J/ApJ/690/1358 Spectra of unusual optical transient SCP 06F6 (Barbary+, 2009)
Discovery of an unusual optical transient with the Hubble Space Telescope.
Barbary K., Dawson K.S., Tokita K., Aldering G., Amanullah R.,
Connolly N.V., Doi M., Faccioli L., Fadeyev V., Fruchter A.S.,
Goldhaber G., Goobar A., Gude A., Huang X., Ihara Y., Konishi K.,
Kowalski M., Lidman C., Meyers J., Morokuma T., Nugent P.,
Perlmutter S., Rubin D., Schlegel D., Spadafora A.L., Suzuki N.,
Swift H.K., Takanashi N., Thomas R.C., Yasuda N.
<Astrophys. J., 690, 1358-1362 (2009)>
=2009ApJ...690.1358B 2009ApJ...690.1358B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Supernovae ; Surveys ; Spectroscopy
Keywords: stars: variables: other
Abstract:
We present observations of SCP 06F6, an unusual optical transient
discovered during the Hubble Space Telescope Cluster Supernova Survey.
The transient brightened over a period of ∼100 days, reached a peak
magnitude of ∼21.0 in both i775 and z850, and then declined over a
similar timescale. There is no host galaxy or progenitor star detected
at the location of the transient to a 3σ upper limit of
i775≥26.4 and z850≥26.1, giving a corresponding lower limit on
the flux increase of a factor of ∼120. Multiple spectra show five
broad absorption bands between 4100Å and 6500Å, and a mostly
featureless continuum longward of 6500Å. The shape of the light
curve is inconsistent with microlensing. The transient's spectrum, in
addition to being inconsistent with all known supernova types, does
not match any spectrum in the Sloan Digital Sky Survey database. We
suggest that the transient may be one of a new class.
Description:
The optical transient was discovered on 2006 February 21 (UT) in
images taken in the course of the HST Cluster SN Survey (P.I.: S.
Perlmutter; K. S. Dawson et al. 2010AAS...21546105S) in a field
centered on the galaxy cluster CL 1432.5+3332.8 (redshift z=1.112;
Elston et al. 2006ApJ...639..816E 2006ApJ...639..816E).
Spectroscopy was acquired on three dates (Figure 3): 2006 April 22
(-25 days) using Subaru FOCAS, 2006 May 18 (+1 day) using the Focal
Reducer and Low Dispersion Spectrograph 2 (FORS2) for the Very Large
Telescope (VLT), and 2006 May 28 (+11 days) with the Keck Low
Resolution Imaging Spectrometer (LRIS).
Objects:
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RA (2000) DE Designation(s)
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14 32 27.4 +33 32 25 SCP 06F6 = [DAB2006b] J143227.42+333225.1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
subaru.dat 21 2999 2006-04-22 Subaru FOCAS spectrum
vlt.dat 21 1277 2006-05-18 VLT FORS2 spectrum
keck.dat 21 8202 2006-05-28 Keck LRIS spectrum
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See also:
J/ApJ/607/665 : Type Ia supernovae at z>1 discovered by HST (Riess+, 2004)
J/ApJ/673/981 : Type Ia supernova rates with HST ACS (Kuznetsova+, 2008)
http://supernova.lbl.gov/ : Supernova Cosmology project (SCP) home page
Byte-by-byte Description of file: subaru.dat vlt.dat keck.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 0.1nm Wave Wavelength in Angstroms (1)
11- 21 E11.4 10mW/m2/nm Flux Flux in units of erg/s/cm2/Angstroms (2)
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Note (1): The Subaru spectrum covers wavelengths longward of 5900Å,
while the VLT and Keck spectra cover bluer wavelengths. The VLT
spectrum (observed at airmass>2) is corrected for differential slit
loss by applying a linear correction with a slope of 0.25 per 1000
Angstroms, derived from a comparison to the Keck spectrum, which
covers the entire wavelength range of the VLT spectrum. The Keck
observation was made at the parallactic angle, while Subaru FOCAS is
equipped with an atmospheric dispersion corrector, making the Keck
and Subaru observations more reliable measures of relative flux.
Note (2): Each spectrum is flux-calibrated to within an overall
multiplicative factor. See fig. 3 of the paper.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 21-Feb-2011