The FLOYDS pipeline runs at LCO headquarters after the observing nights at FTN (Hawaii) and FTS (Australia) end. The pipeline produces a tar file that includes the raw observations, an automatically extracted spectrum, and the guider images that can be used for quality control. Intermediate data products are also provided so that the user can, for example, re-extract the spectrum (from the wavelength-calibrated, flux-calibrated, and rectified 2-D images).
It is also possible to install and run the FLOYDS pipeline interactively, but this is not described here.
The pipeline initially performs the following operations on the science, arc, and flat field frames:
While the preliminary extracted 1-D spectrum may be useful to check the data quality, we consider the 2-D wavelength and flux calibrated image (shown below) the best starting point for users. We encourage users to manually perform the final stages:
Fig. 1 Example 2-D rectified, flux calibrated products from the FLOYDS Pipeline.
The processed FLOYDS data can be retrieved from the LCO science archive. Users can search for data by Proposal ID, date, telescope site, object name, etc. All of the data products for each observation are packaged into a single tar file. The naming convention for the tar file is {Proposal ID}_{Block ID}_{Telescope}_{Day-Obs}_{MJD Reduced}.tar.gz. The Day-Obs corresponds to the local observing night on which the spectrum was taken (this may differ by one day from the UTC date of observation). The MJD Reduced is the Modified Julian Date when the reduction was performed. Because the reduction is done after the local end of the night, the MJD Reduced may be different from the Day-Obs. The Block ID is an internal identifier that is used to associate calibration frames (e.g. arcs and flats) that are taken as part of the same request as the science spectrum.
For example:
LCO2016B-011_0001019682_fts_20170331_57844.tar.gz
The raw data files follow the standard LCO naming convention (e.g. for images). The individual processed data products inside the tar file are named according to {File Type}{Object Name}_{Telescope}_{Day-Obs}_{red/blue}_{Slit Width}_{MJD Reduced}_{Spectrum Number}_{Flux calibrated}.fits. For the file type, the prefix “tt” indicates that the frame has been rectified in both the spatial and wavelength directions, while “n” indicates that the frame has been flat field corrected. The spectrum number corresponds to the exposure number in the block: e.g. for a request that had 2x1800s science spectra, the second exposure would have exposure number = 2. The extension “2df” indicates a flux calibrated spectrum. The final extension "ex" indicates a 1-D extraction of the brightest trace in the frame. The sensitivity functions that were used have a prefix of "sens".
An example set of data products is below:
ogg2m001-en06-20170330-0022-e00.fits (Raw science spectrum) ogg2m001-en06-20170330-0023-a00.fits (Raw flat field observation of a tungsten halogen lamp) ogg2m001-en06-20170330-0024-w00.fits (Raw arc lamp observation) sens_ftn_blu_20140418.fits (Sensitivity function used for the second order, "blue side") sens_ftn_red_20140418.fits (Sensitivity function used for the first order, "red side") arc_sn2016jft_ftn_20170331_blue_2.0_57844_1.fits (2-D arc lamp spectrum of the second order, "blue side") arc_sn2016jft_ftn_20170331_red_2.0_57844_1.fits (2-D arc lamp spectrum of the first order, "red side") ttarc_sn2016jft_ftn_20170331_blue_2.0_57844_1.fits (Rectified 2-D arc lamp spectrum of the second order, "blue side") ttarc_sn2016jft_ftn_20170331_red_2.0_57844_1.fits (Rectified 2-D arc lamp spectrum of the first order, "red side") flatsn2016jft_ftn_20170331_blue_2.0_57844_1.fits (2-D tungsten halogen lamp spectrum (flat field) from the second order, "blue side") flatsn2016jft_ftn_20170331_red_2.0_57844_1.fits (2-D tungsten halogen lamp spectrum (flat field) from the first order, "red side") ttflatsn2016jft_ftn_20170331_blue_2.0_57844_1.fits (Rectified 2-D tungsten halogen lamp spectrum (flat field) from the second order, "blue side") ttflatsn2016jft_ftn_20170331_red_2.0_57844_1.fits (Rectified 2-D tungsten halogen lamp spectrum (flat field) from the first order, "red side") sn2016jft_ftn_20170331_blue_2.0_57844_1.fits (2-D science spectrum from the second order, "blue side") sn2016jft_ftn_20170331_red_2.0_57844_1.fits (2-D science spectrum from the first order, "red side") ttsn2016jft_ftn_20170331_blue_2.0_57844_1.fits (Rectified 2-D science spectrum from the second order, "blue side") ttsn2016jft_ftn_20170331_red_2.0_57844_1.fits (Rectified 2-D science spectrum from the first order, "red side") ttsn2016jft_ftn_20170331_blue_2.0_57844_1_2df.fits (Flux Calibrated, Rectified 2-D science spectrum from the second order, "blue side") ttsn2016jft_ftn_20170331_red_2.0_57844_1_2df.fits (Flux Calibrated, Rectified 2-D science spectrum from the first order, "red side") nttsn2016jft_ftn_20170331_red_2.0_57844_1.fits (Flat Normalized, Rectified 2-D science spectrum from the first order, "red side") nttsn2016jft_ftn_20170331_red_2.0_57844_1_2df.fits (Flux Calibrated, Flat Normalized, Rectified 2-D science spectrum from the first order, "red side") nttsn2016jft_ftn_20170331_merge_2.0_57844_1_2df_ex.fits (Merged 1-D extraction of the brightest trace in the flux calibrated, rectified, and flat normalized, in the red, science spectrum)
The final 1-D merged spectrum is the file ntt.....merge...2df_ex.fits. This is a data cube fits file with the following slices:
The units are 10-20 ergs / s / cm2 / Å for all of the slices.
The tar file also includes images from the acquisition/guider camera that show whether the slit was correctly positioned. It includes a pdf file with thumbnails of the acquisition image, the first guiding image, the raw spectrum, the raw arc lamp spectrum, and the raw flat field observation together with some plots with information on the guiding and the flux of the guiding star during the full exposure. An example of the summary pdf file is shown in Fig. 2.
Filenames are of the form {Object Name}_{Proposal ID}.{tar, pdf}, e.g.:
NGC_6210_HAW2016A-001.tar
NGC_6210_HAW2016A-001.pdf
Fig. 2 Example summary page for a FLOYDS observation. The acquisition image is shown on the top left, while the first guiding image is shown on the top right. The five plots show statistics for the "Guide Star". (Guiding is done using a pattern matching routine on all of the stars in the field, but the brightest star within some tolerance of the pointing center is labeled the "Guide Star".) The first two plots show the total counts and the Full Width Half Maximum (FWHM) of the Guide Star over the duration of the science exposure. The Guide star pixel coordinates (x and y) are then shown plotted against each other to help visualize the noise in the guiding and then over the duration of the science exposure. Thumbnails of the raw science, arc and flat frames complete the summary pdf page.