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J/A+A/526/A28    SDSS-II supernovae NTT and NOT spectroscopy    (Oestman+, 2011)

NTT and NOT spectroscopy of SDSS-II supernovae. Oestman L., Nordin J., Goobar A., Amanullah R., Smith M., Sollerman J., Stanishev V., Stritzinger M.D., Bassett B.A., Davis T.M., Edmondson E., Frieman J.A., Garnavich P.M., Lampeitl H., Leloudas G., Marriner J., Nichol R.C., Romer K., Sako M., Schneider D.P., Zheng C. <Astron. Astrophys., 526, A28 (2011)> =2011A&A...526A..28O
ADC_Keywords: Supernovae ; Surveys ; Spectroscopy Keywords: methods: observational - techniques: spectroscopic - supernovae: general - surveys - cosmology: observations Abstract: The Sloan Digital Sky Survey II (SDSS-II) Supernova Survey, conducted between 2005 and 2007, was designed to detect a large number of type Ia supernovae around z∼0.2, the redshift "gap" between low-z and high-z supernova searches. The survey has provided multi-band (ugriz) photometric lightcurves for variable targets, and supernova candidates were scheduled for spectroscopic observations, primarily to provide supernova classification and accurate redshifts. We present supernova spectra obtained in 2006 and 2007 using the New Technology Telescope (NTT) and the Nordic Optical Telescope (NOT). We provide an atlas of supernova spectra in the range z=0.03-0.32 that complements the well-sampled lightcurves from SDSS-II in the forthcoming three-year SDSS supernova cosmology analysis. The sample can, for example, be used for spectral studies of type Ia supernovae, which are critical for understanding potential systematic effects when supernovae are used to determine cosmological distances. The spectra were reduced in a uniform manner, and special care was taken in estimating the uncertainties for the different processing steps. Host-galaxy light was subtracted when possible and the supernova type fitted using the SuperNova IDentification code (SNID). We also present comparisons between spectral and photometric dating using SALT lightcurve fits to the photometry from SDSS-II, as well as the global distribution of our sample in terms of the lightcurve parameters: stretch and colour. Description: The NTT, located at the La Silla Observatory in Chile, was used for spectroscopic observations of SDSS-II SN candidates from September to December in 2006 and 2007. Thirty-four nights were awarded for the project, out of which 32 had sufficiently good conditions to obtain SN spectra. Through the course of these nights, 244 spectra of SN candidates were obtained. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 39 290 Information about the observations tablea2.dat 107 290 Spectroscopic typing and redshift determination tablea3.dat 19 290 *Spectral quality
Note on tablea3.dat: Both these quantities are very rough estimates and are in most cases likely overestimated.
See also: Byte-by-byte Description of file: tablea1.dat Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID [12778/22284] Source ID number, <SDSS-II SNNNNNN> in Simbad 7- 10 I4 --- SPID Spectrum SPID (1) 12- 17 A6 --- SN IAU name (YYYYaa) 19- 21 A3 --- Tel [NOT NTT] Telescope used 23- 25 F3.1 arcsec Slit Slit width 27- 30 I4 s Texp Exposure time 32- 35 F4.2 --- Air Airmass 37- 39 F3.1 arcsec See Seeing (2)
Note (1): Most of the spectra in the table that lack IAU names are photometric SNe without reliable spectroscopic confirmation and unclassified objects. Note (2): The FWHM seeing at 5000Å for the airmass at which the observations were conducted.
Byte-by-byte Description of file: tablea2.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID [12778/22284] Source ID number 7- 10 I4 --- SPID Spectrum SPID number 12- 24 A13 --- Type1 SDSS SN type (3) 26- 39 A14 --- Type2 NTT/NOT SN type (4) 41- 46 F6.2 d LC ? Number of days in rest frame from B-band maximum obtained from the lightcurve (5) 48- 51 F4.2 d e_LC ? Error on LC 52 A1 --- n_LC [p] Note on LC (6) 54- 58 F5.1 d SNID ? Number of days in rest frame from B-band maximum obtained from SNID (7) 60- 64 F5.1 d e_SNID ? Error on SNID 67- 73 F7.5 --- ze ? SDSS redshift (8) 75- 81 F7.5 --- e_ze ? Error on ze 84- 90 F7.5 --- z ? SNID redshift 92- 98 F7.5 --- e_z ? Error on z 100-107 A8 --- Notes Notes (9)
Note (3): The overall SDSS type which is based on the results from the NTT/NOT analysis in combination with spectra from other telescopes. Note (4): The typing of the individual spectra in this analysis is based on the result from SNID in combination with a visual inspection. If a subtype could be determined, this is given in the table, otherwise only the type. Thus, when the type is given as solely Ia, this means that SNID could not determine if it is a normal SN Ia or a non-normal (peculiar, SN 1991T or SN 1991bg). In the cases where all template spectra which could be matched with the input spectrum with SNID belong to the same SN, the name of the SN is written within parenthesis. When the type is NotSN or Gal, this usually means that the transient was too faint, or the observing conditions were not good enough, so that the contribution from the host galaxy dominates the spectrum. Note (5): An age is given when the object has been classified as a SN Ia, as well as there were enough photometry to build a lightcurve. Note (6): The sign "p" is added after the lightcurve age when the lightcurve lacked photometry either before or after maximum brightness. Note (7): If no error is given, there was only one template fitting the requirements in SNID. Note (8): The object redshifts from Zheng et al. (in preparation), which have their origin in SDSS DR7 redshifts in combination with measurements of both NTT/NOT spectra and other spectra. Note (9): Additional information as follows: s = when the SNID type was determined from the host-galaxy subtracted spectrum f = if there were few template spectra matching the input spectrum, at which fewer than 5 spectra were used to determine the type, the redshift and/or the age v = when the type obtained from SNID was changed after the visual inspection zg = when the redshift is not obtained from SDSS DR7, and determined from galaxy lines zs = when the redshift is not obtained from SDSS DR7, and determined from SN features zt = if the redshift was determined through template fitting
Byte-by-byte Description of file: tablea3.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID [12778/22284] Source ID number 7- 10 I4 --- SPID Spectrum ID number 12- 14 F3.1 --- Host [0/1]?=- Host contamination (10) 15 A1 --- n_Host [e] e when estimation based on an extrapolation of the photometry 17- 19 F3.1 --- Sloss [0/1] Estimated maximum differential slit loss due to atmospheric refraction affecting the SN light in the wavelength region 4000-8000Å (observed frame)
Note (10): The estimated host-galaxy contamination in the observed spectra, i.e. before host-galaxy subtraction has been attempted, for wavelengths corresponding to the g filter in observed frame.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 16-May-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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