ePESSTO+ Year 1+2 - Final SOFI Spectra reduction

Summary:

Data processing for the ePESSTO+ DR1 resulted in 28 reduced SOFI spectra of which 24 are observed with GB, and 4 are observed with GR. One of the GR datasets (SN2019esa 2020-01-17) was not reduced as the data was completely without signal as a result of a technical fault; as noted in the ePESSTO+ nightlog 'the compressor of the cooling unit of SOFI broke in the middle of the night and SOFI started to warm up'. Detailed notes on the data reduction are found below. 

2019-05-01:

The AT2019ahk and SN2019cxx GB observations were calibrated using the LTT3218 GB observations from the same night; the EG274 GB spectroscopic standard star observations from the same night are somehow problematic for the pipeline and not used in the reduction.

2019-05-01:

The SN2019cxx GB observations have some artefacts; the dataset was reduced without the following 4 frames of a sequence of 12 exposures for slightly improved quality: 

SOFI.2019-05-02T02:59:18.912.fits

SOFI.2019-05-02T03:06:20.405.fits

SOFI.2019-05-02T04:03:11.757.fits

SOFI.2019-05-02T04:10:23.127.fits

2019-08-22:

The SN2019ltw GB observations were carried out without obtaining spectroscopic standard star observations during the run; the GD71 GB observations from 2019-10-26 were used to calibrate the reductions. 

2019-09-03:

The SN2019esa GB observations were carried out without obtaining spectroscopic standard star observations during the run; the GD71 GB observations from 2019-10-26 were used to calibrate the reductions. 

2019-10-26:

The SN2019esa GB observations were accompanied by observations of HIP007373 as a telluric standard star; however, there is no signal in the two frames and no other telluric standard observations were carried out during the night or the run. The HIP041871 GB observations from 2019-12-18 were used to calibrate the reductions.

2019-11-20:

The SN2019esa GB+GR observations were accompanied by observations of HIP042690 as a telluric standard star; however, HIP042690 is a B8V type star, and not a G (Sun type) or A (Vega type) star, which the pipeline can use as a telluric standard. No other telluric standard observations were carried out during the night or the run; the HIP61138 GB+GR observations from 2020-01-22 were used to calibrate the reductions. 

2020-01-17:

The SN2019esa GB observations of 8 frames have a major drop in quality at the end of the sequence due to technical problems (see below); the data was reduced without the following two frames: 

SOFI.2020-01-18T03:53:53.366.fits

SOFI.2020-01-18T04:01:04.694.fits

The HIP40415 telluric standard star was observed to calibrate the GB observations of SN2019esa; however, the data is without any signal due to technical problems (see below). The HIP61138 GB observations from 2020-01-22 were used to calibrate the reductions.

2020-01-17:

The SN2019esa GR sequence of the following 4 exposures is without signal and as a result this data was not reduced: 

SOFI.2020-01-18T04:09:32.716.fits

SOFI.2020-01-18T04:21:22.687.fits

SOFI.2020-01-18T04:33:02.822.fits

SOFI.2020-01-18T04:44:56.073.fits

The ePESSTO+ nightlog notes that 'the compressor of the cooling unit of SOFI broke in the middle of the night and SOFI started to warm up', and as a result the observing sequence was aborted.

2020-01-17 & 2020-01-22:

The spectroscopic observations have an unusually large wavelength shift, which results also in the failure of the automatic line identification of the 2020-01-23 arc calibration data.

2020-01-22:

The AT2020oi GB observations were accompanied by observations of HIP61138 as a telluric standard star; however, the usage of the HIP61138 data results in a notable increase of noise in the reductions. The HIP62745 GB observations from the same night and a more similar airmass to that of the science target were used to calibrate the reductions.

2020-02-14:

The AT2020aze GB observations have significant instrumental noise in the upper right quadrant of the detector; therefore, the following 6 images from a sequence of 12 exposures were used for background subtraction, but not for merging the final 2D frame as the target trace falls to the poor quality quadrant in these exposures:

SOFI.2020-02-15T05:43:16.964.fits

SOFI.2020-02-15T05:50:18.459.fits

SOFI.2020-02-15T06:11:42.615.fits

SOFI.2020-02-15T06:18:44.111.fits

SOFI.2020-02-15T06:40:05.027.fits

SOFI.2020-02-15T06:47:06.522.fits

2020-03-16:

The AT2020cui GB observations were carried out without obtaining telluric standard star or spectroscopic standard star observations; the spectroscopic standard star observations of LTT3218 and the telluric standard star observations of HIP47060 from 2020-02-14 were used to calibrate the reductions. 

2020-12-20:

The SN2019esa GB+GR observations have a very low S/N target trace, in particular with GB. In GR the trace becomes non-visible and the following last 6 frames of a sequence of 12 were excluded from the reductions of which the final 4 have significant instrumental noise in the upper right quadrant of the detector:

SOFI.2020-12-21T06:17:46.124.fits

SOFI.2020-12-21T06:29:36.098.fits

SOFI.2020-12-21T06:41:16.238.fits

SOFI.2020-12-21T06:53:06.213.fits

SOFI.2020-12-21T07:04:46.351.fits

SOFI.2020-12-21T07:16:36.326.fits

2021-01-02:

The SN2020acat GB observations have some artefacts affecting the reductions; therefore, the following 2 images from a sequence of 8 exposures were included in the background subtraction, but not for merging the 2D frame for extracting the final reduced spectrum for slightly improved quality:

SOFI.2021-01-03T07:16:35.672.fits

SOFI.2021-01-03T07:38:03.121.fits

2021-04-09:

The AT2017gge GB observations and associated spectroscopic standard GD153 and telluric standard star HIP080118 frames suffer from prominent instrumental noise in the lower right quadrant of the detector. The following 8 frames of 16 were used for background subtraction, but not for merging the final 2D frame as the target trace falls to the poor quality quadrant in these exposures:

SOFI.2021-04-10T06:38:30.833.fits

SOFI.2021-04-10T06:44:18.147.fits

SOFI.2021-04-10T06:51:02.378.fits

SOFI.2021-04-10T07:12:19.977.fits

SOFI.2021-04-10T07:19:21.475.fits

SOFI.2021-04-10T07:40:39.075.fits

SOFI.2021-04-10T07:47:40.570.fits

SOFI.2021-04-10T08:08:58.171.fits

2021-07-31:

The SN2021uds GB observations were accompanied by observations of HIP1258 as a telluric standard star; however, HIP1258 is a F7V type star, and not a G (Sun type) or A (Vega type) star, which the pipeline can use as a telluric standard. No other telluric standard observations were carried out during the night; the Hip000682 observations from 2021-08-06 were used to calibrate the reductions. Furthermore, the following frame from a sequence of 12 was excluded from the final reduction due to a prominent noise feature:

SOFI.2021-08-01T06:12:26.210.fits

2021-07-31 & 2021-08-06:

The SN2021uds GB observations were carried out without obtaining spectroscopic standard star observations; the Feige110 GB observations from 2021-09-24 were used to calibrate the reductions.