MMA Features

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.

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 are required.

It is also possible to upload by right ascension and declination in cases where field IDs are not available. In this case, field_id is replaced by the columns RA and Dec, i.e.

observation_id,RA,Dec,obstime,seeing,limmag,exposure_time,filter,processed_fraction 94434604,30.0,60.0,2458598.8460417003,1.5741500000,20.4070500000,30,ztfr,1.00000 94434651,45.0,45.0,2458598.8465162003,1.5812000000,20.4940500000,30,ztfr,1.00000 94434696,60.0,30.0,2458598.8469676003,1.6499500000,20.5603000000,30,ztfr,1.00000

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”}

GCN Event Ingestion#

We use gcn-kafka to ingest multi-messenger events distributed by the General Coordinates Network (GCN) within SkyPortal.

For configuration, one requires a client_id and client_secret at https://gcn.nasa.gov/quickstart. Once that is available, the configuration file should contain the following information (discuss with your administrators if someone else is deploying will be edited as the below).

gcn:
  server: gcn.nasa.gov
  client_id:
  client_secret:
  notice_types:
    - FERMI_GBM_FLT_POS
    - FERMI_GBM_GND_POS
    - FERMI_GBM_FIN_POS
    - FERMI_GBM_SUBTHRESH
    - LVC_PRELIMINARY
    - LVC_INITIAL
    - LVC_UPDATE
    - LVC_RETRACTION
    - AMON_ICECUBE_COINC
    - AMON_ICECUBE_HESE
    - ICECUBE_ASTROTRACK_GOLD
    - ICECUBE_ASTROTRACK_BRONZE

where notice types are also available from the GCN quickstart guide linked above.

Earthquake Ingestion#

The most important environmental effect on detectors in the IGWN remains teleseismic earthquakes. For this reason, we enable ingestion of earthquakes using the USGS’ PDL client.

In order to deploy the service, one must:

  • Email Michelle Guy (mguy@usgs.gov) with the static IP address of the server and explain the tool’s usage

  • Download the Product Client and place it in the services/pdl_service/ directory.

  • Deploy the Product Client from within services/pdl_service/ by running: ./init.sh start

Contents