Description of the SPECTRA OF V-TYPE CANDIDATES FROM THE SDSS MOC bundle V1.0 ======================================================== Bundle Generation Date: 2020-02-28 Peer Review: 2009 Asteroid Review, 2009-06-03 Discipline node: Small Bodies Node Content description based on the data set catalog file description for the PDS3 version, EAR-A-I0039/I0576-4-SDSSMOCVSPEC-V1.0 ============================================================================================================================== Note: for PDS3 data sets migrated to PDS4, the following text is taken verbatim from the data set description and confidence level note of the PDS3 data set catalog file. In these cases, some details may not be correct as a description of the PDS4 bundle. The spectra in this database were obtained as part of a targeted survey to constrain the population of V-type asteroids in the Main Belt (Moskovitz et al. 2008) [MOSKOVITZETAL2008]. A total of 29 asteroids were observed between November, 2004 and April, 2008 with the Echellete Spectrograph and Imager (ESI, Sheinis et al. 2002) [SHEINISETAL2002] on Keck II and the Supernova Integral Field Spectrograph (SNIFS, Lantz et al. 2004) [LANTZETAL2004] at the University of Hawaii 2.2m telescope. For details on the reduction of these data see Moskovitz et al. (2008a, 2008b) [MOSKOVITZETAL2008, MOSKOVITZETAL2008B] and Willman et al. (2008) [WILLMANETAL2008]. The ESI spectrograph is equipped with a Lincoln Labs 2K x 4K CCD and was used in low dispersion mode with a prism to cover a wavelength range of approximately 0.39 to 1.0 microns. A 1.0 arcsec wide slit was used through 2005, was increased to 1.25 arcsec for 2006 and finally increased to 6.0 arcsec for all subsequent nights. The resolution of ESI with a 6 arc second slit increases with wavelength from approximately 1150 at 0.39 microns to 2900 at 1.0 microns. The slit was aligned with the parallactic angle at the midpoint of each observation and the telescope was guided at non-sidereal rates. All targets were observed at an airmass of less than 1.5. SNIFS is equipped with a blue (3200-5600 Angstrom) and a red-channel (5200-10000 Angstrom) CCD. The blue channel is an E2V thin CCD. The red channel is an E2V deep depleted detector. The resolution of SNIFS ranges from 1000 at 0.4 microns to 1300 at 0.8 microns. The field-of-view of the integral field unit is 6' x 6' with 0.4' spatial resolution. Two of these asteroids were observed with both ESI and SNIFS: 7558 Yurlov and (10537) 1991 RY16. One of the asteroids observed with SNIFS, (60669) 2000 GE4, is presented with only a partial spectrum (5193-9705 Angstrom). This is due to the blue channel of SNIFS being inoperable on the night when 60669 was observed. These spectra are presented in an ASCII data table with three columns: wavelength in Angstroms, reflectance normalized at 5500 Angstroms, and noise per wavelength bin. All of these spectra have been re-binned to a resolution of 25 Angstroms. The noise value is equal to the standard deviation of the reflectances that were combined in each wavelength bin. During the data reduction process, spectra of solar analogs were divided into the raw asteroid spectra to produce values of relative reflectance. The analog(s) that were used in this calibration varied. For ESI the standard procedure was to combine all analogs from the night into a master analog. This single hybrid analog spectrum was then used to calibrate each asteroid spectrum. The following is a list of the analogs that were used for each of the nights with ESI: 2004-11-10: BS448, BS582, BS660, BS720, BS2643, BS8041, BS9107 2005-08-25: BS582, BS720, BS8041 2006-01-04: BS4030, Hya64, SA98-978, SA102-1081 2006-01-05: BS4030, BS9107, Hya64, SA98-978 2006-08-23: BS8041, SA113-276, SA112-133, BS9107, BS720 2006-10-01: SA110-361, SA113-276, SA93-101 2007-03-10: SA98-978, SA102-1081, SA107-684 2008-03-03: Hya64, SA98-978, BS4030 2008-05-10: SA107-998, SA110-361 For SNIFS the standard procedure was to divide each asteroid spectrum by a single solar analog, however for asteroid 7558 Yurlov, a combination of two analogs were used. The following is a list of the analogs that were used for each of the asteroids observed with SNIFS: 7558 Yurlov: BS9107, Hya64 (10537) 1991 RY16: SA93-101 9254 Shunkai: BS5183 9481 Menchu: BS5183 (60669) 2000 GE4: BS5534 Known issues or problems with the data ====================================== The user is referred to two papers which address the quality, processing of and resulting confidence in these data: Moskovitz et al. (2008a, 2008b) [MOSKOVITZETAL2008, MOSKOVITZETAL2008B] and Willman et al. (2008) [WILLMANETAL2008]. The exposure time for asteroid (28517) 2000 DD7 in Table 3 of Moskovitz et al. (2008a) [MOSKOVITZETAL2008] is incorrectly listed as 900 seconds. The correct net exposure time for this asteroid was 3900 seconds. This has been corrected for the data presented here. PDS3 Source =========== Version 1.0 of this bundle was migrated from version 1.0 of the PDS3 data set EAR-A-I0039/I0576-4-SDSSMOCVSPEC-V1.0.