Core Collapse Supernovae – P45-005

Instructions to perform observations for the ToO program Core Collapse Supernovae – P45-005 (PI: J. Sollerman).

Background

A Core-Collapse Supernova is the final explosive death of a massive star.
The study of these stars include a large facet of interesting
astrophysics, from massive stellar evolution, nucleosynthesis, shock
physics, dust production and the compact objects left over in the
explosion: neutron stars or black holes.

This Target-of-Opportunity project at the NOT focus on understanding rare
and unusual supernovae. We collaborate closely with several international
supernova teams, and the SNe are often monitored using many telescopes
around the globe.

NOT is very useful in ToO mode, since we can here get observations when
the other telescopes are not available. In particular, fast and detailed
observations are essential during the early phases of the supernova, when
it evolves quickly.

With these observations, we want to address some of the following
questions:

- Which supernovae produce gamma-ray bursts?
- Which supernovae are most important for producing the heavy elements?
- In which ways can a SN interact with its circumstellar environment?

For the majority of the SNe, we will require optical spectroscopy as well
as photometry (UBVRi). This can typically be done at any time during the
ToO night, as long as the SN is at low airmass.

Instructions

The PI will send an email to the observer with full instructions and may also phone the control room on what to observe and how to carry out the observations.You will be asked to perform one or more of the following:

Spectroscopy of the target SN and a spectroscopic standard with ALFOSC.
Photometry of the target SN with ALFOSC or StanCam.
Acquire bias and flat frames with ALFOSC or StanCam.

This will be achieved using generic sequencer scripts. All scripts are located in the ToO script directory ~obs/scripts/45-005 and are described in detail here. The general procedure for each case is described below. All the necessary information will be provided in the trigger email.

ALFOSC

1. Starting and initializing

If you are using another instrument you have to start and initialize ALFOSC. Instructions how to start and initialize ALFOSC are provided here and here.

2. Focusing

If not already done you have to determine and set the focus position (without filter) in the TCS. Instructions how to determine the focus position are provided here. Determining the focus position is preferred but not required. You may also use the default focus position (23230). The focus position can be set with the tcs.focus-position sequencer command described here or by using the TCS interface directly.

3. Add target SN to TCS catalogue

Append the target SN to the current TCS catalogue with tcs.append-object sequencer command. Command parameters are provided in the trigger email. The command is described in detail here.

4. Photometry

Photometry of the target SN may be done any time during the night when the SN target is at low airmass.

Go to the ToO script directory and run the too-alfosc-photometry.sh sequencer script. This script moves the telescope to the target SN and takes a series of exposures with the specified filters. Script data are provided in the trigger email. The script is described in detail here.

5. Spectroscopy

Spectroscopy of the target SN may be done any time during the night when the SN target is at low airmass.

Go to the ToO script directory and run the too-alfosc-spectroscopy.sh sequencer script. This script moves the telescope to the target SN, positions the target SN on the slit interactively and takes a series of exposures with the specified grism and slit. It also takes spectroscopic flats and wavelength calibration frames. Script data and finding chart to position the target on the slit are provided in the trigger email. The script is described in detail here.

This procedure will usually be requested to be done twice. Once for the target SN and once for a spectroscopic standard. A couple of suitable spectroscopic standards will be suggested in the trigger email. Please use an airmass as close as possible to the airmass of the target SN. A list of spectroscopic standards and their current airmass is provided here.

6. Acquire bias frames

Bias frames may be taken during day or twilight time.

Go to the ToO script directory and run the too.alfosc-bias.sh sequencer script. This script takes a series of bias frames. Script data are provided in the trigger email. The script is described in detail here.

7. Acquire flat frames

Flat frames must be taken during twilight time.

Select a blank field from the TCS catalogue and move the telescope with the tcs.goto-object sequencer command described here or by using the TCS interface directly.

Go to the ToO script directory and run the too-alfocs-flat.sh sequencer script. This script takes a series of flat exposures with the specified filters. Script data are provided in the trigger email. The script is described in detail here.

StanCam

1. Starting and initializing

If you're using another instrument you have to start and initialize StanCam. Instructions how to start and initialize StanCam is provided here and here.

2. Focusing

If not already done you have to determine and set the focus position (with the R filter) in the TCS. Instructions how to determine the focus position are provided here. Determining the the focus is preferred but not required. You may also use the default focus position (23040). The focus position can be set with the tcs.focus-position sequencer command described here or by using the TCS directly.

3. Add target SN to TCS catalogue

Add the target SN to the current TCS catalogue with tcs.append-object sequencer command.. Command parameters are provided in the trigger email. The command is described in detail here.

4. Photometry

Photometry of the target SN may be done any time during the night when the SN target is at low airmass.

Go to the ToO script directory and run the too-stancam-photometry.sh sequencer script. This script moves the telescope to the target SN and takes a series of exposures with the specified filters. Script data are provided in the trigger email. The script is described in detail here.

5. Acquire bias frames

Bias frames may be taken during day or twilight time.

Go to the ToO script directory and run the too.stancam-bias.sh sequencer script. This script takes a series of bias frames. Script data are provided in the trigger email. The script is described in detail here.

6. Acquire flat frames

Flat frames must be taken during twilight time.

Select a blank field from the TCS catalogue and move the telescope with the tcs.goto-object sequencer command described here or by using the TCS interface directly.

Go to the ToO script directory and run the too-stancam-flat.sh sequencer script. This script takes a series of flat exposures with the specified filters. For each filter a test exposure is first taken and the user is requested to adjust the exposure time until a satisfactory count level has been achieved. Script data are provided in the trigger email. The script is described in detail here here.