Step-by-Step APT Guide for MIRI MRS and NIRSpec IFU Observations of SN1987A
Instructions are provided for filling out the JWST APT observing template for the MIRI and NIRSpec Observations of SN 1987A Example Science program, where MIRI MRS and the NIRSpec IFU are used to obtain medium-resolution spectra of knots in the SN 1987A supernova remnant.
The Astronomers Proposal Tool (APT) is used for submitting JWST proposals. There are multiple components to an APT submission: generic proposal information, target information, and exposure specifications for the proposed program. This guide discusses how to fill out the APT observing template for the "MIRI and NIRSpec Observations of SN 1987A" Example Science program.
A filled out APT file can be accessed via the APT menu options File → Retrieve from STScI → Retrieve using Proposal ID, and then entering 27 in the dialogue box.
Fill Out Proposal Information
Main article: JWST Astronomers Proposal Tool overview
After opening APT, we selected "New JWST Proposal" under the "New Document" pull-down menu just above the tree editor at the bottom-left of the top tool bar. On the active GUI window for the Proposal Information entry in the Tree Editor, we entered Title, Abstract, and Category of the proposal and kept Cycle number at its default value.
Enter Proposed Targets
Main article: APT Targets
Target information is entered in the active GUI window for the Targets entry in the tree editor. In this active GUI window, we clicked on the "New Fixed Target" button. We entered SN-1987A in the field for Name in the Proposal, and selected Star for Category. We entered the coordinates for this source: RA = 05 35 27.9680, Dec = -69 16 11.09. Near the Description field, we clicked the "+/-" button, which opens a list of approved keywords and selected Supernovae. Under the Extended drop-down menu, we chose Yes.
We also added a second target, using the "New Fixed Target" button. We entered TACQ-STAR in the field for Name in the Proposal, and selected Star for Category. We entered the coordinates for this source: RA = 05 35 27.5910, Dec = -69 16 09.13. Near the Description field, we clicked the "+/-" button, which opens a list of approved keywords and selected B stars. Under the Extended drop-down menu, we chose No.
Main article: APT Observations
In the active GUI window for the Observations entry in the tree editor, we clicked on the "New Observation Folder" button to specify the observing parameters for the MIRI-MRS part of our program. In the Label field, we entered MIRI. Note that while this label is not required, setting it is useful for visually organizing your observation folders in the tree editor when potentially many targets and/or instrument setups are used. We then clicked "MIRI" in the tree editor to open the observation template to be filled out. In the Instrument pull-down menu in the active GUI window, we selected MIRI, and then we selected the MIRI Medium Resolution Spectroscopy template in the Template pull-down menu. In the Target pull-down menu, we selected the SN-1987A target.
We also added a folder for the NIRSpec IFU observation. Like before, in the active GUI window for the Observations entry in the tree editor, we clicked on the "New Observation Folder" button to specify the observing parameters for the NIRSpec IFU part of our program. In the Label field, we entered NIRspec IFU. We then clicked "NIRspec IFU" in the tree editor to open the observation template to be filled out. In the Instrument pull-down menu in the active GUI window, we selected NIRSPEC, and then we selected the NIRSpec IFU Spectroscopy template in the Template pull-down menu. In the Target pull-down menu, we selected the SN-1987A target.
Complete APT Observation Template for MIRI-MRS
As discussed in the parent article and the Step-by-Step ETC Guide, a set of observations will be taken using all three grating settings for MIRI-MRS; SHORT, MEDIUM, and LONG. Both short and long wavelength detectors for the MRS are used. TA is not chosen for the MRS observation.
We want to use a dither pattern for the MRS observations. We click the Add button under the Dithers field, and a row with dither options appears. Above the Dithers field, in the drop-down menu for Primary Channel, we select All, so that the dither pattern will be optimized for all channels. In the row that appeared in the Dithers field, under the Dither Type heading, we select 4-Point. Under the Optimized For heading, we select EXTENDED SOURCE because we are observing an extended source. Under the Direction heading, NEGATIVE is already selected because it is the only option. APT will refer to this dither configuration in the Exposure Parameters field as Dither 1.
After the Dithers pane in the active GUI window, the Simultaneous Imaging drop-down menu option was set to YES. To the side of this, the Imager Subarray drop-down menu was set to FULL.
Under this in the Exposure Parameters pane, we clicked Add 3 times, each corresponding to the three available MRS grating settings. One click of the Add button here brings up 3 rows: one for the MIRI imager, the next for the MRS long-wavelength detector, and the other for the MRS short-wavelength detector. Under the Wavelength Range column, for the first triplet of rows, the value was set to SHORT (A) for MRSLONG and MRSSHORT rows. For the second and third triplets of rows, the values were set to MEDIUM (B) and LONG(C), respectively.
Under the Filter column, in the Imager rows, F560W was selected for the imaging observation corresponding to the SHORT grating setting, F770W for the imaging observation corresponding to the MEDIUM grating setting, and F1000W for the imaging observation corresponding to the LONG grating setting. Under the Readout Pattern column, FAST was selected. Under the Groups/Int column, the values were set to 282 for the Medium and Long gratings, 255 for the Short grating, and 255 for the simultaneous imaging. Under the Integrations/Exp column, the value was set to 1 for the MRS and 1 for the simultaneous imaging. Under the Exposures/Dith column, the value was set to 1 for all rows. Under the Dither column, the value was set to Dither 1 for all rows. The rest of the entries on each row are determined by APT from the previous entries.
Complete APT Observation Template for the NIRSpec IFU
As discussed in the parent article and the Step-by-Step ETC Guide, an observation will be taken using the G140M disperser and F100LP filter, G235M disperser and F170LP filter, and G395M disperser and F290LP filter for SN 1987A. We choose to perform WATA, as the target is an extended source covering most of the extent of the NIRSpec IFU aperture. In the Target Acquisition Parameters section, for the Target ACQ drop-down menu, we choose TACQ-STAR. Under the Acq Subarray drop-down menu, we choose SUB32, and under the Acq Filter drop-down menu, we choose CLEAR. For the Acq Exposure Time drop-down menu, we choose NRSRAPID.
In the Science Parameters section, the Dither Parameters drop-down menu is set to CYCLING, and the dither SIZE is set to SMALL, with the Starting Point set to 1 and the Number of Points set to 4. This is the same as the 4-point dither pattern, according to the NIRSpec IFU Dither and Nod Patterns page.
In the Gratings/Filters pane in the active GUI window, we click Add 3 times. On the first row, we select G140M/F100LP under the Grating/Filter column, on the second row we select G235M/F170LP, and on the third row we select G395M/F290LP. We select NRSIRS2RAPID under the Readout Pattern column for all 3 rows. Under the Groups/Int column, we enter 29 for all rows. Under the Integrations/Exp column, we enter 1 for all rows. The checkbox under Dither was checked, and Autocal was set to NONE, per the advice given here.
Define Special Requirements
Since SN 1987A is known to be variable (Bouchet et al 2004), we would like the observations to happen at almost the same time. To specify this constraint, we add a timing requirement to the observation.
Under the Special Requirements tab, we click Add, then Timing, then Group/Sequence Observations Link, and in the box that pops up, we click the checkboxes beside the MRS and NIRSpec IFU observations, and we click the checkbox beside Non-interruptible, then click OK. The Special Requirements pan now has a line that reads "Group Observations 2, 3, Non-interruptible".
Run Visit Planner
Main article: APT Visit Planner
To determine the visibility window of our observation, we ran the Visit Planner Tool. First, we click an observation in the tree editor. Then we click the Visit Planner button in the top tool bar, which changes the view in the active GUI window. Then we click the Run All Tools button at the right in the top tool bar. This shows us the observing window(s) for this target over the next ~19 months. APT assures us that all visits are schedulable.
Bouchet, P., et al, 2004, ApJ, 611, 394
High-Resolution Mid-Infrared Imaging of SN 1987A