From: Saul Perlmutter (saul@lbl.gov)
Date: Wed Jun 28 2006 - 18:17:18 PDT
...One extra note to add to the status report: Tony will be trying to
set up a conference call in the next few weeks for discussion of plans,
so watch for email from ALSpadafora@lbl.gov
--Saul
Kyle S Dawson wrote:
>Hi All,
>
>I also feel that I have not done a good job updating everyone with the
>status of the SN search, so let me take this oppurtunity to do so. I'll
>start with a simple laundry list of what we've found, and then summarize
>our initial interpretations and some issues yet unresolved.
>
>There are now 25 clusters in the program. Three of these were added in
>Dec-Apr using free orbits from supernova-less clusters. All three of
>these new clusters come from archival XMM data. Observations are
>complete for 19 clusters. If I remember correctly, the search for SNe
>in 5 of the remaining 6 clusters will end in late July, and the last
>cluster search will end in late Aug. Those dates need to be double checked.
>
>The full cluster list, images of SNe, etc can be found on the TWiki:
>http://hstclustersn.lbl.gov:8081/twiki/bin/view/Supernovae/WebHome
>usrname: TWikiGuest
>passwd: hstclustersn
>
>Current status:
>
>Orbits used: 158 ACS, 21 NICMOS
>Remaining UNscheduled orbits: 7 ACS, 9 NICMOS
>
>***BEGIN LAUNDRY LIST*******
>
>SNe discovered:
>
>Active:
>A-004: Awaiting spectroscopy using Subaru and VLT this week. Host is
>red, possible early type, but SN is too bright to be associated with
>z=1.4 cluster. SN color/mag, consistent with z~1.0-1.2.
>
>Cluster E hosts:
>O-000: z=1.01
>K-000: z=1.41???Waiting better spectroscopy, hopefully tonight
>H-005: z=1.23
>
>Other cluster SNe
>C-001: z=0.98, spectroscopically confirmed Ia, host faint and uncertain
>
>SNe hosted by E type galaxies with no emission lines in background of
>clusters:
>O-006: z=1.31
>C-000: z=1.09
>G-004: z=1.35
>
>low z field SNe (probably not useful for cosmology, maybe for rates)
>N-010: z=0.203, type unknown
>P-001: z=0.92, type unknown
>P-009: z=0.821, Ia
>X-027: z=0.4, type unknown (probably core collapse)
>C-007: host uncertain, type unknown
>G-003: z=0.963, type unknown
>F-008: host uncertain, type unknown
>H-003: z=0.851, Ia
>Z-005: z=0.624, Ia
>
>possible z>1.5 SNe (based on SNe color/mag, host color/mag):
>X-018: one epoch, faint red host
>X-026: two epochs, faint red host
>T-001: one epoch, faint red host
>
>undetermined redshift, discovered this week in reverse subtractions
>(last epoch as ref, first epoch as search). Three have faint hosts that
>appear spiral or irregular, with SNe and host consistent with z>1. We
>hope to find emission lines in spectroscopic observations next spring.
>E-012: faint host
>F-012: faint host, SNe color, lightcurve consistent with z>1 Ia
>K-018: possible cluster E, z=1.41, SN probably not useful for cosmology
>due to poorly sampled lightcurve, very good for rates, spectroscopy of
>host tonight, weather permitting
>L-021: faint host
>
>And finally, one mystery object:
>F-006: galactic, extragalactic, z=0.54, quasar, SNIc, hypernova, pop
>III SN, star??????? Nothing in the lightcurve or spectrum resembles
>anything this group has seen before. The transient is hostless to a
>limiting mag z'>26.5, i'>26.5. At max, the transient has z'=21.2 and
>i'=21.1.
>The lightcurve has a risetime of 100 days with no evolution in color.
>The spectrum has features semi-consistent with a SNIc at z=0.54, but
>lacks key Fe features. We posted an IAUC, or CBET as they are now
>called, and have an article written about it here:
>http://www.newscientistspace.com/article/dn9360-enigmatic-object-baffles-supernova-team.html
>We got more data on this in poor conditions Sunday night at Keck and
>last night at Subaru, there is clear continuum but the spectra are still
>waiting to be reduced.
>
>Unresolved issues: several SNe hosts have not been observed. We got
>murdered with Mauna Kea weather this spring and lost almost all of our
>time. We will try to pick up these redshifts in spring 2007.
>
>*******END LAUNDRY LIST************
>
>Now, as it stands we do have unscheduled orbits. If these orbits are
>still free in Aug, we plan to return to the 5 RCS clusters in the 02-04
>hr range for a second round of searching. We will have deep references
>from the 2005 data for the search, and have Keck DEIMOS time scheduled
>to coincide with these HST visits. We will use 5-10 orbits, depending
>on how many are free. If a SN is found, we will follow the lightcurve
>using the remaining unscheduled orbits. If no SN is found, we will
>preserve those last orbits to use as ToO for a SN search using time
>awarded to PRME et al in cycle 15 for observations of a new set of IRAC
>clusters.
>
>One thing that is very interesting to note is that we have a fairly high
>rate of SNe with z>1 E hosts, but a low rate of late type hosts at this
>redshift. This is very surprising and we do not have an answer for the
>low rate of late type hosts. In terms of cosmology, the z>1 E hosts
>should be extremely useful. The SN are often un-typed, but we plan to
>obtain deep spectroscopy of the hosts in order to place constraints on
>star forming and argue for Ia SNe. We believe these SNe should be
>dust-free as well, but this clearly needs to be explored. These SNe are
>also in the background of massive clusters, and are therefore subject to
>magnification via lensing. In order to use these for cosmology, we will
>need to remove this bias using estimates of cluster masses. We have two
>students working on this, and I'd like them to explore different
>techniques of measuring cluster mass. We may be asking for some help
>with that. For the purposes of cosmology, a 2\sigma measurement of mass
>through weak lensing is probably fine, but it will be very good for the
>two students to learn the other methods as well.
>
>And finally, we plan to perform a rates analysis. This is the best data
>set of high z cluster SNe, and the measurement of rates in the cluster
>environment should be a very good result. To do so, we will need to
>come to some consensus on how to define the cluster environment. The
>cluster sample is clearly inhomogeneous so this may require a bit of
>work. Something to think about for this telecon Marc Postman suggests.
>
>-Kyle
>
>
>----- Original Message -----
>From: Marc Postman <postman@stsci.edu>
>Date: Wednesday, June 28, 2006 9:13 am
>Subject: Cluster science status
>
>
>
>>Saul, Mike, et al.,
>>
>>I am wondering if others feel as out of the loop as I on what's
>>happening with the cluster science part of the program and who is
>>doing what now. If I am not alone in this, it might be time for a
>>telecon to at least get an update on progress and discussion of
>>possible new ideas to pursue with the data.
>>
>>-Marc
>>
>>-----------------------------------------------------------------
>>Marc Postman Email: postman@stsci.edu
>>STScI - CMO Phone: +1-410-338-4340
>>3700 San Martin Drive Fax: +1-410-338-4796
>>Baltimore, MD 21218 U.S.A. http://www.stsci.edu/~postman
>>
>>
>>
>>
>>
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