MMA Features

Skyportal supports multi-messenger astronomy (MMA) features. In particular, we ingest events from GCN; the service controlling this is here: https://github.com/skyportal/skyportal/blob/main/skyportal/services/gcn_service/gcn_service.py.

We ingest gravitational-wave events from the International Gravitational-Wave Network (IGWN), gamma-ray burst events from Fermi Gamma-ray Burst Monitor (GBM), and neutrinos from IceCube. To each GcnEvent is associated a set of Localizations, which are HEALPix-based maps containing the probability density as a function of sky location. Each GcnEvent is identified by its event time, as represented in ISO 8601 format (YYYY-MM-DDTHH:MM:SS.sss). The Localizations are connected to a GcnEvent by this dateobs.

The features are available on the gcn_events page, where information on the events (including the skymaps), and associated triggering of follow-up is available. In particular, Allocations now cover both transient follow-up (as a FollowupRequest) and GCN event follow-up (as an ObservationPlanRequest). The main difference between these two is that a FollowupRequest is a single pointing associated with a particular object. An ObservationPlanRequest (which triggers an associated EventObservationPlan with knowledge of the particular fields, filters, and exposure times to be used) performs tiling of a Localization.

These ObservationPlanRequests in particular are triggered on the front-end from the gcn_events page, with drop down menus creating a schedule for a given instrument. This request creates an EventObservationPlan, which will then have the option of being sent to the instrument through the APIs developed in the FollowupRequest (see the APIs here: https://github.com/skyportal/skyportal/tree/main/skyportal/facility_apis).

To evaluate the efficacy of the executed observation plans, we have the ExecutedObservations table, which is accessible through the observation api. After execution of the requested observations in the EventObservationPlan, the user is responsible for uploading successfully executed observations to the ExecutedObservations table (see below). Users should include information about the time of observation, filter, limiting magnitude, etc. The results of the observations can be compared to the Localizations to determine sky coverage and integrated probability contained with the map.

Follow-up triggering

The vast majority of follow-up instruments will require some form of authentication. All such information is passed through the altdata variable of the Allocations API. We briefly describe the authentication form the available telescopes take below:

  • ATLAS Forced Photometry: A user account must be made on https://fallingstar-data.com/forcedphot/, at which point the authentication takes the form {"api_token": "testtoken"}.

  • KAIT: A username and password are passed as {"username": "username", "password": "password"}.

  • LCO: A user account must be made on https://lco.global/, at which point the authentication takes the form {"PROPOSAL_ID": "your_proposal_ID", "API_TOKEN": "testtoken"}.

  • LT: A proposal ID, username, and password are passed as {"username": "username", "password": "password", "LT_proposalID": "your_proposal_ID"}.

  • SLACK: As discussed further here, slack information is pass as {"slack_workspace": "XXX", "slack_channel": "YYY", "slack_token": "ZZZ"}.

  • SWIFT: A username and password are passed as {"username": "username", "secret": "password"}.

  • ZTF Triggering: An API token for an admin user for Kowalski can be passed as {"access_token": "your_token"}.

  • ZTF Forced Photometry: A user account must be made with the ZTF forced photometry service (see https://zwicky.tf/vgt). The authentication then takes the form {"ipac_http_user": "http_user", "ipac_http_password": "http_password", "ipac_email": "email", "ipac_userpass": "password"} where http_user and http_password are provided in the documentation and ipac_email and ipac_userpass are provided for the specific account. Note that IPAC’s forced photometry database is updated once per hour, on the hour, and requests will only be available after this update.

Uploading executed observations

In addition to making available the observation api, we also include an Observations page to simplify upload and viewing of ExecutedObservations. On this page, simply specify the instrument and upload a file of the form:

observation_id,field_id,obstime,seeing,limmag,exposure_time,filter,processed_fraction 84434604,1,2458598.8460417003,1.5741500000,20.4070500000,30,ztfr,1.00000 84434651,1,2458598.8465162003,1.5812000000,20.4940500000,30,ztfr,1.00000 84434696,1,2458598.8469676003,1.6499500000,20.5603000000,30,ztfr,1.00000

where observation_id (the ID of the observations, does not need to be unique), the field_id, the observation time (in JD or otherwise any unambigious format as specified in the astropy docs such as iso or isot: https://docs.astropy.org/en/stable/time/index.html), the seeing (in arcseconds), the limiting magnitude, the exposure time (in seconds), the filter, and the “processed_fraction” (what fraction of the image was successfully processed) are potential columns. We note that only observation_id, field_id, obstime, filter, and exposure_time required.

Executed Observations API Upload

As part of the ObservationPlanRequest API, it is possible to retrieve ExecutedObservations. We briefly describe the authentication form the available telescopes take below:

  • ZTF: Login information for IRSA, which takes the form: {”tap_service”: “https://irsa.ipac.caltech.edu/TAP”, “tap_username”: “your_password”, “tap_password”: “your_password”}