in SDSS i' band. Reference images were taken on Sep. 30 and Oct.1,
> > 2002. The limiting magnitude of reference images was about 26.6mag
> > (S/N=5 for 2arcsec aperture). All supernovae listed below were
> > discovered on search images from Nov. 3.3 (UT). The magnitudes
> > of the SNe after subtraction from reference images are given in
> > the table below (photometric accuracy 0.1-0.2mag).
> >
> > The supernova spectra were obtained with GMOS on Gemini-N on
> > Nov. 6, 8, and 9; with ESI on KeckII on Nov. 6, 7, 9,
> > and 10; with FORS2 on Yepun (VLT-UT4) on Nov. 7 - 11; and
> > with FOCAS on Subaru on Nov. 12. Redshifts were obtained for 13
> > SNe using either the host galaxy spectrum (denoted with *)
> > or with template spectrum fitting of a SN. SuF02-060 has
> > as spectrum consistent with a Type Ia SN, and it is in
> > an elliptical host galaxy.
> >
> > SCPname R.A. (J2000) Decl. i' z type offset Comments
> > SuF02-060 02:17:34.51 -04:53:46.6 24.5 1.063* Ia 0.0" LC ok. 7
> > points. s=0.80. Spectrum plausible, not convincing. Peter says E galaxy
> > -> Ia. Grism spectra exist.
> > SuF02-017 02:16:45.71 -05:09:51.2 25.0 1.03 Ia no host Feature
> > could be Si 4000 if smoothed, but maybe too broad. LC poor, but declining.
> > s=0.65.
> > SuF02-025 02:16:23.93 -04:49:29.4 24.5 0.606* Ia 0.2" W Si.
> > Confirmed Ia. Excellent LC. s=0.83, including rise.
> > SuF02-001 02:17:00.05 -04:58:19.6 23.4 0.57 Ia 0.5" W aka
> > SuF02-027. Certainly Ia. LC 7 points. Several sigma off, but
> > reasonable s=0.83
> > SuF02-065 02:17:34.53 -05:00:15.4 25.2 1.181* SN 1.3" SSE Peter
> > says LC is like Type II. SN minuit says Ia could fit s=1.07. Big errors,
> > residuals.
> > SuF02-071 02:17:08.63 -05:02:06.4 23.8 0.928* SN 1.4" E At that
> > redshift, Ia features do not seem to match. LC good fit, 7pts, falling,
> > s=0.86.
> > SuF02-037 02:17:43.30 -04:30:56.7 24.6 0.926* SN 0.4" E One bump
> > in the spectrum. Ok LC, rises, falls. 4 points, s=0.77
> > SuF02-000 02:17:42.54 -05:06:34.0 24.8 0.92* SN 0.5" NE Almost
> > all galaxy light in spectrum, but LC good -- rises, falls. s=0.73
> > SuF02-002 02:17:12.24 -04:55:08.7 24.4 0.823* SN 0.3" NW Chris
> > (prelim) says: Wiggles don't seem to match a Ia at this redshift. Now
> > says: Possible SN. Good LC fit, s=0.75
> > SuF02-055 02:18:53.20 -04:32:59.2 23.7 0.66: SN 0.6" N One bump
> > in the spectrum. Well fit LC, but only 4 points. s=1.08
> > SuF02-082 02:18:40.73 -05:03:44.3 25.3 0.623* SN 1.1" NNW
> > Essentially a featureless spectrum. LC not great, but rises, falls, 7
> > points, s=1.01 +/- 0.07
> > SuF02-077 02:18:35.15 -04:26:38.9 25.1 0.59: SN 0.6" NW I don't
> > have the spectrum. LC 4 points, rising, falling, s=0.73
> > SuF02-019 02:17:38.08 -05:08:46.8 24.5 0.505* SN 0.3" NW
> > Featureless, mainly galaxy light. LC poor, but declining.
> >
> > We also report 9 probable SNe. Follow-up photometry was
> > carried out with Suprime-Cam, and we confirmed SN signals
> > on at least 3 epochs among 7 (Nov.3,6,10,28,30,Dec.7,8)
> > for all objects below. They are all either hostless or
> > offset from the host galaxy center, and have light curves
> > consistent with SNe, but have not spectral confirmation.
> >
> > Chris: I don't think we can report a redshift for either of these
> > candidatesin the IAU Circular.
> > SuF02-012 02:18:51.59 -04:47:24.8 25.1 ? SN 0.2" N Many
> > minima in z space. Grism spectra exist. LC poor, but declining @ z=1.3
> > Lifan z=1.03
> > SuF02-007 02:18:52.36 -05:01:13.2 24.8 1.18: SN no host Chris
> > says z=1.54, but that would make it too bright. z uncertain -> type
> > uncertain. LC ok, s=0.99 @ z=1.18
> >
> >
> > SCPname R.A. (J2000) Decl. i' host info.
> > SuF02-028 02:16:56.37 -05:00:57.4 24.9 0.347:* SN 1.5" SE LC rises,
> > falls. Could be a SN. Chris: No evidence for a SN. Another weird one.
> > The spectrum falls off after H-alpha.
> > SuF02-004 02:18:09.01 -04:54:17.9 25.1 0.6" SE LC slow
> > decline, strange last point -- could be a SN.
> > SuF02-086 02:17:16.18 -05:06:02.7 26.2 no host LC 3
> > points + limits. Limits imply falling. Indeterminate. Could be a SN.
> > Lifan z=0.89??? any
> > SuF02-076 02:16:26.37 -05:04:32.5 26.1 no host LC 5
> > points, 3 clustered together, two lower. Probably declining.
> > SuF02-056 02:20:00.03 -04:44:20.2 24.3 0.5" SE LC 3
> > points, 1 limit. Falling.
> > SuF02-057 02:20:13.92 -05:07:36.0 25.6 no host LC Flat.
> > SuF02-J01 02:17:45.97 -04:36:46.2 25.2 0.2" W LC Flat.
> >
> > ----------------------------------------------------------------
> > We probably do not include the following 8.
> > ----------------------------------------------------------------
> > SuF02-061 02:17:22.73 -05:16:56.1 24.7 1.08: ? 0.0" I don't
> > have the spectrum. 3 points on LC falling. Could be a SN. Could be AGN
> > -- zero offset.
> > SuF02-083 02:18:06.22 -05:00:38.1 26.0 1.272* ? 0.4" S Flat
> > spectrum. LC not monotonic, 3 points. Limits imply falling.
> > SuF02-021 02:18:10.56 -04:40:20.6 24.6 0.69 ? 2.9" SSW Two LC
> > points. Drops like a rock. I don't have the spectrum, but Saul's notes
> > don't mention a match to a Ia.
> > SuF02-034 02:18:31.21 -05:01:24.4 25.6 0.2" N LC
> > strange. Very slow rise.
> > SuF02-081 02:20:07.55 -05:08:27.2 25.1 1.478* ? 0.0" Spectrum
> > misses big feature for Ia if z is correct. LC terrible at z=1.48, 3
> > points. Could be AGN -- zero offset.
> > SuF02-051 02:17:27.48 -04:40:45.2 25.4 no host LC 3
> > points, 1 limit. Doesn't seem to fit a light curve.
> > SuF02-005 02:18:35.70 -04:31:11.0 24.6 0.863* ? 0.3" NE No LC.
> > No good SN fit. Chris: Weird. Very broad bump at 8500 Angstroms.
> > SuF02-059 02:20:28.06 -04:58:50.3 25.7 0.269* ? 0.2" E Spectrum
> > pretty flat. How can it be at I=25.7 and z=0.269? LC terrible, 3 points,
> > s=0.55, and huge errors. Is z wrong?
> >
> >
> >
> >
> > Mamoru Doi
> > Institute of Astronomy
> > School of Science
> > University of Tokyo
> > voice +81-422-34-5084
> > fax. +81-422-34-5041
> > doi@ioa.s.u-tokyo.ac.jp
> >
> >
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